1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 277b14db5SEric W. Biederman /* 377b14db5SEric W. Biederman * /proc/sys support 477b14db5SEric W. Biederman */ 51e0edd3fSAlexey Dobriyan #include <linux/init.h> 677b14db5SEric W. Biederman #include <linux/sysctl.h> 7f1ecf068SLucas De Marchi #include <linux/poll.h> 877b14db5SEric W. Biederman #include <linux/proc_fs.h> 987ebdc00SAndrew Morton #include <linux/printk.h> 1077b14db5SEric W. Biederman #include <linux/security.h> 1140401530SAl Viro #include <linux/sched.h> 125b825c3aSIngo Molnar #include <linux/cred.h> 1334286d66SNick Piggin #include <linux/namei.h> 1440401530SAl Viro #include <linux/mm.h> 154bd6a735SMatthew Wilcox (Oracle) #include <linux/uio.h> 161f87f0b5SEric W. Biederman #include <linux/module.h> 177b146cebSAndrey Ignatov #include <linux/bpf-cgroup.h> 183db978d4SVlastimil Babka #include <linux/mount.h> 193ddd9a80SXiaoming Ni #include <linux/kmemleak.h> 2077b14db5SEric W. Biederman #include "internal.h" 2177b14db5SEric W. Biederman 22cb55f27aSMeng Tang #define list_for_each_table_entry(entry, table) \ 23cb55f27aSMeng Tang for ((entry) = (table); (entry)->procname; (entry)++) 24cb55f27aSMeng Tang 25d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 2677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2703a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 289043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 299043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 3077b14db5SEric W. Biederman 31f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 32f9bd6733SEric W. Biederman 33f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 34f9bd6733SEric W. Biederman { } 35f9bd6733SEric W. Biederman }; 36f9bd6733SEric W. Biederman 37ee9efac4SLuis Chamberlain /** 38ee9efac4SLuis Chamberlain * register_sysctl_mount_point() - registers a sysctl mount point 39ee9efac4SLuis Chamberlain * @path: path for the mount point 40ee9efac4SLuis Chamberlain * 41ee9efac4SLuis Chamberlain * Used to create a permanently empty directory to serve as mount point. 42ee9efac4SLuis Chamberlain * There are some subtle but important permission checks this allows in the 43ee9efac4SLuis Chamberlain * case of unprivileged mounts. 44ee9efac4SLuis Chamberlain */ 45ee9efac4SLuis Chamberlain struct ctl_table_header *register_sysctl_mount_point(const char *path) 46ee9efac4SLuis Chamberlain { 47ee9efac4SLuis Chamberlain return register_sysctl(path, sysctl_mount_point); 48ee9efac4SLuis Chamberlain } 49ee9efac4SLuis Chamberlain EXPORT_SYMBOL(register_sysctl_mount_point); 50ee9efac4SLuis Chamberlain 51f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 52f9bd6733SEric W. Biederman { 53f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 54f9bd6733SEric W. Biederman } 55f9bd6733SEric W. Biederman 56f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 57f9bd6733SEric W. Biederman { 58f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 59f9bd6733SEric W. Biederman } 60f9bd6733SEric W. Biederman 61f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 62f9bd6733SEric W. Biederman 63f9bd6733SEric W. Biederman { 64f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 65f9bd6733SEric W. Biederman } 66f9bd6733SEric W. Biederman 67f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 68f1ecf068SLucas De Marchi { 69f1ecf068SLucas De Marchi if (!poll) 70f1ecf068SLucas De Marchi return; 71f1ecf068SLucas De Marchi 72f1ecf068SLucas De Marchi atomic_inc(&poll->event); 73f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 74f1ecf068SLucas De Marchi } 75f1ecf068SLucas De Marchi 76a194558eSEric W. Biederman static struct ctl_table root_table[] = { 77a194558eSEric W. Biederman { 78a194558eSEric W. Biederman .procname = "", 797ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 80a194558eSEric W. Biederman }, 81a194558eSEric W. Biederman { } 82a194558eSEric W. Biederman }; 830e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 840e47c99dSEric W. Biederman .default_set.dir.header = { 851f87f0b5SEric W. Biederman {{.count = 1, 86938aaa4fSEric W. Biederman .nreg = 1, 87ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 880e47c99dSEric W. Biederman .ctl_table_arg = root_table, 891f87f0b5SEric W. Biederman .root = &sysctl_table_root, 901f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 917ec66d06SEric W. Biederman }, 921f87f0b5SEric W. Biederman }; 931f87f0b5SEric W. Biederman 941f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 951f87f0b5SEric W. Biederman 967ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 970e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 9813bcc6a2SEric W. Biederman struct ctl_table **pentry); 990e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 1000e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 1017ec66d06SEric W. Biederman 1026980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 1036980128fSEric W. Biederman { 1046980128fSEric W. Biederman if (dir->header.parent) 1056980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 10687ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 1076980128fSEric W. Biederman } 1086980128fSEric W. Biederman 109076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 110076c3eedSEric W. Biederman { 111076c3eedSEric W. Biederman int cmp; 112076c3eedSEric W. Biederman 113d8fc9b66SMasahiro Yamada cmp = memcmp(name1, name2, min(len1, len2)); 114076c3eedSEric W. Biederman if (cmp == 0) 115076c3eedSEric W. Biederman cmp = len1 - len2; 116076c3eedSEric W. Biederman return cmp; 117076c3eedSEric W. Biederman } 118076c3eedSEric W. Biederman 11960f126d9SEric W. Biederman /* Called under sysctl_lock */ 120076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1210e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 122076c3eedSEric W. Biederman { 123076c3eedSEric W. Biederman struct ctl_table_header *head; 124076c3eedSEric W. Biederman struct ctl_table *entry; 125ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 126076c3eedSEric W. Biederman 127ac13ac6fSEric W. Biederman while (node) 128ac13ac6fSEric W. Biederman { 129ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 130ac13ac6fSEric W. Biederman const char *procname; 131ac13ac6fSEric W. Biederman int cmp; 132ac13ac6fSEric W. Biederman 133ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 134ac13ac6fSEric W. Biederman head = ctl_node->header; 135ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 136ac13ac6fSEric W. Biederman procname = entry->procname; 137ac13ac6fSEric W. Biederman 138ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 139ac13ac6fSEric W. Biederman if (cmp < 0) 140ac13ac6fSEric W. Biederman node = node->rb_left; 141ac13ac6fSEric W. Biederman else if (cmp > 0) 142ac13ac6fSEric W. Biederman node = node->rb_right; 143ac13ac6fSEric W. Biederman else { 144076c3eedSEric W. Biederman *phead = head; 145076c3eedSEric W. Biederman return entry; 146076c3eedSEric W. Biederman } 147076c3eedSEric W. Biederman } 148076c3eedSEric W. Biederman return NULL; 149076c3eedSEric W. Biederman } 150076c3eedSEric W. Biederman 151ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 152ac13ac6fSEric W. Biederman { 153ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 154ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 155ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 156ac13ac6fSEric W. Biederman const char *name = entry->procname; 157ac13ac6fSEric W. Biederman int namelen = strlen(name); 158ac13ac6fSEric W. Biederman 159ac13ac6fSEric W. Biederman while (*p) { 160ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 161ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 162ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 163ac13ac6fSEric W. Biederman const char *parent_name; 164ac13ac6fSEric W. Biederman int cmp; 165ac13ac6fSEric W. Biederman 166ac13ac6fSEric W. Biederman parent = *p; 167ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 168ac13ac6fSEric W. Biederman parent_head = parent_node->header; 169ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 170ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 171ac13ac6fSEric W. Biederman 172ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 173ac13ac6fSEric W. Biederman if (cmp < 0) 174ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 175ac13ac6fSEric W. Biederman else if (cmp > 0) 176ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 177ac13ac6fSEric W. Biederman else { 17887ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 179ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 180153ee1c4SGeert Uytterhoeven pr_cont("%s\n", entry->procname); 181ac13ac6fSEric W. Biederman return -EEXIST; 182ac13ac6fSEric W. Biederman } 183ac13ac6fSEric W. Biederman } 184ac13ac6fSEric W. Biederman 185ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 186ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 187ac13ac6fSEric W. Biederman return 0; 188ac13ac6fSEric W. Biederman } 189ac13ac6fSEric W. Biederman 190ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 191ac13ac6fSEric W. Biederman { 192ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 193ac13ac6fSEric W. Biederman 194ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 195ac13ac6fSEric W. Biederman } 196ac13ac6fSEric W. Biederman 197e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 198e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 199ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 200e0d04529SEric W. Biederman { 2017ec66d06SEric W. Biederman head->ctl_table = table; 202e0d04529SEric W. Biederman head->ctl_table_arg = table; 203e0d04529SEric W. Biederman head->used = 0; 204e0d04529SEric W. Biederman head->count = 1; 205e0d04529SEric W. Biederman head->nreg = 1; 206e0d04529SEric W. Biederman head->unregistering = NULL; 207e0d04529SEric W. Biederman head->root = root; 208e0d04529SEric W. Biederman head->set = set; 209e0d04529SEric W. Biederman head->parent = NULL; 210ac13ac6fSEric W. Biederman head->node = node; 2112fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 212ac13ac6fSEric W. Biederman if (node) { 213ac13ac6fSEric W. Biederman struct ctl_table *entry; 214cb55f27aSMeng Tang 215cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 216ac13ac6fSEric W. Biederman node->header = head; 217cb55f27aSMeng Tang node++; 218cb55f27aSMeng Tang } 219ac13ac6fSEric W. Biederman } 220ac13ac6fSEric W. Biederman } 221e0d04529SEric W. Biederman 2228425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2238425d6aaSEric W. Biederman { 224ac13ac6fSEric W. Biederman struct ctl_table *entry; 225cb55f27aSMeng Tang 226cb55f27aSMeng Tang list_for_each_table_entry(entry, head->ctl_table) 227ac13ac6fSEric W. Biederman erase_entry(head, entry); 2288425d6aaSEric W. Biederman } 2298425d6aaSEric W. Biederman 2300e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2318425d6aaSEric W. Biederman { 232ac13ac6fSEric W. Biederman struct ctl_table *entry; 2330e47c99dSEric W. Biederman int err; 2340e47c99dSEric W. Biederman 235f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 236f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 237f9bd6733SEric W. Biederman return -EROFS; 238f9bd6733SEric W. Biederman 239f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 240f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 241f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 242f9bd6733SEric W. Biederman return -EINVAL; 243f9bd6733SEric W. Biederman set_empty_dir(dir); 244f9bd6733SEric W. Biederman } 245f9bd6733SEric W. Biederman 2460e47c99dSEric W. Biederman dir->header.nreg++; 2477ec66d06SEric W. Biederman header->parent = dir; 2480e47c99dSEric W. Biederman err = insert_links(header); 2490e47c99dSEric W. Biederman if (err) 2500e47c99dSEric W. Biederman goto fail_links; 251cb55f27aSMeng Tang list_for_each_table_entry(entry, header->ctl_table) { 252ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 253ac13ac6fSEric W. Biederman if (err) 254ac13ac6fSEric W. Biederman goto fail; 255ac13ac6fSEric W. Biederman } 2560e47c99dSEric W. Biederman return 0; 257ac13ac6fSEric W. Biederman fail: 258ac13ac6fSEric W. Biederman erase_header(header); 259ac13ac6fSEric W. Biederman put_links(header); 2600e47c99dSEric W. Biederman fail_links: 261f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 262f9bd6733SEric W. Biederman clear_empty_dir(dir); 2630e47c99dSEric W. Biederman header->parent = NULL; 2640e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2650e47c99dSEric W. Biederman return err; 2668425d6aaSEric W. Biederman } 2678425d6aaSEric W. Biederman 2681f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2691f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2701f87f0b5SEric W. Biederman { 2711f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2721f87f0b5SEric W. Biederman return 0; 2731f87f0b5SEric W. Biederman p->used++; 2741f87f0b5SEric W. Biederman return 1; 2751f87f0b5SEric W. Biederman } 2761f87f0b5SEric W. Biederman 2771f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2781f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2791f87f0b5SEric W. Biederman { 2801f87f0b5SEric W. Biederman if (!--p->used) 2811f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2821f87f0b5SEric W. Biederman complete(p->unregistering); 2831f87f0b5SEric W. Biederman } 2841f87f0b5SEric W. Biederman 285f90f3cafSEric W. Biederman static void proc_sys_invalidate_dcache(struct ctl_table_header *head) 286d6cffbbeSKonstantin Khlebnikov { 287f90f3cafSEric W. Biederman proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); 288d6cffbbeSKonstantin Khlebnikov } 289d6cffbbeSKonstantin Khlebnikov 2901f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2911f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2921f87f0b5SEric W. Biederman { 2931f87f0b5SEric W. Biederman /* 2941f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2951f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2961f87f0b5SEric W. Biederman */ 2971f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2981f87f0b5SEric W. Biederman struct completion wait; 2991f87f0b5SEric W. Biederman init_completion(&wait); 3001f87f0b5SEric W. Biederman p->unregistering = &wait; 3011f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3021f87f0b5SEric W. Biederman wait_for_completion(&wait); 3031f87f0b5SEric W. Biederman } else { 3041f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3051f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 306ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3071f87f0b5SEric W. Biederman } 3081f87f0b5SEric W. Biederman /* 309f90f3cafSEric W. Biederman * Invalidate dentries for unregistered sysctls: namespaced sysctls 310d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 311d6cffbbeSKonstantin Khlebnikov */ 312f90f3cafSEric W. Biederman proc_sys_invalidate_dcache(p); 313d6cffbbeSKonstantin Khlebnikov /* 3141f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3151f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3161f87f0b5SEric W. Biederman */ 317ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3188425d6aaSEric W. Biederman erase_header(p); 3191f87f0b5SEric W. Biederman } 3201f87f0b5SEric W. Biederman 3211f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3221f87f0b5SEric W. Biederman { 323ab4a1f24SPrasad Joshi BUG_ON(!head); 3241f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3251f87f0b5SEric W. Biederman if (!use_table(head)) 3261f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3271f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3281f87f0b5SEric W. Biederman return head; 3291f87f0b5SEric W. Biederman } 3301f87f0b5SEric W. Biederman 3311f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3321f87f0b5SEric W. Biederman { 3331f87f0b5SEric W. Biederman if (!head) 3341f87f0b5SEric W. Biederman return; 3351f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3361f87f0b5SEric W. Biederman unuse_table(head); 3371f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3381f87f0b5SEric W. Biederman } 3391f87f0b5SEric W. Biederman 3401f87f0b5SEric W. Biederman static struct ctl_table_set * 34113bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3421f87f0b5SEric W. Biederman { 3431f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3441f87f0b5SEric W. Biederman if (root->lookup) 34513bcc6a2SEric W. Biederman set = root->lookup(root); 3461f87f0b5SEric W. Biederman return set; 3471f87f0b5SEric W. Biederman } 3481f87f0b5SEric W. Biederman 349076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3507ec66d06SEric W. Biederman struct ctl_dir *dir, 351076c3eedSEric W. Biederman const char *name, int namelen) 352076c3eedSEric W. Biederman { 353076c3eedSEric W. Biederman struct ctl_table_header *head; 354076c3eedSEric W. Biederman struct ctl_table *entry; 355076c3eedSEric W. Biederman 356076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3570e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 358076c3eedSEric W. Biederman if (entry && use_table(head)) 359076c3eedSEric W. Biederman *phead = head; 360076c3eedSEric W. Biederman else 361076c3eedSEric W. Biederman entry = NULL; 362076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 363076c3eedSEric W. Biederman return entry; 364076c3eedSEric W. Biederman } 365076c3eedSEric W. Biederman 366ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3671f87f0b5SEric W. Biederman { 368ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3691f87f0b5SEric W. Biederman 370ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 371ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 372ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 373ac13ac6fSEric W. Biederman return ctl_node; 3741f87f0b5SEric W. Biederman } 3751f87f0b5SEric W. Biederman return NULL; 3761f87f0b5SEric W. Biederman } 3771f87f0b5SEric W. Biederman 3787ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3796a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3801f87f0b5SEric W. Biederman { 381ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3827ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 383ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3846a75ce16SEric W. Biederman 3856a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 386ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3876a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 388ac13ac6fSEric W. Biederman if (ctl_node) { 389ac13ac6fSEric W. Biederman head = ctl_node->header; 390ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 391ac13ac6fSEric W. Biederman } 3926a75ce16SEric W. Biederman *phead = head; 3936a75ce16SEric W. Biederman *pentry = entry; 3946a75ce16SEric W. Biederman } 3956a75ce16SEric W. Biederman 3967ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3976a75ce16SEric W. Biederman { 3986a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3996a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 400ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4016a75ce16SEric W. Biederman 4026a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4036a75ce16SEric W. Biederman unuse_table(head); 404ac13ac6fSEric W. Biederman 405ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4066a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 407ac13ac6fSEric W. Biederman head = NULL; 408ac13ac6fSEric W. Biederman if (ctl_node) { 409ac13ac6fSEric W. Biederman head = ctl_node->header; 410ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4116a75ce16SEric W. Biederman } 4126a75ce16SEric W. Biederman *phead = head; 4136a75ce16SEric W. Biederman *pentry = entry; 4141f87f0b5SEric W. Biederman } 4151f87f0b5SEric W. Biederman 4161f87f0b5SEric W. Biederman /* 4171f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4181f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4191f87f0b5SEric W. Biederman */ 4201f87f0b5SEric W. Biederman 4211f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4221f87f0b5SEric W. Biederman { 423091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4241f87f0b5SEric W. Biederman mode >>= 6; 425091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4261f87f0b5SEric W. Biederman mode >>= 3; 4271f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4281f87f0b5SEric W. Biederman return 0; 4291f87f0b5SEric W. Biederman return -EACCES; 4301f87f0b5SEric W. Biederman } 4311f87f0b5SEric W. Biederman 43273f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4331f87f0b5SEric W. Biederman { 43473f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4351f87f0b5SEric W. Biederman int mode; 4361f87f0b5SEric W. Biederman 4371f87f0b5SEric W. Biederman if (root->permissions) 43873f7ef43SEric W. Biederman mode = root->permissions(head, table); 4391f87f0b5SEric W. Biederman else 4401f87f0b5SEric W. Biederman mode = table->mode; 4411f87f0b5SEric W. Biederman 4421f87f0b5SEric W. Biederman return test_perm(mode, op); 4431f87f0b5SEric W. Biederman } 4441f87f0b5SEric W. Biederman 4459043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4469043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 44777b14db5SEric W. Biederman { 448e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 44977b14db5SEric W. Biederman struct inode *inode; 4509043476fSAl Viro struct proc_inode *ei; 45177b14db5SEric W. Biederman 4529043476fSAl Viro inode = new_inode(sb); 45377b14db5SEric W. Biederman if (!inode) 454ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 45577b14db5SEric W. Biederman 45685fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 45785fe4025SChristoph Hellwig 45877b14db5SEric W. Biederman ei = PROC_I(inode); 4599043476fSAl Viro 460d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 461ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 462ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 463ace0c791SEric W. Biederman iput(inode); 464ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 465ace0c791SEric W. Biederman } 466ace0c791SEric W. Biederman ei->sysctl = head; 467ace0c791SEric W. Biederman ei->sysctl_entry = table; 4680afa5ca8SEric W. Biederman hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); 469d6cffbbeSKonstantin Khlebnikov head->count++; 470d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 471d6cffbbeSKonstantin Khlebnikov 472078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4739043476fSAl Viro inode->i_mode = table->mode; 4747ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4759043476fSAl Viro inode->i_mode |= S_IFREG; 47677b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 47777b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4789043476fSAl Viro } else { 4799043476fSAl Viro inode->i_mode |= S_IFDIR; 4809043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4819043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 482f9bd6733SEric W. Biederman if (is_empty_dir(head)) 483f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4849043476fSAl Viro } 485e79c6a4fSDmitry Torokhov 486e79c6a4fSDmitry Torokhov if (root->set_ownership) 487e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 4885ec27ec7SRadoslaw Burny else { 4895ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 4905ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 4915ec27ec7SRadoslaw Burny } 492e79c6a4fSDmitry Torokhov 49377b14db5SEric W. Biederman return inode; 49477b14db5SEric W. Biederman } 49577b14db5SEric W. Biederman 496d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 497d6cffbbeSKonstantin Khlebnikov { 498d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 4990afa5ca8SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); 500d6cffbbeSKonstantin Khlebnikov if (!--head->count) 501d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 502d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 503d6cffbbeSKonstantin Khlebnikov } 504d6cffbbeSKonstantin Khlebnikov 50581324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 50677b14db5SEric W. Biederman { 5073cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5083cc3e046SEric W. Biederman if (!head) 5090e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5103cc3e046SEric W. Biederman return sysctl_head_grab(head); 51177b14db5SEric W. Biederman } 51277b14db5SEric W. Biederman 51377b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 51400cd8dd3SAl Viro unsigned int flags) 51577b14db5SEric W. Biederman { 5169043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5179043476fSAl Viro struct ctl_table_header *h = NULL; 518dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5199043476fSAl Viro struct ctl_table *p; 52077b14db5SEric W. Biederman struct inode *inode; 5219043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5227ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5230e47c99dSEric W. Biederman int ret; 52477b14db5SEric W. Biederman 5259043476fSAl Viro if (IS_ERR(head)) 5269043476fSAl Viro return ERR_CAST(head); 5279043476fSAl Viro 5287ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5299043476fSAl Viro 5307ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5319043476fSAl Viro if (!p) 53277b14db5SEric W. Biederman goto out; 53377b14db5SEric W. Biederman 5344e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 53513bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5360e47c99dSEric W. Biederman err = ERR_PTR(ret); 5370e47c99dSEric W. Biederman if (ret) 5380e47c99dSEric W. Biederman goto out; 5394e757320SEric W. Biederman } 5400e47c99dSEric W. Biederman 5419043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 542ea5751ccSIvan Delalande if (IS_ERR(inode)) { 543ea5751ccSIvan Delalande err = ERR_CAST(inode); 54477b14db5SEric W. Biederman goto out; 545ea5751ccSIvan Delalande } 54677b14db5SEric W. Biederman 547fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 548888e2b03SAl Viro err = d_splice_alias(inode, dentry); 54977b14db5SEric W. Biederman 55077b14db5SEric W. Biederman out: 5516bf61045SFrancesco Ruggeri if (h) 5526bf61045SFrancesco Ruggeri sysctl_head_finish(h); 55377b14db5SEric W. Biederman sysctl_head_finish(head); 55477b14db5SEric W. Biederman return err; 55577b14db5SEric W. Biederman } 55677b14db5SEric W. Biederman 5574bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, 5584bd6a735SMatthew Wilcox (Oracle) int write) 55977b14db5SEric W. Biederman { 5604bd6a735SMatthew Wilcox (Oracle) struct inode *inode = file_inode(iocb->ki_filp); 5619043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5629043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5634bd6a735SMatthew Wilcox (Oracle) size_t count = iov_iter_count(iter); 5644bd6a735SMatthew Wilcox (Oracle) char *kbuf; 5652a2da53bSDavid Howells ssize_t error; 56677b14db5SEric W. Biederman 5679043476fSAl Viro if (IS_ERR(head)) 5689043476fSAl Viro return PTR_ERR(head); 56977b14db5SEric W. Biederman 57077b14db5SEric W. Biederman /* 57177b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 57277b14db5SEric W. Biederman * and won't be until we finish. 57377b14db5SEric W. Biederman */ 57477b14db5SEric W. Biederman error = -EPERM; 57573f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 57677b14db5SEric W. Biederman goto out; 57777b14db5SEric W. Biederman 5789043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5799043476fSAl Viro error = -EINVAL; 5809043476fSAl Viro if (!table->proc_handler) 5819043476fSAl Viro goto out; 5829043476fSAl Viro 583ef9d965bSChristoph Hellwig /* don't even try if the size is too large */ 584d4d80e69SMatthew Wilcox (Oracle) error = -ENOMEM; 585d4d80e69SMatthew Wilcox (Oracle) if (count >= KMALLOC_MAX_SIZE) 586d4d80e69SMatthew Wilcox (Oracle) goto out; 58745089437SJosef Bacik kbuf = kvzalloc(count + 1, GFP_KERNEL); 58832927393SChristoph Hellwig if (!kbuf) 58932927393SChristoph Hellwig goto out; 5904bd6a735SMatthew Wilcox (Oracle) 5914bd6a735SMatthew Wilcox (Oracle) if (write) { 5924bd6a735SMatthew Wilcox (Oracle) error = -EFAULT; 5934bd6a735SMatthew Wilcox (Oracle) if (!copy_from_iter_full(kbuf, count, iter)) 5944bd6a735SMatthew Wilcox (Oracle) goto out_free_buf; 5954bd6a735SMatthew Wilcox (Oracle) kbuf[count] = '\0'; 5964e63acdfSAndrey Ignatov } 5974e63acdfSAndrey Ignatov 59832927393SChristoph Hellwig error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, 5994bd6a735SMatthew Wilcox (Oracle) &iocb->ki_pos); 60032927393SChristoph Hellwig if (error) 60132927393SChristoph Hellwig goto out_free_buf; 60232927393SChristoph Hellwig 60332927393SChristoph Hellwig /* careful: calling conventions are nasty here */ 6044bd6a735SMatthew Wilcox (Oracle) error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); 60532927393SChristoph Hellwig if (error) 60632927393SChristoph Hellwig goto out_free_buf; 60732927393SChristoph Hellwig 60832927393SChristoph Hellwig if (!write) { 60932927393SChristoph Hellwig error = -EFAULT; 6104bd6a735SMatthew Wilcox (Oracle) if (copy_to_iter(kbuf, count, iter) < count) 61132927393SChristoph Hellwig goto out_free_buf; 61232927393SChristoph Hellwig } 61332927393SChristoph Hellwig 6144e63acdfSAndrey Ignatov error = count; 61532927393SChristoph Hellwig out_free_buf: 61645089437SJosef Bacik kvfree(kbuf); 61777b14db5SEric W. Biederman out: 61877b14db5SEric W. Biederman sysctl_head_finish(head); 61977b14db5SEric W. Biederman 62077b14db5SEric W. Biederman return error; 62177b14db5SEric W. Biederman } 62277b14db5SEric W. Biederman 6234bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) 6247708bfb1SPavel Emelyanov { 6254bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 0); 6267708bfb1SPavel Emelyanov } 6277708bfb1SPavel Emelyanov 6284bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) 62977b14db5SEric W. Biederman { 6304bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 1); 63177b14db5SEric W. Biederman } 63277b14db5SEric W. Biederman 633f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 634f1ecf068SLucas De Marchi { 6354e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 636f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 637f1ecf068SLucas De Marchi 6384e474a00SLucas De Marchi /* sysctl was unregistered */ 6394e474a00SLucas De Marchi if (IS_ERR(head)) 6404e474a00SLucas De Marchi return PTR_ERR(head); 6414e474a00SLucas De Marchi 642f1ecf068SLucas De Marchi if (table->poll) 643f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 644f1ecf068SLucas De Marchi 6454e474a00SLucas De Marchi sysctl_head_finish(head); 6464e474a00SLucas De Marchi 647f1ecf068SLucas De Marchi return 0; 648f1ecf068SLucas De Marchi } 649f1ecf068SLucas De Marchi 650076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 651f1ecf068SLucas De Marchi { 652496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6534e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 654f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 655076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6564e474a00SLucas De Marchi unsigned long event; 6574e474a00SLucas De Marchi 6584e474a00SLucas De Marchi /* sysctl was unregistered */ 6594e474a00SLucas De Marchi if (IS_ERR(head)) 660a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 661f1ecf068SLucas De Marchi 662f1ecf068SLucas De Marchi if (!table->proc_handler) 663f1ecf068SLucas De Marchi goto out; 664f1ecf068SLucas De Marchi 665f1ecf068SLucas De Marchi if (!table->poll) 666f1ecf068SLucas De Marchi goto out; 667f1ecf068SLucas De Marchi 6684e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 669f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 670f1ecf068SLucas De Marchi 671f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 672f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 673a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 674f1ecf068SLucas De Marchi } 675f1ecf068SLucas De Marchi 676f1ecf068SLucas De Marchi out: 6774e474a00SLucas De Marchi sysctl_head_finish(head); 6784e474a00SLucas De Marchi 679f1ecf068SLucas De Marchi return ret; 680f1ecf068SLucas De Marchi } 68177b14db5SEric W. Biederman 682f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 683f0c3b509SAl Viro struct dir_context *ctx, 6849043476fSAl Viro struct ctl_table_header *head, 6859043476fSAl Viro struct ctl_table *table) 68677b14db5SEric W. Biederman { 687f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 68877b14db5SEric W. Biederman struct inode *inode; 68977b14db5SEric W. Biederman struct qstr qname; 69077b14db5SEric W. Biederman ino_t ino = 0; 69177b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 69277b14db5SEric W. Biederman 69377b14db5SEric W. Biederman qname.name = table->procname; 69477b14db5SEric W. Biederman qname.len = strlen(table->procname); 6958387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 69677b14db5SEric W. Biederman 69777b14db5SEric W. Biederman child = d_lookup(dir, &qname); 69877b14db5SEric W. Biederman if (!child) { 69976aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 70076aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 70176aab3abSAl Viro if (IS_ERR(child)) 70276aab3abSAl Viro return false; 70376aab3abSAl Viro if (d_in_lookup(child)) { 704888e2b03SAl Viro struct dentry *res; 7059043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 706ea5751ccSIvan Delalande if (IS_ERR(inode)) { 70776aab3abSAl Viro d_lookup_done(child); 7089043476fSAl Viro dput(child); 709f0c3b509SAl Viro return false; 71076aab3abSAl Viro } 711fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 712888e2b03SAl Viro res = d_splice_alias(inode, child); 713888e2b03SAl Viro d_lookup_done(child); 714888e2b03SAl Viro if (unlikely(res)) { 715888e2b03SAl Viro if (IS_ERR(res)) { 716888e2b03SAl Viro dput(child); 717888e2b03SAl Viro return false; 718888e2b03SAl Viro } 719888e2b03SAl Viro dput(child); 720888e2b03SAl Viro child = res; 721888e2b03SAl Viro } 72277b14db5SEric W. Biederman } 72377b14db5SEric W. Biederman } 7242b0143b5SDavid Howells inode = d_inode(child); 72577b14db5SEric W. Biederman ino = inode->i_ino; 72677b14db5SEric W. Biederman type = inode->i_mode >> 12; 72777b14db5SEric W. Biederman dput(child); 728f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7299043476fSAl Viro } 7309043476fSAl Viro 731f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 732f0c3b509SAl Viro struct dir_context *ctx, 7330e47c99dSEric W. Biederman struct ctl_table_header *head, 7340e47c99dSEric W. Biederman struct ctl_table *table) 7350e47c99dSEric W. Biederman { 736f0c3b509SAl Viro bool ret = true; 737a0b0d1c3SDanilo Krummrich 7380e47c99dSEric W. Biederman head = sysctl_head_grab(head); 739a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 740a0b0d1c3SDanilo Krummrich return false; 7410e47c99dSEric W. Biederman 7420e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 743835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7440e47c99dSEric W. Biederman goto out; 7450e47c99dSEric W. Biederman 746f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7470e47c99dSEric W. Biederman out: 7480e47c99dSEric W. Biederman sysctl_head_finish(head); 7490e47c99dSEric W. Biederman return ret; 7500e47c99dSEric W. Biederman } 7510e47c99dSEric W. Biederman 752e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7539043476fSAl Viro unsigned long *pos, struct file *file, 754f0c3b509SAl Viro struct dir_context *ctx) 7559043476fSAl Viro { 756f0c3b509SAl Viro bool res; 7579043476fSAl Viro 758f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 759f0c3b509SAl Viro return true; 7609043476fSAl Viro 7610e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 762f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7630e47c99dSEric W. Biederman else 764f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7659043476fSAl Viro 766f0c3b509SAl Viro if (res) 767f0c3b509SAl Viro ctx->pos = *pos; 7686a75ce16SEric W. Biederman 7696a75ce16SEric W. Biederman return res; 77077b14db5SEric W. Biederman } 77177b14db5SEric W. Biederman 772f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 77377b14db5SEric W. Biederman { 774f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7759043476fSAl Viro struct ctl_table_header *h = NULL; 7766a75ce16SEric W. Biederman struct ctl_table *entry; 7777ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 77877b14db5SEric W. Biederman unsigned long pos; 77977b14db5SEric W. Biederman 7809043476fSAl Viro if (IS_ERR(head)) 7819043476fSAl Viro return PTR_ERR(head); 7829043476fSAl Viro 7837ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 78477b14db5SEric W. Biederman 785f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 78693362fa4SZhou Chengming goto out; 787f0c3b509SAl Viro 78877b14db5SEric W. Biederman pos = 2; 78977b14db5SEric W. Biederman 7907ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 791f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7929043476fSAl Viro sysctl_head_finish(h); 7939043476fSAl Viro break; 79477b14db5SEric W. Biederman } 79577b14db5SEric W. Biederman } 79693362fa4SZhou Chengming out: 79777b14db5SEric W. Biederman sysctl_head_finish(head); 798f0c3b509SAl Viro return 0; 79977b14db5SEric W. Biederman } 80077b14db5SEric W. Biederman 8014609e1f1SChristian Brauner static int proc_sys_permission(struct mnt_idmap *idmap, 802549c7297SChristian Brauner struct inode *inode, int mask) 80377b14db5SEric W. Biederman { 80477b14db5SEric W. Biederman /* 80577b14db5SEric W. Biederman * sysctl entries that are not writeable, 80677b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 80777b14db5SEric W. Biederman */ 808f696a365SMiklos Szeredi struct ctl_table_header *head; 809f696a365SMiklos Szeredi struct ctl_table *table; 81077b14db5SEric W. Biederman int error; 81177b14db5SEric W. Biederman 812f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 813f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 814f696a365SMiklos Szeredi return -EACCES; 815f696a365SMiklos Szeredi 816f696a365SMiklos Szeredi head = grab_header(inode); 8179043476fSAl Viro if (IS_ERR(head)) 8189043476fSAl Viro return PTR_ERR(head); 81977b14db5SEric W. Biederman 820f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8219043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8229043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8239043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 82473f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8259043476fSAl Viro 82677b14db5SEric W. Biederman sysctl_head_finish(head); 82777b14db5SEric W. Biederman return error; 82877b14db5SEric W. Biederman } 82977b14db5SEric W. Biederman 830c1632a0fSChristian Brauner static int proc_sys_setattr(struct mnt_idmap *idmap, 831549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr) 83277b14db5SEric W. Biederman { 8332b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 83477b14db5SEric W. Biederman int error; 83577b14db5SEric W. Biederman 83677b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 83777b14db5SEric W. Biederman return -EPERM; 83877b14db5SEric W. Biederman 839c1632a0fSChristian Brauner error = setattr_prepare(&nop_mnt_idmap, dentry, attr); 8401025774cSChristoph Hellwig if (error) 84177b14db5SEric W. Biederman return error; 8421025774cSChristoph Hellwig 843c1632a0fSChristian Brauner setattr_copy(&nop_mnt_idmap, inode, attr); 8441025774cSChristoph Hellwig mark_inode_dirty(inode); 8451025774cSChristoph Hellwig return 0; 84677b14db5SEric W. Biederman } 84777b14db5SEric W. Biederman 848b74d24f7SChristian Brauner static int proc_sys_getattr(struct mnt_idmap *idmap, 849549c7297SChristian Brauner const struct path *path, struct kstat *stat, 850a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8519043476fSAl Viro { 852a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8539043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8549043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8559043476fSAl Viro 8569043476fSAl Viro if (IS_ERR(head)) 8579043476fSAl Viro return PTR_ERR(head); 8589043476fSAl Viro 859b74d24f7SChristian Brauner generic_fillattr(&nop_mnt_idmap, inode, stat); 8609043476fSAl Viro if (table) 8619043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8629043476fSAl Viro 8639043476fSAl Viro sysctl_head_finish(head); 8649043476fSAl Viro return 0; 8659043476fSAl Viro } 8669043476fSAl Viro 86777b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 868f1ecf068SLucas De Marchi .open = proc_sys_open, 869f1ecf068SLucas De Marchi .poll = proc_sys_poll, 8704bd6a735SMatthew Wilcox (Oracle) .read_iter = proc_sys_read, 8714bd6a735SMatthew Wilcox (Oracle) .write_iter = proc_sys_write, 8724bd6a735SMatthew Wilcox (Oracle) .splice_read = generic_file_splice_read, 8734bd6a735SMatthew Wilcox (Oracle) .splice_write = iter_file_splice_write, 8746038f373SArnd Bergmann .llseek = default_llseek, 8759043476fSAl Viro }; 8769043476fSAl Viro 8779043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 878887df078SPavel Emelyanov .read = generic_read_dir, 879f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8803222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 88177b14db5SEric W. Biederman }; 88277b14db5SEric W. Biederman 88303a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8849043476fSAl Viro .permission = proc_sys_permission, 8859043476fSAl Viro .setattr = proc_sys_setattr, 8869043476fSAl Viro .getattr = proc_sys_getattr, 8879043476fSAl Viro }; 8889043476fSAl Viro 8899043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 89077b14db5SEric W. Biederman .lookup = proc_sys_lookup, 89177b14db5SEric W. Biederman .permission = proc_sys_permission, 89277b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8939043476fSAl Viro .getattr = proc_sys_getattr, 89477b14db5SEric W. Biederman }; 89577b14db5SEric W. Biederman 8960b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 89777b14db5SEric W. Biederman { 8980b728e19SAl Viro if (flags & LOOKUP_RCU) 89934286d66SNick Piggin return -ECHILD; 9002b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 9019043476fSAl Viro } 9029043476fSAl Viro 903fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 9049043476fSAl Viro { 9052b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 9069043476fSAl Viro } 9079043476fSAl Viro 9081f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 9091f87f0b5SEric W. Biederman { 9101f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 9111f87f0b5SEric W. Biederman int res; 9121f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 9131f87f0b5SEric W. Biederman if (p->unregistering) 9141f87f0b5SEric W. Biederman res = 0; 9151f87f0b5SEric W. Biederman else if (!set->is_seen) 9161f87f0b5SEric W. Biederman res = 1; 9171f87f0b5SEric W. Biederman else 9181f87f0b5SEric W. Biederman res = set->is_seen(set); 9191f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9201f87f0b5SEric W. Biederman return res; 9211f87f0b5SEric W. Biederman } 9221f87f0b5SEric W. Biederman 9236fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 924621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9259043476fSAl Viro { 926dfef6dcdSAl Viro struct ctl_table_header *head; 927da53be12SLinus Torvalds struct inode *inode; 928da53be12SLinus Torvalds 92931e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 93031e6b01fSNick Piggin * that inode here can be NULL */ 931dfef6dcdSAl Viro /* AV: can it, indeed? */ 9322b0143b5SDavid Howells inode = d_inode_rcu(dentry); 93331e6b01fSNick Piggin if (!inode) 934dfef6dcdSAl Viro return 1; 935621e155aSNick Piggin if (name->len != len) 9369043476fSAl Viro return 1; 937621e155aSNick Piggin if (memcmp(name->name, str, len)) 9389043476fSAl Viro return 1; 939dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 940dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 94177b14db5SEric W. Biederman } 94277b14db5SEric W. Biederman 943d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 94477b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9459043476fSAl Viro .d_delete = proc_sys_delete, 9469043476fSAl Viro .d_compare = proc_sys_compare, 94777b14db5SEric W. Biederman }; 94877b14db5SEric W. Biederman 9490e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9507ec66d06SEric W. Biederman const char *name, int namelen) 9511f87f0b5SEric W. Biederman { 9527ec66d06SEric W. Biederman struct ctl_table_header *head; 9537ec66d06SEric W. Biederman struct ctl_table *entry; 9541f87f0b5SEric W. Biederman 9550e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9567ec66d06SEric W. Biederman if (!entry) 9577ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 95851f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9597ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 96051f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9611f87f0b5SEric W. Biederman } 9621f87f0b5SEric W. Biederman 9637ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9647ec66d06SEric W. Biederman const char *name, int namelen) 9651f87f0b5SEric W. Biederman { 9667ec66d06SEric W. Biederman struct ctl_table *table; 9677ec66d06SEric W. Biederman struct ctl_dir *new; 968ac13ac6fSEric W. Biederman struct ctl_node *node; 9697ec66d06SEric W. Biederman char *new_name; 9701f87f0b5SEric W. Biederman 971ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 972ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 973ac13ac6fSEric W. Biederman GFP_KERNEL); 9747ec66d06SEric W. Biederman if (!new) 9757ec66d06SEric W. Biederman return NULL; 9767ec66d06SEric W. Biederman 977ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 978ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9797ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9807ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9817ec66d06SEric W. Biederman table[0].procname = new_name; 9827ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 983ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9847ec66d06SEric W. Biederman 9857ec66d06SEric W. Biederman return new; 9861f87f0b5SEric W. Biederman } 9871f87f0b5SEric W. Biederman 98860f126d9SEric W. Biederman /** 98960f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 99060f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 99160f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 99260f126d9SEric W. Biederman * @namelen: The length of name 99360f126d9SEric W. Biederman * 99460f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 99560f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 99660f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 99760f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 99860f126d9SEric W. Biederman * simply dropped. 99960f126d9SEric W. Biederman */ 10000e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 10010e47c99dSEric W. Biederman const char *name, int namelen) 10027ec66d06SEric W. Biederman { 10030e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 10047ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 10050eb97f38SEric W. Biederman int err; 10067ec66d06SEric W. Biederman 10077ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10080e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10097ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10107ec66d06SEric W. Biederman goto found; 10117ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10127ec66d06SEric W. Biederman goto failed; 10137ec66d06SEric W. Biederman 10147ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10157ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 10167ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10177ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10187ec66d06SEric W. Biederman if (!new) 10197ec66d06SEric W. Biederman goto failed; 10207ec66d06SEric W. Biederman 102160f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 10220e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10237ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10247ec66d06SEric W. Biederman goto found; 10257ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10267ec66d06SEric W. Biederman goto failed; 10277ec66d06SEric W. Biederman 102860f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10290eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10300eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10310eb97f38SEric W. Biederman if (err) 10320e47c99dSEric W. Biederman goto failed; 10337ec66d06SEric W. Biederman subdir = new; 10347ec66d06SEric W. Biederman found: 10357ec66d06SEric W. Biederman subdir->header.nreg++; 10367ec66d06SEric W. Biederman failed: 1037a1c83681SViresh Kumar if (IS_ERR(subdir)) { 103887ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10396980128fSEric W. Biederman sysctl_print_dir(dir); 1040153ee1c4SGeert Uytterhoeven pr_cont("%*.*s %ld\n", namelen, namelen, name, 1041153ee1c4SGeert Uytterhoeven PTR_ERR(subdir)); 10421f87f0b5SEric W. Biederman } 10437ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10447ec66d06SEric W. Biederman if (new) 10457ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10467ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10477ec66d06SEric W. Biederman return subdir; 10481f87f0b5SEric W. Biederman } 10491f87f0b5SEric W. Biederman 10500e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10510e47c99dSEric W. Biederman { 10520e47c99dSEric W. Biederman struct ctl_dir *parent; 10530e47c99dSEric W. Biederman const char *procname; 10540e47c99dSEric W. Biederman if (!dir->header.parent) 10550e47c99dSEric W. Biederman return &set->dir; 10560e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10570e47c99dSEric W. Biederman if (IS_ERR(parent)) 10580e47c99dSEric W. Biederman return parent; 10590e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10600e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10610e47c99dSEric W. Biederman } 10620e47c99dSEric W. Biederman 10630e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 106413bcc6a2SEric W. Biederman struct ctl_table **pentry) 10650e47c99dSEric W. Biederman { 10660e47c99dSEric W. Biederman struct ctl_table_header *head; 10670e47c99dSEric W. Biederman struct ctl_table_root *root; 10680e47c99dSEric W. Biederman struct ctl_table_set *set; 10690e47c99dSEric W. Biederman struct ctl_table *entry; 10700e47c99dSEric W. Biederman struct ctl_dir *dir; 10710e47c99dSEric W. Biederman int ret; 10720e47c99dSEric W. Biederman 10730e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10740e47c99dSEric W. Biederman root = (*pentry)->data; 107513bcc6a2SEric W. Biederman set = lookup_header_set(root); 10760e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10770e47c99dSEric W. Biederman if (IS_ERR(dir)) 10780e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10790e47c99dSEric W. Biederman else { 10800e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10810e47c99dSEric W. Biederman head = NULL; 10820e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10830e47c99dSEric W. Biederman ret = -ENOENT; 10840e47c99dSEric W. Biederman if (entry && use_table(head)) { 10850e47c99dSEric W. Biederman unuse_table(*phead); 10860e47c99dSEric W. Biederman *phead = head; 10870e47c99dSEric W. Biederman *pentry = entry; 10880e47c99dSEric W. Biederman ret = 0; 10890e47c99dSEric W. Biederman } 10900e47c99dSEric W. Biederman } 10910e47c99dSEric W. Biederman 10920e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10930e47c99dSEric W. Biederman return ret; 10940e47c99dSEric W. Biederman } 10950e47c99dSEric W. Biederman 10967c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10977c60c48fSEric W. Biederman { 10987c60c48fSEric W. Biederman struct va_format vaf; 10997c60c48fSEric W. Biederman va_list args; 11007c60c48fSEric W. Biederman 11017c60c48fSEric W. Biederman va_start(args, fmt); 11027c60c48fSEric W. Biederman vaf.fmt = fmt; 11037c60c48fSEric W. Biederman vaf.va = &args; 11047c60c48fSEric W. Biederman 110587ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 11067c60c48fSEric W. Biederman path, table->procname, &vaf); 11077c60c48fSEric W. Biederman 11087c60c48fSEric W. Biederman va_end(args); 11097c60c48fSEric W. Biederman return -EINVAL; 11107c60c48fSEric W. Biederman } 11117c60c48fSEric W. Biederman 11124f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 11134f2fec00SLuis R. Rodriguez { 11144f2fec00SLuis R. Rodriguez int err = 0; 11154f2fec00SLuis R. Rodriguez 111661d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 111761d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11184f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 111964a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11204f2fec00SLuis R. Rodriguez } 11214f2fec00SLuis R. Rodriguez 1122cb944413SEric Dumazet if (table->proc_handler == proc_dou8vec_minmax) { 1123cb944413SEric Dumazet if (table->maxlen != sizeof(u8)) 1124cb944413SEric Dumazet err |= sysctl_err(path, table, "array not allowed"); 1125cb944413SEric Dumazet } 1126cb944413SEric Dumazet 1127f1aa2eb5SOndrej Mosnacek if (table->proc_handler == proc_dobool) { 1128f1aa2eb5SOndrej Mosnacek if (table->maxlen != sizeof(bool)) 1129f1aa2eb5SOndrej Mosnacek err |= sysctl_err(path, table, "array not allowed"); 1130f1aa2eb5SOndrej Mosnacek } 1131f1aa2eb5SOndrej Mosnacek 11324f2fec00SLuis R. Rodriguez return err; 11334f2fec00SLuis R. Rodriguez } 11344f2fec00SLuis R. Rodriguez 11357c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11367c60c48fSEric W. Biederman { 1137cb55f27aSMeng Tang struct ctl_table *entry; 11387c60c48fSEric W. Biederman int err = 0; 1139cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1140cb55f27aSMeng Tang if (entry->child) 1141cb55f27aSMeng Tang err |= sysctl_err(path, entry, "Not a file"); 11427c60c48fSEric W. Biederman 1143cb55f27aSMeng Tang if ((entry->proc_handler == proc_dostring) || 1144f1aa2eb5SOndrej Mosnacek (entry->proc_handler == proc_dobool) || 1145cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec) || 1146cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec) || 1147cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec_minmax) || 1148cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_minmax) || 1149cb55f27aSMeng Tang (entry->proc_handler == proc_dou8vec_minmax) || 1150cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_jiffies) || 1151cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_userhz_jiffies) || 1152cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_ms_jiffies) || 1153cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_minmax) || 1154cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 1155cb55f27aSMeng Tang if (!entry->data) 1156cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No data"); 1157cb55f27aSMeng Tang if (!entry->maxlen) 1158cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No maxlen"); 11594f2fec00SLuis R. Rodriguez else 1160cb55f27aSMeng Tang err |= sysctl_check_table_array(path, entry); 11611f87f0b5SEric W. Biederman } 1162cb55f27aSMeng Tang if (!entry->proc_handler) 1163cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No proc_handler"); 11647c60c48fSEric W. Biederman 1165cb55f27aSMeng Tang if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode) 1166cb55f27aSMeng Tang err |= sysctl_err(path, entry, "bogus .mode 0%o", 1167cb55f27aSMeng Tang entry->mode); 11681f87f0b5SEric W. Biederman } 11697c60c48fSEric W. Biederman return err; 11701f87f0b5SEric W. Biederman } 11711f87f0b5SEric W. Biederman 11720e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11730e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11740e47c99dSEric W. Biederman { 11750e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11760e47c99dSEric W. Biederman struct ctl_table_header *links; 1177ac13ac6fSEric W. Biederman struct ctl_node *node; 11780e47c99dSEric W. Biederman char *link_name; 11790e47c99dSEric W. Biederman int nr_entries, name_bytes; 11800e47c99dSEric W. Biederman 11810e47c99dSEric W. Biederman name_bytes = 0; 11820e47c99dSEric W. Biederman nr_entries = 0; 1183cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 11840e47c99dSEric W. Biederman nr_entries++; 11850e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11860e47c99dSEric W. Biederman } 11870e47c99dSEric W. Biederman 11880e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1189ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11900e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11910e47c99dSEric W. Biederman name_bytes, 11920e47c99dSEric W. Biederman GFP_KERNEL); 11930e47c99dSEric W. Biederman 11940e47c99dSEric W. Biederman if (!links) 11950e47c99dSEric W. Biederman return NULL; 11960e47c99dSEric W. Biederman 1197ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1198ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11990e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 1200cb55f27aSMeng Tang link = link_table; 12010e47c99dSEric W. Biederman 1202cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12030e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 12040e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 12050e47c99dSEric W. Biederman link->procname = link_name; 12060e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 12070e47c99dSEric W. Biederman link->data = link_root; 12080e47c99dSEric W. Biederman link_name += len; 1209cb55f27aSMeng Tang link++; 12100e47c99dSEric W. Biederman } 1211ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 12120e47c99dSEric W. Biederman links->nreg = nr_entries; 12130e47c99dSEric W. Biederman 12140e47c99dSEric W. Biederman return links; 12150e47c99dSEric W. Biederman } 12160e47c99dSEric W. Biederman 12170e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 12180e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 12190e47c99dSEric W. Biederman { 12200e47c99dSEric W. Biederman struct ctl_table_header *head; 12210e47c99dSEric W. Biederman struct ctl_table *entry, *link; 12220e47c99dSEric W. Biederman 12230e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 1224cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12250e47c99dSEric W. Biederman const char *procname = entry->procname; 12260e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12270e47c99dSEric W. Biederman if (!link) 12280e47c99dSEric W. Biederman return false; 12290e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12300e47c99dSEric W. Biederman continue; 12310e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12320e47c99dSEric W. Biederman continue; 12330e47c99dSEric W. Biederman return false; 12340e47c99dSEric W. Biederman } 12350e47c99dSEric W. Biederman 12360e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 1237cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12380e47c99dSEric W. Biederman const char *procname = entry->procname; 12390e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12400e47c99dSEric W. Biederman head->nreg++; 12410e47c99dSEric W. Biederman } 12420e47c99dSEric W. Biederman return true; 12430e47c99dSEric W. Biederman } 12440e47c99dSEric W. Biederman 12450e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12460e47c99dSEric W. Biederman { 12470e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12489a521359SLi zeming struct ctl_dir *core_parent; 12490e47c99dSEric W. Biederman struct ctl_table_header *links; 12500e47c99dSEric W. Biederman int err; 12510e47c99dSEric W. Biederman 12520e47c99dSEric W. Biederman if (head->set == root_set) 12530e47c99dSEric W. Biederman return 0; 12540e47c99dSEric W. Biederman 12550e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12560e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12570e47c99dSEric W. Biederman return 0; 12580e47c99dSEric W. Biederman 12590e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12600e47c99dSEric W. Biederman return 0; 12610e47c99dSEric W. Biederman 12620e47c99dSEric W. Biederman core_parent->header.nreg++; 12630e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12640e47c99dSEric W. Biederman 12650e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12660e47c99dSEric W. Biederman 12670e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12680e47c99dSEric W. Biederman err = -ENOMEM; 12690e47c99dSEric W. Biederman if (!links) 12700e47c99dSEric W. Biederman goto out; 12710e47c99dSEric W. Biederman 12720e47c99dSEric W. Biederman err = 0; 12730e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12740e47c99dSEric W. Biederman kfree(links); 12750e47c99dSEric W. Biederman goto out; 12760e47c99dSEric W. Biederman } 12770e47c99dSEric W. Biederman 12780e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12790e47c99dSEric W. Biederman if (err) 12800e47c99dSEric W. Biederman kfree(links); 12810e47c99dSEric W. Biederman out: 12820e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12830e47c99dSEric W. Biederman return err; 12840e47c99dSEric W. Biederman } 12850e47c99dSEric W. Biederman 1286b2f56e55SLuis Chamberlain /* Find the directory for the ctl_table. If one is not found create it. */ 1287b2f56e55SLuis Chamberlain static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path) 1288b2f56e55SLuis Chamberlain { 1289b2f56e55SLuis Chamberlain const char *name, *nextname; 1290b2f56e55SLuis Chamberlain 1291b2f56e55SLuis Chamberlain for (name = path; name; name = nextname) { 1292b2f56e55SLuis Chamberlain int namelen; 1293b2f56e55SLuis Chamberlain nextname = strchr(name, '/'); 1294b2f56e55SLuis Chamberlain if (nextname) { 1295b2f56e55SLuis Chamberlain namelen = nextname - name; 1296b2f56e55SLuis Chamberlain nextname++; 1297b2f56e55SLuis Chamberlain } else { 1298b2f56e55SLuis Chamberlain namelen = strlen(name); 1299b2f56e55SLuis Chamberlain } 1300b2f56e55SLuis Chamberlain if (namelen == 0) 1301b2f56e55SLuis Chamberlain continue; 1302b2f56e55SLuis Chamberlain 1303b2f56e55SLuis Chamberlain /* 1304b2f56e55SLuis Chamberlain * namelen ensures if name is "foo/bar/yay" only foo is 1305b2f56e55SLuis Chamberlain * registered first. We traverse as if using mkdir -p and 1306b2f56e55SLuis Chamberlain * return a ctl_dir for the last directory entry. 1307b2f56e55SLuis Chamberlain */ 1308b2f56e55SLuis Chamberlain dir = get_subdir(dir, name, namelen); 1309b2f56e55SLuis Chamberlain if (IS_ERR(dir)) 1310b2f56e55SLuis Chamberlain break; 1311b2f56e55SLuis Chamberlain } 1312b2f56e55SLuis Chamberlain return dir; 1313b2f56e55SLuis Chamberlain } 1314b2f56e55SLuis Chamberlain 13151f87f0b5SEric W. Biederman /** 1316f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 131760a47a2eSEric W. Biederman * @set: Sysctl tree to register on 13181f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 131967ff3228SLuis Chamberlain * @table: the top-level table structure without any child 13201f87f0b5SEric W. Biederman * 13211f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 13221f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 13231f87f0b5SEric W. Biederman * 13241f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 13251f87f0b5SEric W. Biederman * 13261f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 13271f87f0b5SEric W. Biederman * enter a sysctl file 13281f87f0b5SEric W. Biederman * 13291f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 13301f87f0b5SEric W. Biederman * 13311f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 13321f87f0b5SEric W. Biederman * 1333f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 13341f87f0b5SEric W. Biederman * 1335f728019bSEric W. Biederman * child - must be %NULL. 13361f87f0b5SEric W. Biederman * 13371f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 13381f87f0b5SEric W. Biederman * 13391f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 134067ff3228SLuis Chamberlain * XXX: we should eventually modify these to use long min / max [0] 134167ff3228SLuis Chamberlain * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org 13421f87f0b5SEric W. Biederman * 13431f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 134467ff3228SLuis Chamberlain * under /proc; non-leaf nodes (where child is not NULL) are not allowed, 134567ff3228SLuis Chamberlain * sysctl_check_table() verifies this. 13461f87f0b5SEric W. Biederman * 1347f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1348f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 13491f87f0b5SEric W. Biederman * 13501f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 13511f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 13521f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 13531f87f0b5SEric W. Biederman * 13541f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 13551f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 13561f87f0b5SEric W. Biederman * 13571f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 13581f87f0b5SEric W. Biederman * to the table header on success. 13591f87f0b5SEric W. Biederman */ 13606e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 136160a47a2eSEric W. Biederman struct ctl_table_set *set, 13626e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 13631f87f0b5SEric W. Biederman { 136460a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13651f87f0b5SEric W. Biederman struct ctl_table_header *header; 13667ec66d06SEric W. Biederman struct ctl_dir *dir; 1367ac13ac6fSEric W. Biederman struct ctl_table *entry; 1368ac13ac6fSEric W. Biederman struct ctl_node *node; 1369ac13ac6fSEric W. Biederman int nr_entries = 0; 13701f87f0b5SEric W. Biederman 1371cb55f27aSMeng Tang list_for_each_table_entry(entry, table) 1372ac13ac6fSEric W. Biederman nr_entries++; 1373ac13ac6fSEric W. Biederman 1374ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1375425b9c7fSVasily Averin sizeof(struct ctl_node)*nr_entries, GFP_KERNEL_ACCOUNT); 13761f87f0b5SEric W. Biederman if (!header) 13771f87f0b5SEric W. Biederman return NULL; 13781f87f0b5SEric W. Biederman 1379ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1380ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13817c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13827c60c48fSEric W. Biederman goto fail; 13838d6ecfccSEric W. Biederman 13841f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13850e47c99dSEric W. Biederman dir = &set->dir; 138667ff3228SLuis Chamberlain /* Reference moved down the directory tree get_subdir */ 13877ec66d06SEric W. Biederman dir->header.nreg++; 13887ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13897ec66d06SEric W. Biederman 1390b2f56e55SLuis Chamberlain dir = sysctl_mkdir_p(dir, path); 13917ec66d06SEric W. Biederman if (IS_ERR(dir)) 13927ec66d06SEric W. Biederman goto fail; 13937ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13940e47c99dSEric W. Biederman if (insert_header(dir, header)) 13950e47c99dSEric W. Biederman goto fail_put_dir_locked; 13960e47c99dSEric W. Biederman 13977ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13981f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13991f87f0b5SEric W. Biederman 14001f87f0b5SEric W. Biederman return header; 14010e47c99dSEric W. Biederman 14027ec66d06SEric W. Biederman fail_put_dir_locked: 14037ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 14047c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 14057c60c48fSEric W. Biederman fail: 14067c60c48fSEric W. Biederman kfree(header); 14077c60c48fSEric W. Biederman dump_stack(); 14087c60c48fSEric W. Biederman return NULL; 14091f87f0b5SEric W. Biederman } 14101f87f0b5SEric W. Biederman 1411fea478d4SEric W. Biederman /** 1412fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1413fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1414fea478d4SEric W. Biederman * @table: the table structure 1415fea478d4SEric W. Biederman * 1416fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1417fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1418fea478d4SEric W. Biederman * 1419fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1420fea478d4SEric W. Biederman */ 1421fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1422fea478d4SEric W. Biederman { 1423fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1424fea478d4SEric W. Biederman path, table); 1425fea478d4SEric W. Biederman } 1426fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1427fea478d4SEric W. Biederman 14283ddd9a80SXiaoming Ni /** 14293ddd9a80SXiaoming Ni * __register_sysctl_init() - register sysctl table to path 14303ddd9a80SXiaoming Ni * @path: path name for sysctl base 14313ddd9a80SXiaoming Ni * @table: This is the sysctl table that needs to be registered to the path 14323ddd9a80SXiaoming Ni * @table_name: The name of sysctl table, only used for log printing when 14333ddd9a80SXiaoming Ni * registration fails 14343ddd9a80SXiaoming Ni * 14353ddd9a80SXiaoming Ni * The sysctl interface is used by userspace to query or modify at runtime 14363ddd9a80SXiaoming Ni * a predefined value set on a variable. These variables however have default 14373ddd9a80SXiaoming Ni * values pre-set. Code which depends on these variables will always work even 14383ddd9a80SXiaoming Ni * if register_sysctl() fails. If register_sysctl() fails you'd just loose the 14393ddd9a80SXiaoming Ni * ability to query or modify the sysctls dynamically at run time. Chances of 14403ddd9a80SXiaoming Ni * register_sysctl() failing on init are extremely low, and so for both reasons 14413ddd9a80SXiaoming Ni * this function does not return any error as it is used by initialization code. 14423ddd9a80SXiaoming Ni * 1443*228b09deSLuis Chamberlain * Context: if your base directory does not exist it will be created for you. 14443ddd9a80SXiaoming Ni */ 14453ddd9a80SXiaoming Ni void __init __register_sysctl_init(const char *path, struct ctl_table *table, 14463ddd9a80SXiaoming Ni const char *table_name) 14473ddd9a80SXiaoming Ni { 14483ddd9a80SXiaoming Ni struct ctl_table_header *hdr = register_sysctl(path, table); 14493ddd9a80SXiaoming Ni 14503ddd9a80SXiaoming Ni if (unlikely(!hdr)) { 14513ddd9a80SXiaoming Ni pr_err("failed when register_sysctl %s to %s\n", table_name, path); 14523ddd9a80SXiaoming Ni return; 14533ddd9a80SXiaoming Ni } 14543ddd9a80SXiaoming Ni kmemleak_not_leak(hdr); 14553ddd9a80SXiaoming Ni } 14563ddd9a80SXiaoming Ni 14576e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 14586e9d5164SEric W. Biederman { 14596e9d5164SEric W. Biederman int namelen; 14606e9d5164SEric W. Biederman namelen = strlen(name); 14616e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 14626e9d5164SEric W. Biederman return NULL; 14636e9d5164SEric W. Biederman memcpy(pos, name, namelen); 14646e9d5164SEric W. Biederman pos[namelen] = '/'; 14656e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 14666e9d5164SEric W. Biederman pos += namelen + 1; 14676e9d5164SEric W. Biederman return pos; 14686e9d5164SEric W. Biederman } 14696e9d5164SEric W. Biederman 1470f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1471f728019bSEric W. Biederman { 1472f728019bSEric W. Biederman int has_files = 0; 1473f728019bSEric W. Biederman int nr_subheaders = 0; 1474f728019bSEric W. Biederman struct ctl_table *entry; 1475f728019bSEric W. Biederman 1476f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1477f728019bSEric W. Biederman if (!table || !table->procname) 1478f728019bSEric W. Biederman return 1; 1479f728019bSEric W. Biederman 1480cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1481f728019bSEric W. Biederman if (entry->child) 1482f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1483f728019bSEric W. Biederman else 1484f728019bSEric W. Biederman has_files = 1; 1485f728019bSEric W. Biederman } 1486f728019bSEric W. Biederman return nr_subheaders + has_files; 1487f728019bSEric W. Biederman } 1488f728019bSEric W. Biederman 1489f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 149060a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1491f728019bSEric W. Biederman struct ctl_table *table) 1492f728019bSEric W. Biederman { 1493f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1494f728019bSEric W. Biederman struct ctl_table *entry, *files; 1495f728019bSEric W. Biederman int nr_files = 0; 1496f728019bSEric W. Biederman int nr_dirs = 0; 1497f728019bSEric W. Biederman int err = -ENOMEM; 1498f728019bSEric W. Biederman 1499cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1500f728019bSEric W. Biederman if (entry->child) 1501f728019bSEric W. Biederman nr_dirs++; 1502f728019bSEric W. Biederman else 1503f728019bSEric W. Biederman nr_files++; 1504f728019bSEric W. Biederman } 1505f728019bSEric W. Biederman 1506f728019bSEric W. Biederman files = table; 1507f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1508f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1509f728019bSEric W. Biederman struct ctl_table *new; 15106396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1511f728019bSEric W. Biederman GFP_KERNEL); 1512f728019bSEric W. Biederman if (!files) 1513f728019bSEric W. Biederman goto out; 1514f728019bSEric W. Biederman 1515f728019bSEric W. Biederman ctl_table_arg = files; 1516cb55f27aSMeng Tang new = files; 1517cb55f27aSMeng Tang 1518cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1519f728019bSEric W. Biederman if (entry->child) 1520f728019bSEric W. Biederman continue; 1521f728019bSEric W. Biederman *new = *entry; 1522f728019bSEric W. Biederman new++; 1523f728019bSEric W. Biederman } 1524f728019bSEric W. Biederman } 1525f728019bSEric W. Biederman 1526f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1527f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1528f728019bSEric W. Biederman struct ctl_table_header *header; 152960a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1530f728019bSEric W. Biederman if (!header) { 1531f728019bSEric W. Biederman kfree(ctl_table_arg); 1532f728019bSEric W. Biederman goto out; 1533f728019bSEric W. Biederman } 1534f728019bSEric W. Biederman 1535f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1536f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1537f728019bSEric W. Biederman **subheader = header; 1538f728019bSEric W. Biederman (*subheader)++; 1539f728019bSEric W. Biederman } 1540f728019bSEric W. Biederman 1541f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1542cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1543f728019bSEric W. Biederman char *child_pos; 1544f728019bSEric W. Biederman 1545f728019bSEric W. Biederman if (!entry->child) 1546f728019bSEric W. Biederman continue; 1547f728019bSEric W. Biederman 1548f728019bSEric W. Biederman err = -ENAMETOOLONG; 1549f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1550f728019bSEric W. Biederman if (!child_pos) 1551f728019bSEric W. Biederman goto out; 1552f728019bSEric W. Biederman 1553f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 155460a47a2eSEric W. Biederman set, entry->child); 1555f728019bSEric W. Biederman pos[0] = '\0'; 1556f728019bSEric W. Biederman if (err) 1557f728019bSEric W. Biederman goto out; 1558f728019bSEric W. Biederman } 1559f728019bSEric W. Biederman err = 0; 1560f728019bSEric W. Biederman out: 1561f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1562f728019bSEric W. Biederman return err; 1563f728019bSEric W. Biederman } 1564f728019bSEric W. Biederman 15656e9d5164SEric W. Biederman /** 15666e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 156760a47a2eSEric W. Biederman * @set: Sysctl tree to register on 15686e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15696e9d5164SEric W. Biederman * @table: the top-level table structure 15706e9d5164SEric W. Biederman * 15716e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15726e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15736e9d5164SEric W. Biederman * 15746e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 15756e9d5164SEric W. Biederman */ 15766e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 157760a47a2eSEric W. Biederman struct ctl_table_set *set, 15786e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15796e9d5164SEric W. Biederman { 1580ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1581f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1582f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15836e9d5164SEric W. Biederman const struct ctl_path *component; 15846e9d5164SEric W. Biederman char *new_path, *pos; 15856e9d5164SEric W. Biederman 15866e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15876e9d5164SEric W. Biederman if (!new_path) 15886e9d5164SEric W. Biederman return NULL; 15896e9d5164SEric W. Biederman 15906e9d5164SEric W. Biederman pos[0] = '\0'; 15916e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15926e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15936e9d5164SEric W. Biederman if (!pos) 15946e9d5164SEric W. Biederman goto out; 15956e9d5164SEric W. Biederman } 1596ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1597ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1598ec6a5266SEric W. Biederman if (!pos) 1599ec6a5266SEric W. Biederman goto out; 1600ec6a5266SEric W. Biederman table = table->child; 1601ec6a5266SEric W. Biederman } 1602f728019bSEric W. Biederman if (nr_subheaders == 1) { 160360a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1604ec6a5266SEric W. Biederman if (header) 1605ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1606f728019bSEric W. Biederman } else { 1607f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1608f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1609f728019bSEric W. Biederman if (!header) 1610f728019bSEric W. Biederman goto out; 1611f728019bSEric W. Biederman 1612f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1613f728019bSEric W. Biederman subheader = subheaders; 1614f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1615f728019bSEric W. Biederman 1616f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 161760a47a2eSEric W. Biederman set, table)) 1618f728019bSEric W. Biederman goto err_register_leaves; 1619f728019bSEric W. Biederman } 1620f728019bSEric W. Biederman 16216e9d5164SEric W. Biederman out: 16226e9d5164SEric W. Biederman kfree(new_path); 16236e9d5164SEric W. Biederman return header; 1624f728019bSEric W. Biederman 1625f728019bSEric W. Biederman err_register_leaves: 1626f728019bSEric W. Biederman while (subheader > subheaders) { 1627f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1628f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1629f728019bSEric W. Biederman unregister_sysctl_table(subh); 1630f728019bSEric W. Biederman kfree(table); 1631f728019bSEric W. Biederman } 1632f728019bSEric W. Biederman kfree(header); 1633f728019bSEric W. Biederman header = NULL; 1634f728019bSEric W. Biederman goto out; 16356e9d5164SEric W. Biederman } 16366e9d5164SEric W. Biederman 16371f87f0b5SEric W. Biederman /** 16385b31a7dfSzhouchuangao * register_sysctl_paths - register a sysctl table hierarchy 16391f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 16401f87f0b5SEric W. Biederman * @table: the top-level table structure 16411f87f0b5SEric W. Biederman * 16421f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16431f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16441f87f0b5SEric W. Biederman * 16451f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 16461f87f0b5SEric W. Biederman */ 16471f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 16481f87f0b5SEric W. Biederman struct ctl_table *table) 16491f87f0b5SEric W. Biederman { 165060a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 16511f87f0b5SEric W. Biederman path, table); 16521f87f0b5SEric W. Biederman } 16531f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 16541f87f0b5SEric W. Biederman 16551f87f0b5SEric W. Biederman /** 16561f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 16571f87f0b5SEric W. Biederman * @table: the top-level table structure 16581f87f0b5SEric W. Biederman * 16591f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16601f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16611f87f0b5SEric W. Biederman * 16621f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 16631f87f0b5SEric W. Biederman */ 16641f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 16651f87f0b5SEric W. Biederman { 16661f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 16671f87f0b5SEric W. Biederman 16681f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 16691f87f0b5SEric W. Biederman } 16701f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 16711f87f0b5SEric W. Biederman 167251cb8dfcSLuis Chamberlain int __register_sysctl_base(struct ctl_table *base_table) 167351cb8dfcSLuis Chamberlain { 167451cb8dfcSLuis Chamberlain struct ctl_table_header *hdr; 167551cb8dfcSLuis Chamberlain 167651cb8dfcSLuis Chamberlain hdr = register_sysctl_table(base_table); 167751cb8dfcSLuis Chamberlain kmemleak_not_leak(hdr); 167851cb8dfcSLuis Chamberlain return 0; 167951cb8dfcSLuis Chamberlain } 168051cb8dfcSLuis Chamberlain 16810e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 16820e47c99dSEric W. Biederman { 16830e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 16840e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 16850e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 16860e47c99dSEric W. Biederman struct ctl_dir *core_parent; 16870e47c99dSEric W. Biederman struct ctl_table *entry; 16880e47c99dSEric W. Biederman 16890e47c99dSEric W. Biederman if (header->set == root_set) 16900e47c99dSEric W. Biederman return; 16910e47c99dSEric W. Biederman 16920e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16930e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16940e47c99dSEric W. Biederman return; 16950e47c99dSEric W. Biederman 1696cb55f27aSMeng Tang list_for_each_table_entry(entry, header->ctl_table) { 16970e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16980e47c99dSEric W. Biederman struct ctl_table *link; 16990e47c99dSEric W. Biederman const char *name = entry->procname; 17000e47c99dSEric W. Biederman 17010e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 17020e47c99dSEric W. Biederman if (link && 17030e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 17040e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 17050e47c99dSEric W. Biederman drop_sysctl_table(link_head); 17060e47c99dSEric W. Biederman } 17070e47c99dSEric W. Biederman else { 170887ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 17090e47c99dSEric W. Biederman sysctl_print_dir(parent); 1710153ee1c4SGeert Uytterhoeven pr_cont("%s\n", name); 17110e47c99dSEric W. Biederman } 17120e47c99dSEric W. Biederman } 17130e47c99dSEric W. Biederman } 17140e47c99dSEric W. Biederman 1715938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1716938aaa4fSEric W. Biederman { 17177ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 17187ec66d06SEric W. Biederman 1719938aaa4fSEric W. Biederman if (--header->nreg) 1720938aaa4fSEric W. Biederman return; 1721938aaa4fSEric W. Biederman 172289189557SYueHaibing if (parent) { 17230e47c99dSEric W. Biederman put_links(header); 1724938aaa4fSEric W. Biederman start_unregistering(header); 172589189557SYueHaibing } 172689189557SYueHaibing 1727938aaa4fSEric W. Biederman if (!--header->count) 1728938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 17297ec66d06SEric W. Biederman 17307ec66d06SEric W. Biederman if (parent) 17317ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1732938aaa4fSEric W. Biederman } 1733938aaa4fSEric W. Biederman 17341f87f0b5SEric W. Biederman /** 17351f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 17361f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 17371f87f0b5SEric W. Biederman * 17381f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 17391f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 17401f87f0b5SEric W. Biederman */ 17411f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 17421f87f0b5SEric W. Biederman { 1743f728019bSEric W. Biederman int nr_subheaders; 17441f87f0b5SEric W. Biederman might_sleep(); 17451f87f0b5SEric W. Biederman 17461f87f0b5SEric W. Biederman if (header == NULL) 17471f87f0b5SEric W. Biederman return; 17481f87f0b5SEric W. Biederman 1749f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1750f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1751f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1752f728019bSEric W. Biederman int i; 1753f728019bSEric W. Biederman 1754f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1755f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1756f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1757f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1758f728019bSEric W. Biederman unregister_sysctl_table(subh); 1759f728019bSEric W. Biederman kfree(table); 1760f728019bSEric W. Biederman } 1761f728019bSEric W. Biederman kfree(header); 1762f728019bSEric W. Biederman return; 1763f728019bSEric W. Biederman } 1764f728019bSEric W. Biederman 17651f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1766938aaa4fSEric W. Biederman drop_sysctl_table(header); 17671f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 17681f87f0b5SEric W. Biederman } 17691f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 17701f87f0b5SEric W. Biederman 17710e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 17729eb47c26SEric W. Biederman struct ctl_table_root *root, 17731f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 17741f87f0b5SEric W. Biederman { 17751347440dSDan Carpenter memset(set, 0, sizeof(*set)); 17760e47c99dSEric W. Biederman set->is_seen = is_seen; 1777ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 17781f87f0b5SEric W. Biederman } 17791f87f0b5SEric W. Biederman 178097324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 178197324cd8SEric W. Biederman { 1782ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 178397324cd8SEric W. Biederman } 17841f87f0b5SEric W. Biederman 17851e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 178677b14db5SEric W. Biederman { 1787e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1788e1675231SAlexey Dobriyan 178977b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17909043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 1791d56c0d45SAlexey Dobriyan proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; 179277b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1793de4e83bdSEric W. Biederman 1794d8c0418aSLuis Chamberlain return sysctl_init_bases(); 179577b14db5SEric W. Biederman } 17963db978d4SVlastimil Babka 17970a477e1aSVlastimil Babka struct sysctl_alias { 17980a477e1aSVlastimil Babka const char *kernel_param; 17990a477e1aSVlastimil Babka const char *sysctl_param; 18000a477e1aSVlastimil Babka }; 18010a477e1aSVlastimil Babka 18020a477e1aSVlastimil Babka /* 18030a477e1aSVlastimil Babka * Historically some settings had both sysctl and a command line parameter. 18040a477e1aSVlastimil Babka * With the generic sysctl. parameter support, we can handle them at a single 18050a477e1aSVlastimil Babka * place and only keep the historical name for compatibility. This is not meant 18060a477e1aSVlastimil Babka * to add brand new aliases. When adding existing aliases, consider whether 18070a477e1aSVlastimil Babka * the possibly different moment of changing the value (e.g. from early_param 18080a477e1aSVlastimil Babka * to the moment do_sysctl_args() is called) is an issue for the specific 18090a477e1aSVlastimil Babka * parameter. 18100a477e1aSVlastimil Babka */ 18110a477e1aSVlastimil Babka static const struct sysctl_alias sysctl_aliases[] = { 1812f117955aSGuilherme G. Piccoli {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, 1813b467f3efSVlastimil Babka {"hung_task_panic", "kernel.hung_task_panic" }, 1814f117955aSGuilherme G. Piccoli {"numa_zonelist_order", "vm.numa_zonelist_order" }, 1815f117955aSGuilherme G. Piccoli {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, 1816f117955aSGuilherme G. Piccoli {"softlockup_panic", "kernel.softlockup_panic" }, 18170a477e1aSVlastimil Babka { } 18180a477e1aSVlastimil Babka }; 18190a477e1aSVlastimil Babka 18200a477e1aSVlastimil Babka static const char *sysctl_find_alias(char *param) 18210a477e1aSVlastimil Babka { 18220a477e1aSVlastimil Babka const struct sysctl_alias *alias; 18230a477e1aSVlastimil Babka 18240a477e1aSVlastimil Babka for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { 18250a477e1aSVlastimil Babka if (strcmp(alias->kernel_param, param) == 0) 18260a477e1aSVlastimil Babka return alias->sysctl_param; 18270a477e1aSVlastimil Babka } 18280a477e1aSVlastimil Babka 18290a477e1aSVlastimil Babka return NULL; 18300a477e1aSVlastimil Babka } 18310a477e1aSVlastimil Babka 18323db978d4SVlastimil Babka /* Set sysctl value passed on kernel command line. */ 18333db978d4SVlastimil Babka static int process_sysctl_arg(char *param, char *val, 18343db978d4SVlastimil Babka const char *unused, void *arg) 18353db978d4SVlastimil Babka { 18363db978d4SVlastimil Babka char *path; 18373db978d4SVlastimil Babka struct vfsmount **proc_mnt = arg; 18383db978d4SVlastimil Babka struct file_system_type *proc_fs_type; 18393db978d4SVlastimil Babka struct file *file; 18403db978d4SVlastimil Babka int len; 18413db978d4SVlastimil Babka int err; 18423db978d4SVlastimil Babka loff_t pos = 0; 18433db978d4SVlastimil Babka ssize_t wret; 18443db978d4SVlastimil Babka 18450a477e1aSVlastimil Babka if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { 18463db978d4SVlastimil Babka param += sizeof("sysctl") - 1; 18473db978d4SVlastimil Babka 18483db978d4SVlastimil Babka if (param[0] != '/' && param[0] != '.') 18493db978d4SVlastimil Babka return 0; 18503db978d4SVlastimil Babka 18513db978d4SVlastimil Babka param++; 18520a477e1aSVlastimil Babka } else { 18530a477e1aSVlastimil Babka param = (char *) sysctl_find_alias(param); 18540a477e1aSVlastimil Babka if (!param) 18550a477e1aSVlastimil Babka return 0; 18560a477e1aSVlastimil Babka } 18573db978d4SVlastimil Babka 1858697edcb0SXiaoming Ni if (!val) 1859697edcb0SXiaoming Ni return -EINVAL; 1860697edcb0SXiaoming Ni len = strlen(val); 1861697edcb0SXiaoming Ni if (len == 0) 1862697edcb0SXiaoming Ni return -EINVAL; 1863697edcb0SXiaoming Ni 18643db978d4SVlastimil Babka /* 18653db978d4SVlastimil Babka * To set sysctl options, we use a temporary mount of proc, look up the 18663db978d4SVlastimil Babka * respective sys/ file and write to it. To avoid mounting it when no 18673db978d4SVlastimil Babka * options were given, we mount it only when the first sysctl option is 18683db978d4SVlastimil Babka * found. Why not a persistent mount? There are problems with a 18693db978d4SVlastimil Babka * persistent mount of proc in that it forces userspace not to use any 18703db978d4SVlastimil Babka * proc mount options. 18713db978d4SVlastimil Babka */ 18723db978d4SVlastimil Babka if (!*proc_mnt) { 18733db978d4SVlastimil Babka proc_fs_type = get_fs_type("proc"); 18743db978d4SVlastimil Babka if (!proc_fs_type) { 18753db978d4SVlastimil Babka pr_err("Failed to find procfs to set sysctl from command line\n"); 18763db978d4SVlastimil Babka return 0; 18773db978d4SVlastimil Babka } 18783db978d4SVlastimil Babka *proc_mnt = kern_mount(proc_fs_type); 18793db978d4SVlastimil Babka put_filesystem(proc_fs_type); 18803db978d4SVlastimil Babka if (IS_ERR(*proc_mnt)) { 18813db978d4SVlastimil Babka pr_err("Failed to mount procfs to set sysctl from command line\n"); 18823db978d4SVlastimil Babka return 0; 18833db978d4SVlastimil Babka } 18843db978d4SVlastimil Babka } 18853db978d4SVlastimil Babka 18863db978d4SVlastimil Babka path = kasprintf(GFP_KERNEL, "sys/%s", param); 18873db978d4SVlastimil Babka if (!path) 18883db978d4SVlastimil Babka panic("%s: Failed to allocate path for %s\n", __func__, param); 18893db978d4SVlastimil Babka strreplace(path, '.', '/'); 18903db978d4SVlastimil Babka 1891ffb37ca3SAl Viro file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); 18923db978d4SVlastimil Babka if (IS_ERR(file)) { 18933db978d4SVlastimil Babka err = PTR_ERR(file); 18943db978d4SVlastimil Babka if (err == -ENOENT) 18953db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", 18963db978d4SVlastimil Babka param, val); 18973db978d4SVlastimil Babka else if (err == -EACCES) 18983db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", 18993db978d4SVlastimil Babka param, val); 19003db978d4SVlastimil Babka else 19013db978d4SVlastimil Babka pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", 19023db978d4SVlastimil Babka file, param, val); 19033db978d4SVlastimil Babka goto out; 19043db978d4SVlastimil Babka } 19053db978d4SVlastimil Babka wret = kernel_write(file, val, len, &pos); 19063db978d4SVlastimil Babka if (wret < 0) { 19073db978d4SVlastimil Babka err = wret; 19083db978d4SVlastimil Babka if (err == -EINVAL) 19093db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", 19103db978d4SVlastimil Babka param, val); 19113db978d4SVlastimil Babka else 19123db978d4SVlastimil Babka pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", 19133db978d4SVlastimil Babka ERR_PTR(err), param, val); 19143db978d4SVlastimil Babka } else if (wret != len) { 19153db978d4SVlastimil Babka pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", 19163db978d4SVlastimil Babka wret, len, path, param, val); 19173db978d4SVlastimil Babka } 19183db978d4SVlastimil Babka 19193db978d4SVlastimil Babka err = filp_close(file, NULL); 19203db978d4SVlastimil Babka if (err) 19213db978d4SVlastimil Babka pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", 19223db978d4SVlastimil Babka ERR_PTR(err), param, val); 19233db978d4SVlastimil Babka out: 19243db978d4SVlastimil Babka kfree(path); 19253db978d4SVlastimil Babka return 0; 19263db978d4SVlastimil Babka } 19273db978d4SVlastimil Babka 19283db978d4SVlastimil Babka void do_sysctl_args(void) 19293db978d4SVlastimil Babka { 19303db978d4SVlastimil Babka char *command_line; 19313db978d4SVlastimil Babka struct vfsmount *proc_mnt = NULL; 19323db978d4SVlastimil Babka 19333db978d4SVlastimil Babka command_line = kstrdup(saved_command_line, GFP_KERNEL); 19343db978d4SVlastimil Babka if (!command_line) 19353db978d4SVlastimil Babka panic("%s: Failed to allocate copy of command line\n", __func__); 19363db978d4SVlastimil Babka 19373db978d4SVlastimil Babka parse_args("Setting sysctl args", command_line, 19383db978d4SVlastimil Babka NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); 19393db978d4SVlastimil Babka 19403db978d4SVlastimil Babka if (proc_mnt) 19413db978d4SVlastimil Babka kern_unmount(proc_mnt); 19423db978d4SVlastimil Babka 19433db978d4SVlastimil Babka kfree(command_line); 19443db978d4SVlastimil Babka } 1945