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 22*cb55f27aSMeng Tang #define list_for_each_table_entry(entry, table) \ 23*cb55f27aSMeng Tang for ((entry) = (table); (entry)->procname; (entry)++) 24*cb55f27aSMeng 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 31eec4844fSMatteo Croce /* shared constants to be used in various sysctls */ 3254771613SLuis Chamberlain const int sysctl_vals[] = { -1, 0, 1, 2, 4, 100, 200, 1000, 3000, INT_MAX, 65535 }; 33eec4844fSMatteo Croce EXPORT_SYMBOL(sysctl_vals); 34eec4844fSMatteo Croce 35b1f2aff8SLuis Chamberlain const unsigned long sysctl_long_vals[] = { 0, 1, LONG_MAX }; 36b1f2aff8SLuis Chamberlain EXPORT_SYMBOL_GPL(sysctl_long_vals); 37b1f2aff8SLuis Chamberlain 38f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 39f9bd6733SEric W. Biederman 40f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 41f9bd6733SEric W. Biederman { } 42f9bd6733SEric W. Biederman }; 43f9bd6733SEric W. Biederman 44ee9efac4SLuis Chamberlain /** 45ee9efac4SLuis Chamberlain * register_sysctl_mount_point() - registers a sysctl mount point 46ee9efac4SLuis Chamberlain * @path: path for the mount point 47ee9efac4SLuis Chamberlain * 48ee9efac4SLuis Chamberlain * Used to create a permanently empty directory to serve as mount point. 49ee9efac4SLuis Chamberlain * There are some subtle but important permission checks this allows in the 50ee9efac4SLuis Chamberlain * case of unprivileged mounts. 51ee9efac4SLuis Chamberlain */ 52ee9efac4SLuis Chamberlain struct ctl_table_header *register_sysctl_mount_point(const char *path) 53ee9efac4SLuis Chamberlain { 54ee9efac4SLuis Chamberlain return register_sysctl(path, sysctl_mount_point); 55ee9efac4SLuis Chamberlain } 56ee9efac4SLuis Chamberlain EXPORT_SYMBOL(register_sysctl_mount_point); 57ee9efac4SLuis Chamberlain 58f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 59f9bd6733SEric W. Biederman { 60f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 61f9bd6733SEric W. Biederman } 62f9bd6733SEric W. Biederman 63f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 64f9bd6733SEric W. Biederman { 65f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 66f9bd6733SEric W. Biederman } 67f9bd6733SEric W. Biederman 68f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 69f9bd6733SEric W. Biederman 70f9bd6733SEric W. Biederman { 71f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 72f9bd6733SEric W. Biederman } 73f9bd6733SEric W. Biederman 74f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 75f1ecf068SLucas De Marchi { 76f1ecf068SLucas De Marchi if (!poll) 77f1ecf068SLucas De Marchi return; 78f1ecf068SLucas De Marchi 79f1ecf068SLucas De Marchi atomic_inc(&poll->event); 80f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 81f1ecf068SLucas De Marchi } 82f1ecf068SLucas De Marchi 83a194558eSEric W. Biederman static struct ctl_table root_table[] = { 84a194558eSEric W. Biederman { 85a194558eSEric W. Biederman .procname = "", 867ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 87a194558eSEric W. Biederman }, 88a194558eSEric W. Biederman { } 89a194558eSEric W. Biederman }; 900e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 910e47c99dSEric W. Biederman .default_set.dir.header = { 921f87f0b5SEric W. Biederman {{.count = 1, 93938aaa4fSEric W. Biederman .nreg = 1, 94ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 950e47c99dSEric W. Biederman .ctl_table_arg = root_table, 961f87f0b5SEric W. Biederman .root = &sysctl_table_root, 971f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 987ec66d06SEric W. Biederman }, 991f87f0b5SEric W. Biederman }; 1001f87f0b5SEric W. Biederman 1011f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 1021f87f0b5SEric W. Biederman 1037ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 1040e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 10513bcc6a2SEric W. Biederman struct ctl_table **pentry); 1060e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 1070e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 1087ec66d06SEric W. Biederman 1096980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 1106980128fSEric W. Biederman { 1116980128fSEric W. Biederman if (dir->header.parent) 1126980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 11387ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 1146980128fSEric W. Biederman } 1156980128fSEric W. Biederman 116076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 117076c3eedSEric W. Biederman { 118076c3eedSEric W. Biederman int cmp; 119076c3eedSEric W. Biederman 120d8fc9b66SMasahiro Yamada cmp = memcmp(name1, name2, min(len1, len2)); 121076c3eedSEric W. Biederman if (cmp == 0) 122076c3eedSEric W. Biederman cmp = len1 - len2; 123076c3eedSEric W. Biederman return cmp; 124076c3eedSEric W. Biederman } 125076c3eedSEric W. Biederman 12660f126d9SEric W. Biederman /* Called under sysctl_lock */ 127076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1280e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 129076c3eedSEric W. Biederman { 130076c3eedSEric W. Biederman struct ctl_table_header *head; 131076c3eedSEric W. Biederman struct ctl_table *entry; 132ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 133076c3eedSEric W. Biederman 134ac13ac6fSEric W. Biederman while (node) 135ac13ac6fSEric W. Biederman { 136ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 137ac13ac6fSEric W. Biederman const char *procname; 138ac13ac6fSEric W. Biederman int cmp; 139ac13ac6fSEric W. Biederman 140ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 141ac13ac6fSEric W. Biederman head = ctl_node->header; 142ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 143ac13ac6fSEric W. Biederman procname = entry->procname; 144ac13ac6fSEric W. Biederman 145ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 146ac13ac6fSEric W. Biederman if (cmp < 0) 147ac13ac6fSEric W. Biederman node = node->rb_left; 148ac13ac6fSEric W. Biederman else if (cmp > 0) 149ac13ac6fSEric W. Biederman node = node->rb_right; 150ac13ac6fSEric W. Biederman else { 151076c3eedSEric W. Biederman *phead = head; 152076c3eedSEric W. Biederman return entry; 153076c3eedSEric W. Biederman } 154076c3eedSEric W. Biederman } 155076c3eedSEric W. Biederman return NULL; 156076c3eedSEric W. Biederman } 157076c3eedSEric W. Biederman 158ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 159ac13ac6fSEric W. Biederman { 160ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 161ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 162ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 163ac13ac6fSEric W. Biederman const char *name = entry->procname; 164ac13ac6fSEric W. Biederman int namelen = strlen(name); 165ac13ac6fSEric W. Biederman 166ac13ac6fSEric W. Biederman while (*p) { 167ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 168ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 169ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 170ac13ac6fSEric W. Biederman const char *parent_name; 171ac13ac6fSEric W. Biederman int cmp; 172ac13ac6fSEric W. Biederman 173ac13ac6fSEric W. Biederman parent = *p; 174ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 175ac13ac6fSEric W. Biederman parent_head = parent_node->header; 176ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 177ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 178ac13ac6fSEric W. Biederman 179ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 180ac13ac6fSEric W. Biederman if (cmp < 0) 181ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 182ac13ac6fSEric W. Biederman else if (cmp > 0) 183ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 184ac13ac6fSEric W. Biederman else { 18587ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 186ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 187153ee1c4SGeert Uytterhoeven pr_cont("%s\n", entry->procname); 188ac13ac6fSEric W. Biederman return -EEXIST; 189ac13ac6fSEric W. Biederman } 190ac13ac6fSEric W. Biederman } 191ac13ac6fSEric W. Biederman 192ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 193ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 194ac13ac6fSEric W. Biederman return 0; 195ac13ac6fSEric W. Biederman } 196ac13ac6fSEric W. Biederman 197ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 198ac13ac6fSEric W. Biederman { 199ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 200ac13ac6fSEric W. Biederman 201ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 202ac13ac6fSEric W. Biederman } 203ac13ac6fSEric W. Biederman 204e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 205e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 206ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 207e0d04529SEric W. Biederman { 2087ec66d06SEric W. Biederman head->ctl_table = table; 209e0d04529SEric W. Biederman head->ctl_table_arg = table; 210e0d04529SEric W. Biederman head->used = 0; 211e0d04529SEric W. Biederman head->count = 1; 212e0d04529SEric W. Biederman head->nreg = 1; 213e0d04529SEric W. Biederman head->unregistering = NULL; 214e0d04529SEric W. Biederman head->root = root; 215e0d04529SEric W. Biederman head->set = set; 216e0d04529SEric W. Biederman head->parent = NULL; 217ac13ac6fSEric W. Biederman head->node = node; 2182fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 219ac13ac6fSEric W. Biederman if (node) { 220ac13ac6fSEric W. Biederman struct ctl_table *entry; 221*cb55f27aSMeng Tang 222*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 223ac13ac6fSEric W. Biederman node->header = head; 224*cb55f27aSMeng Tang node++; 225*cb55f27aSMeng Tang } 226ac13ac6fSEric W. Biederman } 227ac13ac6fSEric W. Biederman } 228e0d04529SEric W. Biederman 2298425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2308425d6aaSEric W. Biederman { 231ac13ac6fSEric W. Biederman struct ctl_table *entry; 232*cb55f27aSMeng Tang 233*cb55f27aSMeng Tang list_for_each_table_entry(entry, head->ctl_table) 234ac13ac6fSEric W. Biederman erase_entry(head, entry); 2358425d6aaSEric W. Biederman } 2368425d6aaSEric W. Biederman 2370e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2388425d6aaSEric W. Biederman { 239ac13ac6fSEric W. Biederman struct ctl_table *entry; 2400e47c99dSEric W. Biederman int err; 2410e47c99dSEric W. Biederman 242f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 243f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 244f9bd6733SEric W. Biederman return -EROFS; 245f9bd6733SEric W. Biederman 246f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 247f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 248f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 249f9bd6733SEric W. Biederman return -EINVAL; 250f9bd6733SEric W. Biederman set_empty_dir(dir); 251f9bd6733SEric W. Biederman } 252f9bd6733SEric W. Biederman 2530e47c99dSEric W. Biederman dir->header.nreg++; 2547ec66d06SEric W. Biederman header->parent = dir; 2550e47c99dSEric W. Biederman err = insert_links(header); 2560e47c99dSEric W. Biederman if (err) 2570e47c99dSEric W. Biederman goto fail_links; 258*cb55f27aSMeng Tang list_for_each_table_entry(entry, header->ctl_table) { 259ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 260ac13ac6fSEric W. Biederman if (err) 261ac13ac6fSEric W. Biederman goto fail; 262ac13ac6fSEric W. Biederman } 2630e47c99dSEric W. Biederman return 0; 264ac13ac6fSEric W. Biederman fail: 265ac13ac6fSEric W. Biederman erase_header(header); 266ac13ac6fSEric W. Biederman put_links(header); 2670e47c99dSEric W. Biederman fail_links: 268f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 269f9bd6733SEric W. Biederman clear_empty_dir(dir); 2700e47c99dSEric W. Biederman header->parent = NULL; 2710e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2720e47c99dSEric W. Biederman return err; 2738425d6aaSEric W. Biederman } 2748425d6aaSEric W. Biederman 2751f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2761f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2771f87f0b5SEric W. Biederman { 2781f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2791f87f0b5SEric W. Biederman return 0; 2801f87f0b5SEric W. Biederman p->used++; 2811f87f0b5SEric W. Biederman return 1; 2821f87f0b5SEric W. Biederman } 2831f87f0b5SEric W. Biederman 2841f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2851f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2861f87f0b5SEric W. Biederman { 2871f87f0b5SEric W. Biederman if (!--p->used) 2881f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2891f87f0b5SEric W. Biederman complete(p->unregistering); 2901f87f0b5SEric W. Biederman } 2911f87f0b5SEric W. Biederman 292f90f3cafSEric W. Biederman static void proc_sys_invalidate_dcache(struct ctl_table_header *head) 293d6cffbbeSKonstantin Khlebnikov { 294f90f3cafSEric W. Biederman proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); 295d6cffbbeSKonstantin Khlebnikov } 296d6cffbbeSKonstantin Khlebnikov 2971f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2981f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2991f87f0b5SEric W. Biederman { 3001f87f0b5SEric W. Biederman /* 3011f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 3021f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 3031f87f0b5SEric W. Biederman */ 3041f87f0b5SEric W. Biederman if (unlikely(p->used)) { 3051f87f0b5SEric W. Biederman struct completion wait; 3061f87f0b5SEric W. Biederman init_completion(&wait); 3071f87f0b5SEric W. Biederman p->unregistering = &wait; 3081f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3091f87f0b5SEric W. Biederman wait_for_completion(&wait); 3101f87f0b5SEric W. Biederman } else { 3111f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3121f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 313ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3141f87f0b5SEric W. Biederman } 3151f87f0b5SEric W. Biederman /* 316f90f3cafSEric W. Biederman * Invalidate dentries for unregistered sysctls: namespaced sysctls 317d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 318d6cffbbeSKonstantin Khlebnikov */ 319f90f3cafSEric W. Biederman proc_sys_invalidate_dcache(p); 320d6cffbbeSKonstantin Khlebnikov /* 3211f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3221f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3231f87f0b5SEric W. Biederman */ 324ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3258425d6aaSEric W. Biederman erase_header(p); 3261f87f0b5SEric W. Biederman } 3271f87f0b5SEric W. Biederman 3281f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3291f87f0b5SEric W. Biederman { 330ab4a1f24SPrasad Joshi BUG_ON(!head); 3311f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3321f87f0b5SEric W. Biederman if (!use_table(head)) 3331f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3341f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3351f87f0b5SEric W. Biederman return head; 3361f87f0b5SEric W. Biederman } 3371f87f0b5SEric W. Biederman 3381f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3391f87f0b5SEric W. Biederman { 3401f87f0b5SEric W. Biederman if (!head) 3411f87f0b5SEric W. Biederman return; 3421f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3431f87f0b5SEric W. Biederman unuse_table(head); 3441f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3451f87f0b5SEric W. Biederman } 3461f87f0b5SEric W. Biederman 3471f87f0b5SEric W. Biederman static struct ctl_table_set * 34813bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3491f87f0b5SEric W. Biederman { 3501f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3511f87f0b5SEric W. Biederman if (root->lookup) 35213bcc6a2SEric W. Biederman set = root->lookup(root); 3531f87f0b5SEric W. Biederman return set; 3541f87f0b5SEric W. Biederman } 3551f87f0b5SEric W. Biederman 356076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3577ec66d06SEric W. Biederman struct ctl_dir *dir, 358076c3eedSEric W. Biederman const char *name, int namelen) 359076c3eedSEric W. Biederman { 360076c3eedSEric W. Biederman struct ctl_table_header *head; 361076c3eedSEric W. Biederman struct ctl_table *entry; 362076c3eedSEric W. Biederman 363076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3640e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 365076c3eedSEric W. Biederman if (entry && use_table(head)) 366076c3eedSEric W. Biederman *phead = head; 367076c3eedSEric W. Biederman else 368076c3eedSEric W. Biederman entry = NULL; 369076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 370076c3eedSEric W. Biederman return entry; 371076c3eedSEric W. Biederman } 372076c3eedSEric W. Biederman 373ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3741f87f0b5SEric W. Biederman { 375ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3761f87f0b5SEric W. Biederman 377ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 378ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 379ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 380ac13ac6fSEric W. Biederman return ctl_node; 3811f87f0b5SEric W. Biederman } 3821f87f0b5SEric W. Biederman return NULL; 3831f87f0b5SEric W. Biederman } 3841f87f0b5SEric W. Biederman 3857ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3866a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3871f87f0b5SEric W. Biederman { 388ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3897ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 390ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3916a75ce16SEric W. Biederman 3926a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 393ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3946a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 395ac13ac6fSEric W. Biederman if (ctl_node) { 396ac13ac6fSEric W. Biederman head = ctl_node->header; 397ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 398ac13ac6fSEric W. Biederman } 3996a75ce16SEric W. Biederman *phead = head; 4006a75ce16SEric W. Biederman *pentry = entry; 4016a75ce16SEric W. Biederman } 4026a75ce16SEric W. Biederman 4037ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 4046a75ce16SEric W. Biederman { 4056a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 4066a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 407ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4086a75ce16SEric W. Biederman 4096a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4106a75ce16SEric W. Biederman unuse_table(head); 411ac13ac6fSEric W. Biederman 412ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4136a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 414ac13ac6fSEric W. Biederman head = NULL; 415ac13ac6fSEric W. Biederman if (ctl_node) { 416ac13ac6fSEric W. Biederman head = ctl_node->header; 417ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4186a75ce16SEric W. Biederman } 4196a75ce16SEric W. Biederman *phead = head; 4206a75ce16SEric W. Biederman *pentry = entry; 4211f87f0b5SEric W. Biederman } 4221f87f0b5SEric W. Biederman 4231f87f0b5SEric W. Biederman /* 4241f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4251f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4261f87f0b5SEric W. Biederman */ 4271f87f0b5SEric W. Biederman 4281f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4291f87f0b5SEric W. Biederman { 430091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4311f87f0b5SEric W. Biederman mode >>= 6; 432091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4331f87f0b5SEric W. Biederman mode >>= 3; 4341f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4351f87f0b5SEric W. Biederman return 0; 4361f87f0b5SEric W. Biederman return -EACCES; 4371f87f0b5SEric W. Biederman } 4381f87f0b5SEric W. Biederman 43973f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4401f87f0b5SEric W. Biederman { 44173f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4421f87f0b5SEric W. Biederman int mode; 4431f87f0b5SEric W. Biederman 4441f87f0b5SEric W. Biederman if (root->permissions) 44573f7ef43SEric W. Biederman mode = root->permissions(head, table); 4461f87f0b5SEric W. Biederman else 4471f87f0b5SEric W. Biederman mode = table->mode; 4481f87f0b5SEric W. Biederman 4491f87f0b5SEric W. Biederman return test_perm(mode, op); 4501f87f0b5SEric W. Biederman } 4511f87f0b5SEric W. Biederman 4529043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4539043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 45477b14db5SEric W. Biederman { 455e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 45677b14db5SEric W. Biederman struct inode *inode; 4579043476fSAl Viro struct proc_inode *ei; 45877b14db5SEric W. Biederman 4599043476fSAl Viro inode = new_inode(sb); 46077b14db5SEric W. Biederman if (!inode) 461ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 46277b14db5SEric W. Biederman 46385fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 46485fe4025SChristoph Hellwig 46577b14db5SEric W. Biederman ei = PROC_I(inode); 4669043476fSAl Viro 467d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 468ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 469ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 470ace0c791SEric W. Biederman iput(inode); 471ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 472ace0c791SEric W. Biederman } 473ace0c791SEric W. Biederman ei->sysctl = head; 474ace0c791SEric W. Biederman ei->sysctl_entry = table; 4750afa5ca8SEric W. Biederman hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); 476d6cffbbeSKonstantin Khlebnikov head->count++; 477d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 478d6cffbbeSKonstantin Khlebnikov 479078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4809043476fSAl Viro inode->i_mode = table->mode; 4817ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4829043476fSAl Viro inode->i_mode |= S_IFREG; 48377b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 48477b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4859043476fSAl Viro } else { 4869043476fSAl Viro inode->i_mode |= S_IFDIR; 4879043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4889043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 489f9bd6733SEric W. Biederman if (is_empty_dir(head)) 490f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4919043476fSAl Viro } 492e79c6a4fSDmitry Torokhov 493e79c6a4fSDmitry Torokhov if (root->set_ownership) 494e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 4955ec27ec7SRadoslaw Burny else { 4965ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 4975ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 4985ec27ec7SRadoslaw Burny } 499e79c6a4fSDmitry Torokhov 50077b14db5SEric W. Biederman return inode; 50177b14db5SEric W. Biederman } 50277b14db5SEric W. Biederman 503d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 504d6cffbbeSKonstantin Khlebnikov { 505d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 5060afa5ca8SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); 507d6cffbbeSKonstantin Khlebnikov if (!--head->count) 508d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 509d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 510d6cffbbeSKonstantin Khlebnikov } 511d6cffbbeSKonstantin Khlebnikov 51281324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 51377b14db5SEric W. Biederman { 5143cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5153cc3e046SEric W. Biederman if (!head) 5160e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5173cc3e046SEric W. Biederman return sysctl_head_grab(head); 51877b14db5SEric W. Biederman } 51977b14db5SEric W. Biederman 52077b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 52100cd8dd3SAl Viro unsigned int flags) 52277b14db5SEric W. Biederman { 5239043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5249043476fSAl Viro struct ctl_table_header *h = NULL; 525dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5269043476fSAl Viro struct ctl_table *p; 52777b14db5SEric W. Biederman struct inode *inode; 5289043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5297ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5300e47c99dSEric W. Biederman int ret; 53177b14db5SEric W. Biederman 5329043476fSAl Viro if (IS_ERR(head)) 5339043476fSAl Viro return ERR_CAST(head); 5349043476fSAl Viro 5357ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5369043476fSAl Viro 5377ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5389043476fSAl Viro if (!p) 53977b14db5SEric W. Biederman goto out; 54077b14db5SEric W. Biederman 5414e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 54213bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5430e47c99dSEric W. Biederman err = ERR_PTR(ret); 5440e47c99dSEric W. Biederman if (ret) 5450e47c99dSEric W. Biederman goto out; 5464e757320SEric W. Biederman } 5470e47c99dSEric W. Biederman 5489043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 549ea5751ccSIvan Delalande if (IS_ERR(inode)) { 550ea5751ccSIvan Delalande err = ERR_CAST(inode); 55177b14db5SEric W. Biederman goto out; 552ea5751ccSIvan Delalande } 55377b14db5SEric W. Biederman 554fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 555888e2b03SAl Viro err = d_splice_alias(inode, dentry); 55677b14db5SEric W. Biederman 55777b14db5SEric W. Biederman out: 5586bf61045SFrancesco Ruggeri if (h) 5596bf61045SFrancesco Ruggeri sysctl_head_finish(h); 56077b14db5SEric W. Biederman sysctl_head_finish(head); 56177b14db5SEric W. Biederman return err; 56277b14db5SEric W. Biederman } 56377b14db5SEric W. Biederman 5644bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, 5654bd6a735SMatthew Wilcox (Oracle) int write) 56677b14db5SEric W. Biederman { 5674bd6a735SMatthew Wilcox (Oracle) struct inode *inode = file_inode(iocb->ki_filp); 5689043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5699043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5704bd6a735SMatthew Wilcox (Oracle) size_t count = iov_iter_count(iter); 5714bd6a735SMatthew Wilcox (Oracle) char *kbuf; 5722a2da53bSDavid Howells ssize_t error; 57377b14db5SEric W. Biederman 5749043476fSAl Viro if (IS_ERR(head)) 5759043476fSAl Viro return PTR_ERR(head); 57677b14db5SEric W. Biederman 57777b14db5SEric W. Biederman /* 57877b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 57977b14db5SEric W. Biederman * and won't be until we finish. 58077b14db5SEric W. Biederman */ 58177b14db5SEric W. Biederman error = -EPERM; 58273f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 58377b14db5SEric W. Biederman goto out; 58477b14db5SEric W. Biederman 5859043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5869043476fSAl Viro error = -EINVAL; 5879043476fSAl Viro if (!table->proc_handler) 5889043476fSAl Viro goto out; 5899043476fSAl Viro 590ef9d965bSChristoph Hellwig /* don't even try if the size is too large */ 591d4d80e69SMatthew Wilcox (Oracle) error = -ENOMEM; 592d4d80e69SMatthew Wilcox (Oracle) if (count >= KMALLOC_MAX_SIZE) 593d4d80e69SMatthew Wilcox (Oracle) goto out; 59445089437SJosef Bacik kbuf = kvzalloc(count + 1, GFP_KERNEL); 59532927393SChristoph Hellwig if (!kbuf) 59632927393SChristoph Hellwig goto out; 5974bd6a735SMatthew Wilcox (Oracle) 5984bd6a735SMatthew Wilcox (Oracle) if (write) { 5994bd6a735SMatthew Wilcox (Oracle) error = -EFAULT; 6004bd6a735SMatthew Wilcox (Oracle) if (!copy_from_iter_full(kbuf, count, iter)) 6014bd6a735SMatthew Wilcox (Oracle) goto out_free_buf; 6024bd6a735SMatthew Wilcox (Oracle) kbuf[count] = '\0'; 6034e63acdfSAndrey Ignatov } 6044e63acdfSAndrey Ignatov 60532927393SChristoph Hellwig error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, 6064bd6a735SMatthew Wilcox (Oracle) &iocb->ki_pos); 60732927393SChristoph Hellwig if (error) 60832927393SChristoph Hellwig goto out_free_buf; 60932927393SChristoph Hellwig 61032927393SChristoph Hellwig /* careful: calling conventions are nasty here */ 6114bd6a735SMatthew Wilcox (Oracle) error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); 61232927393SChristoph Hellwig if (error) 61332927393SChristoph Hellwig goto out_free_buf; 61432927393SChristoph Hellwig 61532927393SChristoph Hellwig if (!write) { 61632927393SChristoph Hellwig error = -EFAULT; 6174bd6a735SMatthew Wilcox (Oracle) if (copy_to_iter(kbuf, count, iter) < count) 61832927393SChristoph Hellwig goto out_free_buf; 61932927393SChristoph Hellwig } 62032927393SChristoph Hellwig 6214e63acdfSAndrey Ignatov error = count; 62232927393SChristoph Hellwig out_free_buf: 62345089437SJosef Bacik kvfree(kbuf); 62477b14db5SEric W. Biederman out: 62577b14db5SEric W. Biederman sysctl_head_finish(head); 62677b14db5SEric W. Biederman 62777b14db5SEric W. Biederman return error; 62877b14db5SEric W. Biederman } 62977b14db5SEric W. Biederman 6304bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) 6317708bfb1SPavel Emelyanov { 6324bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 0); 6337708bfb1SPavel Emelyanov } 6347708bfb1SPavel Emelyanov 6354bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) 63677b14db5SEric W. Biederman { 6374bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 1); 63877b14db5SEric W. Biederman } 63977b14db5SEric W. Biederman 640f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 641f1ecf068SLucas De Marchi { 6424e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 643f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 644f1ecf068SLucas De Marchi 6454e474a00SLucas De Marchi /* sysctl was unregistered */ 6464e474a00SLucas De Marchi if (IS_ERR(head)) 6474e474a00SLucas De Marchi return PTR_ERR(head); 6484e474a00SLucas De Marchi 649f1ecf068SLucas De Marchi if (table->poll) 650f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 651f1ecf068SLucas De Marchi 6524e474a00SLucas De Marchi sysctl_head_finish(head); 6534e474a00SLucas De Marchi 654f1ecf068SLucas De Marchi return 0; 655f1ecf068SLucas De Marchi } 656f1ecf068SLucas De Marchi 657076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 658f1ecf068SLucas De Marchi { 659496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6604e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 661f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 662076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6634e474a00SLucas De Marchi unsigned long event; 6644e474a00SLucas De Marchi 6654e474a00SLucas De Marchi /* sysctl was unregistered */ 6664e474a00SLucas De Marchi if (IS_ERR(head)) 667a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 668f1ecf068SLucas De Marchi 669f1ecf068SLucas De Marchi if (!table->proc_handler) 670f1ecf068SLucas De Marchi goto out; 671f1ecf068SLucas De Marchi 672f1ecf068SLucas De Marchi if (!table->poll) 673f1ecf068SLucas De Marchi goto out; 674f1ecf068SLucas De Marchi 6754e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 676f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 677f1ecf068SLucas De Marchi 678f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 679f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 680a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 681f1ecf068SLucas De Marchi } 682f1ecf068SLucas De Marchi 683f1ecf068SLucas De Marchi out: 6844e474a00SLucas De Marchi sysctl_head_finish(head); 6854e474a00SLucas De Marchi 686f1ecf068SLucas De Marchi return ret; 687f1ecf068SLucas De Marchi } 68877b14db5SEric W. Biederman 689f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 690f0c3b509SAl Viro struct dir_context *ctx, 6919043476fSAl Viro struct ctl_table_header *head, 6929043476fSAl Viro struct ctl_table *table) 69377b14db5SEric W. Biederman { 694f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 69577b14db5SEric W. Biederman struct inode *inode; 69677b14db5SEric W. Biederman struct qstr qname; 69777b14db5SEric W. Biederman ino_t ino = 0; 69877b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 69977b14db5SEric W. Biederman 70077b14db5SEric W. Biederman qname.name = table->procname; 70177b14db5SEric W. Biederman qname.len = strlen(table->procname); 7028387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 70377b14db5SEric W. Biederman 70477b14db5SEric W. Biederman child = d_lookup(dir, &qname); 70577b14db5SEric W. Biederman if (!child) { 70676aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 70776aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 70876aab3abSAl Viro if (IS_ERR(child)) 70976aab3abSAl Viro return false; 71076aab3abSAl Viro if (d_in_lookup(child)) { 711888e2b03SAl Viro struct dentry *res; 7129043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 713ea5751ccSIvan Delalande if (IS_ERR(inode)) { 71476aab3abSAl Viro d_lookup_done(child); 7159043476fSAl Viro dput(child); 716f0c3b509SAl Viro return false; 71776aab3abSAl Viro } 718fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 719888e2b03SAl Viro res = d_splice_alias(inode, child); 720888e2b03SAl Viro d_lookup_done(child); 721888e2b03SAl Viro if (unlikely(res)) { 722888e2b03SAl Viro if (IS_ERR(res)) { 723888e2b03SAl Viro dput(child); 724888e2b03SAl Viro return false; 725888e2b03SAl Viro } 726888e2b03SAl Viro dput(child); 727888e2b03SAl Viro child = res; 728888e2b03SAl Viro } 72977b14db5SEric W. Biederman } 73077b14db5SEric W. Biederman } 7312b0143b5SDavid Howells inode = d_inode(child); 73277b14db5SEric W. Biederman ino = inode->i_ino; 73377b14db5SEric W. Biederman type = inode->i_mode >> 12; 73477b14db5SEric W. Biederman dput(child); 735f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7369043476fSAl Viro } 7379043476fSAl Viro 738f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 739f0c3b509SAl Viro struct dir_context *ctx, 7400e47c99dSEric W. Biederman struct ctl_table_header *head, 7410e47c99dSEric W. Biederman struct ctl_table *table) 7420e47c99dSEric W. Biederman { 743f0c3b509SAl Viro bool ret = true; 744a0b0d1c3SDanilo Krummrich 7450e47c99dSEric W. Biederman head = sysctl_head_grab(head); 746a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 747a0b0d1c3SDanilo Krummrich return false; 7480e47c99dSEric W. Biederman 7490e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 750835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7510e47c99dSEric W. Biederman goto out; 7520e47c99dSEric W. Biederman 753f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7540e47c99dSEric W. Biederman out: 7550e47c99dSEric W. Biederman sysctl_head_finish(head); 7560e47c99dSEric W. Biederman return ret; 7570e47c99dSEric W. Biederman } 7580e47c99dSEric W. Biederman 759e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7609043476fSAl Viro unsigned long *pos, struct file *file, 761f0c3b509SAl Viro struct dir_context *ctx) 7629043476fSAl Viro { 763f0c3b509SAl Viro bool res; 7649043476fSAl Viro 765f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 766f0c3b509SAl Viro return true; 7679043476fSAl Viro 7680e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 769f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7700e47c99dSEric W. Biederman else 771f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7729043476fSAl Viro 773f0c3b509SAl Viro if (res) 774f0c3b509SAl Viro ctx->pos = *pos; 7756a75ce16SEric W. Biederman 7766a75ce16SEric W. Biederman return res; 77777b14db5SEric W. Biederman } 77877b14db5SEric W. Biederman 779f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 78077b14db5SEric W. Biederman { 781f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7829043476fSAl Viro struct ctl_table_header *h = NULL; 7836a75ce16SEric W. Biederman struct ctl_table *entry; 7847ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 78577b14db5SEric W. Biederman unsigned long pos; 78677b14db5SEric W. Biederman 7879043476fSAl Viro if (IS_ERR(head)) 7889043476fSAl Viro return PTR_ERR(head); 7899043476fSAl Viro 7907ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 79177b14db5SEric W. Biederman 792f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 79393362fa4SZhou Chengming goto out; 794f0c3b509SAl Viro 79577b14db5SEric W. Biederman pos = 2; 79677b14db5SEric W. Biederman 7977ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 798f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7999043476fSAl Viro sysctl_head_finish(h); 8009043476fSAl Viro break; 80177b14db5SEric W. Biederman } 80277b14db5SEric W. Biederman } 80393362fa4SZhou Chengming out: 80477b14db5SEric W. Biederman sysctl_head_finish(head); 805f0c3b509SAl Viro return 0; 80677b14db5SEric W. Biederman } 80777b14db5SEric W. Biederman 808549c7297SChristian Brauner static int proc_sys_permission(struct user_namespace *mnt_userns, 809549c7297SChristian Brauner struct inode *inode, int mask) 81077b14db5SEric W. Biederman { 81177b14db5SEric W. Biederman /* 81277b14db5SEric W. Biederman * sysctl entries that are not writeable, 81377b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 81477b14db5SEric W. Biederman */ 815f696a365SMiklos Szeredi struct ctl_table_header *head; 816f696a365SMiklos Szeredi struct ctl_table *table; 81777b14db5SEric W. Biederman int error; 81877b14db5SEric W. Biederman 819f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 820f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 821f696a365SMiklos Szeredi return -EACCES; 822f696a365SMiklos Szeredi 823f696a365SMiklos Szeredi head = grab_header(inode); 8249043476fSAl Viro if (IS_ERR(head)) 8259043476fSAl Viro return PTR_ERR(head); 82677b14db5SEric W. Biederman 827f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8289043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8299043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8309043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 83173f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8329043476fSAl Viro 83377b14db5SEric W. Biederman sysctl_head_finish(head); 83477b14db5SEric W. Biederman return error; 83577b14db5SEric W. Biederman } 83677b14db5SEric W. Biederman 837549c7297SChristian Brauner static int proc_sys_setattr(struct user_namespace *mnt_userns, 838549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr) 83977b14db5SEric W. Biederman { 8402b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 84177b14db5SEric W. Biederman int error; 84277b14db5SEric W. Biederman 84377b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 84477b14db5SEric W. Biederman return -EPERM; 84577b14db5SEric W. Biederman 8462f221d6fSChristian Brauner error = setattr_prepare(&init_user_ns, dentry, attr); 8471025774cSChristoph Hellwig if (error) 84877b14db5SEric W. Biederman return error; 8491025774cSChristoph Hellwig 8502f221d6fSChristian Brauner setattr_copy(&init_user_ns, inode, attr); 8511025774cSChristoph Hellwig mark_inode_dirty(inode); 8521025774cSChristoph Hellwig return 0; 85377b14db5SEric W. Biederman } 85477b14db5SEric W. Biederman 855549c7297SChristian Brauner static int proc_sys_getattr(struct user_namespace *mnt_userns, 856549c7297SChristian Brauner const struct path *path, struct kstat *stat, 857a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8589043476fSAl Viro { 859a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8609043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8619043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8629043476fSAl Viro 8639043476fSAl Viro if (IS_ERR(head)) 8649043476fSAl Viro return PTR_ERR(head); 8659043476fSAl Viro 8660d56a451SChristian Brauner generic_fillattr(&init_user_ns, inode, stat); 8679043476fSAl Viro if (table) 8689043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8699043476fSAl Viro 8709043476fSAl Viro sysctl_head_finish(head); 8719043476fSAl Viro return 0; 8729043476fSAl Viro } 8739043476fSAl Viro 87477b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 875f1ecf068SLucas De Marchi .open = proc_sys_open, 876f1ecf068SLucas De Marchi .poll = proc_sys_poll, 8774bd6a735SMatthew Wilcox (Oracle) .read_iter = proc_sys_read, 8784bd6a735SMatthew Wilcox (Oracle) .write_iter = proc_sys_write, 8794bd6a735SMatthew Wilcox (Oracle) .splice_read = generic_file_splice_read, 8804bd6a735SMatthew Wilcox (Oracle) .splice_write = iter_file_splice_write, 8816038f373SArnd Bergmann .llseek = default_llseek, 8829043476fSAl Viro }; 8839043476fSAl Viro 8849043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 885887df078SPavel Emelyanov .read = generic_read_dir, 886f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8873222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 88877b14db5SEric W. Biederman }; 88977b14db5SEric W. Biederman 89003a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8919043476fSAl Viro .permission = proc_sys_permission, 8929043476fSAl Viro .setattr = proc_sys_setattr, 8939043476fSAl Viro .getattr = proc_sys_getattr, 8949043476fSAl Viro }; 8959043476fSAl Viro 8969043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 89777b14db5SEric W. Biederman .lookup = proc_sys_lookup, 89877b14db5SEric W. Biederman .permission = proc_sys_permission, 89977b14db5SEric W. Biederman .setattr = proc_sys_setattr, 9009043476fSAl Viro .getattr = proc_sys_getattr, 90177b14db5SEric W. Biederman }; 90277b14db5SEric W. Biederman 9030b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 90477b14db5SEric W. Biederman { 9050b728e19SAl Viro if (flags & LOOKUP_RCU) 90634286d66SNick Piggin return -ECHILD; 9072b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 9089043476fSAl Viro } 9099043476fSAl Viro 910fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 9119043476fSAl Viro { 9122b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 9139043476fSAl Viro } 9149043476fSAl Viro 9151f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 9161f87f0b5SEric W. Biederman { 9171f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 9181f87f0b5SEric W. Biederman int res; 9191f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 9201f87f0b5SEric W. Biederman if (p->unregistering) 9211f87f0b5SEric W. Biederman res = 0; 9221f87f0b5SEric W. Biederman else if (!set->is_seen) 9231f87f0b5SEric W. Biederman res = 1; 9241f87f0b5SEric W. Biederman else 9251f87f0b5SEric W. Biederman res = set->is_seen(set); 9261f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9271f87f0b5SEric W. Biederman return res; 9281f87f0b5SEric W. Biederman } 9291f87f0b5SEric W. Biederman 9306fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 931621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9329043476fSAl Viro { 933dfef6dcdSAl Viro struct ctl_table_header *head; 934da53be12SLinus Torvalds struct inode *inode; 935da53be12SLinus Torvalds 93631e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 93731e6b01fSNick Piggin * that inode here can be NULL */ 938dfef6dcdSAl Viro /* AV: can it, indeed? */ 9392b0143b5SDavid Howells inode = d_inode_rcu(dentry); 94031e6b01fSNick Piggin if (!inode) 941dfef6dcdSAl Viro return 1; 942621e155aSNick Piggin if (name->len != len) 9439043476fSAl Viro return 1; 944621e155aSNick Piggin if (memcmp(name->name, str, len)) 9459043476fSAl Viro return 1; 946dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 947dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 94877b14db5SEric W. Biederman } 94977b14db5SEric W. Biederman 950d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 95177b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9529043476fSAl Viro .d_delete = proc_sys_delete, 9539043476fSAl Viro .d_compare = proc_sys_compare, 95477b14db5SEric W. Biederman }; 95577b14db5SEric W. Biederman 9560e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9577ec66d06SEric W. Biederman const char *name, int namelen) 9581f87f0b5SEric W. Biederman { 9597ec66d06SEric W. Biederman struct ctl_table_header *head; 9607ec66d06SEric W. Biederman struct ctl_table *entry; 9611f87f0b5SEric W. Biederman 9620e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9637ec66d06SEric W. Biederman if (!entry) 9647ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 96551f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9667ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 96751f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9681f87f0b5SEric W. Biederman } 9691f87f0b5SEric W. Biederman 9707ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9717ec66d06SEric W. Biederman const char *name, int namelen) 9721f87f0b5SEric W. Biederman { 9737ec66d06SEric W. Biederman struct ctl_table *table; 9747ec66d06SEric W. Biederman struct ctl_dir *new; 975ac13ac6fSEric W. Biederman struct ctl_node *node; 9767ec66d06SEric W. Biederman char *new_name; 9771f87f0b5SEric W. Biederman 978ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 979ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 980ac13ac6fSEric W. Biederman GFP_KERNEL); 9817ec66d06SEric W. Biederman if (!new) 9827ec66d06SEric W. Biederman return NULL; 9837ec66d06SEric W. Biederman 984ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 985ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9867ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9877ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9887ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9897ec66d06SEric W. Biederman table[0].procname = new_name; 9907ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 991ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9927ec66d06SEric W. Biederman 9937ec66d06SEric W. Biederman return new; 9941f87f0b5SEric W. Biederman } 9951f87f0b5SEric W. Biederman 99660f126d9SEric W. Biederman /** 99760f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 99860f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 99960f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 100060f126d9SEric W. Biederman * @namelen: The length of name 100160f126d9SEric W. Biederman * 100260f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 100360f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 100460f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 100560f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 100660f126d9SEric W. Biederman * simply dropped. 100760f126d9SEric W. Biederman */ 10080e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 10090e47c99dSEric W. Biederman const char *name, int namelen) 10107ec66d06SEric W. Biederman { 10110e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 10127ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 10130eb97f38SEric W. Biederman int err; 10147ec66d06SEric W. Biederman 10157ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10160e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10177ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10187ec66d06SEric W. Biederman goto found; 10197ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10207ec66d06SEric W. Biederman goto failed; 10217ec66d06SEric W. Biederman 10227ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10237ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 10247ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10257ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10267ec66d06SEric W. Biederman if (!new) 10277ec66d06SEric W. Biederman goto failed; 10287ec66d06SEric W. Biederman 102960f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 10300e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10317ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10327ec66d06SEric W. Biederman goto found; 10337ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10347ec66d06SEric W. Biederman goto failed; 10357ec66d06SEric W. Biederman 103660f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10370eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10380eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10390eb97f38SEric W. Biederman if (err) 10400e47c99dSEric W. Biederman goto failed; 10417ec66d06SEric W. Biederman subdir = new; 10427ec66d06SEric W. Biederman found: 10437ec66d06SEric W. Biederman subdir->header.nreg++; 10447ec66d06SEric W. Biederman failed: 1045a1c83681SViresh Kumar if (IS_ERR(subdir)) { 104687ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10476980128fSEric W. Biederman sysctl_print_dir(dir); 1048153ee1c4SGeert Uytterhoeven pr_cont("%*.*s %ld\n", namelen, namelen, name, 1049153ee1c4SGeert Uytterhoeven PTR_ERR(subdir)); 10501f87f0b5SEric W. Biederman } 10517ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10527ec66d06SEric W. Biederman if (new) 10537ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10547ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10557ec66d06SEric W. Biederman return subdir; 10561f87f0b5SEric W. Biederman } 10571f87f0b5SEric W. Biederman 10580e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10590e47c99dSEric W. Biederman { 10600e47c99dSEric W. Biederman struct ctl_dir *parent; 10610e47c99dSEric W. Biederman const char *procname; 10620e47c99dSEric W. Biederman if (!dir->header.parent) 10630e47c99dSEric W. Biederman return &set->dir; 10640e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10650e47c99dSEric W. Biederman if (IS_ERR(parent)) 10660e47c99dSEric W. Biederman return parent; 10670e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10680e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10690e47c99dSEric W. Biederman } 10700e47c99dSEric W. Biederman 10710e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 107213bcc6a2SEric W. Biederman struct ctl_table **pentry) 10730e47c99dSEric W. Biederman { 10740e47c99dSEric W. Biederman struct ctl_table_header *head; 10750e47c99dSEric W. Biederman struct ctl_table_root *root; 10760e47c99dSEric W. Biederman struct ctl_table_set *set; 10770e47c99dSEric W. Biederman struct ctl_table *entry; 10780e47c99dSEric W. Biederman struct ctl_dir *dir; 10790e47c99dSEric W. Biederman int ret; 10800e47c99dSEric W. Biederman 10810e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10820e47c99dSEric W. Biederman root = (*pentry)->data; 108313bcc6a2SEric W. Biederman set = lookup_header_set(root); 10840e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10850e47c99dSEric W. Biederman if (IS_ERR(dir)) 10860e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10870e47c99dSEric W. Biederman else { 10880e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10890e47c99dSEric W. Biederman head = NULL; 10900e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10910e47c99dSEric W. Biederman ret = -ENOENT; 10920e47c99dSEric W. Biederman if (entry && use_table(head)) { 10930e47c99dSEric W. Biederman unuse_table(*phead); 10940e47c99dSEric W. Biederman *phead = head; 10950e47c99dSEric W. Biederman *pentry = entry; 10960e47c99dSEric W. Biederman ret = 0; 10970e47c99dSEric W. Biederman } 10980e47c99dSEric W. Biederman } 10990e47c99dSEric W. Biederman 11000e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 11010e47c99dSEric W. Biederman return ret; 11020e47c99dSEric W. Biederman } 11030e47c99dSEric W. Biederman 11047c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 11057c60c48fSEric W. Biederman { 11067c60c48fSEric W. Biederman struct va_format vaf; 11077c60c48fSEric W. Biederman va_list args; 11087c60c48fSEric W. Biederman 11097c60c48fSEric W. Biederman va_start(args, fmt); 11107c60c48fSEric W. Biederman vaf.fmt = fmt; 11117c60c48fSEric W. Biederman vaf.va = &args; 11127c60c48fSEric W. Biederman 111387ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 11147c60c48fSEric W. Biederman path, table->procname, &vaf); 11157c60c48fSEric W. Biederman 11167c60c48fSEric W. Biederman va_end(args); 11177c60c48fSEric W. Biederman return -EINVAL; 11187c60c48fSEric W. Biederman } 11197c60c48fSEric W. Biederman 11204f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 11214f2fec00SLuis R. Rodriguez { 11224f2fec00SLuis R. Rodriguez int err = 0; 11234f2fec00SLuis R. Rodriguez 112461d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 112561d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11264f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 112764a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11284f2fec00SLuis R. Rodriguez } 11294f2fec00SLuis R. Rodriguez 1130cb944413SEric Dumazet if (table->proc_handler == proc_dou8vec_minmax) { 1131cb944413SEric Dumazet if (table->maxlen != sizeof(u8)) 1132cb944413SEric Dumazet err |= sysctl_err(path, table, "array not allowed"); 1133cb944413SEric Dumazet } 1134cb944413SEric Dumazet 11354f2fec00SLuis R. Rodriguez return err; 11364f2fec00SLuis R. Rodriguez } 11374f2fec00SLuis R. Rodriguez 11387c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11397c60c48fSEric W. Biederman { 1140*cb55f27aSMeng Tang struct ctl_table *entry; 11417c60c48fSEric W. Biederman int err = 0; 1142*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1143*cb55f27aSMeng Tang if (entry->child) 1144*cb55f27aSMeng Tang err |= sysctl_err(path, entry, "Not a file"); 11457c60c48fSEric W. Biederman 1146*cb55f27aSMeng Tang if ((entry->proc_handler == proc_dostring) || 1147*cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec) || 1148*cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec) || 1149*cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec_minmax) || 1150*cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_minmax) || 1151*cb55f27aSMeng Tang (entry->proc_handler == proc_dou8vec_minmax) || 1152*cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_jiffies) || 1153*cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_userhz_jiffies) || 1154*cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_ms_jiffies) || 1155*cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_minmax) || 1156*cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 1157*cb55f27aSMeng Tang if (!entry->data) 1158*cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No data"); 1159*cb55f27aSMeng Tang if (!entry->maxlen) 1160*cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No maxlen"); 11614f2fec00SLuis R. Rodriguez else 1162*cb55f27aSMeng Tang err |= sysctl_check_table_array(path, entry); 11631f87f0b5SEric W. Biederman } 1164*cb55f27aSMeng Tang if (!entry->proc_handler) 1165*cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No proc_handler"); 11667c60c48fSEric W. Biederman 1167*cb55f27aSMeng Tang if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode) 1168*cb55f27aSMeng Tang err |= sysctl_err(path, entry, "bogus .mode 0%o", 1169*cb55f27aSMeng Tang entry->mode); 11701f87f0b5SEric W. Biederman } 11717c60c48fSEric W. Biederman return err; 11721f87f0b5SEric W. Biederman } 11731f87f0b5SEric W. Biederman 11740e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11750e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11760e47c99dSEric W. Biederman { 11770e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11780e47c99dSEric W. Biederman struct ctl_table_header *links; 1179ac13ac6fSEric W. Biederman struct ctl_node *node; 11800e47c99dSEric W. Biederman char *link_name; 11810e47c99dSEric W. Biederman int nr_entries, name_bytes; 11820e47c99dSEric W. Biederman 11830e47c99dSEric W. Biederman name_bytes = 0; 11840e47c99dSEric W. Biederman nr_entries = 0; 1185*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 11860e47c99dSEric W. Biederman nr_entries++; 11870e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11880e47c99dSEric W. Biederman } 11890e47c99dSEric W. Biederman 11900e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1191ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11920e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11930e47c99dSEric W. Biederman name_bytes, 11940e47c99dSEric W. Biederman GFP_KERNEL); 11950e47c99dSEric W. Biederman 11960e47c99dSEric W. Biederman if (!links) 11970e47c99dSEric W. Biederman return NULL; 11980e47c99dSEric W. Biederman 1199ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1200ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 12010e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 1202*cb55f27aSMeng Tang link = link_table; 12030e47c99dSEric W. Biederman 1204*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12050e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 12060e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 12070e47c99dSEric W. Biederman link->procname = link_name; 12080e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 12090e47c99dSEric W. Biederman link->data = link_root; 12100e47c99dSEric W. Biederman link_name += len; 1211*cb55f27aSMeng Tang link++; 12120e47c99dSEric W. Biederman } 1213ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 12140e47c99dSEric W. Biederman links->nreg = nr_entries; 12150e47c99dSEric W. Biederman 12160e47c99dSEric W. Biederman return links; 12170e47c99dSEric W. Biederman } 12180e47c99dSEric W. Biederman 12190e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 12200e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 12210e47c99dSEric W. Biederman { 12220e47c99dSEric W. Biederman struct ctl_table_header *head; 12230e47c99dSEric W. Biederman struct ctl_table *entry, *link; 12240e47c99dSEric W. Biederman 12250e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 1226*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12270e47c99dSEric W. Biederman const char *procname = entry->procname; 12280e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12290e47c99dSEric W. Biederman if (!link) 12300e47c99dSEric W. Biederman return false; 12310e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12320e47c99dSEric W. Biederman continue; 12330e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12340e47c99dSEric W. Biederman continue; 12350e47c99dSEric W. Biederman return false; 12360e47c99dSEric W. Biederman } 12370e47c99dSEric W. Biederman 12380e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 1239*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 12400e47c99dSEric W. Biederman const char *procname = entry->procname; 12410e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12420e47c99dSEric W. Biederman head->nreg++; 12430e47c99dSEric W. Biederman } 12440e47c99dSEric W. Biederman return true; 12450e47c99dSEric W. Biederman } 12460e47c99dSEric W. Biederman 12470e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12480e47c99dSEric W. Biederman { 12490e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12500e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12510e47c99dSEric W. Biederman struct ctl_table_header *links; 12520e47c99dSEric W. Biederman int err; 12530e47c99dSEric W. Biederman 12540e47c99dSEric W. Biederman if (head->set == root_set) 12550e47c99dSEric W. Biederman return 0; 12560e47c99dSEric W. Biederman 12570e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12580e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12590e47c99dSEric W. Biederman return 0; 12600e47c99dSEric W. Biederman 12610e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12620e47c99dSEric W. Biederman return 0; 12630e47c99dSEric W. Biederman 12640e47c99dSEric W. Biederman core_parent->header.nreg++; 12650e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12660e47c99dSEric W. Biederman 12670e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12680e47c99dSEric W. Biederman 12690e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12700e47c99dSEric W. Biederman err = -ENOMEM; 12710e47c99dSEric W. Biederman if (!links) 12720e47c99dSEric W. Biederman goto out; 12730e47c99dSEric W. Biederman 12740e47c99dSEric W. Biederman err = 0; 12750e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12760e47c99dSEric W. Biederman kfree(links); 12770e47c99dSEric W. Biederman goto out; 12780e47c99dSEric W. Biederman } 12790e47c99dSEric W. Biederman 12800e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12810e47c99dSEric W. Biederman if (err) 12820e47c99dSEric W. Biederman kfree(links); 12830e47c99dSEric W. Biederman out: 12840e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12850e47c99dSEric W. Biederman return err; 12860e47c99dSEric W. Biederman } 12870e47c99dSEric W. Biederman 12881f87f0b5SEric W. Biederman /** 1289f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 129060a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12911f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12921f87f0b5SEric W. Biederman * @table: the top-level table structure 12931f87f0b5SEric W. Biederman * 12941f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12951f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12961f87f0b5SEric W. Biederman * 12971f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12981f87f0b5SEric W. Biederman * 12991f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 13001f87f0b5SEric W. Biederman * enter a sysctl file 13011f87f0b5SEric W. Biederman * 13021f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 13031f87f0b5SEric W. Biederman * 13041f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 13051f87f0b5SEric W. Biederman * 1306f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 13071f87f0b5SEric W. Biederman * 1308f728019bSEric W. Biederman * child - must be %NULL. 13091f87f0b5SEric W. Biederman * 13101f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 13111f87f0b5SEric W. Biederman * 13121f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 13131f87f0b5SEric W. Biederman * 13141f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 13151f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 13161f87f0b5SEric W. Biederman * 1317f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1318f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 13191f87f0b5SEric W. Biederman * 13201f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 13211f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 13221f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 13231f87f0b5SEric W. Biederman * 13241f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 13251f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 13261f87f0b5SEric W. Biederman * 13271f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 13281f87f0b5SEric W. Biederman * to the table header on success. 13291f87f0b5SEric W. Biederman */ 13306e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 133160a47a2eSEric W. Biederman struct ctl_table_set *set, 13326e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 13331f87f0b5SEric W. Biederman { 133460a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13351f87f0b5SEric W. Biederman struct ctl_table_header *header; 13366e9d5164SEric W. Biederman const char *name, *nextname; 13377ec66d06SEric W. Biederman struct ctl_dir *dir; 1338ac13ac6fSEric W. Biederman struct ctl_table *entry; 1339ac13ac6fSEric W. Biederman struct ctl_node *node; 1340ac13ac6fSEric W. Biederman int nr_entries = 0; 13411f87f0b5SEric W. Biederman 1342*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) 1343ac13ac6fSEric W. Biederman nr_entries++; 1344ac13ac6fSEric W. Biederman 1345ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1346ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13471f87f0b5SEric W. Biederman if (!header) 13481f87f0b5SEric W. Biederman return NULL; 13491f87f0b5SEric W. Biederman 1350ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1351ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13527c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13537c60c48fSEric W. Biederman goto fail; 13548d6ecfccSEric W. Biederman 13551f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13560e47c99dSEric W. Biederman dir = &set->dir; 135760f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13587ec66d06SEric W. Biederman dir->header.nreg++; 13597ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13607ec66d06SEric W. Biederman 13617ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13627ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13637ec66d06SEric W. Biederman int namelen; 13647ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13657ec66d06SEric W. Biederman if (nextname) { 13667ec66d06SEric W. Biederman namelen = nextname - name; 13677ec66d06SEric W. Biederman nextname++; 13687ec66d06SEric W. Biederman } else { 13697ec66d06SEric W. Biederman namelen = strlen(name); 13707ec66d06SEric W. Biederman } 13717ec66d06SEric W. Biederman if (namelen == 0) 13721f87f0b5SEric W. Biederman continue; 13737ec66d06SEric W. Biederman 13740e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13757ec66d06SEric W. Biederman if (IS_ERR(dir)) 13767ec66d06SEric W. Biederman goto fail; 13771f87f0b5SEric W. Biederman } 13780e47c99dSEric W. Biederman 13797ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13800e47c99dSEric W. Biederman if (insert_header(dir, header)) 13810e47c99dSEric W. Biederman goto fail_put_dir_locked; 13820e47c99dSEric W. Biederman 13837ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13841f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13851f87f0b5SEric W. Biederman 13861f87f0b5SEric W. Biederman return header; 13870e47c99dSEric W. Biederman 13887ec66d06SEric W. Biederman fail_put_dir_locked: 13897ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13907c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13917c60c48fSEric W. Biederman fail: 13927c60c48fSEric W. Biederman kfree(header); 13937c60c48fSEric W. Biederman dump_stack(); 13947c60c48fSEric W. Biederman return NULL; 13951f87f0b5SEric W. Biederman } 13961f87f0b5SEric W. Biederman 1397fea478d4SEric W. Biederman /** 1398fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1399fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1400fea478d4SEric W. Biederman * @table: the table structure 1401fea478d4SEric W. Biederman * 1402fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1403fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1404fea478d4SEric W. Biederman * 1405fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1406fea478d4SEric W. Biederman */ 1407fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1408fea478d4SEric W. Biederman { 1409fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1410fea478d4SEric W. Biederman path, table); 1411fea478d4SEric W. Biederman } 1412fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1413fea478d4SEric W. Biederman 14143ddd9a80SXiaoming Ni /** 14153ddd9a80SXiaoming Ni * __register_sysctl_init() - register sysctl table to path 14163ddd9a80SXiaoming Ni * @path: path name for sysctl base 14173ddd9a80SXiaoming Ni * @table: This is the sysctl table that needs to be registered to the path 14183ddd9a80SXiaoming Ni * @table_name: The name of sysctl table, only used for log printing when 14193ddd9a80SXiaoming Ni * registration fails 14203ddd9a80SXiaoming Ni * 14213ddd9a80SXiaoming Ni * The sysctl interface is used by userspace to query or modify at runtime 14223ddd9a80SXiaoming Ni * a predefined value set on a variable. These variables however have default 14233ddd9a80SXiaoming Ni * values pre-set. Code which depends on these variables will always work even 14243ddd9a80SXiaoming Ni * if register_sysctl() fails. If register_sysctl() fails you'd just loose the 14253ddd9a80SXiaoming Ni * ability to query or modify the sysctls dynamically at run time. Chances of 14263ddd9a80SXiaoming Ni * register_sysctl() failing on init are extremely low, and so for both reasons 14273ddd9a80SXiaoming Ni * this function does not return any error as it is used by initialization code. 14283ddd9a80SXiaoming Ni * 14293ddd9a80SXiaoming Ni * Context: Can only be called after your respective sysctl base path has been 14303ddd9a80SXiaoming Ni * registered. So for instance, most base directories are registered early on 14313ddd9a80SXiaoming Ni * init before init levels are processed through proc_sys_init() and 1432d8c0418aSLuis Chamberlain * sysctl_init_bases(). 14333ddd9a80SXiaoming Ni */ 14343ddd9a80SXiaoming Ni void __init __register_sysctl_init(const char *path, struct ctl_table *table, 14353ddd9a80SXiaoming Ni const char *table_name) 14363ddd9a80SXiaoming Ni { 14373ddd9a80SXiaoming Ni struct ctl_table_header *hdr = register_sysctl(path, table); 14383ddd9a80SXiaoming Ni 14393ddd9a80SXiaoming Ni if (unlikely(!hdr)) { 14403ddd9a80SXiaoming Ni pr_err("failed when register_sysctl %s to %s\n", table_name, path); 14413ddd9a80SXiaoming Ni return; 14423ddd9a80SXiaoming Ni } 14433ddd9a80SXiaoming Ni kmemleak_not_leak(hdr); 14443ddd9a80SXiaoming Ni } 14453ddd9a80SXiaoming Ni 14466e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 14476e9d5164SEric W. Biederman { 14486e9d5164SEric W. Biederman int namelen; 14496e9d5164SEric W. Biederman namelen = strlen(name); 14506e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 14516e9d5164SEric W. Biederman return NULL; 14526e9d5164SEric W. Biederman memcpy(pos, name, namelen); 14536e9d5164SEric W. Biederman pos[namelen] = '/'; 14546e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 14556e9d5164SEric W. Biederman pos += namelen + 1; 14566e9d5164SEric W. Biederman return pos; 14576e9d5164SEric W. Biederman } 14586e9d5164SEric W. Biederman 1459f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1460f728019bSEric W. Biederman { 1461f728019bSEric W. Biederman int has_files = 0; 1462f728019bSEric W. Biederman int nr_subheaders = 0; 1463f728019bSEric W. Biederman struct ctl_table *entry; 1464f728019bSEric W. Biederman 1465f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1466f728019bSEric W. Biederman if (!table || !table->procname) 1467f728019bSEric W. Biederman return 1; 1468f728019bSEric W. Biederman 1469*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1470f728019bSEric W. Biederman if (entry->child) 1471f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1472f728019bSEric W. Biederman else 1473f728019bSEric W. Biederman has_files = 1; 1474f728019bSEric W. Biederman } 1475f728019bSEric W. Biederman return nr_subheaders + has_files; 1476f728019bSEric W. Biederman } 1477f728019bSEric W. Biederman 1478f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 147960a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1480f728019bSEric W. Biederman struct ctl_table *table) 1481f728019bSEric W. Biederman { 1482f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1483f728019bSEric W. Biederman struct ctl_table *entry, *files; 1484f728019bSEric W. Biederman int nr_files = 0; 1485f728019bSEric W. Biederman int nr_dirs = 0; 1486f728019bSEric W. Biederman int err = -ENOMEM; 1487f728019bSEric W. Biederman 1488*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1489f728019bSEric W. Biederman if (entry->child) 1490f728019bSEric W. Biederman nr_dirs++; 1491f728019bSEric W. Biederman else 1492f728019bSEric W. Biederman nr_files++; 1493f728019bSEric W. Biederman } 1494f728019bSEric W. Biederman 1495f728019bSEric W. Biederman files = table; 1496f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1497f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1498f728019bSEric W. Biederman struct ctl_table *new; 14996396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1500f728019bSEric W. Biederman GFP_KERNEL); 1501f728019bSEric W. Biederman if (!files) 1502f728019bSEric W. Biederman goto out; 1503f728019bSEric W. Biederman 1504f728019bSEric W. Biederman ctl_table_arg = files; 1505*cb55f27aSMeng Tang new = files; 1506*cb55f27aSMeng Tang 1507*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1508f728019bSEric W. Biederman if (entry->child) 1509f728019bSEric W. Biederman continue; 1510f728019bSEric W. Biederman *new = *entry; 1511f728019bSEric W. Biederman new++; 1512f728019bSEric W. Biederman } 1513f728019bSEric W. Biederman } 1514f728019bSEric W. Biederman 1515f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1516f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1517f728019bSEric W. Biederman struct ctl_table_header *header; 151860a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1519f728019bSEric W. Biederman if (!header) { 1520f728019bSEric W. Biederman kfree(ctl_table_arg); 1521f728019bSEric W. Biederman goto out; 1522f728019bSEric W. Biederman } 1523f728019bSEric W. Biederman 1524f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1525f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1526f728019bSEric W. Biederman **subheader = header; 1527f728019bSEric W. Biederman (*subheader)++; 1528f728019bSEric W. Biederman } 1529f728019bSEric W. Biederman 1530f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1531*cb55f27aSMeng Tang list_for_each_table_entry(entry, table) { 1532f728019bSEric W. Biederman char *child_pos; 1533f728019bSEric W. Biederman 1534f728019bSEric W. Biederman if (!entry->child) 1535f728019bSEric W. Biederman continue; 1536f728019bSEric W. Biederman 1537f728019bSEric W. Biederman err = -ENAMETOOLONG; 1538f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1539f728019bSEric W. Biederman if (!child_pos) 1540f728019bSEric W. Biederman goto out; 1541f728019bSEric W. Biederman 1542f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 154360a47a2eSEric W. Biederman set, entry->child); 1544f728019bSEric W. Biederman pos[0] = '\0'; 1545f728019bSEric W. Biederman if (err) 1546f728019bSEric W. Biederman goto out; 1547f728019bSEric W. Biederman } 1548f728019bSEric W. Biederman err = 0; 1549f728019bSEric W. Biederman out: 1550f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1551f728019bSEric W. Biederman return err; 1552f728019bSEric W. Biederman } 1553f728019bSEric W. Biederman 15546e9d5164SEric W. Biederman /** 15556e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 155660a47a2eSEric W. Biederman * @set: Sysctl tree to register on 15576e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15586e9d5164SEric W. Biederman * @table: the top-level table structure 15596e9d5164SEric W. Biederman * 15606e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15616e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15626e9d5164SEric W. Biederman * 15636e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 15646e9d5164SEric W. Biederman */ 15656e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 156660a47a2eSEric W. Biederman struct ctl_table_set *set, 15676e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15686e9d5164SEric W. Biederman { 1569ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1570f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1571f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15726e9d5164SEric W. Biederman const struct ctl_path *component; 15736e9d5164SEric W. Biederman char *new_path, *pos; 15746e9d5164SEric W. Biederman 15756e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15766e9d5164SEric W. Biederman if (!new_path) 15776e9d5164SEric W. Biederman return NULL; 15786e9d5164SEric W. Biederman 15796e9d5164SEric W. Biederman pos[0] = '\0'; 15806e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15816e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15826e9d5164SEric W. Biederman if (!pos) 15836e9d5164SEric W. Biederman goto out; 15846e9d5164SEric W. Biederman } 1585ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1586ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1587ec6a5266SEric W. Biederman if (!pos) 1588ec6a5266SEric W. Biederman goto out; 1589ec6a5266SEric W. Biederman table = table->child; 1590ec6a5266SEric W. Biederman } 1591f728019bSEric W. Biederman if (nr_subheaders == 1) { 159260a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1593ec6a5266SEric W. Biederman if (header) 1594ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1595f728019bSEric W. Biederman } else { 1596f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1597f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1598f728019bSEric W. Biederman if (!header) 1599f728019bSEric W. Biederman goto out; 1600f728019bSEric W. Biederman 1601f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1602f728019bSEric W. Biederman subheader = subheaders; 1603f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1604f728019bSEric W. Biederman 1605f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 160660a47a2eSEric W. Biederman set, table)) 1607f728019bSEric W. Biederman goto err_register_leaves; 1608f728019bSEric W. Biederman } 1609f728019bSEric W. Biederman 16106e9d5164SEric W. Biederman out: 16116e9d5164SEric W. Biederman kfree(new_path); 16126e9d5164SEric W. Biederman return header; 1613f728019bSEric W. Biederman 1614f728019bSEric W. Biederman err_register_leaves: 1615f728019bSEric W. Biederman while (subheader > subheaders) { 1616f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1617f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1618f728019bSEric W. Biederman unregister_sysctl_table(subh); 1619f728019bSEric W. Biederman kfree(table); 1620f728019bSEric W. Biederman } 1621f728019bSEric W. Biederman kfree(header); 1622f728019bSEric W. Biederman header = NULL; 1623f728019bSEric W. Biederman goto out; 16246e9d5164SEric W. Biederman } 16256e9d5164SEric W. Biederman 16261f87f0b5SEric W. Biederman /** 16275b31a7dfSzhouchuangao * register_sysctl_paths - register a sysctl table hierarchy 16281f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 16291f87f0b5SEric W. Biederman * @table: the top-level table structure 16301f87f0b5SEric W. Biederman * 16311f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16321f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16331f87f0b5SEric W. Biederman * 16341f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 16351f87f0b5SEric W. Biederman */ 16361f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 16371f87f0b5SEric W. Biederman struct ctl_table *table) 16381f87f0b5SEric W. Biederman { 163960a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 16401f87f0b5SEric W. Biederman path, table); 16411f87f0b5SEric W. Biederman } 16421f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 16431f87f0b5SEric W. Biederman 16441f87f0b5SEric W. Biederman /** 16451f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 16461f87f0b5SEric W. Biederman * @table: the top-level table structure 16471f87f0b5SEric W. Biederman * 16481f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16491f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16501f87f0b5SEric W. Biederman * 16511f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 16521f87f0b5SEric W. Biederman */ 16531f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 16541f87f0b5SEric W. Biederman { 16551f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 16561f87f0b5SEric W. Biederman 16571f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 16581f87f0b5SEric W. Biederman } 16591f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 16601f87f0b5SEric W. Biederman 166151cb8dfcSLuis Chamberlain int __register_sysctl_base(struct ctl_table *base_table) 166251cb8dfcSLuis Chamberlain { 166351cb8dfcSLuis Chamberlain struct ctl_table_header *hdr; 166451cb8dfcSLuis Chamberlain 166551cb8dfcSLuis Chamberlain hdr = register_sysctl_table(base_table); 166651cb8dfcSLuis Chamberlain kmemleak_not_leak(hdr); 166751cb8dfcSLuis Chamberlain return 0; 166851cb8dfcSLuis Chamberlain } 166951cb8dfcSLuis Chamberlain 16700e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 16710e47c99dSEric W. Biederman { 16720e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 16730e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 16740e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 16750e47c99dSEric W. Biederman struct ctl_dir *core_parent; 16760e47c99dSEric W. Biederman struct ctl_table *entry; 16770e47c99dSEric W. Biederman 16780e47c99dSEric W. Biederman if (header->set == root_set) 16790e47c99dSEric W. Biederman return; 16800e47c99dSEric W. Biederman 16810e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16820e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16830e47c99dSEric W. Biederman return; 16840e47c99dSEric W. Biederman 1685*cb55f27aSMeng Tang list_for_each_table_entry(entry, header->ctl_table) { 16860e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16870e47c99dSEric W. Biederman struct ctl_table *link; 16880e47c99dSEric W. Biederman const char *name = entry->procname; 16890e47c99dSEric W. Biederman 16900e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16910e47c99dSEric W. Biederman if (link && 16920e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16930e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16940e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16950e47c99dSEric W. Biederman } 16960e47c99dSEric W. Biederman else { 169787ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16980e47c99dSEric W. Biederman sysctl_print_dir(parent); 1699153ee1c4SGeert Uytterhoeven pr_cont("%s\n", name); 17000e47c99dSEric W. Biederman } 17010e47c99dSEric W. Biederman } 17020e47c99dSEric W. Biederman } 17030e47c99dSEric W. Biederman 1704938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1705938aaa4fSEric W. Biederman { 17067ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 17077ec66d06SEric W. Biederman 1708938aaa4fSEric W. Biederman if (--header->nreg) 1709938aaa4fSEric W. Biederman return; 1710938aaa4fSEric W. Biederman 171189189557SYueHaibing if (parent) { 17120e47c99dSEric W. Biederman put_links(header); 1713938aaa4fSEric W. Biederman start_unregistering(header); 171489189557SYueHaibing } 171589189557SYueHaibing 1716938aaa4fSEric W. Biederman if (!--header->count) 1717938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 17187ec66d06SEric W. Biederman 17197ec66d06SEric W. Biederman if (parent) 17207ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1721938aaa4fSEric W. Biederman } 1722938aaa4fSEric W. Biederman 17231f87f0b5SEric W. Biederman /** 17241f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 17251f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 17261f87f0b5SEric W. Biederman * 17271f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 17281f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 17291f87f0b5SEric W. Biederman */ 17301f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 17311f87f0b5SEric W. Biederman { 1732f728019bSEric W. Biederman int nr_subheaders; 17331f87f0b5SEric W. Biederman might_sleep(); 17341f87f0b5SEric W. Biederman 17351f87f0b5SEric W. Biederman if (header == NULL) 17361f87f0b5SEric W. Biederman return; 17371f87f0b5SEric W. Biederman 1738f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1739f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1740f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1741f728019bSEric W. Biederman int i; 1742f728019bSEric W. Biederman 1743f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1744f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1745f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1746f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1747f728019bSEric W. Biederman unregister_sysctl_table(subh); 1748f728019bSEric W. Biederman kfree(table); 1749f728019bSEric W. Biederman } 1750f728019bSEric W. Biederman kfree(header); 1751f728019bSEric W. Biederman return; 1752f728019bSEric W. Biederman } 1753f728019bSEric W. Biederman 17541f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1755938aaa4fSEric W. Biederman drop_sysctl_table(header); 17561f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 17571f87f0b5SEric W. Biederman } 17581f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 17591f87f0b5SEric W. Biederman 17600e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 17619eb47c26SEric W. Biederman struct ctl_table_root *root, 17621f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 17631f87f0b5SEric W. Biederman { 17641347440dSDan Carpenter memset(set, 0, sizeof(*set)); 17650e47c99dSEric W. Biederman set->is_seen = is_seen; 1766ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 17671f87f0b5SEric W. Biederman } 17681f87f0b5SEric W. Biederman 176997324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 177097324cd8SEric W. Biederman { 1771ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 177297324cd8SEric W. Biederman } 17731f87f0b5SEric W. Biederman 17741e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 177577b14db5SEric W. Biederman { 1776e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1777e1675231SAlexey Dobriyan 177877b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17799043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 1780d56c0d45SAlexey Dobriyan proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; 178177b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1782de4e83bdSEric W. Biederman 1783d8c0418aSLuis Chamberlain return sysctl_init_bases(); 178477b14db5SEric W. Biederman } 17853db978d4SVlastimil Babka 17860a477e1aSVlastimil Babka struct sysctl_alias { 17870a477e1aSVlastimil Babka const char *kernel_param; 17880a477e1aSVlastimil Babka const char *sysctl_param; 17890a477e1aSVlastimil Babka }; 17900a477e1aSVlastimil Babka 17910a477e1aSVlastimil Babka /* 17920a477e1aSVlastimil Babka * Historically some settings had both sysctl and a command line parameter. 17930a477e1aSVlastimil Babka * With the generic sysctl. parameter support, we can handle them at a single 17940a477e1aSVlastimil Babka * place and only keep the historical name for compatibility. This is not meant 17950a477e1aSVlastimil Babka * to add brand new aliases. When adding existing aliases, consider whether 17960a477e1aSVlastimil Babka * the possibly different moment of changing the value (e.g. from early_param 17970a477e1aSVlastimil Babka * to the moment do_sysctl_args() is called) is an issue for the specific 17980a477e1aSVlastimil Babka * parameter. 17990a477e1aSVlastimil Babka */ 18000a477e1aSVlastimil Babka static const struct sysctl_alias sysctl_aliases[] = { 1801f117955aSGuilherme G. Piccoli {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, 1802b467f3efSVlastimil Babka {"hung_task_panic", "kernel.hung_task_panic" }, 1803f117955aSGuilherme G. Piccoli {"numa_zonelist_order", "vm.numa_zonelist_order" }, 1804f117955aSGuilherme G. Piccoli {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, 1805f117955aSGuilherme G. Piccoli {"softlockup_panic", "kernel.softlockup_panic" }, 18060a477e1aSVlastimil Babka { } 18070a477e1aSVlastimil Babka }; 18080a477e1aSVlastimil Babka 18090a477e1aSVlastimil Babka static const char *sysctl_find_alias(char *param) 18100a477e1aSVlastimil Babka { 18110a477e1aSVlastimil Babka const struct sysctl_alias *alias; 18120a477e1aSVlastimil Babka 18130a477e1aSVlastimil Babka for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { 18140a477e1aSVlastimil Babka if (strcmp(alias->kernel_param, param) == 0) 18150a477e1aSVlastimil Babka return alias->sysctl_param; 18160a477e1aSVlastimil Babka } 18170a477e1aSVlastimil Babka 18180a477e1aSVlastimil Babka return NULL; 18190a477e1aSVlastimil Babka } 18200a477e1aSVlastimil Babka 18213db978d4SVlastimil Babka /* Set sysctl value passed on kernel command line. */ 18223db978d4SVlastimil Babka static int process_sysctl_arg(char *param, char *val, 18233db978d4SVlastimil Babka const char *unused, void *arg) 18243db978d4SVlastimil Babka { 18253db978d4SVlastimil Babka char *path; 18263db978d4SVlastimil Babka struct vfsmount **proc_mnt = arg; 18273db978d4SVlastimil Babka struct file_system_type *proc_fs_type; 18283db978d4SVlastimil Babka struct file *file; 18293db978d4SVlastimil Babka int len; 18303db978d4SVlastimil Babka int err; 18313db978d4SVlastimil Babka loff_t pos = 0; 18323db978d4SVlastimil Babka ssize_t wret; 18333db978d4SVlastimil Babka 18340a477e1aSVlastimil Babka if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { 18353db978d4SVlastimil Babka param += sizeof("sysctl") - 1; 18363db978d4SVlastimil Babka 18373db978d4SVlastimil Babka if (param[0] != '/' && param[0] != '.') 18383db978d4SVlastimil Babka return 0; 18393db978d4SVlastimil Babka 18403db978d4SVlastimil Babka param++; 18410a477e1aSVlastimil Babka } else { 18420a477e1aSVlastimil Babka param = (char *) sysctl_find_alias(param); 18430a477e1aSVlastimil Babka if (!param) 18440a477e1aSVlastimil Babka return 0; 18450a477e1aSVlastimil Babka } 18463db978d4SVlastimil Babka 1847697edcb0SXiaoming Ni if (!val) 1848697edcb0SXiaoming Ni return -EINVAL; 1849697edcb0SXiaoming Ni len = strlen(val); 1850697edcb0SXiaoming Ni if (len == 0) 1851697edcb0SXiaoming Ni return -EINVAL; 1852697edcb0SXiaoming Ni 18533db978d4SVlastimil Babka /* 18543db978d4SVlastimil Babka * To set sysctl options, we use a temporary mount of proc, look up the 18553db978d4SVlastimil Babka * respective sys/ file and write to it. To avoid mounting it when no 18563db978d4SVlastimil Babka * options were given, we mount it only when the first sysctl option is 18573db978d4SVlastimil Babka * found. Why not a persistent mount? There are problems with a 18583db978d4SVlastimil Babka * persistent mount of proc in that it forces userspace not to use any 18593db978d4SVlastimil Babka * proc mount options. 18603db978d4SVlastimil Babka */ 18613db978d4SVlastimil Babka if (!*proc_mnt) { 18623db978d4SVlastimil Babka proc_fs_type = get_fs_type("proc"); 18633db978d4SVlastimil Babka if (!proc_fs_type) { 18643db978d4SVlastimil Babka pr_err("Failed to find procfs to set sysctl from command line\n"); 18653db978d4SVlastimil Babka return 0; 18663db978d4SVlastimil Babka } 18673db978d4SVlastimil Babka *proc_mnt = kern_mount(proc_fs_type); 18683db978d4SVlastimil Babka put_filesystem(proc_fs_type); 18693db978d4SVlastimil Babka if (IS_ERR(*proc_mnt)) { 18703db978d4SVlastimil Babka pr_err("Failed to mount procfs to set sysctl from command line\n"); 18713db978d4SVlastimil Babka return 0; 18723db978d4SVlastimil Babka } 18733db978d4SVlastimil Babka } 18743db978d4SVlastimil Babka 18753db978d4SVlastimil Babka path = kasprintf(GFP_KERNEL, "sys/%s", param); 18763db978d4SVlastimil Babka if (!path) 18773db978d4SVlastimil Babka panic("%s: Failed to allocate path for %s\n", __func__, param); 18783db978d4SVlastimil Babka strreplace(path, '.', '/'); 18793db978d4SVlastimil Babka 1880ffb37ca3SAl Viro file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); 18813db978d4SVlastimil Babka if (IS_ERR(file)) { 18823db978d4SVlastimil Babka err = PTR_ERR(file); 18833db978d4SVlastimil Babka if (err == -ENOENT) 18843db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", 18853db978d4SVlastimil Babka param, val); 18863db978d4SVlastimil Babka else if (err == -EACCES) 18873db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", 18883db978d4SVlastimil Babka param, val); 18893db978d4SVlastimil Babka else 18903db978d4SVlastimil Babka pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", 18913db978d4SVlastimil Babka file, param, val); 18923db978d4SVlastimil Babka goto out; 18933db978d4SVlastimil Babka } 18943db978d4SVlastimil Babka wret = kernel_write(file, val, len, &pos); 18953db978d4SVlastimil Babka if (wret < 0) { 18963db978d4SVlastimil Babka err = wret; 18973db978d4SVlastimil Babka if (err == -EINVAL) 18983db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", 18993db978d4SVlastimil Babka param, val); 19003db978d4SVlastimil Babka else 19013db978d4SVlastimil Babka pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", 19023db978d4SVlastimil Babka ERR_PTR(err), param, val); 19033db978d4SVlastimil Babka } else if (wret != len) { 19043db978d4SVlastimil Babka pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", 19053db978d4SVlastimil Babka wret, len, path, param, val); 19063db978d4SVlastimil Babka } 19073db978d4SVlastimil Babka 19083db978d4SVlastimil Babka err = filp_close(file, NULL); 19093db978d4SVlastimil Babka if (err) 19103db978d4SVlastimil Babka pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", 19113db978d4SVlastimil Babka ERR_PTR(err), param, val); 19123db978d4SVlastimil Babka out: 19133db978d4SVlastimil Babka kfree(path); 19143db978d4SVlastimil Babka return 0; 19153db978d4SVlastimil Babka } 19163db978d4SVlastimil Babka 19173db978d4SVlastimil Babka void do_sysctl_args(void) 19183db978d4SVlastimil Babka { 19193db978d4SVlastimil Babka char *command_line; 19203db978d4SVlastimil Babka struct vfsmount *proc_mnt = NULL; 19213db978d4SVlastimil Babka 19223db978d4SVlastimil Babka command_line = kstrdup(saved_command_line, GFP_KERNEL); 19233db978d4SVlastimil Babka if (!command_line) 19243db978d4SVlastimil Babka panic("%s: Failed to allocate copy of command line\n", __func__); 19253db978d4SVlastimil Babka 19263db978d4SVlastimil Babka parse_args("Setting sysctl args", command_line, 19273db978d4SVlastimil Babka NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); 19283db978d4SVlastimil Babka 19293db978d4SVlastimil Babka if (proc_mnt) 19303db978d4SVlastimil Babka kern_unmount(proc_mnt); 19313db978d4SVlastimil Babka 19323db978d4SVlastimil Babka kfree(command_line); 19333db978d4SVlastimil Babka } 1934