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 25f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 26f9bd6733SEric W. Biederman 27f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 28f9bd6733SEric W. Biederman { } 29f9bd6733SEric W. Biederman }; 30f9bd6733SEric W. Biederman 31f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 32f9bd6733SEric W. Biederman { 33f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 34f9bd6733SEric W. Biederman } 35f9bd6733SEric W. Biederman 36f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 37f9bd6733SEric W. Biederman { 38f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 39f9bd6733SEric W. Biederman } 40f9bd6733SEric W. Biederman 41f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 42f9bd6733SEric W. Biederman 43f9bd6733SEric W. Biederman { 44f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 45f9bd6733SEric W. Biederman } 46f9bd6733SEric W. Biederman 47f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 48f1ecf068SLucas De Marchi { 49f1ecf068SLucas De Marchi if (!poll) 50f1ecf068SLucas De Marchi return; 51f1ecf068SLucas De Marchi 52f1ecf068SLucas De Marchi atomic_inc(&poll->event); 53f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 54f1ecf068SLucas De Marchi } 55f1ecf068SLucas De Marchi 56a194558eSEric W. Biederman static struct ctl_table root_table[] = { 57a194558eSEric W. Biederman { 58a194558eSEric W. Biederman .procname = "", 597ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 60a194558eSEric W. Biederman }, 61a194558eSEric W. Biederman { } 62a194558eSEric W. Biederman }; 630e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 640e47c99dSEric W. Biederman .default_set.dir.header = { 651f87f0b5SEric W. Biederman {{.count = 1, 66938aaa4fSEric W. Biederman .nreg = 1, 67ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 680e47c99dSEric W. Biederman .ctl_table_arg = root_table, 691f87f0b5SEric W. Biederman .root = &sysctl_table_root, 701f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 717ec66d06SEric W. Biederman }, 721f87f0b5SEric W. Biederman }; 731f87f0b5SEric W. Biederman 741f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 751f87f0b5SEric W. Biederman 767ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 770e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 7813bcc6a2SEric W. Biederman struct ctl_table **pentry); 790e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 800e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 817ec66d06SEric W. Biederman 826980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 836980128fSEric W. Biederman { 846980128fSEric W. Biederman if (dir->header.parent) 856980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 8687ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 876980128fSEric W. Biederman } 886980128fSEric W. Biederman 89076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 90076c3eedSEric W. Biederman { 91076c3eedSEric W. Biederman int minlen; 92076c3eedSEric W. Biederman int cmp; 93076c3eedSEric W. Biederman 94076c3eedSEric W. Biederman minlen = len1; 95076c3eedSEric W. Biederman if (minlen > len2) 96076c3eedSEric W. Biederman minlen = len2; 97076c3eedSEric W. Biederman 98076c3eedSEric W. Biederman cmp = memcmp(name1, name2, minlen); 99076c3eedSEric W. Biederman if (cmp == 0) 100076c3eedSEric W. Biederman cmp = len1 - len2; 101076c3eedSEric W. Biederman return cmp; 102076c3eedSEric W. Biederman } 103076c3eedSEric W. Biederman 10460f126d9SEric W. Biederman /* Called under sysctl_lock */ 105076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1060e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 107076c3eedSEric W. Biederman { 108076c3eedSEric W. Biederman struct ctl_table_header *head; 109076c3eedSEric W. Biederman struct ctl_table *entry; 110ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 111076c3eedSEric W. Biederman 112ac13ac6fSEric W. Biederman while (node) 113ac13ac6fSEric W. Biederman { 114ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 115ac13ac6fSEric W. Biederman const char *procname; 116ac13ac6fSEric W. Biederman int cmp; 117ac13ac6fSEric W. Biederman 118ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 119ac13ac6fSEric W. Biederman head = ctl_node->header; 120ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 121ac13ac6fSEric W. Biederman procname = entry->procname; 122ac13ac6fSEric W. Biederman 123ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 124ac13ac6fSEric W. Biederman if (cmp < 0) 125ac13ac6fSEric W. Biederman node = node->rb_left; 126ac13ac6fSEric W. Biederman else if (cmp > 0) 127ac13ac6fSEric W. Biederman node = node->rb_right; 128ac13ac6fSEric W. Biederman else { 129076c3eedSEric W. Biederman *phead = head; 130076c3eedSEric W. Biederman return entry; 131076c3eedSEric W. Biederman } 132076c3eedSEric W. Biederman } 133076c3eedSEric W. Biederman return NULL; 134076c3eedSEric W. Biederman } 135076c3eedSEric W. Biederman 136ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 137ac13ac6fSEric W. Biederman { 138ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 139ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 140ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 141ac13ac6fSEric W. Biederman const char *name = entry->procname; 142ac13ac6fSEric W. Biederman int namelen = strlen(name); 143ac13ac6fSEric W. Biederman 144ac13ac6fSEric W. Biederman while (*p) { 145ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 146ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 147ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 148ac13ac6fSEric W. Biederman const char *parent_name; 149ac13ac6fSEric W. Biederman int cmp; 150ac13ac6fSEric W. Biederman 151ac13ac6fSEric W. Biederman parent = *p; 152ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 153ac13ac6fSEric W. Biederman parent_head = parent_node->header; 154ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 155ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 156ac13ac6fSEric W. Biederman 157ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 158ac13ac6fSEric W. Biederman if (cmp < 0) 159ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 160ac13ac6fSEric W. Biederman else if (cmp > 0) 161ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 162ac13ac6fSEric W. Biederman else { 16387ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 164ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 16587ebdc00SAndrew Morton pr_cont("/%s\n", entry->procname); 166ac13ac6fSEric W. Biederman return -EEXIST; 167ac13ac6fSEric W. Biederman } 168ac13ac6fSEric W. Biederman } 169ac13ac6fSEric W. Biederman 170ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 171ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 172ac13ac6fSEric W. Biederman return 0; 173ac13ac6fSEric W. Biederman } 174ac13ac6fSEric W. Biederman 175ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 176ac13ac6fSEric W. Biederman { 177ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 178ac13ac6fSEric W. Biederman 179ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 180ac13ac6fSEric W. Biederman } 181ac13ac6fSEric W. Biederman 182e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 183e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 184ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 185e0d04529SEric W. Biederman { 1867ec66d06SEric W. Biederman head->ctl_table = table; 187e0d04529SEric W. Biederman head->ctl_table_arg = table; 188e0d04529SEric W. Biederman head->used = 0; 189e0d04529SEric W. Biederman head->count = 1; 190e0d04529SEric W. Biederman head->nreg = 1; 191e0d04529SEric W. Biederman head->unregistering = NULL; 192e0d04529SEric W. Biederman head->root = root; 193e0d04529SEric W. Biederman head->set = set; 194e0d04529SEric W. Biederman head->parent = NULL; 195ac13ac6fSEric W. Biederman head->node = node; 1962fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 197ac13ac6fSEric W. Biederman if (node) { 198ac13ac6fSEric W. Biederman struct ctl_table *entry; 1994c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 200ac13ac6fSEric W. Biederman node->header = head; 201ac13ac6fSEric W. Biederman } 202ac13ac6fSEric W. Biederman } 203e0d04529SEric W. Biederman 2048425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2058425d6aaSEric W. Biederman { 206ac13ac6fSEric W. Biederman struct ctl_table *entry; 207ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 208ac13ac6fSEric W. Biederman erase_entry(head, entry); 2098425d6aaSEric W. Biederman } 2108425d6aaSEric W. Biederman 2110e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2128425d6aaSEric W. Biederman { 213ac13ac6fSEric W. Biederman struct ctl_table *entry; 2140e47c99dSEric W. Biederman int err; 2150e47c99dSEric W. Biederman 216f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 217f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 218f9bd6733SEric W. Biederman return -EROFS; 219f9bd6733SEric W. Biederman 220f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 221f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 222f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 223f9bd6733SEric W. Biederman return -EINVAL; 224f9bd6733SEric W. Biederman set_empty_dir(dir); 225f9bd6733SEric W. Biederman } 226f9bd6733SEric W. Biederman 2270e47c99dSEric W. Biederman dir->header.nreg++; 2287ec66d06SEric W. Biederman header->parent = dir; 2290e47c99dSEric W. Biederman err = insert_links(header); 2300e47c99dSEric W. Biederman if (err) 2310e47c99dSEric W. Biederman goto fail_links; 232ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 233ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 234ac13ac6fSEric W. Biederman if (err) 235ac13ac6fSEric W. Biederman goto fail; 236ac13ac6fSEric W. Biederman } 2370e47c99dSEric W. Biederman return 0; 238ac13ac6fSEric W. Biederman fail: 239ac13ac6fSEric W. Biederman erase_header(header); 240ac13ac6fSEric W. Biederman put_links(header); 2410e47c99dSEric W. Biederman fail_links: 242f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 243f9bd6733SEric W. Biederman clear_empty_dir(dir); 2440e47c99dSEric W. Biederman header->parent = NULL; 2450e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2460e47c99dSEric W. Biederman return err; 2478425d6aaSEric W. Biederman } 2488425d6aaSEric W. Biederman 2491f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2501f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2511f87f0b5SEric W. Biederman { 2521f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2531f87f0b5SEric W. Biederman return 0; 2541f87f0b5SEric W. Biederman p->used++; 2551f87f0b5SEric W. Biederman return 1; 2561f87f0b5SEric W. Biederman } 2571f87f0b5SEric W. Biederman 2581f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2591f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2601f87f0b5SEric W. Biederman { 2611f87f0b5SEric W. Biederman if (!--p->used) 2621f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2631f87f0b5SEric W. Biederman complete(p->unregistering); 2641f87f0b5SEric W. Biederman } 2651f87f0b5SEric W. Biederman 266d6cffbbeSKonstantin Khlebnikov static void proc_sys_prune_dcache(struct ctl_table_header *head) 267d6cffbbeSKonstantin Khlebnikov { 2682fd1d2c4SEric W. Biederman struct inode *inode; 269d6cffbbeSKonstantin Khlebnikov struct proc_inode *ei; 2702fd1d2c4SEric W. Biederman struct hlist_node *node; 2712fd1d2c4SEric W. Biederman struct super_block *sb; 272d6cffbbeSKonstantin Khlebnikov 273ace0c791SEric W. Biederman rcu_read_lock(); 2742fd1d2c4SEric W. Biederman for (;;) { 2752fd1d2c4SEric W. Biederman node = hlist_first_rcu(&head->inodes); 2762fd1d2c4SEric W. Biederman if (!node) 2772fd1d2c4SEric W. Biederman break; 2782fd1d2c4SEric W. Biederman ei = hlist_entry(node, struct proc_inode, sysctl_inodes); 2792fd1d2c4SEric W. Biederman spin_lock(&sysctl_lock); 2802fd1d2c4SEric W. Biederman hlist_del_init_rcu(&ei->sysctl_inodes); 2812fd1d2c4SEric W. Biederman spin_unlock(&sysctl_lock); 2822fd1d2c4SEric W. Biederman 2832fd1d2c4SEric W. Biederman inode = &ei->vfs_inode; 2842fd1d2c4SEric W. Biederman sb = inode->i_sb; 2852fd1d2c4SEric W. Biederman if (!atomic_inc_not_zero(&sb->s_active)) 2862fd1d2c4SEric W. Biederman continue; 2872fd1d2c4SEric W. Biederman inode = igrab(inode); 288ace0c791SEric W. Biederman rcu_read_unlock(); 2892fd1d2c4SEric W. Biederman if (unlikely(!inode)) { 2902fd1d2c4SEric W. Biederman deactivate_super(sb); 2912fd1d2c4SEric W. Biederman rcu_read_lock(); 2922fd1d2c4SEric W. Biederman continue; 2932fd1d2c4SEric W. Biederman } 2942fd1d2c4SEric W. Biederman 295d6cffbbeSKonstantin Khlebnikov d_prune_aliases(inode); 2962fd1d2c4SEric W. Biederman iput(inode); 2972fd1d2c4SEric W. Biederman deactivate_super(sb); 2982fd1d2c4SEric W. Biederman 299ace0c791SEric W. Biederman rcu_read_lock(); 300d6cffbbeSKonstantin Khlebnikov } 301ace0c791SEric W. Biederman rcu_read_unlock(); 302d6cffbbeSKonstantin Khlebnikov } 303d6cffbbeSKonstantin Khlebnikov 3041f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 3051f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 3061f87f0b5SEric W. Biederman { 3071f87f0b5SEric W. Biederman /* 3081f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 3091f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 3101f87f0b5SEric W. Biederman */ 3111f87f0b5SEric W. Biederman if (unlikely(p->used)) { 3121f87f0b5SEric W. Biederman struct completion wait; 3131f87f0b5SEric W. Biederman init_completion(&wait); 3141f87f0b5SEric W. Biederman p->unregistering = &wait; 3151f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3161f87f0b5SEric W. Biederman wait_for_completion(&wait); 3171f87f0b5SEric W. Biederman } else { 3181f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 3191f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 320ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 3211f87f0b5SEric W. Biederman } 3221f87f0b5SEric W. Biederman /* 323d6cffbbeSKonstantin Khlebnikov * Prune dentries for unregistered sysctls: namespaced sysctls 324d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 325d6cffbbeSKonstantin Khlebnikov */ 326d6cffbbeSKonstantin Khlebnikov proc_sys_prune_dcache(p); 327d6cffbbeSKonstantin Khlebnikov /* 3281f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 3291f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 3301f87f0b5SEric W. Biederman */ 331ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3328425d6aaSEric W. Biederman erase_header(p); 3331f87f0b5SEric W. Biederman } 3341f87f0b5SEric W. Biederman 3351f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3361f87f0b5SEric W. Biederman { 337ab4a1f24SPrasad Joshi BUG_ON(!head); 3381f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3391f87f0b5SEric W. Biederman if (!use_table(head)) 3401f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3411f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3421f87f0b5SEric W. Biederman return head; 3431f87f0b5SEric W. Biederman } 3441f87f0b5SEric W. Biederman 3451f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3461f87f0b5SEric W. Biederman { 3471f87f0b5SEric W. Biederman if (!head) 3481f87f0b5SEric W. Biederman return; 3491f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3501f87f0b5SEric W. Biederman unuse_table(head); 3511f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3521f87f0b5SEric W. Biederman } 3531f87f0b5SEric W. Biederman 3541f87f0b5SEric W. Biederman static struct ctl_table_set * 35513bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3561f87f0b5SEric W. Biederman { 3571f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3581f87f0b5SEric W. Biederman if (root->lookup) 35913bcc6a2SEric W. Biederman set = root->lookup(root); 3601f87f0b5SEric W. Biederman return set; 3611f87f0b5SEric W. Biederman } 3621f87f0b5SEric W. Biederman 363076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3647ec66d06SEric W. Biederman struct ctl_dir *dir, 365076c3eedSEric W. Biederman const char *name, int namelen) 366076c3eedSEric W. Biederman { 367076c3eedSEric W. Biederman struct ctl_table_header *head; 368076c3eedSEric W. Biederman struct ctl_table *entry; 369076c3eedSEric W. Biederman 370076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3710e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 372076c3eedSEric W. Biederman if (entry && use_table(head)) 373076c3eedSEric W. Biederman *phead = head; 374076c3eedSEric W. Biederman else 375076c3eedSEric W. Biederman entry = NULL; 376076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 377076c3eedSEric W. Biederman return entry; 378076c3eedSEric W. Biederman } 379076c3eedSEric W. Biederman 380ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3811f87f0b5SEric W. Biederman { 382ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3831f87f0b5SEric W. Biederman 384ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 385ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 386ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 387ac13ac6fSEric W. Biederman return ctl_node; 3881f87f0b5SEric W. Biederman } 3891f87f0b5SEric W. Biederman return NULL; 3901f87f0b5SEric W. Biederman } 3911f87f0b5SEric W. Biederman 3927ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3936a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3941f87f0b5SEric W. Biederman { 395ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3967ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 397ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3986a75ce16SEric W. Biederman 3996a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 400ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 4016a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 402ac13ac6fSEric W. Biederman if (ctl_node) { 403ac13ac6fSEric W. Biederman head = ctl_node->header; 404ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 405ac13ac6fSEric W. Biederman } 4066a75ce16SEric W. Biederman *phead = head; 4076a75ce16SEric W. Biederman *pentry = entry; 4086a75ce16SEric W. Biederman } 4096a75ce16SEric W. Biederman 4107ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 4116a75ce16SEric W. Biederman { 4126a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 4136a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 414ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 4156a75ce16SEric W. Biederman 4166a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 4176a75ce16SEric W. Biederman unuse_table(head); 418ac13ac6fSEric W. Biederman 419ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 4206a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 421ac13ac6fSEric W. Biederman head = NULL; 422ac13ac6fSEric W. Biederman if (ctl_node) { 423ac13ac6fSEric W. Biederman head = ctl_node->header; 424ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 4256a75ce16SEric W. Biederman } 4266a75ce16SEric W. Biederman *phead = head; 4276a75ce16SEric W. Biederman *pentry = entry; 4281f87f0b5SEric W. Biederman } 4291f87f0b5SEric W. Biederman 4301f87f0b5SEric W. Biederman /* 4311f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4321f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4331f87f0b5SEric W. Biederman */ 4341f87f0b5SEric W. Biederman 4351f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4361f87f0b5SEric W. Biederman { 437091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4381f87f0b5SEric W. Biederman mode >>= 6; 439091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4401f87f0b5SEric W. Biederman mode >>= 3; 4411f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4421f87f0b5SEric W. Biederman return 0; 4431f87f0b5SEric W. Biederman return -EACCES; 4441f87f0b5SEric W. Biederman } 4451f87f0b5SEric W. Biederman 44673f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4471f87f0b5SEric W. Biederman { 44873f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4491f87f0b5SEric W. Biederman int mode; 4501f87f0b5SEric W. Biederman 4511f87f0b5SEric W. Biederman if (root->permissions) 45273f7ef43SEric W. Biederman mode = root->permissions(head, table); 4531f87f0b5SEric W. Biederman else 4541f87f0b5SEric W. Biederman mode = table->mode; 4551f87f0b5SEric W. Biederman 4561f87f0b5SEric W. Biederman return test_perm(mode, op); 4571f87f0b5SEric W. Biederman } 4581f87f0b5SEric W. Biederman 4599043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4609043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 46177b14db5SEric W. Biederman { 462e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 46377b14db5SEric W. Biederman struct inode *inode; 4649043476fSAl Viro struct proc_inode *ei; 46577b14db5SEric W. Biederman 4669043476fSAl Viro inode = new_inode(sb); 46777b14db5SEric W. Biederman if (!inode) 468ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 46977b14db5SEric W. Biederman 47085fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 47185fe4025SChristoph Hellwig 47277b14db5SEric W. Biederman ei = PROC_I(inode); 4739043476fSAl Viro 474d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 475ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 476ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 477ace0c791SEric W. Biederman iput(inode); 478ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 479ace0c791SEric W. Biederman } 480ace0c791SEric W. Biederman ei->sysctl = head; 481ace0c791SEric W. Biederman ei->sysctl_entry = table; 4822fd1d2c4SEric W. Biederman hlist_add_head_rcu(&ei->sysctl_inodes, &head->inodes); 483d6cffbbeSKonstantin Khlebnikov head->count++; 484d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 485d6cffbbeSKonstantin Khlebnikov 486078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4879043476fSAl Viro inode->i_mode = table->mode; 4887ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4899043476fSAl Viro inode->i_mode |= S_IFREG; 49077b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 49177b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4929043476fSAl Viro } else { 4939043476fSAl Viro inode->i_mode |= S_IFDIR; 4949043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4959043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 496f9bd6733SEric W. Biederman if (is_empty_dir(head)) 497f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4989043476fSAl Viro } 499e79c6a4fSDmitry Torokhov 500e79c6a4fSDmitry Torokhov if (root->set_ownership) 501e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 5025ec27ec7SRadoslaw Burny else { 5035ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 5045ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 5055ec27ec7SRadoslaw Burny } 506e79c6a4fSDmitry Torokhov 50777b14db5SEric W. Biederman return inode; 50877b14db5SEric W. Biederman } 50977b14db5SEric W. Biederman 510d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 511d6cffbbeSKonstantin Khlebnikov { 512d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 5132fd1d2c4SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sysctl_inodes); 514d6cffbbeSKonstantin Khlebnikov if (!--head->count) 515d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 516d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 517d6cffbbeSKonstantin Khlebnikov } 518d6cffbbeSKonstantin Khlebnikov 51981324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 52077b14db5SEric W. Biederman { 5213cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 5223cc3e046SEric W. Biederman if (!head) 5230e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 5243cc3e046SEric W. Biederman return sysctl_head_grab(head); 52577b14db5SEric W. Biederman } 52677b14db5SEric W. Biederman 52777b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 52800cd8dd3SAl Viro unsigned int flags) 52977b14db5SEric W. Biederman { 5309043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5319043476fSAl Viro struct ctl_table_header *h = NULL; 532dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5339043476fSAl Viro struct ctl_table *p; 53477b14db5SEric W. Biederman struct inode *inode; 5359043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5367ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5370e47c99dSEric W. Biederman int ret; 53877b14db5SEric W. Biederman 5399043476fSAl Viro if (IS_ERR(head)) 5409043476fSAl Viro return ERR_CAST(head); 5419043476fSAl Viro 5427ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5439043476fSAl Viro 5447ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5459043476fSAl Viro if (!p) 54677b14db5SEric W. Biederman goto out; 54777b14db5SEric W. Biederman 5484e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 54913bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5500e47c99dSEric W. Biederman err = ERR_PTR(ret); 5510e47c99dSEric W. Biederman if (ret) 5520e47c99dSEric W. Biederman goto out; 5534e757320SEric W. Biederman } 5540e47c99dSEric W. Biederman 5559043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 556ea5751ccSIvan Delalande if (IS_ERR(inode)) { 557ea5751ccSIvan Delalande err = ERR_CAST(inode); 55877b14db5SEric W. Biederman goto out; 559ea5751ccSIvan Delalande } 56077b14db5SEric W. Biederman 561fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 562888e2b03SAl Viro err = d_splice_alias(inode, dentry); 56377b14db5SEric W. Biederman 56477b14db5SEric W. Biederman out: 5656bf61045SFrancesco Ruggeri if (h) 5666bf61045SFrancesco Ruggeri sysctl_head_finish(h); 56777b14db5SEric W. Biederman sysctl_head_finish(head); 56877b14db5SEric W. Biederman return err; 56977b14db5SEric W. Biederman } 57077b14db5SEric W. Biederman 5717708bfb1SPavel Emelyanov static ssize_t proc_sys_call_handler(struct file *filp, void __user *buf, 5727708bfb1SPavel Emelyanov size_t count, loff_t *ppos, int write) 57377b14db5SEric W. Biederman { 574496ad9aaSAl Viro struct inode *inode = file_inode(filp); 5759043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5769043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5774e63acdfSAndrey Ignatov void *new_buf = NULL; 5782a2da53bSDavid Howells ssize_t error; 57977b14db5SEric W. Biederman 5809043476fSAl Viro if (IS_ERR(head)) 5819043476fSAl Viro return PTR_ERR(head); 58277b14db5SEric W. Biederman 58377b14db5SEric W. Biederman /* 58477b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 58577b14db5SEric W. Biederman * and won't be until we finish. 58677b14db5SEric W. Biederman */ 58777b14db5SEric W. Biederman error = -EPERM; 58873f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 58977b14db5SEric W. Biederman goto out; 59077b14db5SEric W. Biederman 5919043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5929043476fSAl Viro error = -EINVAL; 5939043476fSAl Viro if (!table->proc_handler) 5949043476fSAl Viro goto out; 5959043476fSAl Viro 5964e63acdfSAndrey Ignatov error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, buf, &count, 597e1550bfeSAndrey Ignatov ppos, &new_buf); 5987b146cebSAndrey Ignatov if (error) 5997b146cebSAndrey Ignatov goto out; 6007b146cebSAndrey Ignatov 60177b14db5SEric W. Biederman /* careful: calling conventions are nasty here */ 6024e63acdfSAndrey Ignatov if (new_buf) { 6034e63acdfSAndrey Ignatov mm_segment_t old_fs; 6044e63acdfSAndrey Ignatov 6054e63acdfSAndrey Ignatov old_fs = get_fs(); 6064e63acdfSAndrey Ignatov set_fs(KERNEL_DS); 6074e63acdfSAndrey Ignatov error = table->proc_handler(table, write, (void __user *)new_buf, 6084e63acdfSAndrey Ignatov &count, ppos); 6094e63acdfSAndrey Ignatov set_fs(old_fs); 6104e63acdfSAndrey Ignatov kfree(new_buf); 6114e63acdfSAndrey Ignatov } else { 6124e63acdfSAndrey Ignatov error = table->proc_handler(table, write, buf, &count, ppos); 6134e63acdfSAndrey Ignatov } 6144e63acdfSAndrey Ignatov 61577b14db5SEric W. Biederman if (!error) 6164e63acdfSAndrey Ignatov error = count; 61777b14db5SEric W. Biederman out: 61877b14db5SEric W. Biederman sysctl_head_finish(head); 61977b14db5SEric W. Biederman 62077b14db5SEric W. Biederman return error; 62177b14db5SEric W. Biederman } 62277b14db5SEric W. Biederman 6237708bfb1SPavel Emelyanov static ssize_t proc_sys_read(struct file *filp, char __user *buf, 6247708bfb1SPavel Emelyanov size_t count, loff_t *ppos) 6257708bfb1SPavel Emelyanov { 6267708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 0); 6277708bfb1SPavel Emelyanov } 6287708bfb1SPavel Emelyanov 62977b14db5SEric W. Biederman static ssize_t proc_sys_write(struct file *filp, const char __user *buf, 63077b14db5SEric W. Biederman size_t count, loff_t *ppos) 63177b14db5SEric W. Biederman { 6327708bfb1SPavel Emelyanov return proc_sys_call_handler(filp, (void __user *)buf, count, ppos, 1); 63377b14db5SEric W. Biederman } 63477b14db5SEric W. Biederman 635f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 636f1ecf068SLucas De Marchi { 6374e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 638f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 639f1ecf068SLucas De Marchi 6404e474a00SLucas De Marchi /* sysctl was unregistered */ 6414e474a00SLucas De Marchi if (IS_ERR(head)) 6424e474a00SLucas De Marchi return PTR_ERR(head); 6434e474a00SLucas De Marchi 644f1ecf068SLucas De Marchi if (table->poll) 645f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 646f1ecf068SLucas De Marchi 6474e474a00SLucas De Marchi sysctl_head_finish(head); 6484e474a00SLucas De Marchi 649f1ecf068SLucas De Marchi return 0; 650f1ecf068SLucas De Marchi } 651f1ecf068SLucas De Marchi 652076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 653f1ecf068SLucas De Marchi { 654496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6554e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 656f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 657076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6584e474a00SLucas De Marchi unsigned long event; 6594e474a00SLucas De Marchi 6604e474a00SLucas De Marchi /* sysctl was unregistered */ 6614e474a00SLucas De Marchi if (IS_ERR(head)) 662a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 663f1ecf068SLucas De Marchi 664f1ecf068SLucas De Marchi if (!table->proc_handler) 665f1ecf068SLucas De Marchi goto out; 666f1ecf068SLucas De Marchi 667f1ecf068SLucas De Marchi if (!table->poll) 668f1ecf068SLucas De Marchi goto out; 669f1ecf068SLucas De Marchi 6704e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 671f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 672f1ecf068SLucas De Marchi 673f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 674f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 675a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 676f1ecf068SLucas De Marchi } 677f1ecf068SLucas De Marchi 678f1ecf068SLucas De Marchi out: 6794e474a00SLucas De Marchi sysctl_head_finish(head); 6804e474a00SLucas De Marchi 681f1ecf068SLucas De Marchi return ret; 682f1ecf068SLucas De Marchi } 68377b14db5SEric W. Biederman 684f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 685f0c3b509SAl Viro struct dir_context *ctx, 6869043476fSAl Viro struct ctl_table_header *head, 6879043476fSAl Viro struct ctl_table *table) 68877b14db5SEric W. Biederman { 689f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 69077b14db5SEric W. Biederman struct inode *inode; 69177b14db5SEric W. Biederman struct qstr qname; 69277b14db5SEric W. Biederman ino_t ino = 0; 69377b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 69477b14db5SEric W. Biederman 69577b14db5SEric W. Biederman qname.name = table->procname; 69677b14db5SEric W. Biederman qname.len = strlen(table->procname); 6978387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 69877b14db5SEric W. Biederman 69977b14db5SEric W. Biederman child = d_lookup(dir, &qname); 70077b14db5SEric W. Biederman if (!child) { 70176aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 70276aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 70376aab3abSAl Viro if (IS_ERR(child)) 70476aab3abSAl Viro return false; 70576aab3abSAl Viro if (d_in_lookup(child)) { 706888e2b03SAl Viro struct dentry *res; 7079043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 708ea5751ccSIvan Delalande if (IS_ERR(inode)) { 70976aab3abSAl Viro d_lookup_done(child); 7109043476fSAl Viro dput(child); 711f0c3b509SAl Viro return false; 71276aab3abSAl Viro } 713fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 714888e2b03SAl Viro res = d_splice_alias(inode, child); 715888e2b03SAl Viro d_lookup_done(child); 716888e2b03SAl Viro if (unlikely(res)) { 717888e2b03SAl Viro if (IS_ERR(res)) { 718888e2b03SAl Viro dput(child); 719888e2b03SAl Viro return false; 720888e2b03SAl Viro } 721888e2b03SAl Viro dput(child); 722888e2b03SAl Viro child = res; 723888e2b03SAl Viro } 72477b14db5SEric W. Biederman } 72577b14db5SEric W. Biederman } 7262b0143b5SDavid Howells inode = d_inode(child); 72777b14db5SEric W. Biederman ino = inode->i_ino; 72877b14db5SEric W. Biederman type = inode->i_mode >> 12; 72977b14db5SEric W. Biederman dput(child); 730f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7319043476fSAl Viro } 7329043476fSAl Viro 733f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 734f0c3b509SAl Viro struct dir_context *ctx, 7350e47c99dSEric W. Biederman struct ctl_table_header *head, 7360e47c99dSEric W. Biederman struct ctl_table *table) 7370e47c99dSEric W. Biederman { 738f0c3b509SAl Viro bool ret = true; 739a0b0d1c3SDanilo Krummrich 7400e47c99dSEric W. Biederman head = sysctl_head_grab(head); 741a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 742a0b0d1c3SDanilo Krummrich return false; 7430e47c99dSEric W. Biederman 7440e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 745835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7460e47c99dSEric W. Biederman goto out; 7470e47c99dSEric W. Biederman 748f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7490e47c99dSEric W. Biederman out: 7500e47c99dSEric W. Biederman sysctl_head_finish(head); 7510e47c99dSEric W. Biederman return ret; 7520e47c99dSEric W. Biederman } 7530e47c99dSEric W. Biederman 754e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7559043476fSAl Viro unsigned long *pos, struct file *file, 756f0c3b509SAl Viro struct dir_context *ctx) 7579043476fSAl Viro { 758f0c3b509SAl Viro bool res; 7599043476fSAl Viro 760f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 761f0c3b509SAl Viro return true; 7629043476fSAl Viro 7630e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 764f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7650e47c99dSEric W. Biederman else 766f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7679043476fSAl Viro 768f0c3b509SAl Viro if (res) 769f0c3b509SAl Viro ctx->pos = *pos; 7706a75ce16SEric W. Biederman 7716a75ce16SEric W. Biederman return res; 77277b14db5SEric W. Biederman } 77377b14db5SEric W. Biederman 774f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 77577b14db5SEric W. Biederman { 776f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7779043476fSAl Viro struct ctl_table_header *h = NULL; 7786a75ce16SEric W. Biederman struct ctl_table *entry; 7797ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 78077b14db5SEric W. Biederman unsigned long pos; 78177b14db5SEric W. Biederman 7829043476fSAl Viro if (IS_ERR(head)) 7839043476fSAl Viro return PTR_ERR(head); 7849043476fSAl Viro 7857ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 78677b14db5SEric W. Biederman 787f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 78893362fa4SZhou Chengming goto out; 789f0c3b509SAl Viro 79077b14db5SEric W. Biederman pos = 2; 79177b14db5SEric W. Biederman 7927ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 793f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7949043476fSAl Viro sysctl_head_finish(h); 7959043476fSAl Viro break; 79677b14db5SEric W. Biederman } 79777b14db5SEric W. Biederman } 79893362fa4SZhou Chengming out: 79977b14db5SEric W. Biederman sysctl_head_finish(head); 800f0c3b509SAl Viro return 0; 80177b14db5SEric W. Biederman } 80277b14db5SEric W. Biederman 80310556cb2SAl Viro static int proc_sys_permission(struct inode *inode, int mask) 80477b14db5SEric W. Biederman { 80577b14db5SEric W. Biederman /* 80677b14db5SEric W. Biederman * sysctl entries that are not writeable, 80777b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 80877b14db5SEric W. Biederman */ 809f696a365SMiklos Szeredi struct ctl_table_header *head; 810f696a365SMiklos Szeredi struct ctl_table *table; 81177b14db5SEric W. Biederman int error; 81277b14db5SEric W. Biederman 813f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 814f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 815f696a365SMiklos Szeredi return -EACCES; 816f696a365SMiklos Szeredi 817f696a365SMiklos Szeredi head = grab_header(inode); 8189043476fSAl Viro if (IS_ERR(head)) 8199043476fSAl Viro return PTR_ERR(head); 82077b14db5SEric W. Biederman 821f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8229043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8239043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8249043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 82573f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8269043476fSAl Viro 82777b14db5SEric W. Biederman sysctl_head_finish(head); 82877b14db5SEric W. Biederman return error; 82977b14db5SEric W. Biederman } 83077b14db5SEric W. Biederman 83177b14db5SEric W. Biederman static int proc_sys_setattr(struct dentry *dentry, struct iattr *attr) 83277b14db5SEric W. Biederman { 8332b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 83477b14db5SEric W. Biederman int error; 83577b14db5SEric W. Biederman 83677b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 83777b14db5SEric W. Biederman return -EPERM; 83877b14db5SEric W. Biederman 83931051c85SJan Kara error = setattr_prepare(dentry, attr); 8401025774cSChristoph Hellwig if (error) 84177b14db5SEric W. Biederman return error; 8421025774cSChristoph Hellwig 8431025774cSChristoph Hellwig setattr_copy(inode, attr); 8441025774cSChristoph Hellwig mark_inode_dirty(inode); 8451025774cSChristoph Hellwig return 0; 84677b14db5SEric W. Biederman } 84777b14db5SEric W. Biederman 848a528d35eSDavid Howells static int proc_sys_getattr(const struct path *path, struct kstat *stat, 849a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8509043476fSAl Viro { 851a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8529043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8539043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8549043476fSAl Viro 8559043476fSAl Viro if (IS_ERR(head)) 8569043476fSAl Viro return PTR_ERR(head); 8579043476fSAl Viro 8589043476fSAl Viro generic_fillattr(inode, stat); 8599043476fSAl Viro if (table) 8609043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8619043476fSAl Viro 8629043476fSAl Viro sysctl_head_finish(head); 8639043476fSAl Viro return 0; 8649043476fSAl Viro } 8659043476fSAl Viro 86677b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 867f1ecf068SLucas De Marchi .open = proc_sys_open, 868f1ecf068SLucas De Marchi .poll = proc_sys_poll, 86977b14db5SEric W. Biederman .read = proc_sys_read, 87077b14db5SEric W. Biederman .write = proc_sys_write, 8716038f373SArnd Bergmann .llseek = default_llseek, 8729043476fSAl Viro }; 8739043476fSAl Viro 8749043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations = { 875887df078SPavel Emelyanov .read = generic_read_dir, 876f50752eaSAl Viro .iterate_shared = proc_sys_readdir, 8773222a3e5SChristoph Hellwig .llseek = generic_file_llseek, 87877b14db5SEric W. Biederman }; 87977b14db5SEric W. Biederman 88003a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations = { 8819043476fSAl Viro .permission = proc_sys_permission, 8829043476fSAl Viro .setattr = proc_sys_setattr, 8839043476fSAl Viro .getattr = proc_sys_getattr, 8849043476fSAl Viro }; 8859043476fSAl Viro 8869043476fSAl Viro static const struct inode_operations proc_sys_dir_operations = { 88777b14db5SEric W. Biederman .lookup = proc_sys_lookup, 88877b14db5SEric W. Biederman .permission = proc_sys_permission, 88977b14db5SEric W. Biederman .setattr = proc_sys_setattr, 8909043476fSAl Viro .getattr = proc_sys_getattr, 89177b14db5SEric W. Biederman }; 89277b14db5SEric W. Biederman 8930b728e19SAl Viro static int proc_sys_revalidate(struct dentry *dentry, unsigned int flags) 89477b14db5SEric W. Biederman { 8950b728e19SAl Viro if (flags & LOOKUP_RCU) 89634286d66SNick Piggin return -ECHILD; 8972b0143b5SDavid Howells return !PROC_I(d_inode(dentry))->sysctl->unregistering; 8989043476fSAl Viro } 8999043476fSAl Viro 900fe15ce44SNick Piggin static int proc_sys_delete(const struct dentry *dentry) 9019043476fSAl Viro { 9022b0143b5SDavid Howells return !!PROC_I(d_inode(dentry))->sysctl->unregistering; 9039043476fSAl Viro } 9049043476fSAl Viro 9051f87f0b5SEric W. Biederman static int sysctl_is_seen(struct ctl_table_header *p) 9061f87f0b5SEric W. Biederman { 9071f87f0b5SEric W. Biederman struct ctl_table_set *set = p->set; 9081f87f0b5SEric W. Biederman int res; 9091f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 9101f87f0b5SEric W. Biederman if (p->unregistering) 9111f87f0b5SEric W. Biederman res = 0; 9121f87f0b5SEric W. Biederman else if (!set->is_seen) 9131f87f0b5SEric W. Biederman res = 1; 9141f87f0b5SEric W. Biederman else 9151f87f0b5SEric W. Biederman res = set->is_seen(set); 9161f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 9171f87f0b5SEric W. Biederman return res; 9181f87f0b5SEric W. Biederman } 9191f87f0b5SEric W. Biederman 9206fa67e70SAl Viro static int proc_sys_compare(const struct dentry *dentry, 921621e155aSNick Piggin unsigned int len, const char *str, const struct qstr *name) 9229043476fSAl Viro { 923dfef6dcdSAl Viro struct ctl_table_header *head; 924da53be12SLinus Torvalds struct inode *inode; 925da53be12SLinus Torvalds 92631e6b01fSNick Piggin /* Although proc doesn't have negative dentries, rcu-walk means 92731e6b01fSNick Piggin * that inode here can be NULL */ 928dfef6dcdSAl Viro /* AV: can it, indeed? */ 9292b0143b5SDavid Howells inode = d_inode_rcu(dentry); 93031e6b01fSNick Piggin if (!inode) 931dfef6dcdSAl Viro return 1; 932621e155aSNick Piggin if (name->len != len) 9339043476fSAl Viro return 1; 934621e155aSNick Piggin if (memcmp(name->name, str, len)) 9359043476fSAl Viro return 1; 936dfef6dcdSAl Viro head = rcu_dereference(PROC_I(inode)->sysctl); 937dfef6dcdSAl Viro return !head || !sysctl_is_seen(head); 93877b14db5SEric W. Biederman } 93977b14db5SEric W. Biederman 940d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations = { 94177b14db5SEric W. Biederman .d_revalidate = proc_sys_revalidate, 9429043476fSAl Viro .d_delete = proc_sys_delete, 9439043476fSAl Viro .d_compare = proc_sys_compare, 94477b14db5SEric W. Biederman }; 94577b14db5SEric W. Biederman 9460e47c99dSEric W. Biederman static struct ctl_dir *find_subdir(struct ctl_dir *dir, 9477ec66d06SEric W. Biederman const char *name, int namelen) 9481f87f0b5SEric W. Biederman { 9497ec66d06SEric W. Biederman struct ctl_table_header *head; 9507ec66d06SEric W. Biederman struct ctl_table *entry; 9511f87f0b5SEric W. Biederman 9520e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 9537ec66d06SEric W. Biederman if (!entry) 9547ec66d06SEric W. Biederman return ERR_PTR(-ENOENT); 95551f72f4aSEric W. Biederman if (!S_ISDIR(entry->mode)) 9567ec66d06SEric W. Biederman return ERR_PTR(-ENOTDIR); 95751f72f4aSEric W. Biederman return container_of(head, struct ctl_dir, header); 9581f87f0b5SEric W. Biederman } 9591f87f0b5SEric W. Biederman 9607ec66d06SEric W. Biederman static struct ctl_dir *new_dir(struct ctl_table_set *set, 9617ec66d06SEric W. Biederman const char *name, int namelen) 9621f87f0b5SEric W. Biederman { 9637ec66d06SEric W. Biederman struct ctl_table *table; 9647ec66d06SEric W. Biederman struct ctl_dir *new; 965ac13ac6fSEric W. Biederman struct ctl_node *node; 9667ec66d06SEric W. Biederman char *new_name; 9671f87f0b5SEric W. Biederman 968ac13ac6fSEric W. Biederman new = kzalloc(sizeof(*new) + sizeof(struct ctl_node) + 969ac13ac6fSEric W. Biederman sizeof(struct ctl_table)*2 + namelen + 1, 970ac13ac6fSEric W. Biederman GFP_KERNEL); 9717ec66d06SEric W. Biederman if (!new) 9727ec66d06SEric W. Biederman return NULL; 9737ec66d06SEric W. Biederman 974ac13ac6fSEric W. Biederman node = (struct ctl_node *)(new + 1); 975ac13ac6fSEric W. Biederman table = (struct ctl_table *)(node + 1); 9767ec66d06SEric W. Biederman new_name = (char *)(table + 2); 9777ec66d06SEric W. Biederman memcpy(new_name, name, namelen); 9787ec66d06SEric W. Biederman new_name[namelen] = '\0'; 9797ec66d06SEric W. Biederman table[0].procname = new_name; 9807ec66d06SEric W. Biederman table[0].mode = S_IFDIR|S_IRUGO|S_IXUGO; 981ac13ac6fSEric W. Biederman init_header(&new->header, set->dir.header.root, set, node, table); 9827ec66d06SEric W. Biederman 9837ec66d06SEric W. Biederman return new; 9841f87f0b5SEric W. Biederman } 9851f87f0b5SEric W. Biederman 98660f126d9SEric W. Biederman /** 98760f126d9SEric W. Biederman * get_subdir - find or create a subdir with the specified name. 98860f126d9SEric W. Biederman * @dir: Directory to create the subdirectory in 98960f126d9SEric W. Biederman * @name: The name of the subdirectory to find or create 99060f126d9SEric W. Biederman * @namelen: The length of name 99160f126d9SEric W. Biederman * 99260f126d9SEric W. Biederman * Takes a directory with an elevated reference count so we know that 99360f126d9SEric W. Biederman * if we drop the lock the directory will not go away. Upon success 99460f126d9SEric W. Biederman * the reference is moved from @dir to the returned subdirectory. 99560f126d9SEric W. Biederman * Upon error an error code is returned and the reference on @dir is 99660f126d9SEric W. Biederman * simply dropped. 99760f126d9SEric W. Biederman */ 9980e47c99dSEric W. Biederman static struct ctl_dir *get_subdir(struct ctl_dir *dir, 9990e47c99dSEric W. Biederman const char *name, int namelen) 10007ec66d06SEric W. Biederman { 10010e47c99dSEric W. Biederman struct ctl_table_set *set = dir->header.set; 10027ec66d06SEric W. Biederman struct ctl_dir *subdir, *new = NULL; 10030eb97f38SEric W. Biederman int err; 10047ec66d06SEric W. Biederman 10057ec66d06SEric W. Biederman spin_lock(&sysctl_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 10127ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10137ec66d06SEric W. Biederman new = new_dir(set, name, namelen); 10147ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 10157ec66d06SEric W. Biederman subdir = ERR_PTR(-ENOMEM); 10167ec66d06SEric W. Biederman if (!new) 10177ec66d06SEric W. Biederman goto failed; 10187ec66d06SEric W. Biederman 101960f126d9SEric W. Biederman /* Was the subdir added while we dropped the lock? */ 10200e47c99dSEric W. Biederman subdir = find_subdir(dir, name, namelen); 10217ec66d06SEric W. Biederman if (!IS_ERR(subdir)) 10227ec66d06SEric W. Biederman goto found; 10237ec66d06SEric W. Biederman if (PTR_ERR(subdir) != -ENOENT) 10247ec66d06SEric W. Biederman goto failed; 10257ec66d06SEric W. Biederman 102660f126d9SEric W. Biederman /* Nope. Use the our freshly made directory entry. */ 10270eb97f38SEric W. Biederman err = insert_header(dir, &new->header); 10280eb97f38SEric W. Biederman subdir = ERR_PTR(err); 10290eb97f38SEric W. Biederman if (err) 10300e47c99dSEric W. Biederman goto failed; 10317ec66d06SEric W. Biederman subdir = new; 10327ec66d06SEric W. Biederman found: 10337ec66d06SEric W. Biederman subdir->header.nreg++; 10347ec66d06SEric W. Biederman failed: 1035a1c83681SViresh Kumar if (IS_ERR(subdir)) { 103687ebdc00SAndrew Morton pr_err("sysctl could not get directory: "); 10376980128fSEric W. Biederman sysctl_print_dir(dir); 103887ebdc00SAndrew Morton pr_cont("/%*.*s %ld\n", 10397ec66d06SEric W. Biederman namelen, namelen, name, PTR_ERR(subdir)); 10401f87f0b5SEric W. Biederman } 10417ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 10427ec66d06SEric W. Biederman if (new) 10437ec66d06SEric W. Biederman drop_sysctl_table(&new->header); 10447ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 10457ec66d06SEric W. Biederman return subdir; 10461f87f0b5SEric W. Biederman } 10471f87f0b5SEric W. Biederman 10480e47c99dSEric W. Biederman static struct ctl_dir *xlate_dir(struct ctl_table_set *set, struct ctl_dir *dir) 10490e47c99dSEric W. Biederman { 10500e47c99dSEric W. Biederman struct ctl_dir *parent; 10510e47c99dSEric W. Biederman const char *procname; 10520e47c99dSEric W. Biederman if (!dir->header.parent) 10530e47c99dSEric W. Biederman return &set->dir; 10540e47c99dSEric W. Biederman parent = xlate_dir(set, dir->header.parent); 10550e47c99dSEric W. Biederman if (IS_ERR(parent)) 10560e47c99dSEric W. Biederman return parent; 10570e47c99dSEric W. Biederman procname = dir->header.ctl_table[0].procname; 10580e47c99dSEric W. Biederman return find_subdir(parent, procname, strlen(procname)); 10590e47c99dSEric W. Biederman } 10600e47c99dSEric W. Biederman 10610e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 106213bcc6a2SEric W. Biederman struct ctl_table **pentry) 10630e47c99dSEric W. Biederman { 10640e47c99dSEric W. Biederman struct ctl_table_header *head; 10650e47c99dSEric W. Biederman struct ctl_table_root *root; 10660e47c99dSEric W. Biederman struct ctl_table_set *set; 10670e47c99dSEric W. Biederman struct ctl_table *entry; 10680e47c99dSEric W. Biederman struct ctl_dir *dir; 10690e47c99dSEric W. Biederman int ret; 10700e47c99dSEric W. Biederman 10710e47c99dSEric W. Biederman ret = 0; 10720e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 10730e47c99dSEric W. Biederman root = (*pentry)->data; 107413bcc6a2SEric W. Biederman set = lookup_header_set(root); 10750e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10760e47c99dSEric W. Biederman if (IS_ERR(dir)) 10770e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10780e47c99dSEric W. Biederman else { 10790e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10800e47c99dSEric W. Biederman head = NULL; 10810e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10820e47c99dSEric W. Biederman ret = -ENOENT; 10830e47c99dSEric W. Biederman if (entry && use_table(head)) { 10840e47c99dSEric W. Biederman unuse_table(*phead); 10850e47c99dSEric W. Biederman *phead = head; 10860e47c99dSEric W. Biederman *pentry = entry; 10870e47c99dSEric W. Biederman ret = 0; 10880e47c99dSEric W. Biederman } 10890e47c99dSEric W. Biederman } 10900e47c99dSEric W. Biederman 10910e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10920e47c99dSEric W. Biederman return ret; 10930e47c99dSEric W. Biederman } 10940e47c99dSEric W. Biederman 10957c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10967c60c48fSEric W. Biederman { 10977c60c48fSEric W. Biederman struct va_format vaf; 10987c60c48fSEric W. Biederman va_list args; 10997c60c48fSEric W. Biederman 11007c60c48fSEric W. Biederman va_start(args, fmt); 11017c60c48fSEric W. Biederman vaf.fmt = fmt; 11027c60c48fSEric W. Biederman vaf.va = &args; 11037c60c48fSEric W. Biederman 110487ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 11057c60c48fSEric W. Biederman path, table->procname, &vaf); 11067c60c48fSEric W. Biederman 11077c60c48fSEric W. Biederman va_end(args); 11087c60c48fSEric W. Biederman return -EINVAL; 11097c60c48fSEric W. Biederman } 11107c60c48fSEric W. Biederman 11114f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 11124f2fec00SLuis R. Rodriguez { 11134f2fec00SLuis R. Rodriguez int err = 0; 11144f2fec00SLuis R. Rodriguez 111561d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 111661d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11174f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 111864a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11194f2fec00SLuis R. Rodriguez } 11204f2fec00SLuis R. Rodriguez 11214f2fec00SLuis R. Rodriguez return err; 11224f2fec00SLuis R. Rodriguez } 11234f2fec00SLuis R. Rodriguez 11247c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11257c60c48fSEric W. Biederman { 11267c60c48fSEric W. Biederman int err = 0; 11277c60c48fSEric W. Biederman for (; table->procname; table++) { 11287c60c48fSEric W. Biederman if (table->child) 112989c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 11307c60c48fSEric W. Biederman 11311f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 11321f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 11331680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 113461d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 11351f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 11361f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 11371f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 11381f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 11391f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 11401f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 11411f87f0b5SEric W. Biederman if (!table->data) 114289c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 11431f87f0b5SEric W. Biederman if (!table->maxlen) 114489c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 11454f2fec00SLuis R. Rodriguez else 11464f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11471f87f0b5SEric W. Biederman } 11481f87f0b5SEric W. Biederman if (!table->proc_handler) 114989c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11507c60c48fSEric W. Biederman 11517c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 115289c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11537c60c48fSEric W. Biederman table->mode); 11541f87f0b5SEric W. Biederman } 11557c60c48fSEric W. Biederman return err; 11561f87f0b5SEric W. Biederman } 11571f87f0b5SEric W. Biederman 11580e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11590e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11600e47c99dSEric W. Biederman { 11610e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11620e47c99dSEric W. Biederman struct ctl_table_header *links; 1163ac13ac6fSEric W. Biederman struct ctl_node *node; 11640e47c99dSEric W. Biederman char *link_name; 11650e47c99dSEric W. Biederman int nr_entries, name_bytes; 11660e47c99dSEric W. Biederman 11670e47c99dSEric W. Biederman name_bytes = 0; 11680e47c99dSEric W. Biederman nr_entries = 0; 11690e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11700e47c99dSEric W. Biederman nr_entries++; 11710e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11720e47c99dSEric W. Biederman } 11730e47c99dSEric W. Biederman 11740e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1175ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11760e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11770e47c99dSEric W. Biederman name_bytes, 11780e47c99dSEric W. Biederman GFP_KERNEL); 11790e47c99dSEric W. Biederman 11800e47c99dSEric W. Biederman if (!links) 11810e47c99dSEric W. Biederman return NULL; 11820e47c99dSEric W. Biederman 1183ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1184ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11850e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11860e47c99dSEric W. Biederman 11870e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11880e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11890e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11900e47c99dSEric W. Biederman link->procname = link_name; 11910e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11920e47c99dSEric W. Biederman link->data = link_root; 11930e47c99dSEric W. Biederman link_name += len; 11940e47c99dSEric W. Biederman } 1195ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11960e47c99dSEric W. Biederman links->nreg = nr_entries; 11970e47c99dSEric W. Biederman 11980e47c99dSEric W. Biederman return links; 11990e47c99dSEric W. Biederman } 12000e47c99dSEric W. Biederman 12010e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 12020e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 12030e47c99dSEric W. Biederman { 12040e47c99dSEric W. Biederman struct ctl_table_header *head; 12050e47c99dSEric W. Biederman struct ctl_table *entry, *link; 12060e47c99dSEric W. Biederman 12070e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 12080e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12090e47c99dSEric W. Biederman const char *procname = entry->procname; 12100e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12110e47c99dSEric W. Biederman if (!link) 12120e47c99dSEric W. Biederman return false; 12130e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12140e47c99dSEric W. Biederman continue; 12150e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12160e47c99dSEric W. Biederman continue; 12170e47c99dSEric W. Biederman return false; 12180e47c99dSEric W. Biederman } 12190e47c99dSEric W. Biederman 12200e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 12210e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12220e47c99dSEric W. Biederman const char *procname = entry->procname; 12230e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12240e47c99dSEric W. Biederman head->nreg++; 12250e47c99dSEric W. Biederman } 12260e47c99dSEric W. Biederman return true; 12270e47c99dSEric W. Biederman } 12280e47c99dSEric W. Biederman 12290e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12300e47c99dSEric W. Biederman { 12310e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12320e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12330e47c99dSEric W. Biederman struct ctl_table_header *links; 12340e47c99dSEric W. Biederman int err; 12350e47c99dSEric W. Biederman 12360e47c99dSEric W. Biederman if (head->set == root_set) 12370e47c99dSEric W. Biederman return 0; 12380e47c99dSEric W. Biederman 12390e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12400e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12410e47c99dSEric W. Biederman return 0; 12420e47c99dSEric W. Biederman 12430e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12440e47c99dSEric W. Biederman return 0; 12450e47c99dSEric W. Biederman 12460e47c99dSEric W. Biederman core_parent->header.nreg++; 12470e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12480e47c99dSEric W. Biederman 12490e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12500e47c99dSEric W. Biederman 12510e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12520e47c99dSEric W. Biederman err = -ENOMEM; 12530e47c99dSEric W. Biederman if (!links) 12540e47c99dSEric W. Biederman goto out; 12550e47c99dSEric W. Biederman 12560e47c99dSEric W. Biederman err = 0; 12570e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12580e47c99dSEric W. Biederman kfree(links); 12590e47c99dSEric W. Biederman goto out; 12600e47c99dSEric W. Biederman } 12610e47c99dSEric W. Biederman 12620e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12630e47c99dSEric W. Biederman if (err) 12640e47c99dSEric W. Biederman kfree(links); 12650e47c99dSEric W. Biederman out: 12660e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12670e47c99dSEric W. Biederman return err; 12680e47c99dSEric W. Biederman } 12690e47c99dSEric W. Biederman 12701f87f0b5SEric W. Biederman /** 1271f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 127260a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12731f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12741f87f0b5SEric W. Biederman * @table: the top-level table structure 12751f87f0b5SEric W. Biederman * 12761f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12771f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12781f87f0b5SEric W. Biederman * 12791f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12801f87f0b5SEric W. Biederman * 12811f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12821f87f0b5SEric W. Biederman * enter a sysctl file 12831f87f0b5SEric W. Biederman * 12841f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12851f87f0b5SEric W. Biederman * 12861f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12871f87f0b5SEric W. Biederman * 1288f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12891f87f0b5SEric W. Biederman * 1290f728019bSEric W. Biederman * child - must be %NULL. 12911f87f0b5SEric W. Biederman * 12921f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12931f87f0b5SEric W. Biederman * 12941f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12951f87f0b5SEric W. Biederman * 12961f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12971f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12981f87f0b5SEric W. Biederman * 1299f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1300f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 13011f87f0b5SEric W. Biederman * 13021f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 13031f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 13041f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 13051f87f0b5SEric W. Biederman * 13061f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 13071f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 13081f87f0b5SEric W. Biederman * 13091f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 13101f87f0b5SEric W. Biederman * to the table header on success. 13111f87f0b5SEric W. Biederman */ 13126e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 131360a47a2eSEric W. Biederman struct ctl_table_set *set, 13146e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 13151f87f0b5SEric W. Biederman { 131660a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13171f87f0b5SEric W. Biederman struct ctl_table_header *header; 13186e9d5164SEric W. Biederman const char *name, *nextname; 13197ec66d06SEric W. Biederman struct ctl_dir *dir; 1320ac13ac6fSEric W. Biederman struct ctl_table *entry; 1321ac13ac6fSEric W. Biederman struct ctl_node *node; 1322ac13ac6fSEric W. Biederman int nr_entries = 0; 13231f87f0b5SEric W. Biederman 1324ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1325ac13ac6fSEric W. Biederman nr_entries++; 1326ac13ac6fSEric W. Biederman 1327ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1328ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13291f87f0b5SEric W. Biederman if (!header) 13301f87f0b5SEric W. Biederman return NULL; 13311f87f0b5SEric W. Biederman 1332ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1333ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13347c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13357c60c48fSEric W. Biederman goto fail; 13368d6ecfccSEric W. Biederman 13371f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13380e47c99dSEric W. Biederman dir = &set->dir; 133960f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13407ec66d06SEric W. Biederman dir->header.nreg++; 13417ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13427ec66d06SEric W. Biederman 13437ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13447ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13457ec66d06SEric W. Biederman int namelen; 13467ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13477ec66d06SEric W. Biederman if (nextname) { 13487ec66d06SEric W. Biederman namelen = nextname - name; 13497ec66d06SEric W. Biederman nextname++; 13507ec66d06SEric W. Biederman } else { 13517ec66d06SEric W. Biederman namelen = strlen(name); 13527ec66d06SEric W. Biederman } 13537ec66d06SEric W. Biederman if (namelen == 0) 13541f87f0b5SEric W. Biederman continue; 13557ec66d06SEric W. Biederman 13560e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13577ec66d06SEric W. Biederman if (IS_ERR(dir)) 13587ec66d06SEric W. Biederman goto fail; 13591f87f0b5SEric W. Biederman } 13600e47c99dSEric W. Biederman 13617ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13620e47c99dSEric W. Biederman if (insert_header(dir, header)) 13630e47c99dSEric W. Biederman goto fail_put_dir_locked; 13640e47c99dSEric W. Biederman 13657ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13661f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13671f87f0b5SEric W. Biederman 13681f87f0b5SEric W. Biederman return header; 13690e47c99dSEric W. Biederman 13707ec66d06SEric W. Biederman fail_put_dir_locked: 13717ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13727c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13737c60c48fSEric W. Biederman fail: 13747c60c48fSEric W. Biederman kfree(header); 13757c60c48fSEric W. Biederman dump_stack(); 13767c60c48fSEric W. Biederman return NULL; 13771f87f0b5SEric W. Biederman } 13781f87f0b5SEric W. Biederman 1379fea478d4SEric W. Biederman /** 1380fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1381fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1382fea478d4SEric W. Biederman * @table: the table structure 1383fea478d4SEric W. Biederman * 1384fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1385fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1386fea478d4SEric W. Biederman * 1387fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1388fea478d4SEric W. Biederman */ 1389fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1390fea478d4SEric W. Biederman { 1391fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1392fea478d4SEric W. Biederman path, table); 1393fea478d4SEric W. Biederman } 1394fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1395fea478d4SEric W. Biederman 13966e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 13976e9d5164SEric W. Biederman { 13986e9d5164SEric W. Biederman int namelen; 13996e9d5164SEric W. Biederman namelen = strlen(name); 14006e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 14016e9d5164SEric W. Biederman return NULL; 14026e9d5164SEric W. Biederman memcpy(pos, name, namelen); 14036e9d5164SEric W. Biederman pos[namelen] = '/'; 14046e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 14056e9d5164SEric W. Biederman pos += namelen + 1; 14066e9d5164SEric W. Biederman return pos; 14076e9d5164SEric W. Biederman } 14086e9d5164SEric W. Biederman 1409f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1410f728019bSEric W. Biederman { 1411f728019bSEric W. Biederman int has_files = 0; 1412f728019bSEric W. Biederman int nr_subheaders = 0; 1413f728019bSEric W. Biederman struct ctl_table *entry; 1414f728019bSEric W. Biederman 1415f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1416f728019bSEric W. Biederman if (!table || !table->procname) 1417f728019bSEric W. Biederman return 1; 1418f728019bSEric W. Biederman 1419f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1420f728019bSEric W. Biederman if (entry->child) 1421f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1422f728019bSEric W. Biederman else 1423f728019bSEric W. Biederman has_files = 1; 1424f728019bSEric W. Biederman } 1425f728019bSEric W. Biederman return nr_subheaders + has_files; 1426f728019bSEric W. Biederman } 1427f728019bSEric W. Biederman 1428f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 142960a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1430f728019bSEric W. Biederman struct ctl_table *table) 1431f728019bSEric W. Biederman { 1432f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1433f728019bSEric W. Biederman struct ctl_table *entry, *files; 1434f728019bSEric W. Biederman int nr_files = 0; 1435f728019bSEric W. Biederman int nr_dirs = 0; 1436f728019bSEric W. Biederman int err = -ENOMEM; 1437f728019bSEric W. Biederman 1438f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1439f728019bSEric W. Biederman if (entry->child) 1440f728019bSEric W. Biederman nr_dirs++; 1441f728019bSEric W. Biederman else 1442f728019bSEric W. Biederman nr_files++; 1443f728019bSEric W. Biederman } 1444f728019bSEric W. Biederman 1445f728019bSEric W. Biederman files = table; 1446f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1447f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1448f728019bSEric W. Biederman struct ctl_table *new; 14496396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1450f728019bSEric W. Biederman GFP_KERNEL); 1451f728019bSEric W. Biederman if (!files) 1452f728019bSEric W. Biederman goto out; 1453f728019bSEric W. Biederman 1454f728019bSEric W. Biederman ctl_table_arg = files; 1455f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1456f728019bSEric W. Biederman if (entry->child) 1457f728019bSEric W. Biederman continue; 1458f728019bSEric W. Biederman *new = *entry; 1459f728019bSEric W. Biederman new++; 1460f728019bSEric W. Biederman } 1461f728019bSEric W. Biederman } 1462f728019bSEric W. Biederman 1463f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1464f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1465f728019bSEric W. Biederman struct ctl_table_header *header; 146660a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1467f728019bSEric W. Biederman if (!header) { 1468f728019bSEric W. Biederman kfree(ctl_table_arg); 1469f728019bSEric W. Biederman goto out; 1470f728019bSEric W. Biederman } 1471f728019bSEric W. Biederman 1472f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1473f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1474f728019bSEric W. Biederman **subheader = header; 1475f728019bSEric W. Biederman (*subheader)++; 1476f728019bSEric W. Biederman } 1477f728019bSEric W. Biederman 1478f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1479f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1480f728019bSEric W. Biederman char *child_pos; 1481f728019bSEric W. Biederman 1482f728019bSEric W. Biederman if (!entry->child) 1483f728019bSEric W. Biederman continue; 1484f728019bSEric W. Biederman 1485f728019bSEric W. Biederman err = -ENAMETOOLONG; 1486f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1487f728019bSEric W. Biederman if (!child_pos) 1488f728019bSEric W. Biederman goto out; 1489f728019bSEric W. Biederman 1490f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 149160a47a2eSEric W. Biederman set, entry->child); 1492f728019bSEric W. Biederman pos[0] = '\0'; 1493f728019bSEric W. Biederman if (err) 1494f728019bSEric W. Biederman goto out; 1495f728019bSEric W. Biederman } 1496f728019bSEric W. Biederman err = 0; 1497f728019bSEric W. Biederman out: 1498f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1499f728019bSEric W. Biederman return err; 1500f728019bSEric W. Biederman } 1501f728019bSEric W. Biederman 15026e9d5164SEric W. Biederman /** 15036e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 150460a47a2eSEric W. Biederman * @set: Sysctl tree to register on 15056e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15066e9d5164SEric W. Biederman * @table: the top-level table structure 15076e9d5164SEric W. Biederman * 15086e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15096e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15106e9d5164SEric W. Biederman * 15116e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 15126e9d5164SEric W. Biederman */ 15136e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 151460a47a2eSEric W. Biederman struct ctl_table_set *set, 15156e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15166e9d5164SEric W. Biederman { 1517ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1518f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1519f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15206e9d5164SEric W. Biederman const struct ctl_path *component; 15216e9d5164SEric W. Biederman char *new_path, *pos; 15226e9d5164SEric W. Biederman 15236e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15246e9d5164SEric W. Biederman if (!new_path) 15256e9d5164SEric W. Biederman return NULL; 15266e9d5164SEric W. Biederman 15276e9d5164SEric W. Biederman pos[0] = '\0'; 15286e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15296e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15306e9d5164SEric W. Biederman if (!pos) 15316e9d5164SEric W. Biederman goto out; 15326e9d5164SEric W. Biederman } 1533ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1534ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1535ec6a5266SEric W. Biederman if (!pos) 1536ec6a5266SEric W. Biederman goto out; 1537ec6a5266SEric W. Biederman table = table->child; 1538ec6a5266SEric W. Biederman } 1539f728019bSEric W. Biederman if (nr_subheaders == 1) { 154060a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1541ec6a5266SEric W. Biederman if (header) 1542ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1543f728019bSEric W. Biederman } else { 1544f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1545f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1546f728019bSEric W. Biederman if (!header) 1547f728019bSEric W. Biederman goto out; 1548f728019bSEric W. Biederman 1549f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1550f728019bSEric W. Biederman subheader = subheaders; 1551f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1552f728019bSEric W. Biederman 1553f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 155460a47a2eSEric W. Biederman set, table)) 1555f728019bSEric W. Biederman goto err_register_leaves; 1556f728019bSEric W. Biederman } 1557f728019bSEric W. Biederman 15586e9d5164SEric W. Biederman out: 15596e9d5164SEric W. Biederman kfree(new_path); 15606e9d5164SEric W. Biederman return header; 1561f728019bSEric W. Biederman 1562f728019bSEric W. Biederman err_register_leaves: 1563f728019bSEric W. Biederman while (subheader > subheaders) { 1564f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1565f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1566f728019bSEric W. Biederman unregister_sysctl_table(subh); 1567f728019bSEric W. Biederman kfree(table); 1568f728019bSEric W. Biederman } 1569f728019bSEric W. Biederman kfree(header); 1570f728019bSEric W. Biederman header = NULL; 1571f728019bSEric W. Biederman goto out; 15726e9d5164SEric W. Biederman } 15736e9d5164SEric W. Biederman 15741f87f0b5SEric W. Biederman /** 15751f87f0b5SEric W. Biederman * register_sysctl_table_path - register a sysctl table hierarchy 15761f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15771f87f0b5SEric W. Biederman * @table: the top-level table structure 15781f87f0b5SEric W. Biederman * 15791f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15801f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15811f87f0b5SEric W. Biederman * 15821f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 15831f87f0b5SEric W. Biederman */ 15841f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 15851f87f0b5SEric W. Biederman struct ctl_table *table) 15861f87f0b5SEric W. Biederman { 158760a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 15881f87f0b5SEric W. Biederman path, table); 15891f87f0b5SEric W. Biederman } 15901f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 15911f87f0b5SEric W. Biederman 15921f87f0b5SEric W. Biederman /** 15931f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 15941f87f0b5SEric W. Biederman * @table: the top-level table structure 15951f87f0b5SEric W. Biederman * 15961f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15971f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15981f87f0b5SEric W. Biederman * 15991f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 16001f87f0b5SEric W. Biederman */ 16011f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 16021f87f0b5SEric W. Biederman { 16031f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 16041f87f0b5SEric W. Biederman 16051f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 16061f87f0b5SEric W. Biederman } 16071f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 16081f87f0b5SEric W. Biederman 16090e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 16100e47c99dSEric W. Biederman { 16110e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 16120e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 16130e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 16140e47c99dSEric W. Biederman struct ctl_dir *core_parent; 16150e47c99dSEric W. Biederman struct ctl_table *entry; 16160e47c99dSEric W. Biederman 16170e47c99dSEric W. Biederman if (header->set == root_set) 16180e47c99dSEric W. Biederman return; 16190e47c99dSEric W. Biederman 16200e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16210e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16220e47c99dSEric W. Biederman return; 16230e47c99dSEric W. Biederman 16240e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 16250e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16260e47c99dSEric W. Biederman struct ctl_table *link; 16270e47c99dSEric W. Biederman const char *name = entry->procname; 16280e47c99dSEric W. Biederman 16290e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16300e47c99dSEric W. Biederman if (link && 16310e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16320e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16330e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16340e47c99dSEric W. Biederman } 16350e47c99dSEric W. Biederman else { 163687ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16370e47c99dSEric W. Biederman sysctl_print_dir(parent); 163887ebdc00SAndrew Morton pr_cont("/%s\n", name); 16390e47c99dSEric W. Biederman } 16400e47c99dSEric W. Biederman } 16410e47c99dSEric W. Biederman } 16420e47c99dSEric W. Biederman 1643938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1644938aaa4fSEric W. Biederman { 16457ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16467ec66d06SEric W. Biederman 1647938aaa4fSEric W. Biederman if (--header->nreg) 1648938aaa4fSEric W. Biederman return; 1649938aaa4fSEric W. Biederman 165089189557SYueHaibing if (parent) { 16510e47c99dSEric W. Biederman put_links(header); 1652938aaa4fSEric W. Biederman start_unregistering(header); 165389189557SYueHaibing } 165489189557SYueHaibing 1655938aaa4fSEric W. Biederman if (!--header->count) 1656938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16577ec66d06SEric W. Biederman 16587ec66d06SEric W. Biederman if (parent) 16597ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1660938aaa4fSEric W. Biederman } 1661938aaa4fSEric W. Biederman 16621f87f0b5SEric W. Biederman /** 16631f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16641f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16651f87f0b5SEric W. Biederman * 16661f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16671f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16681f87f0b5SEric W. Biederman */ 16691f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16701f87f0b5SEric W. Biederman { 1671f728019bSEric W. Biederman int nr_subheaders; 16721f87f0b5SEric W. Biederman might_sleep(); 16731f87f0b5SEric W. Biederman 16741f87f0b5SEric W. Biederman if (header == NULL) 16751f87f0b5SEric W. Biederman return; 16761f87f0b5SEric W. Biederman 1677f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1678f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1679f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1680f728019bSEric W. Biederman int i; 1681f728019bSEric W. Biederman 1682f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1683f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1684f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1685f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1686f728019bSEric W. Biederman unregister_sysctl_table(subh); 1687f728019bSEric W. Biederman kfree(table); 1688f728019bSEric W. Biederman } 1689f728019bSEric W. Biederman kfree(header); 1690f728019bSEric W. Biederman return; 1691f728019bSEric W. Biederman } 1692f728019bSEric W. Biederman 16931f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1694938aaa4fSEric W. Biederman drop_sysctl_table(header); 16951f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 16961f87f0b5SEric W. Biederman } 16971f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 16981f87f0b5SEric W. Biederman 16990e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 17009eb47c26SEric W. Biederman struct ctl_table_root *root, 17011f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 17021f87f0b5SEric W. Biederman { 17031347440dSDan Carpenter memset(set, 0, sizeof(*set)); 17040e47c99dSEric W. Biederman set->is_seen = is_seen; 1705ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 17061f87f0b5SEric W. Biederman } 17071f87f0b5SEric W. Biederman 170897324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 170997324cd8SEric W. Biederman { 1710ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 171197324cd8SEric W. Biederman } 17121f87f0b5SEric W. Biederman 17131e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 171477b14db5SEric W. Biederman { 1715e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1716e1675231SAlexey Dobriyan 171777b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17189043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 17199043476fSAl Viro proc_sys_root->proc_fops = &proc_sys_dir_file_operations; 172077b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1721de4e83bdSEric W. Biederman 1722de4e83bdSEric W. Biederman return sysctl_init(); 172377b14db5SEric W. Biederman } 1724