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 2218d4b42eSJoel Granados #define list_for_each_table_entry(entry, header) \ 2318d4b42eSJoel Granados for ((entry) = (header->ctl_table); (entry)->procname; (entry)++) 24cb55f27aSMeng Tang 25d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 2677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2703a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 289043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 299043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 3077b14db5SEric W. Biederman 31f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 327fffbc71STom Rix static struct ctl_table sysctl_mount_point[] = { 332f2665c1SJoel Granados {.type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY } 34f9bd6733SEric W. Biederman }; 35f9bd6733SEric W. Biederman 36ee9efac4SLuis Chamberlain /** 37ee9efac4SLuis Chamberlain * register_sysctl_mount_point() - registers a sysctl mount point 38ee9efac4SLuis Chamberlain * @path: path for the mount point 39ee9efac4SLuis Chamberlain * 40ee9efac4SLuis Chamberlain * Used to create a permanently empty directory to serve as mount point. 41ee9efac4SLuis Chamberlain * There are some subtle but important permission checks this allows in the 42ee9efac4SLuis Chamberlain * case of unprivileged mounts. 43ee9efac4SLuis Chamberlain */ 44ee9efac4SLuis Chamberlain struct ctl_table_header *register_sysctl_mount_point(const char *path) 45ee9efac4SLuis Chamberlain { 46ee9efac4SLuis Chamberlain return register_sysctl(path, sysctl_mount_point); 47ee9efac4SLuis Chamberlain } 48ee9efac4SLuis Chamberlain EXPORT_SYMBOL(register_sysctl_mount_point); 49ee9efac4SLuis Chamberlain 502f2665c1SJoel Granados #define sysctl_is_perm_empty_ctl_table(tptr) \ 512f2665c1SJoel Granados (tptr[0].type == SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY) 522f2665c1SJoel Granados #define sysctl_is_perm_empty_ctl_header(hptr) \ 532f2665c1SJoel Granados (sysctl_is_perm_empty_ctl_table(hptr->ctl_table)) 542f2665c1SJoel Granados #define sysctl_set_perm_empty_ctl_header(hptr) \ 552f2665c1SJoel Granados (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_PERMANENTLY_EMPTY) 562f2665c1SJoel Granados #define sysctl_clear_perm_empty_ctl_header(hptr) \ 572f2665c1SJoel Granados (hptr->ctl_table[0].type = SYSCTL_TABLE_TYPE_DEFAULT) 58f9bd6733SEric W. Biederman 59f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 60f1ecf068SLucas De Marchi { 61f1ecf068SLucas De Marchi if (!poll) 62f1ecf068SLucas De Marchi return; 63f1ecf068SLucas De Marchi 64f1ecf068SLucas De Marchi atomic_inc(&poll->event); 65f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 66f1ecf068SLucas De Marchi } 67f1ecf068SLucas De Marchi 68a194558eSEric W. Biederman static struct ctl_table root_table[] = { 69a194558eSEric W. Biederman { 70a194558eSEric W. Biederman .procname = "", 717ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 72a194558eSEric W. Biederman }, 73a194558eSEric W. Biederman { } 74a194558eSEric W. Biederman }; 750e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 760e47c99dSEric W. Biederman .default_set.dir.header = { 771f87f0b5SEric W. Biederman {{.count = 1, 78938aaa4fSEric W. Biederman .nreg = 1, 79ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 800e47c99dSEric W. Biederman .ctl_table_arg = root_table, 811f87f0b5SEric W. Biederman .root = &sysctl_table_root, 821f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 837ec66d06SEric W. Biederman }, 841f87f0b5SEric W. Biederman }; 851f87f0b5SEric W. Biederman 861f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 871f87f0b5SEric W. Biederman 887ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 890e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 9013bcc6a2SEric W. Biederman struct ctl_table **pentry); 910e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 920e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 937ec66d06SEric W. Biederman 946980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 956980128fSEric W. Biederman { 966980128fSEric W. Biederman if (dir->header.parent) 976980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 9887ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 996980128fSEric W. Biederman } 1006980128fSEric W. Biederman 101076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 102076c3eedSEric W. Biederman { 103076c3eedSEric W. Biederman int cmp; 104076c3eedSEric W. Biederman 105d8fc9b66SMasahiro Yamada cmp = memcmp(name1, name2, min(len1, len2)); 106076c3eedSEric W. Biederman if (cmp == 0) 107076c3eedSEric W. Biederman cmp = len1 - len2; 108076c3eedSEric W. Biederman return cmp; 109076c3eedSEric W. Biederman } 110076c3eedSEric W. Biederman 11160f126d9SEric W. Biederman /* Called under sysctl_lock */ 112076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1130e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 114076c3eedSEric W. Biederman { 115076c3eedSEric W. Biederman struct ctl_table_header *head; 116076c3eedSEric W. Biederman struct ctl_table *entry; 117ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 118076c3eedSEric W. Biederman 119ac13ac6fSEric W. Biederman while (node) 120ac13ac6fSEric W. Biederman { 121ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 122ac13ac6fSEric W. Biederman const char *procname; 123ac13ac6fSEric W. Biederman int cmp; 124ac13ac6fSEric W. Biederman 125ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 126ac13ac6fSEric W. Biederman head = ctl_node->header; 127ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 128ac13ac6fSEric W. Biederman procname = entry->procname; 129ac13ac6fSEric W. Biederman 130ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 131ac13ac6fSEric W. Biederman if (cmp < 0) 132ac13ac6fSEric W. Biederman node = node->rb_left; 133ac13ac6fSEric W. Biederman else if (cmp > 0) 134ac13ac6fSEric W. Biederman node = node->rb_right; 135ac13ac6fSEric W. Biederman else { 136076c3eedSEric W. Biederman *phead = head; 137076c3eedSEric W. Biederman return entry; 138076c3eedSEric W. Biederman } 139076c3eedSEric W. Biederman } 140076c3eedSEric W. Biederman return NULL; 141076c3eedSEric W. Biederman } 142076c3eedSEric W. Biederman 143ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 144ac13ac6fSEric W. Biederman { 145ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 146ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 147ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 148ac13ac6fSEric W. Biederman const char *name = entry->procname; 149ac13ac6fSEric W. Biederman int namelen = strlen(name); 150ac13ac6fSEric W. Biederman 151ac13ac6fSEric W. Biederman while (*p) { 152ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 153ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 154ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 155ac13ac6fSEric W. Biederman const char *parent_name; 156ac13ac6fSEric W. Biederman int cmp; 157ac13ac6fSEric W. Biederman 158ac13ac6fSEric W. Biederman parent = *p; 159ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 160ac13ac6fSEric W. Biederman parent_head = parent_node->header; 161ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 162ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 163ac13ac6fSEric W. Biederman 164ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 165ac13ac6fSEric W. Biederman if (cmp < 0) 166ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 167ac13ac6fSEric W. Biederman else if (cmp > 0) 168ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 169ac13ac6fSEric W. Biederman else { 17087ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 171ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 172153ee1c4SGeert Uytterhoeven pr_cont("%s\n", entry->procname); 173ac13ac6fSEric W. Biederman return -EEXIST; 174ac13ac6fSEric W. Biederman } 175ac13ac6fSEric W. Biederman } 176ac13ac6fSEric W. Biederman 177ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 178ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 179ac13ac6fSEric W. Biederman return 0; 180ac13ac6fSEric W. Biederman } 181ac13ac6fSEric W. Biederman 182ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 183ac13ac6fSEric W. Biederman { 184ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 185ac13ac6fSEric W. Biederman 186ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 187ac13ac6fSEric W. Biederman } 188ac13ac6fSEric W. Biederman 189e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 190e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 191b1f01e2bSJoel Granados struct ctl_node *node, struct ctl_table *table, size_t table_size) 192e0d04529SEric W. Biederman { 1937ec66d06SEric W. Biederman head->ctl_table = table; 194b1f01e2bSJoel Granados head->ctl_table_size = table_size; 195e0d04529SEric W. Biederman head->ctl_table_arg = table; 196e0d04529SEric W. Biederman head->used = 0; 197e0d04529SEric W. Biederman head->count = 1; 198e0d04529SEric W. Biederman head->nreg = 1; 199e0d04529SEric W. Biederman head->unregistering = NULL; 200e0d04529SEric W. Biederman head->root = root; 201e0d04529SEric W. Biederman head->set = set; 202e0d04529SEric W. Biederman head->parent = NULL; 203ac13ac6fSEric W. Biederman head->node = node; 2042fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 205ac13ac6fSEric W. Biederman if (node) { 206ac13ac6fSEric W. Biederman struct ctl_table *entry; 207cb55f27aSMeng Tang 20818d4b42eSJoel Granados list_for_each_table_entry(entry, head) { 209ac13ac6fSEric W. Biederman node->header = head; 210cb55f27aSMeng Tang node++; 211cb55f27aSMeng Tang } 212ac13ac6fSEric W. Biederman } 213ac13ac6fSEric W. Biederman } 214e0d04529SEric W. Biederman 2158425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2168425d6aaSEric W. Biederman { 217ac13ac6fSEric W. Biederman struct ctl_table *entry; 218cb55f27aSMeng Tang 21918d4b42eSJoel Granados list_for_each_table_entry(entry, head) 220ac13ac6fSEric W. Biederman erase_entry(head, entry); 2218425d6aaSEric W. Biederman } 2228425d6aaSEric W. Biederman 2230e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2248425d6aaSEric W. Biederman { 225ac13ac6fSEric W. Biederman struct ctl_table *entry; 2262f2665c1SJoel Granados struct ctl_table_header *dir_h = &dir->header; 2270e47c99dSEric W. Biederman int err; 2280e47c99dSEric W. Biederman 2292f2665c1SJoel Granados 230f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 2312f2665c1SJoel Granados if (sysctl_is_perm_empty_ctl_header(dir_h)) 232f9bd6733SEric W. Biederman return -EROFS; 233f9bd6733SEric W. Biederman 234f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 2352f2665c1SJoel Granados if (sysctl_is_perm_empty_ctl_table(header->ctl_table)) { 236f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 237f9bd6733SEric W. Biederman return -EINVAL; 2382f2665c1SJoel Granados sysctl_set_perm_empty_ctl_header(dir_h); 239f9bd6733SEric W. Biederman } 240f9bd6733SEric W. Biederman 2412f2665c1SJoel Granados dir_h->nreg++; 2427ec66d06SEric W. Biederman header->parent = dir; 2430e47c99dSEric W. Biederman err = insert_links(header); 2440e47c99dSEric W. Biederman if (err) 2450e47c99dSEric W. Biederman goto fail_links; 24618d4b42eSJoel Granados list_for_each_table_entry(entry, header) { 247ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 248ac13ac6fSEric W. Biederman if (err) 249ac13ac6fSEric W. Biederman goto fail; 250ac13ac6fSEric W. Biederman } 2510e47c99dSEric W. Biederman return 0; 252ac13ac6fSEric W. Biederman fail: 253ac13ac6fSEric W. Biederman erase_header(header); 254ac13ac6fSEric W. Biederman put_links(header); 2550e47c99dSEric W. Biederman fail_links: 256f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 2572f2665c1SJoel Granados sysctl_clear_perm_empty_ctl_header(dir_h); 2580e47c99dSEric W. Biederman header->parent = NULL; 2592f2665c1SJoel Granados drop_sysctl_table(dir_h); 2600e47c99dSEric W. Biederman return err; 2618425d6aaSEric W. Biederman } 2628425d6aaSEric W. Biederman 2631f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2641f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2651f87f0b5SEric W. Biederman { 2661f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2671f87f0b5SEric W. Biederman return 0; 2681f87f0b5SEric W. Biederman p->used++; 2691f87f0b5SEric W. Biederman return 1; 2701f87f0b5SEric W. Biederman } 2711f87f0b5SEric W. Biederman 2721f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2731f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2741f87f0b5SEric W. Biederman { 2751f87f0b5SEric W. Biederman if (!--p->used) 2761f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2771f87f0b5SEric W. Biederman complete(p->unregistering); 2781f87f0b5SEric W. Biederman } 2791f87f0b5SEric W. Biederman 280f90f3cafSEric W. Biederman static void proc_sys_invalidate_dcache(struct ctl_table_header *head) 281d6cffbbeSKonstantin Khlebnikov { 282f90f3cafSEric W. Biederman proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); 283d6cffbbeSKonstantin Khlebnikov } 284d6cffbbeSKonstantin Khlebnikov 2851f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2861f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2871f87f0b5SEric W. Biederman { 2881f87f0b5SEric W. Biederman /* 2891f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2901f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2911f87f0b5SEric W. Biederman */ 2921f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2931f87f0b5SEric W. Biederman struct completion wait; 2941f87f0b5SEric W. Biederman init_completion(&wait); 2951f87f0b5SEric W. Biederman p->unregistering = &wait; 2961f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2971f87f0b5SEric W. Biederman wait_for_completion(&wait); 2981f87f0b5SEric W. Biederman } else { 2991f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3001f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 301ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3021f87f0b5SEric W. Biederman } 3031f87f0b5SEric W. Biederman /* 304f90f3cafSEric W. Biederman * Invalidate dentries for unregistered sysctls: namespaced sysctls 305d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 306d6cffbbeSKonstantin Khlebnikov */ 307f90f3cafSEric W. Biederman proc_sys_invalidate_dcache(p); 308d6cffbbeSKonstantin Khlebnikov /* 3091f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3101f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3111f87f0b5SEric W. Biederman */ 312ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3138425d6aaSEric W. Biederman erase_header(p); 3141f87f0b5SEric W. Biederman } 3151f87f0b5SEric W. Biederman 3161f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3171f87f0b5SEric W. Biederman { 318ab4a1f24SPrasad Joshi BUG_ON(!head); 3191f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3201f87f0b5SEric W. Biederman if (!use_table(head)) 3211f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3221f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3231f87f0b5SEric W. Biederman return head; 3241f87f0b5SEric W. Biederman } 3251f87f0b5SEric W. Biederman 3261f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3271f87f0b5SEric W. Biederman { 3281f87f0b5SEric W. Biederman if (!head) 3291f87f0b5SEric W. Biederman return; 3301f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3311f87f0b5SEric W. Biederman unuse_table(head); 3321f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3331f87f0b5SEric W. Biederman } 3341f87f0b5SEric W. Biederman 3351f87f0b5SEric W. Biederman static struct ctl_table_set * 33613bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3371f87f0b5SEric W. Biederman { 3381f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3391f87f0b5SEric W. Biederman if (root->lookup) 34013bcc6a2SEric W. Biederman set = root->lookup(root); 3411f87f0b5SEric W. Biederman return set; 3421f87f0b5SEric W. Biederman } 3431f87f0b5SEric W. Biederman 344076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3457ec66d06SEric W. Biederman struct ctl_dir *dir, 346076c3eedSEric W. Biederman const char *name, int namelen) 347076c3eedSEric W. Biederman { 348076c3eedSEric W. Biederman struct ctl_table_header *head; 349076c3eedSEric W. Biederman struct ctl_table *entry; 350076c3eedSEric W. Biederman 351076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3520e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 353076c3eedSEric W. Biederman if (entry && use_table(head)) 354076c3eedSEric W. Biederman *phead = head; 355076c3eedSEric W. Biederman else 356076c3eedSEric W. Biederman entry = NULL; 357076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 358076c3eedSEric W. Biederman return entry; 359076c3eedSEric W. Biederman } 360076c3eedSEric W. Biederman 361ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3621f87f0b5SEric W. Biederman { 363ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3641f87f0b5SEric W. Biederman 365ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 366ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 367ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 368ac13ac6fSEric W. Biederman return ctl_node; 3691f87f0b5SEric W. Biederman } 3701f87f0b5SEric W. Biederman return NULL; 3711f87f0b5SEric W. Biederman } 3721f87f0b5SEric W. Biederman 3737ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3746a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3751f87f0b5SEric W. Biederman { 376ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3777ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 378ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3796a75ce16SEric W. Biederman 3806a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 381ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3826a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 383ac13ac6fSEric W. Biederman if (ctl_node) { 384ac13ac6fSEric W. Biederman head = ctl_node->header; 385ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 386ac13ac6fSEric W. Biederman } 3876a75ce16SEric W. Biederman *phead = head; 3886a75ce16SEric W. Biederman *pentry = entry; 3896a75ce16SEric W. Biederman } 3906a75ce16SEric W. Biederman 3917ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3926a75ce16SEric W. Biederman { 3936a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3946a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 395ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3966a75ce16SEric W. Biederman 3976a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3986a75ce16SEric W. Biederman unuse_table(head); 399ac13ac6fSEric W. Biederman 400ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4016a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 402ac13ac6fSEric W. Biederman head = NULL; 403ac13ac6fSEric W. Biederman if (ctl_node) { 404ac13ac6fSEric W. Biederman head = ctl_node->header; 405ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4066a75ce16SEric W. Biederman } 4076a75ce16SEric W. Biederman *phead = head; 4086a75ce16SEric W. Biederman *pentry = entry; 4091f87f0b5SEric W. Biederman } 4101f87f0b5SEric W. Biederman 4111f87f0b5SEric W. Biederman /* 4121f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4131f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4141f87f0b5SEric W. Biederman */ 4151f87f0b5SEric W. Biederman 4161f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4171f87f0b5SEric W. Biederman { 418091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4191f87f0b5SEric W. Biederman mode >>= 6; 420091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4211f87f0b5SEric W. Biederman mode >>= 3; 4221f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4231f87f0b5SEric W. Biederman return 0; 4241f87f0b5SEric W. Biederman return -EACCES; 4251f87f0b5SEric W. Biederman } 4261f87f0b5SEric W. Biederman 42773f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4281f87f0b5SEric W. Biederman { 42973f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4301f87f0b5SEric W. Biederman int mode; 4311f87f0b5SEric W. Biederman 4321f87f0b5SEric W. Biederman if (root->permissions) 43373f7ef43SEric W. Biederman mode = root->permissions(head, table); 4341f87f0b5SEric W. Biederman else 4351f87f0b5SEric W. Biederman mode = table->mode; 4361f87f0b5SEric W. Biederman 4371f87f0b5SEric W. Biederman return test_perm(mode, op); 4381f87f0b5SEric W. Biederman } 4391f87f0b5SEric W. Biederman 4409043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4419043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 44277b14db5SEric W. Biederman { 443e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 44477b14db5SEric W. Biederman struct inode *inode; 4459043476fSAl Viro struct proc_inode *ei; 44677b14db5SEric W. Biederman 4479043476fSAl Viro inode = new_inode(sb); 44877b14db5SEric W. Biederman if (!inode) 449ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 45077b14db5SEric W. Biederman 45185fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 45285fe4025SChristoph Hellwig 45377b14db5SEric W. Biederman ei = PROC_I(inode); 4549043476fSAl Viro 455d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 456ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 457ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 458ace0c791SEric W. Biederman iput(inode); 459ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 460ace0c791SEric W. Biederman } 461ace0c791SEric W. Biederman ei->sysctl = head; 462ace0c791SEric W. Biederman ei->sysctl_entry = table; 4630afa5ca8SEric W. Biederman hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); 464d6cffbbeSKonstantin Khlebnikov head->count++; 465d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 466d6cffbbeSKonstantin Khlebnikov 467078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4689043476fSAl Viro inode->i_mode = table->mode; 4697ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4709043476fSAl Viro inode->i_mode |= S_IFREG; 47177b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 47277b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4739043476fSAl Viro } else { 4749043476fSAl Viro inode->i_mode |= S_IFDIR; 4759043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4769043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 4772f2665c1SJoel Granados if (sysctl_is_perm_empty_ctl_header(head)) 478f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4799043476fSAl Viro } 480e79c6a4fSDmitry Torokhov 481e79c6a4fSDmitry Torokhov if (root->set_ownership) 482e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 4835ec27ec7SRadoslaw Burny else { 4845ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 4855ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 4865ec27ec7SRadoslaw Burny } 487e79c6a4fSDmitry Torokhov 48877b14db5SEric W. Biederman return inode; 48977b14db5SEric W. Biederman } 49077b14db5SEric W. Biederman 491d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 492d6cffbbeSKonstantin Khlebnikov { 493d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 4940afa5ca8SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); 495d6cffbbeSKonstantin Khlebnikov if (!--head->count) 496d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 497d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 498d6cffbbeSKonstantin Khlebnikov } 499d6cffbbeSKonstantin Khlebnikov 50081324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 50177b14db5SEric W. Biederman { 5023cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5033cc3e046SEric W. Biederman if (!head) 5040e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5053cc3e046SEric W. Biederman return sysctl_head_grab(head); 50677b14db5SEric W. Biederman } 50777b14db5SEric W. Biederman 50877b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 50900cd8dd3SAl Viro unsigned int flags) 51077b14db5SEric W. Biederman { 5119043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5129043476fSAl Viro struct ctl_table_header *h = NULL; 513dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5149043476fSAl Viro struct ctl_table *p; 51577b14db5SEric W. Biederman struct inode *inode; 5169043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5177ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5180e47c99dSEric W. Biederman int ret; 51977b14db5SEric W. Biederman 5209043476fSAl Viro if (IS_ERR(head)) 5219043476fSAl Viro return ERR_CAST(head); 5229043476fSAl Viro 5237ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5249043476fSAl Viro 5257ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5269043476fSAl Viro if (!p) 52777b14db5SEric W. Biederman goto out; 52877b14db5SEric W. Biederman 5294e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 53013bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5310e47c99dSEric W. Biederman err = ERR_PTR(ret); 5320e47c99dSEric W. Biederman if (ret) 5330e47c99dSEric W. Biederman goto out; 5344e757320SEric W. Biederman } 5350e47c99dSEric W. Biederman 5369043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 537ea5751ccSIvan Delalande if (IS_ERR(inode)) { 538ea5751ccSIvan Delalande err = ERR_CAST(inode); 53977b14db5SEric W. Biederman goto out; 540ea5751ccSIvan Delalande } 54177b14db5SEric W. Biederman 542fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 543888e2b03SAl Viro err = d_splice_alias(inode, dentry); 54477b14db5SEric W. Biederman 54577b14db5SEric W. Biederman out: 5466bf61045SFrancesco Ruggeri if (h) 5476bf61045SFrancesco Ruggeri sysctl_head_finish(h); 54877b14db5SEric W. Biederman sysctl_head_finish(head); 54977b14db5SEric W. Biederman return err; 55077b14db5SEric W. Biederman } 55177b14db5SEric W. Biederman 5524bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, 5534bd6a735SMatthew Wilcox (Oracle) int write) 55477b14db5SEric W. Biederman { 5554bd6a735SMatthew Wilcox (Oracle) struct inode *inode = file_inode(iocb->ki_filp); 5569043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5579043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5584bd6a735SMatthew Wilcox (Oracle) size_t count = iov_iter_count(iter); 5594bd6a735SMatthew Wilcox (Oracle) char *kbuf; 5602a2da53bSDavid Howells ssize_t error; 56177b14db5SEric W. Biederman 5629043476fSAl Viro if (IS_ERR(head)) 5639043476fSAl Viro return PTR_ERR(head); 56477b14db5SEric W. Biederman 56577b14db5SEric W. Biederman /* 56677b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 56777b14db5SEric W. Biederman * and won't be until we finish. 56877b14db5SEric W. Biederman */ 56977b14db5SEric W. Biederman error = -EPERM; 57073f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 57177b14db5SEric W. Biederman goto out; 57277b14db5SEric W. Biederman 5739043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5749043476fSAl Viro error = -EINVAL; 5759043476fSAl Viro if (!table->proc_handler) 5769043476fSAl Viro goto out; 5779043476fSAl Viro 578ef9d965bSChristoph Hellwig /* don't even try if the size is too large */ 579d4d80e69SMatthew Wilcox (Oracle) error = -ENOMEM; 580d4d80e69SMatthew Wilcox (Oracle) if (count >= KMALLOC_MAX_SIZE) 581d4d80e69SMatthew Wilcox (Oracle) goto out; 58245089437SJosef Bacik kbuf = kvzalloc(count + 1, GFP_KERNEL); 58332927393SChristoph Hellwig if (!kbuf) 58432927393SChristoph Hellwig goto out; 5854bd6a735SMatthew Wilcox (Oracle) 5864bd6a735SMatthew Wilcox (Oracle) if (write) { 5874bd6a735SMatthew Wilcox (Oracle) error = -EFAULT; 5884bd6a735SMatthew Wilcox (Oracle) if (!copy_from_iter_full(kbuf, count, iter)) 5894bd6a735SMatthew Wilcox (Oracle) goto out_free_buf; 5904bd6a735SMatthew Wilcox (Oracle) kbuf[count] = '\0'; 5914e63acdfSAndrey Ignatov } 5924e63acdfSAndrey Ignatov 59332927393SChristoph Hellwig error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, 5944bd6a735SMatthew Wilcox (Oracle) &iocb->ki_pos); 59532927393SChristoph Hellwig if (error) 59632927393SChristoph Hellwig goto out_free_buf; 59732927393SChristoph Hellwig 59832927393SChristoph Hellwig /* careful: calling conventions are nasty here */ 5994bd6a735SMatthew Wilcox (Oracle) error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); 60032927393SChristoph Hellwig if (error) 60132927393SChristoph Hellwig goto out_free_buf; 60232927393SChristoph Hellwig 60332927393SChristoph Hellwig if (!write) { 60432927393SChristoph Hellwig error = -EFAULT; 6054bd6a735SMatthew Wilcox (Oracle) if (copy_to_iter(kbuf, count, iter) < count) 60632927393SChristoph Hellwig goto out_free_buf; 60732927393SChristoph Hellwig } 60832927393SChristoph Hellwig 6094e63acdfSAndrey Ignatov error = count; 61032927393SChristoph Hellwig out_free_buf: 61145089437SJosef Bacik kvfree(kbuf); 61277b14db5SEric W. Biederman out: 61377b14db5SEric W. Biederman sysctl_head_finish(head); 61477b14db5SEric W. Biederman 61577b14db5SEric W. Biederman return error; 61677b14db5SEric W. Biederman } 61777b14db5SEric W. Biederman 6184bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) 6197708bfb1SPavel Emelyanov { 6204bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 0); 6217708bfb1SPavel Emelyanov } 6227708bfb1SPavel Emelyanov 6234bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) 62477b14db5SEric W. Biederman { 6254bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 1); 62677b14db5SEric W. Biederman } 62777b14db5SEric W. Biederman 628f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 629f1ecf068SLucas De Marchi { 6304e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 631f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 632f1ecf068SLucas De Marchi 6334e474a00SLucas De Marchi /* sysctl was unregistered */ 6344e474a00SLucas De Marchi if (IS_ERR(head)) 6354e474a00SLucas De Marchi return PTR_ERR(head); 6364e474a00SLucas De Marchi 637f1ecf068SLucas De Marchi if (table->poll) 638f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 639f1ecf068SLucas De Marchi 6404e474a00SLucas De Marchi sysctl_head_finish(head); 6414e474a00SLucas De Marchi 642f1ecf068SLucas De Marchi return 0; 643f1ecf068SLucas De Marchi } 644f1ecf068SLucas De Marchi 645076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 646f1ecf068SLucas De Marchi { 647496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6484e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 649f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 650076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6514e474a00SLucas De Marchi unsigned long event; 6524e474a00SLucas De Marchi 6534e474a00SLucas De Marchi /* sysctl was unregistered */ 6544e474a00SLucas De Marchi if (IS_ERR(head)) 655a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 656f1ecf068SLucas De Marchi 657f1ecf068SLucas De Marchi if (!table->proc_handler) 658f1ecf068SLucas De Marchi goto out; 659f1ecf068SLucas De Marchi 660f1ecf068SLucas De Marchi if (!table->poll) 661f1ecf068SLucas De Marchi goto out; 662f1ecf068SLucas De Marchi 6634e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 664f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 665f1ecf068SLucas De Marchi 666f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 667f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 668a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 669f1ecf068SLucas De Marchi } 670f1ecf068SLucas De Marchi 671f1ecf068SLucas De Marchi out: 6724e474a00SLucas De Marchi sysctl_head_finish(head); 6734e474a00SLucas De Marchi 674f1ecf068SLucas De Marchi return ret; 675f1ecf068SLucas De Marchi } 67677b14db5SEric W. Biederman 677f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 678f0c3b509SAl Viro struct dir_context *ctx, 6799043476fSAl Viro struct ctl_table_header *head, 6809043476fSAl Viro struct ctl_table *table) 68177b14db5SEric W. Biederman { 682f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 68377b14db5SEric W. Biederman struct inode *inode; 68477b14db5SEric W. Biederman struct qstr qname; 68577b14db5SEric W. Biederman ino_t ino = 0; 68677b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 68777b14db5SEric W. Biederman 68877b14db5SEric W. Biederman qname.name = table->procname; 68977b14db5SEric W. Biederman qname.len = strlen(table->procname); 6908387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 69177b14db5SEric W. Biederman 69277b14db5SEric W. Biederman child = d_lookup(dir, &qname); 69377b14db5SEric W. Biederman if (!child) { 69476aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 69576aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 69676aab3abSAl Viro if (IS_ERR(child)) 69776aab3abSAl Viro return false; 69876aab3abSAl Viro if (d_in_lookup(child)) { 699888e2b03SAl Viro struct dentry *res; 7009043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 701ea5751ccSIvan Delalande if (IS_ERR(inode)) { 70276aab3abSAl Viro d_lookup_done(child); 7039043476fSAl Viro dput(child); 704f0c3b509SAl Viro return false; 70576aab3abSAl Viro } 706fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 707888e2b03SAl Viro res = d_splice_alias(inode, child); 708888e2b03SAl Viro d_lookup_done(child); 709888e2b03SAl Viro if (unlikely(res)) { 710888e2b03SAl Viro if (IS_ERR(res)) { 711888e2b03SAl Viro dput(child); 712888e2b03SAl Viro return false; 713888e2b03SAl Viro } 714888e2b03SAl Viro dput(child); 715888e2b03SAl Viro child = res; 716888e2b03SAl Viro } 71777b14db5SEric W. Biederman } 71877b14db5SEric W. Biederman } 7192b0143b5SDavid Howells inode = d_inode(child); 72077b14db5SEric W. Biederman ino = inode->i_ino; 72177b14db5SEric W. Biederman type = inode->i_mode >> 12; 72277b14db5SEric W. Biederman dput(child); 723f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7249043476fSAl Viro } 7259043476fSAl Viro 726f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 727f0c3b509SAl Viro struct dir_context *ctx, 7280e47c99dSEric W. Biederman struct ctl_table_header *head, 7290e47c99dSEric W. Biederman struct ctl_table *table) 7300e47c99dSEric W. Biederman { 731f0c3b509SAl Viro bool ret = true; 732a0b0d1c3SDanilo Krummrich 7330e47c99dSEric W. Biederman head = sysctl_head_grab(head); 734a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 735a0b0d1c3SDanilo Krummrich return false; 7360e47c99dSEric W. Biederman 7370e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 738835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7390e47c99dSEric W. Biederman goto out; 7400e47c99dSEric W. Biederman 741f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7420e47c99dSEric W. Biederman out: 7430e47c99dSEric W. Biederman sysctl_head_finish(head); 7440e47c99dSEric W. Biederman return ret; 7450e47c99dSEric W. Biederman } 7460e47c99dSEric W. Biederman 747e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7489043476fSAl Viro unsigned long *pos, struct file *file, 749f0c3b509SAl Viro struct dir_context *ctx) 7509043476fSAl Viro { 751f0c3b509SAl Viro bool res; 7529043476fSAl Viro 753f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 754f0c3b509SAl Viro return true; 7559043476fSAl Viro 7560e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 757f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7580e47c99dSEric W. Biederman else 759f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7609043476fSAl Viro 761f0c3b509SAl Viro if (res) 762f0c3b509SAl Viro ctx->pos = *pos; 7636a75ce16SEric W. Biederman 7646a75ce16SEric W. Biederman return res; 76577b14db5SEric W. Biederman } 76677b14db5SEric W. Biederman 767f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 76877b14db5SEric W. Biederman { 769f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7709043476fSAl Viro struct ctl_table_header *h = NULL; 7716a75ce16SEric W. Biederman struct ctl_table *entry; 7727ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 77377b14db5SEric W. Biederman unsigned long pos; 77477b14db5SEric W. Biederman 7759043476fSAl Viro if (IS_ERR(head)) 7769043476fSAl Viro return PTR_ERR(head); 7779043476fSAl Viro 7787ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 77977b14db5SEric W. Biederman 780f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 78193362fa4SZhou Chengming goto out; 782f0c3b509SAl Viro 78377b14db5SEric W. Biederman pos = 2; 78477b14db5SEric W. Biederman 7857ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 786f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7879043476fSAl Viro sysctl_head_finish(h); 7889043476fSAl Viro break; 78977b14db5SEric W. Biederman } 79077b14db5SEric W. Biederman } 79193362fa4SZhou Chengming out: 79277b14db5SEric W. Biederman sysctl_head_finish(head); 793f0c3b509SAl Viro return 0; 79477b14db5SEric W. Biederman } 79577b14db5SEric W. Biederman 7964609e1f1SChristian Brauner static int proc_sys_permission(struct mnt_idmap *idmap, 797549c7297SChristian Brauner struct inode *inode, int mask) 79877b14db5SEric W. Biederman { 79977b14db5SEric W. Biederman /* 80077b14db5SEric W. Biederman * sysctl entries that are not writeable, 80177b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 80277b14db5SEric W. Biederman */ 803f696a365SMiklos Szeredi struct ctl_table_header *head; 804f696a365SMiklos Szeredi struct ctl_table *table; 80577b14db5SEric W. Biederman int error; 80677b14db5SEric W. Biederman 807f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 808f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 809f696a365SMiklos Szeredi return -EACCES; 810f696a365SMiklos Szeredi 811f696a365SMiklos Szeredi head = grab_header(inode); 8129043476fSAl Viro if (IS_ERR(head)) 8139043476fSAl Viro return PTR_ERR(head); 81477b14db5SEric W. Biederman 815f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8169043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8179043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8189043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 81973f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8209043476fSAl Viro 82177b14db5SEric W. Biederman sysctl_head_finish(head); 82277b14db5SEric W. Biederman return error; 82377b14db5SEric W. Biederman } 82477b14db5SEric W. Biederman 825c1632a0fSChristian Brauner static int proc_sys_setattr(struct mnt_idmap *idmap, 826549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr) 82777b14db5SEric W. Biederman { 8282b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 82977b14db5SEric W. Biederman int error; 83077b14db5SEric W. Biederman 83177b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 83277b14db5SEric W. Biederman return -EPERM; 83377b14db5SEric W. Biederman 834c1632a0fSChristian Brauner error = setattr_prepare(&nop_mnt_idmap, dentry, attr); 8351025774cSChristoph Hellwig if (error) 83677b14db5SEric W. Biederman return error; 8371025774cSChristoph Hellwig 838c1632a0fSChristian Brauner setattr_copy(&nop_mnt_idmap, inode, attr); 8391025774cSChristoph Hellwig return 0; 84077b14db5SEric W. Biederman } 84177b14db5SEric W. Biederman 842b74d24f7SChristian Brauner static int proc_sys_getattr(struct mnt_idmap *idmap, 843549c7297SChristian Brauner const struct path *path, struct kstat *stat, 844a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8459043476fSAl Viro { 846a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8479043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8489043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8499043476fSAl Viro 8509043476fSAl Viro if (IS_ERR(head)) 8519043476fSAl Viro return PTR_ERR(head); 8529043476fSAl Viro 853b74d24f7SChristian Brauner generic_fillattr(&nop_mnt_idmap, inode, stat); 8549043476fSAl Viro if (table) 8559043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8569043476fSAl Viro 8579043476fSAl Viro sysctl_head_finish(head); 8589043476fSAl Viro return 0; 8599043476fSAl Viro } 8609043476fSAl Viro 86177b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 862f1ecf068SLucas De Marchi .open = proc_sys_open, 863f1ecf068SLucas De Marchi .poll = proc_sys_poll, 8644bd6a735SMatthew Wilcox (Oracle) .read_iter = proc_sys_read, 8654bd6a735SMatthew Wilcox (Oracle) .write_iter = proc_sys_write, 866b0072734SDavid Howells .splice_read = copy_splice_read, 8674bd6a735SMatthew Wilcox (Oracle) .splice_write = iter_file_splice_write, 8686038f373SArnd Bergmann .llseek = default_llseek, 8699043476fSAl Viro }; 8709043476fSAl Viro 8719043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 872887df078SPavel Emelyanov .read = generic_read_dir, 873f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8743222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 87577b14db5SEric W. Biederman }; 87677b14db5SEric W. Biederman 87703a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8789043476fSAl Viro .permission = proc_sys_permission, 8799043476fSAl Viro .setattr = proc_sys_setattr, 8809043476fSAl Viro .getattr = proc_sys_getattr, 8819043476fSAl Viro }; 8829043476fSAl Viro 8839043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 88477b14db5SEric W. Biederman .lookup = proc_sys_lookup, 88577b14db5SEric W. Biederman .permission = proc_sys_permission, 88677b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8879043476fSAl Viro .getattr = proc_sys_getattr, 88877b14db5SEric W. Biederman }; 88977b14db5SEric W. Biederman 8900b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 89177b14db5SEric W. Biederman { 8920b728e19SAl Viro if (flags & LOOKUP_RCU) 89334286d66SNick Piggin return -ECHILD; 8942b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8959043476fSAl Viro } 8969043476fSAl Viro 897fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8989043476fSAl Viro { 8992b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 9009043476fSAl Viro } 9019043476fSAl Viro 9021f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 9031f87f0b5SEric W. Biederman { 9041f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 9051f87f0b5SEric W. Biederman int res; 9061f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 9071f87f0b5SEric W. Biederman if (p->unregistering) 9081f87f0b5SEric W. Biederman res = 0; 9091f87f0b5SEric W. Biederman else if (!set->is_seen) 9101f87f0b5SEric W. Biederman res = 1; 9111f87f0b5SEric W. Biederman else 9121f87f0b5SEric W. Biederman res = set->is_seen(set); 9131f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9141f87f0b5SEric W. Biederman return res; 9151f87f0b5SEric W. Biederman } 9161f87f0b5SEric W. Biederman 9176fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 918621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9199043476fSAl Viro { 920dfef6dcdSAl Viro struct ctl_table_header *head; 921da53be12SLinus Torvalds struct inode *inode; 922da53be12SLinus Torvalds 92331e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 92431e6b01fSNick Piggin * that inode here can be NULL */ 925dfef6dcdSAl Viro /* AV: can it, indeed? */ 9262b0143b5SDavid Howells inode = d_inode_rcu(dentry); 92731e6b01fSNick Piggin if (!inode) 928dfef6dcdSAl Viro return 1; 929621e155aSNick Piggin if (name->len != len) 9309043476fSAl Viro return 1; 931621e155aSNick Piggin if (memcmp(name->name, str, len)) 9329043476fSAl Viro return 1; 933dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 934dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 93577b14db5SEric W. Biederman } 93677b14db5SEric W. Biederman 937d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 93877b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9399043476fSAl Viro .d_delete = proc_sys_delete, 9409043476fSAl Viro .d_compare = proc_sys_compare, 94177b14db5SEric W. Biederman }; 94277b14db5SEric W. Biederman 9430e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9447ec66d06SEric W. Biederman const char *name, int namelen) 9451f87f0b5SEric W. Biederman { 9467ec66d06SEric W. Biederman struct ctl_table_header *head; 9477ec66d06SEric W. Biederman struct ctl_table *entry; 9481f87f0b5SEric W. Biederman 9490e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9507ec66d06SEric W. Biederman if (!entry) 9517ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 95251f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9537ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 95451f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9551f87f0b5SEric W. Biederman } 9561f87f0b5SEric W. Biederman 9577ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9587ec66d06SEric W. Biederman const char *name, int namelen) 9591f87f0b5SEric W. Biederman { 9607ec66d06SEric W. Biederman struct ctl_table *table; 9617ec66d06SEric W. Biederman struct ctl_dir *new; 962ac13ac6fSEric W. Biederman struct ctl_node *node; 9637ec66d06SEric W. Biederman char *new_name; 9641f87f0b5SEric W. Biederman 965ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 966ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 967ac13ac6fSEric W. Biederman GFP_KERNEL); 9687ec66d06SEric W. Biederman if (!new) 9697ec66d06SEric W. Biederman return NULL; 9707ec66d06SEric W. Biederman 971ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 972ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9737ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9747ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9757ec66d06SEric W. Biederman table[0].procname = new_name; 9767ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 977b1f01e2bSJoel Granados init_header(&new->header, set->dir.header.root, set, node, table, 1); 9787ec66d06SEric W. Biederman 9797ec66d06SEric W. Biederman return new; 9801f87f0b5SEric W. Biederman } 9811f87f0b5SEric W. Biederman 98260f126d9SEric W. Biederman /** 98360f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 98460f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 98560f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 98660f126d9SEric W. Biederman * @namelen: The length of name 98760f126d9SEric W. Biederman * 98860f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 98960f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 99060f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 99160f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 99260f126d9SEric W. Biederman * simply dropped. 99360f126d9SEric W. Biederman */ 9940e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9950e47c99dSEric W. Biederman const char *name, int namelen) 9967ec66d06SEric W. Biederman { 9970e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9987ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9990eb97f38SEric W. Biederman int err; 10007ec66d06SEric W. Biederman 10017ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10020e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10037ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10047ec66d06SEric W. Biederman goto found; 10057ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10067ec66d06SEric W. Biederman goto failed; 10077ec66d06SEric W. Biederman 10087ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10097ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 10107ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10117ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10127ec66d06SEric W. Biederman if (!new) 10137ec66d06SEric W. Biederman goto failed; 10147ec66d06SEric W. Biederman 101560f126d9SEric W. Biederman /* Was the subdir added while we dropped the 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 102260f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10230eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10240eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10250eb97f38SEric W. Biederman if (err) 10260e47c99dSEric W. Biederman goto failed; 10277ec66d06SEric W. Biederman subdir = new; 10287ec66d06SEric W. Biederman found: 10297ec66d06SEric W. Biederman subdir->header.nreg++; 10307ec66d06SEric W. Biederman failed: 1031a1c83681SViresh Kumar if (IS_ERR(subdir)) { 103287ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10336980128fSEric W. Biederman sysctl_print_dir(dir); 1034153ee1c4SGeert Uytterhoeven pr_cont("%*.*s %ld\n", namelen, namelen, name, 1035153ee1c4SGeert Uytterhoeven PTR_ERR(subdir)); 10361f87f0b5SEric W. Biederman } 10377ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10387ec66d06SEric W. Biederman if (new) 10397ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10407ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10417ec66d06SEric W. Biederman return subdir; 10421f87f0b5SEric W. Biederman } 10431f87f0b5SEric W. Biederman 10440e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10450e47c99dSEric W. Biederman { 10460e47c99dSEric W. Biederman struct ctl_dir *parent; 10470e47c99dSEric W. Biederman const char *procname; 10480e47c99dSEric W. Biederman if (!dir->header.parent) 10490e47c99dSEric W. Biederman return &set->dir; 10500e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10510e47c99dSEric W. Biederman if (IS_ERR(parent)) 10520e47c99dSEric W. Biederman return parent; 10530e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10540e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10550e47c99dSEric W. Biederman } 10560e47c99dSEric W. Biederman 10570e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 105813bcc6a2SEric W. Biederman struct ctl_table **pentry) 10590e47c99dSEric W. Biederman { 10600e47c99dSEric W. Biederman struct ctl_table_header *head; 10610e47c99dSEric W. Biederman struct ctl_table_root *root; 10620e47c99dSEric W. Biederman struct ctl_table_set *set; 10630e47c99dSEric W. Biederman struct ctl_table *entry; 10640e47c99dSEric W. Biederman struct ctl_dir *dir; 10650e47c99dSEric W. Biederman int ret; 10660e47c99dSEric W. Biederman 10670e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10680e47c99dSEric W. Biederman root = (*pentry)->data; 106913bcc6a2SEric W. Biederman set = lookup_header_set(root); 10700e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10710e47c99dSEric W. Biederman if (IS_ERR(dir)) 10720e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10730e47c99dSEric W. Biederman else { 10740e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10750e47c99dSEric W. Biederman head = NULL; 10760e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10770e47c99dSEric W. Biederman ret = -ENOENT; 10780e47c99dSEric W. Biederman if (entry && use_table(head)) { 10790e47c99dSEric W. Biederman unuse_table(*phead); 10800e47c99dSEric W. Biederman *phead = head; 10810e47c99dSEric W. Biederman *pentry = entry; 10820e47c99dSEric W. Biederman ret = 0; 10830e47c99dSEric W. Biederman } 10840e47c99dSEric W. Biederman } 10850e47c99dSEric W. Biederman 10860e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10870e47c99dSEric W. Biederman return ret; 10880e47c99dSEric W. Biederman } 10890e47c99dSEric W. Biederman 10907c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10917c60c48fSEric W. Biederman { 10927c60c48fSEric W. Biederman struct va_format vaf; 10937c60c48fSEric W. Biederman va_list args; 10947c60c48fSEric W. Biederman 10957c60c48fSEric W. Biederman va_start(args, fmt); 10967c60c48fSEric W. Biederman vaf.fmt = fmt; 10977c60c48fSEric W. Biederman vaf.va = &args; 10987c60c48fSEric W. Biederman 109987ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 11007c60c48fSEric W. Biederman path, table->procname, &vaf); 11017c60c48fSEric W. Biederman 11027c60c48fSEric W. Biederman va_end(args); 11037c60c48fSEric W. Biederman return -EINVAL; 11047c60c48fSEric W. Biederman } 11057c60c48fSEric W. Biederman 11064f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 11074f2fec00SLuis R. Rodriguez { 11084f2fec00SLuis R. Rodriguez int err = 0; 11094f2fec00SLuis R. Rodriguez 111061d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 111161d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11124f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 111364a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11144f2fec00SLuis R. Rodriguez } 11154f2fec00SLuis R. Rodriguez 1116cb944413SEric Dumazet if (table->proc_handler == proc_dou8vec_minmax) { 1117cb944413SEric Dumazet if (table->maxlen != sizeof(u8)) 1118cb944413SEric Dumazet err |= sysctl_err(path, table, "array not allowed"); 1119cb944413SEric Dumazet } 1120cb944413SEric Dumazet 1121f1aa2eb5SOndrej Mosnacek if (table->proc_handler == proc_dobool) { 1122f1aa2eb5SOndrej Mosnacek if (table->maxlen != sizeof(bool)) 1123f1aa2eb5SOndrej Mosnacek err |= sysctl_err(path, table, "array not allowed"); 1124f1aa2eb5SOndrej Mosnacek } 1125f1aa2eb5SOndrej Mosnacek 11264f2fec00SLuis R. Rodriguez return err; 11274f2fec00SLuis R. Rodriguez } 11284f2fec00SLuis R. Rodriguez 1129cc9f7ee0SJoel Granados static int sysctl_check_table(const char *path, struct ctl_table_header *header) 11307c60c48fSEric W. Biederman { 1131cb55f27aSMeng Tang struct ctl_table *entry; 11327c60c48fSEric W. Biederman int err = 0; 113318d4b42eSJoel Granados list_for_each_table_entry(entry, header) { 1134cb55f27aSMeng Tang if ((entry->proc_handler == proc_dostring) || 1135f1aa2eb5SOndrej Mosnacek (entry->proc_handler == proc_dobool) || 1136cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec) || 1137cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec) || 1138cb55f27aSMeng Tang (entry->proc_handler == proc_douintvec_minmax) || 1139cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_minmax) || 1140cb55f27aSMeng Tang (entry->proc_handler == proc_dou8vec_minmax) || 1141cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_jiffies) || 1142cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_userhz_jiffies) || 1143cb55f27aSMeng Tang (entry->proc_handler == proc_dointvec_ms_jiffies) || 1144cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_minmax) || 1145cb55f27aSMeng Tang (entry->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 1146cb55f27aSMeng Tang if (!entry->data) 1147cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No data"); 1148cb55f27aSMeng Tang if (!entry->maxlen) 1149cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No maxlen"); 11504f2fec00SLuis R. Rodriguez else 1151cb55f27aSMeng Tang err |= sysctl_check_table_array(path, entry); 11521f87f0b5SEric W. Biederman } 1153cb55f27aSMeng Tang if (!entry->proc_handler) 1154cb55f27aSMeng Tang err |= sysctl_err(path, entry, "No proc_handler"); 11557c60c48fSEric W. Biederman 1156cb55f27aSMeng Tang if ((entry->mode & (S_IRUGO|S_IWUGO)) != entry->mode) 1157cb55f27aSMeng Tang err |= sysctl_err(path, entry, "bogus .mode 0%o", 1158cb55f27aSMeng Tang entry->mode); 11591f87f0b5SEric W. Biederman } 11607c60c48fSEric W. Biederman return err; 11611f87f0b5SEric W. Biederman } 11621f87f0b5SEric W. Biederman 1163cc9f7ee0SJoel Granados static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_header *head) 11640e47c99dSEric W. Biederman { 11650e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11660e47c99dSEric W. Biederman struct ctl_table_header *links; 1167ac13ac6fSEric W. Biederman struct ctl_node *node; 11680e47c99dSEric W. Biederman char *link_name; 11690e47c99dSEric W. Biederman int nr_entries, name_bytes; 11700e47c99dSEric W. Biederman 11710e47c99dSEric W. Biederman name_bytes = 0; 11720e47c99dSEric W. Biederman nr_entries = 0; 117318d4b42eSJoel Granados list_for_each_table_entry(entry, head) { 11740e47c99dSEric W. Biederman nr_entries++; 11750e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11760e47c99dSEric W. Biederman } 11770e47c99dSEric W. Biederman 11780e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1179ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11800e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11810e47c99dSEric W. Biederman name_bytes, 11820e47c99dSEric W. Biederman GFP_KERNEL); 11830e47c99dSEric W. Biederman 11840e47c99dSEric W. Biederman if (!links) 11850e47c99dSEric W. Biederman return NULL; 11860e47c99dSEric W. Biederman 1187ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1188ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11890e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 1190cb55f27aSMeng Tang link = link_table; 11910e47c99dSEric W. Biederman 119218d4b42eSJoel Granados list_for_each_table_entry(entry, head) { 11930e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11940e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11950e47c99dSEric W. Biederman link->procname = link_name; 11960e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 1197cc9f7ee0SJoel Granados link->data = head->root; 11980e47c99dSEric W. Biederman link_name += len; 1199cb55f27aSMeng Tang link++; 12000e47c99dSEric W. Biederman } 1201b1f01e2bSJoel Granados init_header(links, dir->header.root, dir->header.set, node, link_table, 1202b1f01e2bSJoel Granados head->ctl_table_size); 12030e47c99dSEric W. Biederman links->nreg = nr_entries; 12040e47c99dSEric W. Biederman 12050e47c99dSEric W. Biederman return links; 12060e47c99dSEric W. Biederman } 12070e47c99dSEric W. Biederman 12080e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 1209cc9f7ee0SJoel Granados struct ctl_table_header *header, 1210cc9f7ee0SJoel Granados struct ctl_table_root *link_root) 12110e47c99dSEric W. Biederman { 1212cc9f7ee0SJoel Granados struct ctl_table_header *tmp_head; 12130e47c99dSEric W. Biederman struct ctl_table *entry, *link; 12140e47c99dSEric W. Biederman 12150e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 121618d4b42eSJoel Granados list_for_each_table_entry(entry, header) { 12170e47c99dSEric W. Biederman const char *procname = entry->procname; 1218cc9f7ee0SJoel Granados link = find_entry(&tmp_head, dir, procname, strlen(procname)); 12190e47c99dSEric W. Biederman if (!link) 12200e47c99dSEric W. Biederman return false; 12210e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12220e47c99dSEric W. Biederman continue; 12230e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12240e47c99dSEric W. Biederman continue; 12250e47c99dSEric W. Biederman return false; 12260e47c99dSEric W. Biederman } 12270e47c99dSEric W. Biederman 12280e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 122918d4b42eSJoel Granados list_for_each_table_entry(entry, header) { 12300e47c99dSEric W. Biederman const char *procname = entry->procname; 1231cc9f7ee0SJoel Granados link = find_entry(&tmp_head, dir, procname, strlen(procname)); 1232cc9f7ee0SJoel Granados tmp_head->nreg++; 12330e47c99dSEric W. Biederman } 12340e47c99dSEric W. Biederman return true; 12350e47c99dSEric W. Biederman } 12360e47c99dSEric W. Biederman 12370e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12380e47c99dSEric W. Biederman { 12390e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12409a521359SLi zeming struct ctl_dir *core_parent; 12410e47c99dSEric W. Biederman struct ctl_table_header *links; 12420e47c99dSEric W. Biederman int err; 12430e47c99dSEric W. Biederman 12440e47c99dSEric W. Biederman if (head->set == root_set) 12450e47c99dSEric W. Biederman return 0; 12460e47c99dSEric W. Biederman 12470e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12480e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12490e47c99dSEric W. Biederman return 0; 12500e47c99dSEric W. Biederman 1251cc9f7ee0SJoel Granados if (get_links(core_parent, head, head->root)) 12520e47c99dSEric W. Biederman return 0; 12530e47c99dSEric W. Biederman 12540e47c99dSEric W. Biederman core_parent->header.nreg++; 12550e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12560e47c99dSEric W. Biederman 1257cc9f7ee0SJoel Granados links = new_links(core_parent, head); 12580e47c99dSEric W. Biederman 12590e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12600e47c99dSEric W. Biederman err = -ENOMEM; 12610e47c99dSEric W. Biederman if (!links) 12620e47c99dSEric W. Biederman goto out; 12630e47c99dSEric W. Biederman 12640e47c99dSEric W. Biederman err = 0; 1265cc9f7ee0SJoel Granados if (get_links(core_parent, head, head->root)) { 12660e47c99dSEric W. Biederman kfree(links); 12670e47c99dSEric W. Biederman goto out; 12680e47c99dSEric W. Biederman } 12690e47c99dSEric W. Biederman 12700e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12710e47c99dSEric W. Biederman if (err) 12720e47c99dSEric W. Biederman kfree(links); 12730e47c99dSEric W. Biederman out: 12740e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12750e47c99dSEric W. Biederman return err; 12760e47c99dSEric W. Biederman } 12770e47c99dSEric W. Biederman 1278b2f56e55SLuis Chamberlain /* Find the directory for the ctl_table. If one is not found create it. */ 1279b2f56e55SLuis Chamberlain static struct ctl_dir *sysctl_mkdir_p(struct ctl_dir *dir, const char *path) 1280b2f56e55SLuis Chamberlain { 1281b2f56e55SLuis Chamberlain const char *name, *nextname; 1282b2f56e55SLuis Chamberlain 1283b2f56e55SLuis Chamberlain for (name = path; name; name = nextname) { 1284b2f56e55SLuis Chamberlain int namelen; 1285b2f56e55SLuis Chamberlain nextname = strchr(name, '/'); 1286b2f56e55SLuis Chamberlain if (nextname) { 1287b2f56e55SLuis Chamberlain namelen = nextname - name; 1288b2f56e55SLuis Chamberlain nextname++; 1289b2f56e55SLuis Chamberlain } else { 1290b2f56e55SLuis Chamberlain namelen = strlen(name); 1291b2f56e55SLuis Chamberlain } 1292b2f56e55SLuis Chamberlain if (namelen == 0) 1293b2f56e55SLuis Chamberlain continue; 1294b2f56e55SLuis Chamberlain 1295b2f56e55SLuis Chamberlain /* 1296b2f56e55SLuis Chamberlain * namelen ensures if name is "foo/bar/yay" only foo is 1297b2f56e55SLuis Chamberlain * registered first. We traverse as if using mkdir -p and 1298b2f56e55SLuis Chamberlain * return a ctl_dir for the last directory entry. 1299b2f56e55SLuis Chamberlain */ 1300b2f56e55SLuis Chamberlain dir = get_subdir(dir, name, namelen); 1301b2f56e55SLuis Chamberlain if (IS_ERR(dir)) 1302b2f56e55SLuis Chamberlain break; 1303b2f56e55SLuis Chamberlain } 1304b2f56e55SLuis Chamberlain return dir; 1305b2f56e55SLuis Chamberlain } 1306b2f56e55SLuis Chamberlain 13071f87f0b5SEric W. Biederman /** 1308f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 130960a47a2eSEric W. Biederman * @set: Sysctl tree to register on 13101f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 13111dc8689eSLuis Chamberlain * @table: the top-level table structure without any child. This table 13121dc8689eSLuis Chamberlain * should not be free'd after registration. So it should not be 13131dc8689eSLuis Chamberlain * used on stack. It can either be a global or dynamically allocated 13141dc8689eSLuis Chamberlain * by the caller and free'd later after sysctl unregistration. 1315*bff97cf1SJoel Granados * @table_size : The number of elements in table 13161f87f0b5SEric W. Biederman * 13171f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 13181f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 13191f87f0b5SEric W. Biederman * 13201f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 13211f87f0b5SEric W. Biederman * 13221f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 13231f87f0b5SEric W. Biederman * enter a sysctl file 13241f87f0b5SEric W. Biederman * 13251f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 13261f87f0b5SEric W. Biederman * 13271f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 13281f87f0b5SEric W. Biederman * 1329f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 13301f87f0b5SEric W. Biederman * 1331f728019bSEric W. Biederman * child - must be %NULL. 13321f87f0b5SEric W. Biederman * 13331f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 13341f87f0b5SEric W. Biederman * 13351f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 133667ff3228SLuis Chamberlain * XXX: we should eventually modify these to use long min / max [0] 133767ff3228SLuis Chamberlain * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org 13381f87f0b5SEric W. Biederman * 13391f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 134067ff3228SLuis Chamberlain * under /proc; non-leaf nodes (where child is not NULL) are not allowed, 134167ff3228SLuis Chamberlain * sysctl_check_table() verifies this. 13421f87f0b5SEric W. Biederman * 1343f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1344f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 13451f87f0b5SEric W. Biederman * 13461f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 13471f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 13481f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 13491f87f0b5SEric W. Biederman * 13501f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 13511f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 13521f87f0b5SEric W. Biederman * 13531f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 13541f87f0b5SEric W. Biederman * to the table header on success. 13551f87f0b5SEric W. Biederman */ 13566e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 135760a47a2eSEric W. Biederman struct ctl_table_set *set, 1358*bff97cf1SJoel Granados const char *path, struct ctl_table *table, size_t table_size) 13591f87f0b5SEric W. Biederman { 136060a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13611f87f0b5SEric W. Biederman struct ctl_table_header *header; 13627ec66d06SEric W. Biederman struct ctl_dir *dir; 1363ac13ac6fSEric W. Biederman struct ctl_node *node; 1364ac13ac6fSEric W. Biederman 1365ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1366*bff97cf1SJoel Granados sizeof(struct ctl_node)*table_size, GFP_KERNEL_ACCOUNT); 13671f87f0b5SEric W. Biederman if (!header) 13681f87f0b5SEric W. Biederman return NULL; 13691f87f0b5SEric W. Biederman 1370ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1371*bff97cf1SJoel Granados init_header(header, root, set, node, table, table_size); 1372cc9f7ee0SJoel Granados if (sysctl_check_table(path, header)) 13737c60c48fSEric W. Biederman goto fail; 13748d6ecfccSEric W. Biederman 13751f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13760e47c99dSEric W. Biederman dir = &set->dir; 137767ff3228SLuis Chamberlain /* Reference moved down the directory tree get_subdir */ 13787ec66d06SEric W. Biederman dir->header.nreg++; 13797ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13807ec66d06SEric W. Biederman 1381b2f56e55SLuis Chamberlain dir = sysctl_mkdir_p(dir, path); 13827ec66d06SEric W. Biederman if (IS_ERR(dir)) 13837ec66d06SEric W. Biederman goto fail; 13847ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13850e47c99dSEric W. Biederman if (insert_header(dir, header)) 13860e47c99dSEric W. Biederman goto fail_put_dir_locked; 13870e47c99dSEric W. Biederman 13887ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13891f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13901f87f0b5SEric W. Biederman 13911f87f0b5SEric W. Biederman return header; 13920e47c99dSEric W. Biederman 13937ec66d06SEric W. Biederman fail_put_dir_locked: 13947ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13957c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13967c60c48fSEric W. Biederman fail: 13977c60c48fSEric W. Biederman kfree(header); 13987c60c48fSEric W. Biederman return NULL; 13991f87f0b5SEric W. Biederman } 14001f87f0b5SEric W. Biederman 1401fea478d4SEric W. Biederman /** 1402fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 14031dc8689eSLuis Chamberlain * @path: The path to the directory the sysctl table is in. If the path 14041dc8689eSLuis Chamberlain * doesn't exist we will create it for you. 14051dc8689eSLuis Chamberlain * @table: the table structure. The calller must ensure the life of the @table 14061dc8689eSLuis Chamberlain * will be kept during the lifetime use of the syctl. It must not be freed 14071dc8689eSLuis Chamberlain * until unregister_sysctl_table() is called with the given returned table 14081dc8689eSLuis Chamberlain * with this registration. If your code is non modular then you don't need 14091dc8689eSLuis Chamberlain * to call unregister_sysctl_table() and can instead use something like 14101dc8689eSLuis Chamberlain * register_sysctl_init() which does not care for the result of the syctl 14111dc8689eSLuis Chamberlain * registration. 1412fea478d4SEric W. Biederman * 1413fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1414fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1415fea478d4SEric W. Biederman * 1416fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1417fea478d4SEric W. Biederman */ 1418fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1419fea478d4SEric W. Biederman { 1420*bff97cf1SJoel Granados int count = 0; 1421*bff97cf1SJoel Granados struct ctl_table *entry; 1422*bff97cf1SJoel Granados struct ctl_table_header t_hdr; 1423*bff97cf1SJoel Granados 1424*bff97cf1SJoel Granados t_hdr.ctl_table = table; 1425*bff97cf1SJoel Granados list_for_each_table_entry(entry, (&t_hdr)) 1426*bff97cf1SJoel Granados count++; 1427fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1428*bff97cf1SJoel Granados path, table, count); 1429fea478d4SEric W. Biederman } 1430fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1431fea478d4SEric W. Biederman 14323ddd9a80SXiaoming Ni /** 14333ddd9a80SXiaoming Ni * __register_sysctl_init() - register sysctl table to path 14341dc8689eSLuis Chamberlain * @path: path name for sysctl base. If that path doesn't exist we will create 14351dc8689eSLuis Chamberlain * it for you. 14361dc8689eSLuis Chamberlain * @table: This is the sysctl table that needs to be registered to the path. 14371dc8689eSLuis Chamberlain * The caller must ensure the life of the @table will be kept during the 14381dc8689eSLuis Chamberlain * lifetime use of the sysctl. 14393ddd9a80SXiaoming Ni * @table_name: The name of sysctl table, only used for log printing when 14403ddd9a80SXiaoming Ni * registration fails 14413ddd9a80SXiaoming Ni * 14423ddd9a80SXiaoming Ni * The sysctl interface is used by userspace to query or modify at runtime 14433ddd9a80SXiaoming Ni * a predefined value set on a variable. These variables however have default 14443ddd9a80SXiaoming Ni * values pre-set. Code which depends on these variables will always work even 14453ddd9a80SXiaoming Ni * if register_sysctl() fails. If register_sysctl() fails you'd just loose the 14463ddd9a80SXiaoming Ni * ability to query or modify the sysctls dynamically at run time. Chances of 14473ddd9a80SXiaoming Ni * register_sysctl() failing on init are extremely low, and so for both reasons 14483ddd9a80SXiaoming Ni * this function does not return any error as it is used by initialization code. 14493ddd9a80SXiaoming Ni * 1450228b09deSLuis Chamberlain * Context: if your base directory does not exist it will be created for you. 14513ddd9a80SXiaoming Ni */ 14523ddd9a80SXiaoming Ni void __init __register_sysctl_init(const char *path, struct ctl_table *table, 14533ddd9a80SXiaoming Ni const char *table_name) 14543ddd9a80SXiaoming Ni { 14553ddd9a80SXiaoming Ni struct ctl_table_header *hdr = register_sysctl(path, table); 14563ddd9a80SXiaoming Ni 14573ddd9a80SXiaoming Ni if (unlikely(!hdr)) { 14583ddd9a80SXiaoming Ni pr_err("failed when register_sysctl %s to %s\n", table_name, path); 14593ddd9a80SXiaoming Ni return; 14603ddd9a80SXiaoming Ni } 14613ddd9a80SXiaoming Ni kmemleak_not_leak(hdr); 14623ddd9a80SXiaoming Ni } 14633ddd9a80SXiaoming Ni 14640e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 14650e47c99dSEric W. Biederman { 14660e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 14670e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 14680e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 14690e47c99dSEric W. Biederman struct ctl_dir *core_parent; 14700e47c99dSEric W. Biederman struct ctl_table *entry; 14710e47c99dSEric W. Biederman 14720e47c99dSEric W. Biederman if (header->set == root_set) 14730e47c99dSEric W. Biederman return; 14740e47c99dSEric W. Biederman 14750e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 14760e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 14770e47c99dSEric W. Biederman return; 14780e47c99dSEric W. Biederman 147918d4b42eSJoel Granados list_for_each_table_entry(entry, header) { 14800e47c99dSEric W. Biederman struct ctl_table_header *link_head; 14810e47c99dSEric W. Biederman struct ctl_table *link; 14820e47c99dSEric W. Biederman const char *name = entry->procname; 14830e47c99dSEric W. Biederman 14840e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 14850e47c99dSEric W. Biederman if (link && 14860e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 14870e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 14880e47c99dSEric W. Biederman drop_sysctl_table(link_head); 14890e47c99dSEric W. Biederman } 14900e47c99dSEric W. Biederman else { 149187ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 14920e47c99dSEric W. Biederman sysctl_print_dir(parent); 1493153ee1c4SGeert Uytterhoeven pr_cont("%s\n", name); 14940e47c99dSEric W. Biederman } 14950e47c99dSEric W. Biederman } 14960e47c99dSEric W. Biederman } 14970e47c99dSEric W. Biederman 1498938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1499938aaa4fSEric W. Biederman { 15007ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 15017ec66d06SEric W. Biederman 1502938aaa4fSEric W. Biederman if (--header->nreg) 1503938aaa4fSEric W. Biederman return; 1504938aaa4fSEric W. Biederman 150589189557SYueHaibing if (parent) { 15060e47c99dSEric W. Biederman put_links(header); 1507938aaa4fSEric W. Biederman start_unregistering(header); 150889189557SYueHaibing } 150989189557SYueHaibing 1510938aaa4fSEric W. Biederman if (!--header->count) 1511938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 15127ec66d06SEric W. Biederman 15137ec66d06SEric W. Biederman if (parent) 15147ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1515938aaa4fSEric W. Biederman } 1516938aaa4fSEric W. Biederman 15171f87f0b5SEric W. Biederman /** 15181f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 151919c4e618SJoel Granados * @header: the header returned from register_sysctl or __register_sysctl_table 15201f87f0b5SEric W. Biederman * 15211f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 15221f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 15231f87f0b5SEric W. Biederman */ 15241f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 15251f87f0b5SEric W. Biederman { 15261f87f0b5SEric W. Biederman might_sleep(); 15271f87f0b5SEric W. Biederman 15281f87f0b5SEric W. Biederman if (header == NULL) 15291f87f0b5SEric W. Biederman return; 15301f87f0b5SEric W. Biederman 15311f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1532938aaa4fSEric W. Biederman drop_sysctl_table(header); 15331f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 15341f87f0b5SEric W. Biederman } 15351f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 15361f87f0b5SEric W. Biederman 15370e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 15389eb47c26SEric W. Biederman struct ctl_table_root *root, 15391f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 15401f87f0b5SEric W. Biederman { 15411347440dSDan Carpenter memset(set, 0, sizeof(*set)); 15420e47c99dSEric W. Biederman set->is_seen = is_seen; 1543b1f01e2bSJoel Granados init_header(&set->dir.header, root, set, NULL, root_table, 1); 15441f87f0b5SEric W. Biederman } 15451f87f0b5SEric W. Biederman 154697324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 154797324cd8SEric W. Biederman { 1548ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 154997324cd8SEric W. Biederman } 15501f87f0b5SEric W. Biederman 15511e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 155277b14db5SEric W. Biederman { 1553e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1554e1675231SAlexey Dobriyan 155577b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 15569043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 1557d56c0d45SAlexey Dobriyan proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; 155877b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1559de4e83bdSEric W. Biederman 1560d8c0418aSLuis Chamberlain return sysctl_init_bases(); 156177b14db5SEric W. Biederman } 15623db978d4SVlastimil Babka 15630a477e1aSVlastimil Babka struct sysctl_alias { 15640a477e1aSVlastimil Babka const char *kernel_param; 15650a477e1aSVlastimil Babka const char *sysctl_param; 15660a477e1aSVlastimil Babka }; 15670a477e1aSVlastimil Babka 15680a477e1aSVlastimil Babka /* 15690a477e1aSVlastimil Babka * Historically some settings had both sysctl and a command line parameter. 15700a477e1aSVlastimil Babka * With the generic sysctl. parameter support, we can handle them at a single 15710a477e1aSVlastimil Babka * place and only keep the historical name for compatibility. This is not meant 15720a477e1aSVlastimil Babka * to add brand new aliases. When adding existing aliases, consider whether 15730a477e1aSVlastimil Babka * the possibly different moment of changing the value (e.g. from early_param 15740a477e1aSVlastimil Babka * to the moment do_sysctl_args() is called) is an issue for the specific 15750a477e1aSVlastimil Babka * parameter. 15760a477e1aSVlastimil Babka */ 15770a477e1aSVlastimil Babka static const struct sysctl_alias sysctl_aliases[] = { 1578f117955aSGuilherme G. Piccoli {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, 1579b467f3efSVlastimil Babka {"hung_task_panic", "kernel.hung_task_panic" }, 1580f117955aSGuilherme G. Piccoli {"numa_zonelist_order", "vm.numa_zonelist_order" }, 1581f117955aSGuilherme G. Piccoli {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, 1582f117955aSGuilherme G. Piccoli {"softlockup_panic", "kernel.softlockup_panic" }, 15830a477e1aSVlastimil Babka { } 15840a477e1aSVlastimil Babka }; 15850a477e1aSVlastimil Babka 15860a477e1aSVlastimil Babka static const char *sysctl_find_alias(char *param) 15870a477e1aSVlastimil Babka { 15880a477e1aSVlastimil Babka const struct sysctl_alias *alias; 15890a477e1aSVlastimil Babka 15900a477e1aSVlastimil Babka for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { 15910a477e1aSVlastimil Babka if (strcmp(alias->kernel_param, param) == 0) 15920a477e1aSVlastimil Babka return alias->sysctl_param; 15930a477e1aSVlastimil Babka } 15940a477e1aSVlastimil Babka 15950a477e1aSVlastimil Babka return NULL; 15960a477e1aSVlastimil Babka } 15970a477e1aSVlastimil Babka 15983db978d4SVlastimil Babka /* Set sysctl value passed on kernel command line. */ 15993db978d4SVlastimil Babka static int process_sysctl_arg(char *param, char *val, 16003db978d4SVlastimil Babka const char *unused, void *arg) 16013db978d4SVlastimil Babka { 16023db978d4SVlastimil Babka char *path; 16033db978d4SVlastimil Babka struct vfsmount **proc_mnt = arg; 16043db978d4SVlastimil Babka struct file_system_type *proc_fs_type; 16053db978d4SVlastimil Babka struct file *file; 16063db978d4SVlastimil Babka int len; 16073db978d4SVlastimil Babka int err; 16083db978d4SVlastimil Babka loff_t pos = 0; 16093db978d4SVlastimil Babka ssize_t wret; 16103db978d4SVlastimil Babka 16110a477e1aSVlastimil Babka if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { 16123db978d4SVlastimil Babka param += sizeof("sysctl") - 1; 16133db978d4SVlastimil Babka 16143db978d4SVlastimil Babka if (param[0] != '/' && param[0] != '.') 16153db978d4SVlastimil Babka return 0; 16163db978d4SVlastimil Babka 16173db978d4SVlastimil Babka param++; 16180a477e1aSVlastimil Babka } else { 16190a477e1aSVlastimil Babka param = (char *) sysctl_find_alias(param); 16200a477e1aSVlastimil Babka if (!param) 16210a477e1aSVlastimil Babka return 0; 16220a477e1aSVlastimil Babka } 16233db978d4SVlastimil Babka 1624697edcb0SXiaoming Ni if (!val) 1625697edcb0SXiaoming Ni return -EINVAL; 1626697edcb0SXiaoming Ni len = strlen(val); 1627697edcb0SXiaoming Ni if (len == 0) 1628697edcb0SXiaoming Ni return -EINVAL; 1629697edcb0SXiaoming Ni 16303db978d4SVlastimil Babka /* 16313db978d4SVlastimil Babka * To set sysctl options, we use a temporary mount of proc, look up the 16323db978d4SVlastimil Babka * respective sys/ file and write to it. To avoid mounting it when no 16333db978d4SVlastimil Babka * options were given, we mount it only when the first sysctl option is 16343db978d4SVlastimil Babka * found. Why not a persistent mount? There are problems with a 16353db978d4SVlastimil Babka * persistent mount of proc in that it forces userspace not to use any 16363db978d4SVlastimil Babka * proc mount options. 16373db978d4SVlastimil Babka */ 16383db978d4SVlastimil Babka if (!*proc_mnt) { 16393db978d4SVlastimil Babka proc_fs_type = get_fs_type("proc"); 16403db978d4SVlastimil Babka if (!proc_fs_type) { 16413db978d4SVlastimil Babka pr_err("Failed to find procfs to set sysctl from command line\n"); 16423db978d4SVlastimil Babka return 0; 16433db978d4SVlastimil Babka } 16443db978d4SVlastimil Babka *proc_mnt = kern_mount(proc_fs_type); 16453db978d4SVlastimil Babka put_filesystem(proc_fs_type); 16463db978d4SVlastimil Babka if (IS_ERR(*proc_mnt)) { 16473db978d4SVlastimil Babka pr_err("Failed to mount procfs to set sysctl from command line\n"); 16483db978d4SVlastimil Babka return 0; 16493db978d4SVlastimil Babka } 16503db978d4SVlastimil Babka } 16513db978d4SVlastimil Babka 16523db978d4SVlastimil Babka path = kasprintf(GFP_KERNEL, "sys/%s", param); 16533db978d4SVlastimil Babka if (!path) 16543db978d4SVlastimil Babka panic("%s: Failed to allocate path for %s\n", __func__, param); 16553db978d4SVlastimil Babka strreplace(path, '.', '/'); 16563db978d4SVlastimil Babka 1657ffb37ca3SAl Viro file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); 16583db978d4SVlastimil Babka if (IS_ERR(file)) { 16593db978d4SVlastimil Babka err = PTR_ERR(file); 16603db978d4SVlastimil Babka if (err == -ENOENT) 16613db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", 16623db978d4SVlastimil Babka param, val); 16633db978d4SVlastimil Babka else if (err == -EACCES) 16643db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", 16653db978d4SVlastimil Babka param, val); 16663db978d4SVlastimil Babka else 16673db978d4SVlastimil Babka pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", 16683db978d4SVlastimil Babka file, param, val); 16693db978d4SVlastimil Babka goto out; 16703db978d4SVlastimil Babka } 16713db978d4SVlastimil Babka wret = kernel_write(file, val, len, &pos); 16723db978d4SVlastimil Babka if (wret < 0) { 16733db978d4SVlastimil Babka err = wret; 16743db978d4SVlastimil Babka if (err == -EINVAL) 16753db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", 16763db978d4SVlastimil Babka param, val); 16773db978d4SVlastimil Babka else 16783db978d4SVlastimil Babka pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", 16793db978d4SVlastimil Babka ERR_PTR(err), param, val); 16803db978d4SVlastimil Babka } else if (wret != len) { 16813db978d4SVlastimil Babka pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", 16823db978d4SVlastimil Babka wret, len, path, param, val); 16833db978d4SVlastimil Babka } 16843db978d4SVlastimil Babka 16853db978d4SVlastimil Babka err = filp_close(file, NULL); 16863db978d4SVlastimil Babka if (err) 16873db978d4SVlastimil Babka pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", 16883db978d4SVlastimil Babka ERR_PTR(err), param, val); 16893db978d4SVlastimil Babka out: 16903db978d4SVlastimil Babka kfree(path); 16913db978d4SVlastimil Babka return 0; 16923db978d4SVlastimil Babka } 16933db978d4SVlastimil Babka 16943db978d4SVlastimil Babka void do_sysctl_args(void) 16953db978d4SVlastimil Babka { 16963db978d4SVlastimil Babka char *command_line; 16973db978d4SVlastimil Babka struct vfsmount *proc_mnt = NULL; 16983db978d4SVlastimil Babka 16993db978d4SVlastimil Babka command_line = kstrdup(saved_command_line, GFP_KERNEL); 17003db978d4SVlastimil Babka if (!command_line) 17013db978d4SVlastimil Babka panic("%s: Failed to allocate copy of command line\n", __func__); 17023db978d4SVlastimil Babka 17033db978d4SVlastimil Babka parse_args("Setting sysctl args", command_line, 17043db978d4SVlastimil Babka NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); 17053db978d4SVlastimil Babka 17063db978d4SVlastimil Babka if (proc_mnt) 17073db978d4SVlastimil Babka kern_unmount(proc_mnt); 17083db978d4SVlastimil Babka 17093db978d4SVlastimil Babka kfree(command_line); 17103db978d4SVlastimil Babka } 1711