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> 151f87f0b5SEric W. Biederman #include <linux/module.h> 167b146cebSAndrey Ignatov #include <linux/bpf-cgroup.h> 1777b14db5SEric W. Biederman #include "internal.h" 1877b14db5SEric W. Biederman 19d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 2077b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2103a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 229043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 239043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2477b14db5SEric W. Biederman 25eec4844fSMatteo Croce /* shared constants to be used in various sysctls */ 26eec4844fSMatteo Croce const int sysctl_vals[] = { 0, 1, INT_MAX }; 27eec4844fSMatteo Croce EXPORT_SYMBOL(sysctl_vals); 28eec4844fSMatteo Croce 29f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 30f9bd6733SEric W. Biederman 31f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 32f9bd6733SEric W. Biederman { } 33f9bd6733SEric W. Biederman }; 34f9bd6733SEric W. Biederman 35f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 36f9bd6733SEric W. Biederman { 37f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 38f9bd6733SEric W. Biederman } 39f9bd6733SEric W. Biederman 40f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 41f9bd6733SEric W. Biederman { 42f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 43f9bd6733SEric W. Biederman } 44f9bd6733SEric W. Biederman 45f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 46f9bd6733SEric W. Biederman 47f9bd6733SEric W. Biederman { 48f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 49f9bd6733SEric W. Biederman } 50f9bd6733SEric W. Biederman 51f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 52f1ecf068SLucas De Marchi { 53f1ecf068SLucas De Marchi if (!poll) 54f1ecf068SLucas De Marchi return; 55f1ecf068SLucas De Marchi 56f1ecf068SLucas De Marchi atomic_inc(&poll->event); 57f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 58f1ecf068SLucas De Marchi } 59f1ecf068SLucas De Marchi 60a194558eSEric W. Biederman static struct ctl_table root_table[] = { 61a194558eSEric W. Biederman { 62a194558eSEric W. Biederman .procname = "", 637ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 64a194558eSEric W. Biederman }, 65a194558eSEric W. Biederman { } 66a194558eSEric W. Biederman }; 670e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 680e47c99dSEric W. Biederman .default_set.dir.header = { 691f87f0b5SEric W. Biederman {{.count = 1, 70938aaa4fSEric W. Biederman .nreg = 1, 71ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 720e47c99dSEric W. Biederman .ctl_table_arg = root_table, 731f87f0b5SEric W. Biederman .root = &sysctl_table_root, 741f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 757ec66d06SEric W. Biederman }, 761f87f0b5SEric W. Biederman }; 771f87f0b5SEric W. Biederman 781f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 791f87f0b5SEric W. Biederman 807ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 810e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 8213bcc6a2SEric W. Biederman struct ctl_table **pentry); 830e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 840e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 857ec66d06SEric W. Biederman 866980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 876980128fSEric W. Biederman { 886980128fSEric W. Biederman if (dir->header.parent) 896980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 9087ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 916980128fSEric W. Biederman } 926980128fSEric W. Biederman 93076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 94076c3eedSEric W. Biederman { 95076c3eedSEric W. Biederman int minlen; 96076c3eedSEric W. Biederman int cmp; 97076c3eedSEric W. Biederman 98076c3eedSEric W. Biederman minlen = len1; 99076c3eedSEric W. Biederman if (minlen > len2) 100076c3eedSEric W. Biederman minlen = len2; 101076c3eedSEric W. Biederman 102076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 103076c3eedSEric W. Biederman if (cmp == 0) 104076c3eedSEric W. Biederman cmp = len1 - len2; 105076c3eedSEric W. Biederman return cmp; 106076c3eedSEric W. Biederman } 107076c3eedSEric W. Biederman 10860f126d9SEric W. Biederman /* Called under sysctl_lock */ 109076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1100e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 111076c3eedSEric W. Biederman { 112076c3eedSEric W. Biederman struct ctl_table_header *head; 113076c3eedSEric W. Biederman struct ctl_table *entry; 114ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 115076c3eedSEric W. Biederman 116ac13ac6fSEric W. Biederman while (node) 117ac13ac6fSEric W. Biederman { 118ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 119ac13ac6fSEric W. Biederman const char *procname; 120ac13ac6fSEric W. Biederman int cmp; 121ac13ac6fSEric W. Biederman 122ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 123ac13ac6fSEric W. Biederman head = ctl_node->header; 124ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 125ac13ac6fSEric W. Biederman procname = entry->procname; 126ac13ac6fSEric W. Biederman 127ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 128ac13ac6fSEric W. Biederman if (cmp < 0) 129ac13ac6fSEric W. Biederman node = node->rb_left; 130ac13ac6fSEric W. Biederman else if (cmp > 0) 131ac13ac6fSEric W. Biederman node = node->rb_right; 132ac13ac6fSEric W. Biederman else { 133076c3eedSEric W. Biederman *phead = head; 134076c3eedSEric W. Biederman return entry; 135076c3eedSEric W. Biederman } 136076c3eedSEric W. Biederman } 137076c3eedSEric W. Biederman return NULL; 138076c3eedSEric W. Biederman } 139076c3eedSEric W. Biederman 140ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 141ac13ac6fSEric W. Biederman { 142ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 143ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 144ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 145ac13ac6fSEric W. Biederman const char *name = entry->procname; 146ac13ac6fSEric W. Biederman int namelen = strlen(name); 147ac13ac6fSEric W. Biederman 148ac13ac6fSEric W. Biederman while (*p) { 149ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 150ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 151ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 152ac13ac6fSEric W. Biederman const char *parent_name; 153ac13ac6fSEric W. Biederman int cmp; 154ac13ac6fSEric W. Biederman 155ac13ac6fSEric W. Biederman parent = *p; 156ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 157ac13ac6fSEric W. Biederman parent_head = parent_node->header; 158ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 159ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 160ac13ac6fSEric W. Biederman 161ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 162ac13ac6fSEric W. Biederman if (cmp < 0) 163ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 164ac13ac6fSEric W. Biederman else if (cmp > 0) 165ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 166ac13ac6fSEric W. Biederman else { 16787ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 168ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16987ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 170ac13ac6fSEric W. Biederman return -EEXIST; 171ac13ac6fSEric W. Biederman } 172ac13ac6fSEric W. Biederman } 173ac13ac6fSEric W. Biederman 174ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 175ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 176ac13ac6fSEric W. Biederman return 0; 177ac13ac6fSEric W. Biederman } 178ac13ac6fSEric W. Biederman 179ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 180ac13ac6fSEric W. Biederman { 181ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 182ac13ac6fSEric W. Biederman 183ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 184ac13ac6fSEric W. Biederman } 185ac13ac6fSEric W. Biederman 186e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 187e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 188ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 189e0d04529SEric W. Biederman { 1907ec66d06SEric W. Biederman head->ctl_table = table; 191e0d04529SEric W. Biederman head->ctl_table_arg = table; 192e0d04529SEric W. Biederman head->used = 0; 193e0d04529SEric W. Biederman head->count = 1; 194e0d04529SEric W. Biederman head->nreg = 1; 195e0d04529SEric W. Biederman head->unregistering = NULL; 196e0d04529SEric W. Biederman head->root = root; 197e0d04529SEric W. Biederman head->set = set; 198e0d04529SEric W. Biederman head->parent = NULL; 199ac13ac6fSEric W. Biederman head->node = node; 2002fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 201ac13ac6fSEric W. Biederman if (node) { 202ac13ac6fSEric W. Biederman struct ctl_table *entry; 2034c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 204ac13ac6fSEric W. Biederman node->header = head; 205ac13ac6fSEric W. Biederman } 206ac13ac6fSEric W. Biederman } 207e0d04529SEric W. Biederman 2088425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2098425d6aaSEric W. Biederman { 210ac13ac6fSEric W. Biederman struct ctl_table *entry; 211ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 212ac13ac6fSEric W. Biederman erase_entry(head, entry); 2138425d6aaSEric W. Biederman } 2148425d6aaSEric W. Biederman 2150e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2168425d6aaSEric W. Biederman { 217ac13ac6fSEric W. Biederman struct ctl_table *entry; 2180e47c99dSEric W. Biederman int err; 2190e47c99dSEric W. Biederman 220f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 221f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 222f9bd6733SEric W. Biederman return -EROFS; 223f9bd6733SEric W. Biederman 224f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 225f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 226f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 227f9bd6733SEric W. Biederman return -EINVAL; 228f9bd6733SEric W. Biederman set_empty_dir(dir); 229f9bd6733SEric W. Biederman } 230f9bd6733SEric W. Biederman 2310e47c99dSEric W. Biederman dir->header.nreg++; 2327ec66d06SEric W. Biederman header->parent = dir; 2330e47c99dSEric W. Biederman err = insert_links(header); 2340e47c99dSEric W. Biederman if (err) 2350e47c99dSEric W. Biederman goto fail_links; 236ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 237ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 238ac13ac6fSEric W. Biederman if (err) 239ac13ac6fSEric W. Biederman goto fail; 240ac13ac6fSEric W. Biederman } 2410e47c99dSEric W. Biederman return 0; 242ac13ac6fSEric W. Biederman fail: 243ac13ac6fSEric W. Biederman erase_header(header); 244ac13ac6fSEric W. Biederman put_links(header); 2450e47c99dSEric W. Biederman fail_links: 246f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 247f9bd6733SEric W. Biederman clear_empty_dir(dir); 2480e47c99dSEric W. Biederman header->parent = NULL; 2490e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2500e47c99dSEric W. Biederman return err; 2518425d6aaSEric W. Biederman } 2528425d6aaSEric W. Biederman 2531f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2541f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2551f87f0b5SEric W. Biederman { 2561f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2571f87f0b5SEric W. Biederman return 0; 2581f87f0b5SEric W. Biederman p->used++; 2591f87f0b5SEric W. Biederman return 1; 2601f87f0b5SEric W. Biederman } 2611f87f0b5SEric W. Biederman 2621f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2631f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2641f87f0b5SEric W. Biederman { 2651f87f0b5SEric W. Biederman if (!--p->used) 2661f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2671f87f0b5SEric W. Biederman complete(p->unregistering); 2681f87f0b5SEric W. Biederman } 2691f87f0b5SEric W. Biederman 270f90f3cafSEric W. Biederman static void proc_sys_invalidate_dcache(struct ctl_table_header *head) 271d6cffbbeSKonstantin Khlebnikov { 272f90f3cafSEric W. Biederman proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); 273d6cffbbeSKonstantin Khlebnikov } 274d6cffbbeSKonstantin Khlebnikov 2751f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2761f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2771f87f0b5SEric W. Biederman { 2781f87f0b5SEric W. Biederman /* 2791f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2801f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2811f87f0b5SEric W. Biederman */ 2821f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2831f87f0b5SEric W. Biederman struct completion wait; 2841f87f0b5SEric W. Biederman init_completion(&wait); 2851f87f0b5SEric W. Biederman p->unregistering = &wait; 2861f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2871f87f0b5SEric W. Biederman wait_for_completion(&wait); 2881f87f0b5SEric W. Biederman } else { 2891f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 2901f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 291ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 2921f87f0b5SEric W. Biederman } 2931f87f0b5SEric W. Biederman /* 294f90f3cafSEric W. Biederman * Invalidate dentries for unregistered sysctls: namespaced sysctls 295d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 296d6cffbbeSKonstantin Khlebnikov */ 297f90f3cafSEric W. Biederman proc_sys_invalidate_dcache(p); 298d6cffbbeSKonstantin Khlebnikov /* 2991f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3001f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3011f87f0b5SEric W. Biederman */ 302ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3038425d6aaSEric W. Biederman erase_header(p); 3041f87f0b5SEric W. Biederman } 3051f87f0b5SEric W. Biederman 3061f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3071f87f0b5SEric W. Biederman { 308ab4a1f24SPrasad Joshi BUG_ON(!head); 3091f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3101f87f0b5SEric W. Biederman if (!use_table(head)) 3111f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3121f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3131f87f0b5SEric W. Biederman return head; 3141f87f0b5SEric W. Biederman } 3151f87f0b5SEric W. Biederman 3161f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3171f87f0b5SEric W. Biederman { 3181f87f0b5SEric W. Biederman if (!head) 3191f87f0b5SEric W. Biederman return; 3201f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3211f87f0b5SEric W. Biederman unuse_table(head); 3221f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3231f87f0b5SEric W. Biederman } 3241f87f0b5SEric W. Biederman 3251f87f0b5SEric W. Biederman static struct ctl_table_set * 32613bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3271f87f0b5SEric W. Biederman { 3281f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3291f87f0b5SEric W. Biederman if (root->lookup) 33013bcc6a2SEric W. Biederman set = root->lookup(root); 3311f87f0b5SEric W. Biederman return set; 3321f87f0b5SEric W. Biederman } 3331f87f0b5SEric W. Biederman 334076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3357ec66d06SEric W. Biederman struct ctl_dir *dir, 336076c3eedSEric W. Biederman const char *name, int namelen) 337076c3eedSEric W. Biederman { 338076c3eedSEric W. Biederman struct ctl_table_header *head; 339076c3eedSEric W. Biederman struct ctl_table *entry; 340076c3eedSEric W. Biederman 341076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3420e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 343076c3eedSEric W. Biederman if (entry && use_table(head)) 344076c3eedSEric W. Biederman *phead = head; 345076c3eedSEric W. Biederman else 346076c3eedSEric W. Biederman entry = NULL; 347076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 348076c3eedSEric W. Biederman return entry; 349076c3eedSEric W. Biederman } 350076c3eedSEric W. Biederman 351ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3521f87f0b5SEric W. Biederman { 353ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3541f87f0b5SEric W. Biederman 355ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 356ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 357ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 358ac13ac6fSEric W. Biederman return ctl_node; 3591f87f0b5SEric W. Biederman } 3601f87f0b5SEric W. Biederman return NULL; 3611f87f0b5SEric W. Biederman } 3621f87f0b5SEric W. Biederman 3637ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3646a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3651f87f0b5SEric W. Biederman { 366ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3677ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 368ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3696a75ce16SEric W. Biederman 3706a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 371ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3726a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 373ac13ac6fSEric W. Biederman if (ctl_node) { 374ac13ac6fSEric W. Biederman head = ctl_node->header; 375ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 376ac13ac6fSEric W. Biederman } 3776a75ce16SEric W. Biederman *phead = head; 3786a75ce16SEric W. Biederman *pentry = entry; 3796a75ce16SEric W. Biederman } 3806a75ce16SEric W. Biederman 3817ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3826a75ce16SEric W. Biederman { 3836a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3846a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 385ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3866a75ce16SEric W. Biederman 3876a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3886a75ce16SEric W. Biederman unuse_table(head); 389ac13ac6fSEric W. Biederman 390ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 3916a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 392ac13ac6fSEric W. Biederman head = NULL; 393ac13ac6fSEric W. Biederman if (ctl_node) { 394ac13ac6fSEric W. Biederman head = ctl_node->header; 395ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 3966a75ce16SEric W. Biederman } 3976a75ce16SEric W. Biederman *phead = head; 3986a75ce16SEric W. Biederman *pentry = entry; 3991f87f0b5SEric W. Biederman } 4001f87f0b5SEric W. Biederman 4011f87f0b5SEric W. Biederman /* 4021f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4031f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4041f87f0b5SEric W. Biederman */ 4051f87f0b5SEric W. Biederman 4061f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4071f87f0b5SEric W. Biederman { 408091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4091f87f0b5SEric W. Biederman mode >>= 6; 410091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4111f87f0b5SEric W. Biederman mode >>= 3; 4121f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4131f87f0b5SEric W. Biederman return 0; 4141f87f0b5SEric W. Biederman return -EACCES; 4151f87f0b5SEric W. Biederman } 4161f87f0b5SEric W. Biederman 41773f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4181f87f0b5SEric W. Biederman { 41973f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4201f87f0b5SEric W. Biederman int mode; 4211f87f0b5SEric W. Biederman 4221f87f0b5SEric W. Biederman if (root->permissions) 42373f7ef43SEric W. Biederman mode = root->permissions(head, table); 4241f87f0b5SEric W. Biederman else 4251f87f0b5SEric W. Biederman mode = table->mode; 4261f87f0b5SEric W. Biederman 4271f87f0b5SEric W. Biederman return test_perm(mode, op); 4281f87f0b5SEric W. Biederman } 4291f87f0b5SEric W. Biederman 4309043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4319043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 43277b14db5SEric W. Biederman { 433e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 43477b14db5SEric W. Biederman struct inode *inode; 4359043476fSAl Viro struct proc_inode *ei; 43677b14db5SEric W. Biederman 4379043476fSAl Viro inode = new_inode(sb); 43877b14db5SEric W. Biederman if (!inode) 439ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 44077b14db5SEric W. Biederman 44185fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 44285fe4025SChristoph Hellwig 44377b14db5SEric W. Biederman ei = PROC_I(inode); 4449043476fSAl Viro 445d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 446ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 447ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 448ace0c791SEric W. Biederman iput(inode); 449ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 450ace0c791SEric W. Biederman } 451ace0c791SEric W. Biederman ei->sysctl = head; 452ace0c791SEric W. Biederman ei->sysctl_entry = table; 4530afa5ca8SEric W. Biederman hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); 454d6cffbbeSKonstantin Khlebnikov head->count++; 455d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 456d6cffbbeSKonstantin Khlebnikov 457078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4589043476fSAl Viro inode->i_mode = table->mode; 4597ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4609043476fSAl Viro inode->i_mode |= S_IFREG; 46177b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 46277b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4639043476fSAl Viro } else { 4649043476fSAl Viro inode->i_mode |= S_IFDIR; 4659043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4669043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 467f9bd6733SEric W. Biederman if (is_empty_dir(head)) 468f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4699043476fSAl Viro } 470e79c6a4fSDmitry Torokhov 471e79c6a4fSDmitry Torokhov if (root->set_ownership) 472e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 4735ec27ec7SRadoslaw Burny else { 4745ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 4755ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 4765ec27ec7SRadoslaw Burny } 477e79c6a4fSDmitry Torokhov 47877b14db5SEric W. Biederman return inode; 47977b14db5SEric W. Biederman } 48077b14db5SEric W. Biederman 481d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 482d6cffbbeSKonstantin Khlebnikov { 483d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 4840afa5ca8SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); 485d6cffbbeSKonstantin Khlebnikov if (!--head->count) 486d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 487d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 488d6cffbbeSKonstantin Khlebnikov } 489d6cffbbeSKonstantin Khlebnikov 49081324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 49177b14db5SEric W. Biederman { 4923cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 4933cc3e046SEric W. Biederman if (!head) 4940e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 4953cc3e046SEric W. Biederman return sysctl_head_grab(head); 49677b14db5SEric W. Biederman } 49777b14db5SEric W. Biederman 49877b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 49900cd8dd3SAl Viro unsigned int flags) 50077b14db5SEric W. Biederman { 5019043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5029043476fSAl Viro struct ctl_table_header *h = NULL; 503dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5049043476fSAl Viro struct ctl_table *p; 50577b14db5SEric W. Biederman struct inode *inode; 5069043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5077ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5080e47c99dSEric W. Biederman int ret; 50977b14db5SEric W. Biederman 5109043476fSAl Viro if (IS_ERR(head)) 5119043476fSAl Viro return ERR_CAST(head); 5129043476fSAl Viro 5137ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5149043476fSAl Viro 5157ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5169043476fSAl Viro if (!p) 51777b14db5SEric W. Biederman goto out; 51877b14db5SEric W. Biederman 5194e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 52013bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5210e47c99dSEric W. Biederman err = ERR_PTR(ret); 5220e47c99dSEric W. Biederman if (ret) 5230e47c99dSEric W. Biederman goto out; 5244e757320SEric W. Biederman } 5250e47c99dSEric W. Biederman 5269043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 527ea5751ccSIvan Delalande if (IS_ERR(inode)) { 528ea5751ccSIvan Delalande err = ERR_CAST(inode); 52977b14db5SEric W. Biederman goto out; 530ea5751ccSIvan Delalande } 53177b14db5SEric W. Biederman 532fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 533888e2b03SAl Viro err = d_splice_alias(inode, dentry); 53477b14db5SEric W. Biederman 53577b14db5SEric W. Biederman out: 5366bf61045SFrancesco Ruggeri if (h) 5376bf61045SFrancesco Ruggeri sysctl_head_finish(h); 53877b14db5SEric W. Biederman sysctl_head_finish(head); 53977b14db5SEric W. Biederman return err; 54077b14db5SEric W. Biederman } 54177b14db5SEric W. Biederman 54232927393SChristoph Hellwig static ssize_t proc_sys_call_handler(struct file *filp, void __user *ubuf, 5437708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 54477b14db5SEric W. Biederman { 545496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5469043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5479043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 54832927393SChristoph Hellwig void *kbuf; 5492a2da53bSDavid Howells ssize_t error; 55077b14db5SEric W. Biederman 5519043476fSAl Viro if (IS_ERR(head)) 5529043476fSAl Viro return PTR_ERR(head); 55377b14db5SEric W. Biederman 55477b14db5SEric W. Biederman /* 55577b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 55677b14db5SEric W. Biederman * and won't be until we finish. 55777b14db5SEric W. Biederman */ 55877b14db5SEric W. Biederman error = -EPERM; 55973f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 56077b14db5SEric W. Biederman goto out; 56177b14db5SEric W. Biederman 5629043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5639043476fSAl Viro error = -EINVAL; 5649043476fSAl Viro if (!table->proc_handler) 5659043476fSAl Viro goto out; 5669043476fSAl Viro 567ef9d965bSChristoph Hellwig /* don't even try if the size is too large */ 568ef9d965bSChristoph Hellwig if (count > KMALLOC_MAX_SIZE) 569ef9d965bSChristoph Hellwig return -ENOMEM; 570ef9d965bSChristoph Hellwig 57132927393SChristoph Hellwig if (write) { 57232927393SChristoph Hellwig kbuf = memdup_user_nul(ubuf, count); 57332927393SChristoph Hellwig if (IS_ERR(kbuf)) { 57432927393SChristoph Hellwig error = PTR_ERR(kbuf); 5757b146cebSAndrey Ignatov goto out; 57632927393SChristoph Hellwig } 5774e63acdfSAndrey Ignatov } else { 57832927393SChristoph Hellwig error = -ENOMEM; 57932927393SChristoph Hellwig kbuf = kzalloc(count, GFP_KERNEL); 58032927393SChristoph Hellwig if (!kbuf) 58132927393SChristoph Hellwig goto out; 5824e63acdfSAndrey Ignatov } 5834e63acdfSAndrey Ignatov 58432927393SChristoph Hellwig error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, 58532927393SChristoph Hellwig ppos); 58632927393SChristoph Hellwig if (error) 58732927393SChristoph Hellwig goto out_free_buf; 58832927393SChristoph Hellwig 58932927393SChristoph Hellwig /* careful: calling conventions are nasty here */ 59032927393SChristoph Hellwig error = table->proc_handler(table, write, kbuf, &count, ppos); 59132927393SChristoph Hellwig if (error) 59232927393SChristoph Hellwig goto out_free_buf; 59332927393SChristoph Hellwig 59432927393SChristoph Hellwig if (!write) { 59532927393SChristoph Hellwig error = -EFAULT; 59632927393SChristoph Hellwig if (copy_to_user(ubuf, kbuf, count)) 59732927393SChristoph Hellwig goto out_free_buf; 59832927393SChristoph Hellwig } 59932927393SChristoph Hellwig 6004e63acdfSAndrey Ignatov error = count; 60132927393SChristoph Hellwig out_free_buf: 60232927393SChristoph Hellwig kfree(kbuf); 60377b14db5SEric W. Biederman out: 60477b14db5SEric W. Biederman sysctl_head_finish(head); 60577b14db5SEric W. Biederman 60677b14db5SEric W. Biederman return error; 60777b14db5SEric W. Biederman } 60877b14db5SEric W. Biederman 6097708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 6107708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 6117708bfb1SPavel Emelyanov { 6127708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 6137708bfb1SPavel Emelyanov } 6147708bfb1SPavel Emelyanov 61577b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 61677b14db5SEric W. Biederman size_t count, loff_t *ppos) 61777b14db5SEric W. Biederman { 6187708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 61977b14db5SEric W. Biederman } 62077b14db5SEric W. Biederman 621f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 622f1ecf068SLucas De Marchi { 6234e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 624f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 625f1ecf068SLucas De Marchi 6264e474a00SLucas De Marchi /* sysctl was unregistered */ 6274e474a00SLucas De Marchi if (IS_ERR(head)) 6284e474a00SLucas De Marchi return PTR_ERR(head); 6294e474a00SLucas De Marchi 630f1ecf068SLucas De Marchi if (table->poll) 631f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 632f1ecf068SLucas De Marchi 6334e474a00SLucas De Marchi sysctl_head_finish(head); 6344e474a00SLucas De Marchi 635f1ecf068SLucas De Marchi return 0; 636f1ecf068SLucas De Marchi } 637f1ecf068SLucas De Marchi 638076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 639f1ecf068SLucas De Marchi { 640496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6414e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 642f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 643076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6444e474a00SLucas De Marchi unsigned long event; 6454e474a00SLucas De Marchi 6464e474a00SLucas De Marchi /* sysctl was unregistered */ 6474e474a00SLucas De Marchi if (IS_ERR(head)) 648a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 649f1ecf068SLucas De Marchi 650f1ecf068SLucas De Marchi if (!table->proc_handler) 651f1ecf068SLucas De Marchi goto out; 652f1ecf068SLucas De Marchi 653f1ecf068SLucas De Marchi if (!table->poll) 654f1ecf068SLucas De Marchi goto out; 655f1ecf068SLucas De Marchi 6564e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 657f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 658f1ecf068SLucas De Marchi 659f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 660f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 661a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 662f1ecf068SLucas De Marchi } 663f1ecf068SLucas De Marchi 664f1ecf068SLucas De Marchi out: 6654e474a00SLucas De Marchi sysctl_head_finish(head); 6664e474a00SLucas De Marchi 667f1ecf068SLucas De Marchi return ret; 668f1ecf068SLucas De Marchi } 66977b14db5SEric W. Biederman 670f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 671f0c3b509SAl Viro struct dir_context *ctx, 6729043476fSAl Viro struct ctl_table_header *head, 6739043476fSAl Viro struct ctl_table *table) 67477b14db5SEric W. Biederman { 675f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 67677b14db5SEric W. Biederman struct inode *inode; 67777b14db5SEric W. Biederman struct qstr qname; 67877b14db5SEric W. Biederman ino_t ino = 0; 67977b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 68077b14db5SEric W. Biederman 68177b14db5SEric W. Biederman qname.name = table->procname; 68277b14db5SEric W. Biederman qname.len = strlen(table->procname); 6838387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 68477b14db5SEric W. Biederman 68577b14db5SEric W. Biederman child = d_lookup(dir, &qname); 68677b14db5SEric W. Biederman if (!child) { 68776aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 68876aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 68976aab3abSAl Viro if (IS_ERR(child)) 69076aab3abSAl Viro return false; 69176aab3abSAl Viro if (d_in_lookup(child)) { 692888e2b03SAl Viro struct dentry *res; 6939043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 694ea5751ccSIvan Delalande if (IS_ERR(inode)) { 69576aab3abSAl Viro d_lookup_done(child); 6969043476fSAl Viro dput(child); 697f0c3b509SAl Viro return false; 69876aab3abSAl Viro } 699fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 700888e2b03SAl Viro res = d_splice_alias(inode, child); 701888e2b03SAl Viro d_lookup_done(child); 702888e2b03SAl Viro if (unlikely(res)) { 703888e2b03SAl Viro if (IS_ERR(res)) { 704888e2b03SAl Viro dput(child); 705888e2b03SAl Viro return false; 706888e2b03SAl Viro } 707888e2b03SAl Viro dput(child); 708888e2b03SAl Viro child = res; 709888e2b03SAl Viro } 71077b14db5SEric W. Biederman } 71177b14db5SEric W. Biederman } 7122b0143b5SDavid Howells inode = d_inode(child); 71377b14db5SEric W. Biederman ino = inode->i_ino; 71477b14db5SEric W. Biederman type = inode->i_mode >> 12; 71577b14db5SEric W. Biederman dput(child); 716f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7179043476fSAl Viro } 7189043476fSAl Viro 719f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 720f0c3b509SAl Viro struct dir_context *ctx, 7210e47c99dSEric W. Biederman struct ctl_table_header *head, 7220e47c99dSEric W. Biederman struct ctl_table *table) 7230e47c99dSEric W. Biederman { 724f0c3b509SAl Viro bool ret = true; 725a0b0d1c3SDanilo Krummrich 7260e47c99dSEric W. Biederman head = sysctl_head_grab(head); 727a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 728a0b0d1c3SDanilo Krummrich return false; 7290e47c99dSEric W. Biederman 7300e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 731835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7320e47c99dSEric W. Biederman goto out; 7330e47c99dSEric W. Biederman 734f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7350e47c99dSEric W. Biederman out: 7360e47c99dSEric W. Biederman sysctl_head_finish(head); 7370e47c99dSEric W. Biederman return ret; 7380e47c99dSEric W. Biederman } 7390e47c99dSEric W. Biederman 740e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7419043476fSAl Viro unsigned long *pos, struct file *file, 742f0c3b509SAl Viro struct dir_context *ctx) 7439043476fSAl Viro { 744f0c3b509SAl Viro bool res; 7459043476fSAl Viro 746f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 747f0c3b509SAl Viro return true; 7489043476fSAl Viro 7490e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 750f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7510e47c99dSEric W. Biederman else 752f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7539043476fSAl Viro 754f0c3b509SAl Viro if (res) 755f0c3b509SAl Viro ctx->pos = *pos; 7566a75ce16SEric W. Biederman 7576a75ce16SEric W. Biederman return res; 75877b14db5SEric W. Biederman } 75977b14db5SEric W. Biederman 760f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 76177b14db5SEric W. Biederman { 762f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7639043476fSAl Viro struct ctl_table_header *h = NULL; 7646a75ce16SEric W. Biederman struct ctl_table *entry; 7657ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 76677b14db5SEric W. Biederman unsigned long pos; 76777b14db5SEric W. Biederman 7689043476fSAl Viro if (IS_ERR(head)) 7699043476fSAl Viro return PTR_ERR(head); 7709043476fSAl Viro 7717ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 77277b14db5SEric W. Biederman 773f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 77493362fa4SZhou Chengming goto out; 775f0c3b509SAl Viro 77677b14db5SEric W. Biederman pos = 2; 77777b14db5SEric W. Biederman 7787ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 779f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7809043476fSAl Viro sysctl_head_finish(h); 7819043476fSAl Viro break; 78277b14db5SEric W. Biederman } 78377b14db5SEric W. Biederman } 78493362fa4SZhou Chengming out: 78577b14db5SEric W. Biederman sysctl_head_finish(head); 786f0c3b509SAl Viro return 0; 78777b14db5SEric W. Biederman } 78877b14db5SEric W. Biederman 78910556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 79077b14db5SEric W. Biederman { 79177b14db5SEric W. Biederman /* 79277b14db5SEric W. Biederman * sysctl entries that are not writeable, 79377b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 79477b14db5SEric W. Biederman */ 795f696a365SMiklos Szeredi struct ctl_table_header *head; 796f696a365SMiklos Szeredi struct ctl_table *table; 79777b14db5SEric W. Biederman int error; 79877b14db5SEric W. Biederman 799f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 800f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 801f696a365SMiklos Szeredi return -EACCES; 802f696a365SMiklos Szeredi 803f696a365SMiklos Szeredi head = grab_header(inode); 8049043476fSAl Viro if (IS_ERR(head)) 8059043476fSAl Viro return PTR_ERR(head); 80677b14db5SEric W. Biederman 807f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8089043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8099043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8109043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 81173f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8129043476fSAl Viro 81377b14db5SEric W. Biederman sysctl_head_finish(head); 81477b14db5SEric W. Biederman return error; 81577b14db5SEric W. Biederman } 81677b14db5SEric W. Biederman 81777b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 81877b14db5SEric W. Biederman { 8192b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 82077b14db5SEric W. Biederman int error; 82177b14db5SEric W. Biederman 82277b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 82377b14db5SEric W. Biederman return -EPERM; 82477b14db5SEric W. Biederman 82531051c85SJan Kara error = setattr_prepare(dentry, attr); 8261025774cSChristoph Hellwig if (error) 82777b14db5SEric W. Biederman return error; 8281025774cSChristoph Hellwig 8291025774cSChristoph Hellwig setattr_copy(inode, attr); 8301025774cSChristoph Hellwig mark_inode_dirty(inode); 8311025774cSChristoph Hellwig return 0; 83277b14db5SEric W. Biederman } 83377b14db5SEric W. Biederman 834a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 835a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8369043476fSAl Viro { 837a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8389043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8399043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8409043476fSAl Viro 8419043476fSAl Viro if (IS_ERR(head)) 8429043476fSAl Viro return PTR_ERR(head); 8439043476fSAl Viro 8449043476fSAl Viro generic_fillattr(inode, stat); 8459043476fSAl Viro if (table) 8469043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8479043476fSAl Viro 8489043476fSAl Viro sysctl_head_finish(head); 8499043476fSAl Viro return 0; 8509043476fSAl Viro } 8519043476fSAl Viro 85277b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 853f1ecf068SLucas De Marchi .open = proc_sys_open, 854f1ecf068SLucas De Marchi .poll = proc_sys_poll, 85577b14db5SEric W. Biederman .read = proc_sys_read, 85677b14db5SEric W. Biederman .write = proc_sys_write, 8576038f373SArnd Bergmann .llseek = default_llseek, 8589043476fSAl Viro }; 8599043476fSAl Viro 8609043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 861887df078SPavel Emelyanov .read = generic_read_dir, 862f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8633222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 86477b14db5SEric W. Biederman }; 86577b14db5SEric W. Biederman 86603a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8679043476fSAl Viro .permission = proc_sys_permission, 8689043476fSAl Viro .setattr = proc_sys_setattr, 8699043476fSAl Viro .getattr = proc_sys_getattr, 8709043476fSAl Viro }; 8719043476fSAl Viro 8729043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 87377b14db5SEric W. Biederman .lookup = proc_sys_lookup, 87477b14db5SEric W. Biederman .permission = proc_sys_permission, 87577b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8769043476fSAl Viro .getattr = proc_sys_getattr, 87777b14db5SEric W. Biederman }; 87877b14db5SEric W. Biederman 8790b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 88077b14db5SEric W. Biederman { 8810b728e19SAl Viro if (flags & LOOKUP_RCU) 88234286d66SNick Piggin return -ECHILD; 8832b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8849043476fSAl Viro } 8859043476fSAl Viro 886fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 8879043476fSAl Viro { 8882b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 8899043476fSAl Viro } 8909043476fSAl Viro 8911f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 8921f87f0b5SEric W. Biederman { 8931f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 8941f87f0b5SEric W. Biederman int res; 8951f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 8961f87f0b5SEric W. Biederman if (p->unregistering) 8971f87f0b5SEric W. Biederman res = 0; 8981f87f0b5SEric W. Biederman else if (!set->is_seen) 8991f87f0b5SEric W. Biederman res = 1; 9001f87f0b5SEric W. Biederman else 9011f87f0b5SEric W. Biederman res = set->is_seen(set); 9021f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9031f87f0b5SEric W. Biederman return res; 9041f87f0b5SEric W. Biederman } 9051f87f0b5SEric W. Biederman 9066fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 907621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9089043476fSAl Viro { 909dfef6dcdSAl Viro struct ctl_table_header *head; 910da53be12SLinus Torvalds struct inode *inode; 911da53be12SLinus Torvalds 91231e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 91331e6b01fSNick Piggin * that inode here can be NULL */ 914dfef6dcdSAl Viro /* AV: can it, indeed? */ 9152b0143b5SDavid Howells inode = d_inode_rcu(dentry); 91631e6b01fSNick Piggin if (!inode) 917dfef6dcdSAl Viro return 1; 918621e155aSNick Piggin if (name->len != len) 9199043476fSAl Viro return 1; 920621e155aSNick Piggin if (memcmp(name->name, str, len)) 9219043476fSAl Viro return 1; 922dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 923dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 92477b14db5SEric W. Biederman } 92577b14db5SEric W. Biederman 926d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 92777b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9289043476fSAl Viro .d_delete = proc_sys_delete, 9299043476fSAl Viro .d_compare = proc_sys_compare, 93077b14db5SEric W. Biederman }; 93177b14db5SEric W. Biederman 9320e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9337ec66d06SEric W. Biederman const char *name, int namelen) 9341f87f0b5SEric W. Biederman { 9357ec66d06SEric W. Biederman struct ctl_table_header *head; 9367ec66d06SEric W. Biederman struct ctl_table *entry; 9371f87f0b5SEric W. Biederman 9380e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9397ec66d06SEric W. Biederman if (!entry) 9407ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 94151f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9427ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 94351f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9441f87f0b5SEric W. Biederman } 9451f87f0b5SEric W. Biederman 9467ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9477ec66d06SEric W. Biederman const char *name, int namelen) 9481f87f0b5SEric W. Biederman { 9497ec66d06SEric W. Biederman struct ctl_table *table; 9507ec66d06SEric W. Biederman struct ctl_dir *new; 951ac13ac6fSEric W. Biederman struct ctl_node *node; 9527ec66d06SEric W. Biederman char *new_name; 9531f87f0b5SEric W. Biederman 954ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 955ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 956ac13ac6fSEric W. Biederman GFP_KERNEL); 9577ec66d06SEric W. Biederman if (!new) 9587ec66d06SEric W. Biederman return NULL; 9597ec66d06SEric W. Biederman 960ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 961ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9627ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9637ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9647ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9657ec66d06SEric W. Biederman table[0].procname = new_name; 9667ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 967ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9687ec66d06SEric W. Biederman 9697ec66d06SEric W. Biederman return new; 9701f87f0b5SEric W. Biederman } 9711f87f0b5SEric W. Biederman 97260f126d9SEric W. Biederman /** 97360f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 97460f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 97560f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 97660f126d9SEric W. Biederman * @namelen: The length of name 97760f126d9SEric W. Biederman * 97860f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 97960f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 98060f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 98160f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 98260f126d9SEric W. Biederman * simply dropped. 98360f126d9SEric W. Biederman */ 9840e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9850e47c99dSEric W. Biederman const char *name, int namelen) 9867ec66d06SEric W. Biederman { 9870e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 9887ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 9890eb97f38SEric W. Biederman int err; 9907ec66d06SEric W. Biederman 9917ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 9920e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 9937ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 9947ec66d06SEric W. Biederman goto found; 9957ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 9967ec66d06SEric W. Biederman goto failed; 9977ec66d06SEric W. Biederman 9987ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 9997ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 10007ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10017ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10027ec66d06SEric W. Biederman if (!new) 10037ec66d06SEric W. Biederman goto failed; 10047ec66d06SEric W. Biederman 100560f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 10060e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10077ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10087ec66d06SEric W. Biederman goto found; 10097ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10107ec66d06SEric W. Biederman goto failed; 10117ec66d06SEric W. Biederman 101260f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10130eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10140eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10150eb97f38SEric W. Biederman if (err) 10160e47c99dSEric W. Biederman goto failed; 10177ec66d06SEric W. Biederman subdir = new; 10187ec66d06SEric W. Biederman found: 10197ec66d06SEric W. Biederman subdir->header.nreg++; 10207ec66d06SEric W. Biederman failed: 1021a1c83681SViresh Kumar if (IS_ERR(subdir)) { 102287ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10236980128fSEric W. Biederman sysctl_print_dir(dir); 102487ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 10257ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 10261f87f0b5SEric W. Biederman } 10277ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10287ec66d06SEric W. Biederman if (new) 10297ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10307ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10317ec66d06SEric W. Biederman return subdir; 10321f87f0b5SEric W. Biederman } 10331f87f0b5SEric W. Biederman 10340e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10350e47c99dSEric W. Biederman { 10360e47c99dSEric W. Biederman struct ctl_dir *parent; 10370e47c99dSEric W. Biederman const char *procname; 10380e47c99dSEric W. Biederman if (!dir->header.parent) 10390e47c99dSEric W. Biederman return &set->dir; 10400e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10410e47c99dSEric W. Biederman if (IS_ERR(parent)) 10420e47c99dSEric W. Biederman return parent; 10430e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10440e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10450e47c99dSEric W. Biederman } 10460e47c99dSEric W. Biederman 10470e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 104813bcc6a2SEric W. Biederman struct ctl_table **pentry) 10490e47c99dSEric W. Biederman { 10500e47c99dSEric W. Biederman struct ctl_table_header *head; 10510e47c99dSEric W. Biederman struct ctl_table_root *root; 10520e47c99dSEric W. Biederman struct ctl_table_set *set; 10530e47c99dSEric W. Biederman struct ctl_table *entry; 10540e47c99dSEric W. Biederman struct ctl_dir *dir; 10550e47c99dSEric W. Biederman int ret; 10560e47c99dSEric W. Biederman 10570e47c99dSEric W. Biederman ret = 0; 10580e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10590e47c99dSEric W. Biederman root = (*pentry)->data; 106013bcc6a2SEric W. Biederman set = lookup_header_set(root); 10610e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10620e47c99dSEric W. Biederman if (IS_ERR(dir)) 10630e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10640e47c99dSEric W. Biederman else { 10650e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10660e47c99dSEric W. Biederman head = NULL; 10670e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10680e47c99dSEric W. Biederman ret = -ENOENT; 10690e47c99dSEric W. Biederman if (entry && use_table(head)) { 10700e47c99dSEric W. Biederman unuse_table(*phead); 10710e47c99dSEric W. Biederman *phead = head; 10720e47c99dSEric W. Biederman *pentry = entry; 10730e47c99dSEric W. Biederman ret = 0; 10740e47c99dSEric W. Biederman } 10750e47c99dSEric W. Biederman } 10760e47c99dSEric W. Biederman 10770e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10780e47c99dSEric W. Biederman return ret; 10790e47c99dSEric W. Biederman } 10800e47c99dSEric W. Biederman 10817c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10827c60c48fSEric W. Biederman { 10837c60c48fSEric W. Biederman struct va_format vaf; 10847c60c48fSEric W. Biederman va_list args; 10857c60c48fSEric W. Biederman 10867c60c48fSEric W. Biederman va_start(args, fmt); 10877c60c48fSEric W. Biederman vaf.fmt = fmt; 10887c60c48fSEric W. Biederman vaf.va = &args; 10897c60c48fSEric W. Biederman 109087ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10917c60c48fSEric W. Biederman path, table->procname, &vaf); 10927c60c48fSEric W. Biederman 10937c60c48fSEric W. Biederman va_end(args); 10947c60c48fSEric W. Biederman return -EINVAL; 10957c60c48fSEric W. Biederman } 10967c60c48fSEric W. Biederman 10974f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 10984f2fec00SLuis R. Rodriguez { 10994f2fec00SLuis R. Rodriguez int err = 0; 11004f2fec00SLuis R. Rodriguez 110161d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 110261d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11034f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 110464a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11054f2fec00SLuis R. Rodriguez } 11064f2fec00SLuis R. Rodriguez 11074f2fec00SLuis R. Rodriguez return err; 11084f2fec00SLuis R. Rodriguez } 11094f2fec00SLuis R. Rodriguez 11107c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11117c60c48fSEric W. Biederman { 11127c60c48fSEric W. Biederman int err = 0; 11137c60c48fSEric W. Biederman for (; table->procname; table++) { 11147c60c48fSEric W. Biederman if (table->child) 111589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 11167c60c48fSEric W. Biederman 11171f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 11181f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 11191680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 112061d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 11211f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 11221f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 11231f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 11241f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 11251f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 11261f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 11271f87f0b5SEric W. Biederman if (!table->data) 112889c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 11291f87f0b5SEric W. Biederman if (!table->maxlen) 113089c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 11314f2fec00SLuis R. Rodriguez else 11324f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11331f87f0b5SEric W. Biederman } 11341f87f0b5SEric W. Biederman if (!table->proc_handler) 113589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11367c60c48fSEric W. Biederman 11377c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 113889c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11397c60c48fSEric W. Biederman table->mode); 11401f87f0b5SEric W. Biederman } 11417c60c48fSEric W. Biederman return err; 11421f87f0b5SEric W. Biederman } 11431f87f0b5SEric W. Biederman 11440e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11450e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11460e47c99dSEric W. Biederman { 11470e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11480e47c99dSEric W. Biederman struct ctl_table_header *links; 1149ac13ac6fSEric W. Biederman struct ctl_node *node; 11500e47c99dSEric W. Biederman char *link_name; 11510e47c99dSEric W. Biederman int nr_entries, name_bytes; 11520e47c99dSEric W. Biederman 11530e47c99dSEric W. Biederman name_bytes = 0; 11540e47c99dSEric W. Biederman nr_entries = 0; 11550e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11560e47c99dSEric W. Biederman nr_entries++; 11570e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11580e47c99dSEric W. Biederman } 11590e47c99dSEric W. Biederman 11600e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1161ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11620e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11630e47c99dSEric W. Biederman name_bytes, 11640e47c99dSEric W. Biederman GFP_KERNEL); 11650e47c99dSEric W. Biederman 11660e47c99dSEric W. Biederman if (!links) 11670e47c99dSEric W. Biederman return NULL; 11680e47c99dSEric W. Biederman 1169ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1170ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11710e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11720e47c99dSEric W. Biederman 11730e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11740e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11750e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11760e47c99dSEric W. Biederman link->procname = link_name; 11770e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11780e47c99dSEric W. Biederman link->data = link_root; 11790e47c99dSEric W. Biederman link_name += len; 11800e47c99dSEric W. Biederman } 1181ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11820e47c99dSEric W. Biederman links->nreg = nr_entries; 11830e47c99dSEric W. Biederman 11840e47c99dSEric W. Biederman return links; 11850e47c99dSEric W. Biederman } 11860e47c99dSEric W. Biederman 11870e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11880e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11890e47c99dSEric W. Biederman { 11900e47c99dSEric W. Biederman struct ctl_table_header *head; 11910e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11920e47c99dSEric W. Biederman 11930e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11940e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11950e47c99dSEric W. Biederman const char *procname = entry->procname; 11960e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 11970e47c99dSEric W. Biederman if (!link) 11980e47c99dSEric W. Biederman return false; 11990e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12000e47c99dSEric W. Biederman continue; 12010e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12020e47c99dSEric W. Biederman continue; 12030e47c99dSEric W. Biederman return false; 12040e47c99dSEric W. Biederman } 12050e47c99dSEric W. Biederman 12060e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 12070e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12080e47c99dSEric W. Biederman const char *procname = entry->procname; 12090e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12100e47c99dSEric W. Biederman head->nreg++; 12110e47c99dSEric W. Biederman } 12120e47c99dSEric W. Biederman return true; 12130e47c99dSEric W. Biederman } 12140e47c99dSEric W. Biederman 12150e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12160e47c99dSEric W. Biederman { 12170e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12180e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12190e47c99dSEric W. Biederman struct ctl_table_header *links; 12200e47c99dSEric W. Biederman int err; 12210e47c99dSEric W. Biederman 12220e47c99dSEric W. Biederman if (head->set == root_set) 12230e47c99dSEric W. Biederman return 0; 12240e47c99dSEric W. Biederman 12250e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12260e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12270e47c99dSEric W. Biederman return 0; 12280e47c99dSEric W. Biederman 12290e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12300e47c99dSEric W. Biederman return 0; 12310e47c99dSEric W. Biederman 12320e47c99dSEric W. Biederman core_parent->header.nreg++; 12330e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12340e47c99dSEric W. Biederman 12350e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12360e47c99dSEric W. Biederman 12370e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12380e47c99dSEric W. Biederman err = -ENOMEM; 12390e47c99dSEric W. Biederman if (!links) 12400e47c99dSEric W. Biederman goto out; 12410e47c99dSEric W. Biederman 12420e47c99dSEric W. Biederman err = 0; 12430e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12440e47c99dSEric W. Biederman kfree(links); 12450e47c99dSEric W. Biederman goto out; 12460e47c99dSEric W. Biederman } 12470e47c99dSEric W. Biederman 12480e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12490e47c99dSEric W. Biederman if (err) 12500e47c99dSEric W. Biederman kfree(links); 12510e47c99dSEric W. Biederman out: 12520e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12530e47c99dSEric W. Biederman return err; 12540e47c99dSEric W. Biederman } 12550e47c99dSEric W. Biederman 12561f87f0b5SEric W. Biederman /** 1257f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 125860a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12591f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12601f87f0b5SEric W. Biederman * @table: the top-level table structure 12611f87f0b5SEric W. Biederman * 12621f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12631f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12641f87f0b5SEric W. Biederman * 12651f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12661f87f0b5SEric W. Biederman * 12671f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12681f87f0b5SEric W. Biederman * enter a sysctl file 12691f87f0b5SEric W. Biederman * 12701f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12711f87f0b5SEric W. Biederman * 12721f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12731f87f0b5SEric W. Biederman * 1274f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12751f87f0b5SEric W. Biederman * 1276f728019bSEric W. Biederman * child - must be %NULL. 12771f87f0b5SEric W. Biederman * 12781f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12791f87f0b5SEric W. Biederman * 12801f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12811f87f0b5SEric W. Biederman * 12821f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12831f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12841f87f0b5SEric W. Biederman * 1285f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1286f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12871f87f0b5SEric W. Biederman * 12881f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12891f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12901f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12911f87f0b5SEric W. Biederman * 12921f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12931f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12941f87f0b5SEric W. Biederman * 12951f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 12961f87f0b5SEric W. Biederman * to the table header on success. 12971f87f0b5SEric W. Biederman */ 12986e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 129960a47a2eSEric W. Biederman struct ctl_table_set *set, 13006e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 13011f87f0b5SEric W. Biederman { 130260a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13031f87f0b5SEric W. Biederman struct ctl_table_header *header; 13046e9d5164SEric W. Biederman const char *name, *nextname; 13057ec66d06SEric W. Biederman struct ctl_dir *dir; 1306ac13ac6fSEric W. Biederman struct ctl_table *entry; 1307ac13ac6fSEric W. Biederman struct ctl_node *node; 1308ac13ac6fSEric W. Biederman int nr_entries = 0; 13091f87f0b5SEric W. Biederman 1310ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1311ac13ac6fSEric W. Biederman nr_entries++; 1312ac13ac6fSEric W. Biederman 1313ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1314ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13151f87f0b5SEric W. Biederman if (!header) 13161f87f0b5SEric W. Biederman return NULL; 13171f87f0b5SEric W. Biederman 1318ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1319ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13207c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13217c60c48fSEric W. Biederman goto fail; 13228d6ecfccSEric W. Biederman 13231f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13240e47c99dSEric W. Biederman dir = &set->dir; 132560f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13267ec66d06SEric W. Biederman dir->header.nreg++; 13277ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13287ec66d06SEric W. Biederman 13297ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13307ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13317ec66d06SEric W. Biederman int namelen; 13327ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13337ec66d06SEric W. Biederman if (nextname) { 13347ec66d06SEric W. Biederman namelen = nextname - name; 13357ec66d06SEric W. Biederman nextname++; 13367ec66d06SEric W. Biederman } else { 13377ec66d06SEric W. Biederman namelen = strlen(name); 13387ec66d06SEric W. Biederman } 13397ec66d06SEric W. Biederman if (namelen == 0) 13401f87f0b5SEric W. Biederman continue; 13417ec66d06SEric W. Biederman 13420e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13437ec66d06SEric W. Biederman if (IS_ERR(dir)) 13447ec66d06SEric W. Biederman goto fail; 13451f87f0b5SEric W. Biederman } 13460e47c99dSEric W. Biederman 13477ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13480e47c99dSEric W. Biederman if (insert_header(dir, header)) 13490e47c99dSEric W. Biederman goto fail_put_dir_locked; 13500e47c99dSEric W. Biederman 13517ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13521f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13531f87f0b5SEric W. Biederman 13541f87f0b5SEric W. Biederman return header; 13550e47c99dSEric W. Biederman 13567ec66d06SEric W. Biederman fail_put_dir_locked: 13577ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13587c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13597c60c48fSEric W. Biederman fail: 13607c60c48fSEric W. Biederman kfree(header); 13617c60c48fSEric W. Biederman dump_stack(); 13627c60c48fSEric W. Biederman return NULL; 13631f87f0b5SEric W. Biederman } 13641f87f0b5SEric W. Biederman 1365fea478d4SEric W. Biederman /** 1366fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1367fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1368fea478d4SEric W. Biederman * @table: the table structure 1369fea478d4SEric W. Biederman * 1370fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1371fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1372fea478d4SEric W. Biederman * 1373fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1374fea478d4SEric W. Biederman */ 1375fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1376fea478d4SEric W. Biederman { 1377fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1378fea478d4SEric W. Biederman path, table); 1379fea478d4SEric W. Biederman } 1380fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1381fea478d4SEric W. Biederman 13826e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13836e9d5164SEric W. Biederman { 13846e9d5164SEric W. Biederman int namelen; 13856e9d5164SEric W. Biederman namelen = strlen(name); 13866e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 13876e9d5164SEric W. Biederman return NULL; 13886e9d5164SEric W. Biederman memcpy(pos, name, namelen); 13896e9d5164SEric W. Biederman pos[namelen] = '/'; 13906e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 13916e9d5164SEric W. Biederman pos += namelen + 1; 13926e9d5164SEric W. Biederman return pos; 13936e9d5164SEric W. Biederman } 13946e9d5164SEric W. Biederman 1395f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1396f728019bSEric W. Biederman { 1397f728019bSEric W. Biederman int has_files = 0; 1398f728019bSEric W. Biederman int nr_subheaders = 0; 1399f728019bSEric W. Biederman struct ctl_table *entry; 1400f728019bSEric W. Biederman 1401f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1402f728019bSEric W. Biederman if (!table || !table->procname) 1403f728019bSEric W. Biederman return 1; 1404f728019bSEric W. Biederman 1405f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1406f728019bSEric W. Biederman if (entry->child) 1407f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1408f728019bSEric W. Biederman else 1409f728019bSEric W. Biederman has_files = 1; 1410f728019bSEric W. Biederman } 1411f728019bSEric W. Biederman return nr_subheaders + has_files; 1412f728019bSEric W. Biederman } 1413f728019bSEric W. Biederman 1414f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 141560a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1416f728019bSEric W. Biederman struct ctl_table *table) 1417f728019bSEric W. Biederman { 1418f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1419f728019bSEric W. Biederman struct ctl_table *entry, *files; 1420f728019bSEric W. Biederman int nr_files = 0; 1421f728019bSEric W. Biederman int nr_dirs = 0; 1422f728019bSEric W. Biederman int err = -ENOMEM; 1423f728019bSEric W. Biederman 1424f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1425f728019bSEric W. Biederman if (entry->child) 1426f728019bSEric W. Biederman nr_dirs++; 1427f728019bSEric W. Biederman else 1428f728019bSEric W. Biederman nr_files++; 1429f728019bSEric W. Biederman } 1430f728019bSEric W. Biederman 1431f728019bSEric W. Biederman files = table; 1432f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1433f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1434f728019bSEric W. Biederman struct ctl_table *new; 14356396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1436f728019bSEric W. Biederman GFP_KERNEL); 1437f728019bSEric W. Biederman if (!files) 1438f728019bSEric W. Biederman goto out; 1439f728019bSEric W. Biederman 1440f728019bSEric W. Biederman ctl_table_arg = files; 1441f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1442f728019bSEric W. Biederman if (entry->child) 1443f728019bSEric W. Biederman continue; 1444f728019bSEric W. Biederman *new = *entry; 1445f728019bSEric W. Biederman new++; 1446f728019bSEric W. Biederman } 1447f728019bSEric W. Biederman } 1448f728019bSEric W. Biederman 1449f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1450f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1451f728019bSEric W. Biederman struct ctl_table_header *header; 145260a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1453f728019bSEric W. Biederman if (!header) { 1454f728019bSEric W. Biederman kfree(ctl_table_arg); 1455f728019bSEric W. Biederman goto out; 1456f728019bSEric W. Biederman } 1457f728019bSEric W. Biederman 1458f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1459f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1460f728019bSEric W. Biederman **subheader = header; 1461f728019bSEric W. Biederman (*subheader)++; 1462f728019bSEric W. Biederman } 1463f728019bSEric W. Biederman 1464f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1465f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1466f728019bSEric W. Biederman char *child_pos; 1467f728019bSEric W. Biederman 1468f728019bSEric W. Biederman if (!entry->child) 1469f728019bSEric W. Biederman continue; 1470f728019bSEric W. Biederman 1471f728019bSEric W. Biederman err = -ENAMETOOLONG; 1472f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1473f728019bSEric W. Biederman if (!child_pos) 1474f728019bSEric W. Biederman goto out; 1475f728019bSEric W. Biederman 1476f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 147760a47a2eSEric W. Biederman set, entry->child); 1478f728019bSEric W. Biederman pos[0] = '\0'; 1479f728019bSEric W. Biederman if (err) 1480f728019bSEric W. Biederman goto out; 1481f728019bSEric W. Biederman } 1482f728019bSEric W. Biederman err = 0; 1483f728019bSEric W. Biederman out: 1484f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1485f728019bSEric W. Biederman return err; 1486f728019bSEric W. Biederman } 1487f728019bSEric W. Biederman 14886e9d5164SEric W. Biederman /** 14896e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 149060a47a2eSEric W. Biederman * @set: Sysctl tree to register on 14916e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 14926e9d5164SEric W. Biederman * @table: the top-level table structure 14936e9d5164SEric W. Biederman * 14946e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 14956e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 14966e9d5164SEric W. Biederman * 14976e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 14986e9d5164SEric W. Biederman */ 14996e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 150060a47a2eSEric W. Biederman struct ctl_table_set *set, 15016e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15026e9d5164SEric W. Biederman { 1503ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1504f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1505f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15066e9d5164SEric W. Biederman const struct ctl_path *component; 15076e9d5164SEric W. Biederman char *new_path, *pos; 15086e9d5164SEric W. Biederman 15096e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15106e9d5164SEric W. Biederman if (!new_path) 15116e9d5164SEric W. Biederman return NULL; 15126e9d5164SEric W. Biederman 15136e9d5164SEric W. Biederman pos[0] = '\0'; 15146e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15156e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15166e9d5164SEric W. Biederman if (!pos) 15176e9d5164SEric W. Biederman goto out; 15186e9d5164SEric W. Biederman } 1519ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1520ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1521ec6a5266SEric W. Biederman if (!pos) 1522ec6a5266SEric W. Biederman goto out; 1523ec6a5266SEric W. Biederman table = table->child; 1524ec6a5266SEric W. Biederman } 1525f728019bSEric W. Biederman if (nr_subheaders == 1) { 152660a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1527ec6a5266SEric W. Biederman if (header) 1528ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1529f728019bSEric W. Biederman } else { 1530f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1531f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1532f728019bSEric W. Biederman if (!header) 1533f728019bSEric W. Biederman goto out; 1534f728019bSEric W. Biederman 1535f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1536f728019bSEric W. Biederman subheader = subheaders; 1537f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1538f728019bSEric W. Biederman 1539f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 154060a47a2eSEric W. Biederman set, table)) 1541f728019bSEric W. Biederman goto err_register_leaves; 1542f728019bSEric W. Biederman } 1543f728019bSEric W. Biederman 15446e9d5164SEric W. Biederman out: 15456e9d5164SEric W. Biederman kfree(new_path); 15466e9d5164SEric W. Biederman return header; 1547f728019bSEric W. Biederman 1548f728019bSEric W. Biederman err_register_leaves: 1549f728019bSEric W. Biederman while (subheader > subheaders) { 1550f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1551f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1552f728019bSEric W. Biederman unregister_sysctl_table(subh); 1553f728019bSEric W. Biederman kfree(table); 1554f728019bSEric W. Biederman } 1555f728019bSEric W. Biederman kfree(header); 1556f728019bSEric W. Biederman header = NULL; 1557f728019bSEric W. Biederman goto out; 15586e9d5164SEric W. Biederman } 15596e9d5164SEric W. Biederman 15601f87f0b5SEric W. Biederman /** 15611f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15621f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15631f87f0b5SEric W. Biederman * @table: the top-level table structure 15641f87f0b5SEric W. Biederman * 15651f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15661f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15671f87f0b5SEric W. Biederman * 15681f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15691f87f0b5SEric W. Biederman */ 15701f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15711f87f0b5SEric W. Biederman struct ctl_table *table) 15721f87f0b5SEric W. Biederman { 157360a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15741f87f0b5SEric W. Biederman path, table); 15751f87f0b5SEric W. Biederman } 15761f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15771f87f0b5SEric W. Biederman 15781f87f0b5SEric W. Biederman /** 15791f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15801f87f0b5SEric W. Biederman * @table: the top-level table structure 15811f87f0b5SEric W. Biederman * 15821f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15831f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15841f87f0b5SEric W. Biederman * 15851f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 15861f87f0b5SEric W. Biederman */ 15871f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 15881f87f0b5SEric W. Biederman { 15891f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 15901f87f0b5SEric W. Biederman 15911f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 15921f87f0b5SEric W. Biederman } 15931f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 15941f87f0b5SEric W. Biederman 15950e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 15960e47c99dSEric W. Biederman { 15970e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 15980e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 15990e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 16000e47c99dSEric W. Biederman struct ctl_dir *core_parent; 16010e47c99dSEric W. Biederman struct ctl_table *entry; 16020e47c99dSEric W. Biederman 16030e47c99dSEric W. Biederman if (header->set == root_set) 16040e47c99dSEric W. Biederman return; 16050e47c99dSEric W. Biederman 16060e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16070e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16080e47c99dSEric W. Biederman return; 16090e47c99dSEric W. Biederman 16100e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 16110e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16120e47c99dSEric W. Biederman struct ctl_table *link; 16130e47c99dSEric W. Biederman const char *name = entry->procname; 16140e47c99dSEric W. Biederman 16150e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16160e47c99dSEric W. Biederman if (link && 16170e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16180e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16190e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16200e47c99dSEric W. Biederman } 16210e47c99dSEric W. Biederman else { 162287ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16230e47c99dSEric W. Biederman sysctl_print_dir(parent); 162487ebdc00SAndrew Morton pr_cont("/%s\n", name); 16250e47c99dSEric W. Biederman } 16260e47c99dSEric W. Biederman } 16270e47c99dSEric W. Biederman } 16280e47c99dSEric W. Biederman 1629938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1630938aaa4fSEric W. Biederman { 16317ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16327ec66d06SEric W. Biederman 1633938aaa4fSEric W. Biederman if (--header->nreg) 1634938aaa4fSEric W. Biederman return; 1635938aaa4fSEric W. Biederman 163689189557SYueHaibing if (parent) { 16370e47c99dSEric W. Biederman put_links(header); 1638938aaa4fSEric W. Biederman start_unregistering(header); 163989189557SYueHaibing } 164089189557SYueHaibing 1641938aaa4fSEric W. Biederman if (!--header->count) 1642938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16437ec66d06SEric W. Biederman 16447ec66d06SEric W. Biederman if (parent) 16457ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1646938aaa4fSEric W. Biederman } 1647938aaa4fSEric W. Biederman 16481f87f0b5SEric W. Biederman /** 16491f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16501f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16511f87f0b5SEric W. Biederman * 16521f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16531f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16541f87f0b5SEric W. Biederman */ 16551f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16561f87f0b5SEric W. Biederman { 1657f728019bSEric W. Biederman int nr_subheaders; 16581f87f0b5SEric W. Biederman might_sleep(); 16591f87f0b5SEric W. Biederman 16601f87f0b5SEric W. Biederman if (header == NULL) 16611f87f0b5SEric W. Biederman return; 16621f87f0b5SEric W. Biederman 1663f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1664f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1665f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1666f728019bSEric W. Biederman int i; 1667f728019bSEric W. Biederman 1668f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1669f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1670f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1671f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1672f728019bSEric W. Biederman unregister_sysctl_table(subh); 1673f728019bSEric W. Biederman kfree(table); 1674f728019bSEric W. Biederman } 1675f728019bSEric W. Biederman kfree(header); 1676f728019bSEric W. Biederman return; 1677f728019bSEric W. Biederman } 1678f728019bSEric W. Biederman 16791f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1680938aaa4fSEric W. Biederman drop_sysctl_table(header); 16811f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16821f87f0b5SEric W. Biederman } 16831f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16841f87f0b5SEric W. Biederman 16850e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 16869eb47c26SEric W. Biederman struct ctl_table_root *root, 16871f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 16881f87f0b5SEric W. Biederman { 16891347440dSDan Carpenter memset(set, 0, sizeof(*set)); 16900e47c99dSEric W. Biederman set->is_seen = is_seen; 1691ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 16921f87f0b5SEric W. Biederman } 16931f87f0b5SEric W. Biederman 169497324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 169597324cd8SEric W. Biederman { 1696ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 169797324cd8SEric W. Biederman } 16981f87f0b5SEric W. Biederman 16991e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 170077b14db5SEric W. Biederman { 1701e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1702e1675231SAlexey Dobriyan 170377b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17049043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 1705d56c0d45SAlexey Dobriyan proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; 170677b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1707de4e83bdSEric W. Biederman 1708de4e83bdSEric W. Biederman return sysctl_init(); 170977b14db5SEric W. Biederman } 1710