1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 277b14db5SEric W. Biederman /* 377b14db5SEric W. Biederman * /proc/sys support 477b14db5SEric W. Biederman */ 51e0edd3fSAlexey Dobriyan #include <linux/init.h> 677b14db5SEric W. Biederman #include <linux/sysctl.h> 7f1ecf068SLucas De Marchi #include <linux/poll.h> 877b14db5SEric W. Biederman #include <linux/proc_fs.h> 987ebdc00SAndrew Morton #include <linux/printk.h> 1077b14db5SEric W. Biederman #include <linux/security.h> 1140401530SAl Viro #include <linux/sched.h> 125b825c3aSIngo Molnar #include <linux/cred.h> 1334286d66SNick Piggin #include <linux/namei.h> 1440401530SAl Viro #include <linux/mm.h> 154bd6a735SMatthew Wilcox (Oracle) #include <linux/uio.h> 161f87f0b5SEric W. Biederman #include <linux/module.h> 177b146cebSAndrey Ignatov #include <linux/bpf-cgroup.h> 183db978d4SVlastimil Babka #include <linux/mount.h> 19*3ddd9a80SXiaoming Ni #include <linux/kmemleak.h> 2077b14db5SEric W. Biederman #include "internal.h" 2177b14db5SEric W. Biederman 22d72f71ebSAl Viro static const struct dentry_operations proc_sys_dentry_operations; 2377b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations; 2403a44825SJan Engelhardt static const struct inode_operations proc_sys_inode_operations; 259043476fSAl Viro static const struct file_operations proc_sys_dir_file_operations; 269043476fSAl Viro static const struct inode_operations proc_sys_dir_operations; 2777b14db5SEric W. Biederman 28eec4844fSMatteo Croce /* shared constants to be used in various sysctls */ 29eec4844fSMatteo Croce const int sysctl_vals[] = { 0, 1, INT_MAX }; 30eec4844fSMatteo Croce EXPORT_SYMBOL(sysctl_vals); 31eec4844fSMatteo Croce 32f9bd6733SEric W. Biederman /* Support for permanently empty directories */ 33f9bd6733SEric W. Biederman 34f9bd6733SEric W. Biederman struct ctl_table sysctl_mount_point[] = { 35f9bd6733SEric W. Biederman { } 36f9bd6733SEric W. Biederman }; 37f9bd6733SEric W. Biederman 38f9bd6733SEric W. Biederman static bool is_empty_dir(struct ctl_table_header *head) 39f9bd6733SEric W. Biederman { 40f9bd6733SEric W. Biederman return head->ctl_table[0].child == sysctl_mount_point; 41f9bd6733SEric W. Biederman } 42f9bd6733SEric W. Biederman 43f9bd6733SEric W. Biederman static void set_empty_dir(struct ctl_dir *dir) 44f9bd6733SEric W. Biederman { 45f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = sysctl_mount_point; 46f9bd6733SEric W. Biederman } 47f9bd6733SEric W. Biederman 48f9bd6733SEric W. Biederman static void clear_empty_dir(struct ctl_dir *dir) 49f9bd6733SEric W. Biederman 50f9bd6733SEric W. Biederman { 51f9bd6733SEric W. Biederman dir->header.ctl_table[0].child = NULL; 52f9bd6733SEric W. Biederman } 53f9bd6733SEric W. Biederman 54f1ecf068SLucas De Marchi void proc_sys_poll_notify(struct ctl_table_poll *poll) 55f1ecf068SLucas De Marchi { 56f1ecf068SLucas De Marchi if (!poll) 57f1ecf068SLucas De Marchi return; 58f1ecf068SLucas De Marchi 59f1ecf068SLucas De Marchi atomic_inc(&poll->event); 60f1ecf068SLucas De Marchi wake_up_interruptible(&poll->wait); 61f1ecf068SLucas De Marchi } 62f1ecf068SLucas De Marchi 63a194558eSEric W. Biederman static struct ctl_table root_table[] = { 64a194558eSEric W. Biederman { 65a194558eSEric W. Biederman .procname = "", 667ec66d06SEric W. Biederman .mode = S_IFDIR|S_IRUGO|S_IXUGO, 67a194558eSEric W. Biederman }, 68a194558eSEric W. Biederman { } 69a194558eSEric W. Biederman }; 700e47c99dSEric W. Biederman static struct ctl_table_root sysctl_table_root = { 710e47c99dSEric W. Biederman .default_set.dir.header = { 721f87f0b5SEric W. Biederman {{.count = 1, 73938aaa4fSEric W. Biederman .nreg = 1, 74ac13ac6fSEric W. Biederman .ctl_table = root_table }}, 750e47c99dSEric W. Biederman .ctl_table_arg = root_table, 761f87f0b5SEric W. Biederman .root = &sysctl_table_root, 771f87f0b5SEric W. Biederman .set = &sysctl_table_root.default_set, 787ec66d06SEric W. Biederman }, 791f87f0b5SEric W. Biederman }; 801f87f0b5SEric W. Biederman 811f87f0b5SEric W. Biederman static DEFINE_SPINLOCK(sysctl_lock); 821f87f0b5SEric W. Biederman 837ec66d06SEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header); 840e47c99dSEric W. Biederman static int sysctl_follow_link(struct ctl_table_header **phead, 8513bcc6a2SEric W. Biederman struct ctl_table **pentry); 860e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head); 870e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header); 887ec66d06SEric W. Biederman 896980128fSEric W. Biederman static void sysctl_print_dir(struct ctl_dir *dir) 906980128fSEric W. Biederman { 916980128fSEric W. Biederman if (dir->header.parent) 926980128fSEric W. Biederman sysctl_print_dir(dir->header.parent); 9387ebdc00SAndrew Morton pr_cont("%s/", dir->header.ctl_table[0].procname); 946980128fSEric W. Biederman } 956980128fSEric W. Biederman 96076c3eedSEric W. Biederman static int namecmp(const char *name1, int len1, const char *name2, int len2) 97076c3eedSEric W. Biederman { 98076c3eedSEric W. Biederman int cmp; 99076c3eedSEric W. Biederman 100d8fc9b66SMasahiro Yamada cmp = memcmp(name1, name2, min(len1, len2)); 101076c3eedSEric W. Biederman if (cmp == 0) 102076c3eedSEric W. Biederman cmp = len1 - len2; 103076c3eedSEric W. Biederman return cmp; 104076c3eedSEric W. Biederman } 105076c3eedSEric W. Biederman 10660f126d9SEric W. Biederman /* Called under sysctl_lock */ 107076c3eedSEric W. Biederman static struct ctl_table *find_entry(struct ctl_table_header **phead, 1080e47c99dSEric W. Biederman struct ctl_dir *dir, const char *name, int namelen) 109076c3eedSEric W. Biederman { 110076c3eedSEric W. Biederman struct ctl_table_header *head; 111076c3eedSEric W. Biederman struct ctl_table *entry; 112ac13ac6fSEric W. Biederman struct rb_node *node = dir->root.rb_node; 113076c3eedSEric W. Biederman 114ac13ac6fSEric W. Biederman while (node) 115ac13ac6fSEric W. Biederman { 116ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 117ac13ac6fSEric W. Biederman const char *procname; 118ac13ac6fSEric W. Biederman int cmp; 119ac13ac6fSEric W. Biederman 120ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 121ac13ac6fSEric W. Biederman head = ctl_node->header; 122ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 123ac13ac6fSEric W. Biederman procname = entry->procname; 124ac13ac6fSEric W. Biederman 125ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, procname, strlen(procname)); 126ac13ac6fSEric W. Biederman if (cmp < 0) 127ac13ac6fSEric W. Biederman node = node->rb_left; 128ac13ac6fSEric W. Biederman else if (cmp > 0) 129ac13ac6fSEric W. Biederman node = node->rb_right; 130ac13ac6fSEric W. Biederman else { 131076c3eedSEric W. Biederman *phead = head; 132076c3eedSEric W. Biederman return entry; 133076c3eedSEric W. Biederman } 134076c3eedSEric W. Biederman } 135076c3eedSEric W. Biederman return NULL; 136076c3eedSEric W. Biederman } 137076c3eedSEric W. Biederman 138ac13ac6fSEric W. Biederman static int insert_entry(struct ctl_table_header *head, struct ctl_table *entry) 139ac13ac6fSEric W. Biederman { 140ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 141ac13ac6fSEric W. Biederman struct rb_node **p = &head->parent->root.rb_node; 142ac13ac6fSEric W. Biederman struct rb_node *parent = NULL; 143ac13ac6fSEric W. Biederman const char *name = entry->procname; 144ac13ac6fSEric W. Biederman int namelen = strlen(name); 145ac13ac6fSEric W. Biederman 146ac13ac6fSEric W. Biederman while (*p) { 147ac13ac6fSEric W. Biederman struct ctl_table_header *parent_head; 148ac13ac6fSEric W. Biederman struct ctl_table *parent_entry; 149ac13ac6fSEric W. Biederman struct ctl_node *parent_node; 150ac13ac6fSEric W. Biederman const char *parent_name; 151ac13ac6fSEric W. Biederman int cmp; 152ac13ac6fSEric W. Biederman 153ac13ac6fSEric W. Biederman parent = *p; 154ac13ac6fSEric W. Biederman parent_node = rb_entry(parent, struct ctl_node, node); 155ac13ac6fSEric W. Biederman parent_head = parent_node->header; 156ac13ac6fSEric W. Biederman parent_entry = &parent_head->ctl_table[parent_node - parent_head->node]; 157ac13ac6fSEric W. Biederman parent_name = parent_entry->procname; 158ac13ac6fSEric W. Biederman 159ac13ac6fSEric W. Biederman cmp = namecmp(name, namelen, parent_name, strlen(parent_name)); 160ac13ac6fSEric W. Biederman if (cmp < 0) 161ac13ac6fSEric W. Biederman p = &(*p)->rb_left; 162ac13ac6fSEric W. Biederman else if (cmp > 0) 163ac13ac6fSEric W. Biederman p = &(*p)->rb_right; 164ac13ac6fSEric W. Biederman else { 16587ebdc00SAndrew Morton pr_err("sysctl duplicate entry: "); 166ac13ac6fSEric W. Biederman sysctl_print_dir(head->parent); 167153ee1c4SGeert Uytterhoeven pr_cont("%s\n", entry->procname); 168ac13ac6fSEric W. Biederman return -EEXIST; 169ac13ac6fSEric W. Biederman } 170ac13ac6fSEric W. Biederman } 171ac13ac6fSEric W. Biederman 172ac13ac6fSEric W. Biederman rb_link_node(node, parent, p); 173ea5272f5SMichel Lespinasse rb_insert_color(node, &head->parent->root); 174ac13ac6fSEric W. Biederman return 0; 175ac13ac6fSEric W. Biederman } 176ac13ac6fSEric W. Biederman 177ac13ac6fSEric W. Biederman static void erase_entry(struct ctl_table_header *head, struct ctl_table *entry) 178ac13ac6fSEric W. Biederman { 179ac13ac6fSEric W. Biederman struct rb_node *node = &head->node[entry - head->ctl_table].node; 180ac13ac6fSEric W. Biederman 181ac13ac6fSEric W. Biederman rb_erase(node, &head->parent->root); 182ac13ac6fSEric W. Biederman } 183ac13ac6fSEric W. Biederman 184e0d04529SEric W. Biederman static void init_header(struct ctl_table_header *head, 185e0d04529SEric W. Biederman struct ctl_table_root *root, struct ctl_table_set *set, 186ac13ac6fSEric W. Biederman struct ctl_node *node, struct ctl_table *table) 187e0d04529SEric W. Biederman { 1887ec66d06SEric W. Biederman head->ctl_table = table; 189e0d04529SEric W. Biederman head->ctl_table_arg = table; 190e0d04529SEric W. Biederman head->used = 0; 191e0d04529SEric W. Biederman head->count = 1; 192e0d04529SEric W. Biederman head->nreg = 1; 193e0d04529SEric W. Biederman head->unregistering = NULL; 194e0d04529SEric W. Biederman head->root = root; 195e0d04529SEric W. Biederman head->set = set; 196e0d04529SEric W. Biederman head->parent = NULL; 197ac13ac6fSEric W. Biederman head->node = node; 1982fd1d2c4SEric W. Biederman INIT_HLIST_HEAD(&head->inodes); 199ac13ac6fSEric W. Biederman if (node) { 200ac13ac6fSEric W. Biederman struct ctl_table *entry; 2014c199a93SMichel Lespinasse for (entry = table; entry->procname; entry++, node++) 202ac13ac6fSEric W. Biederman node->header = head; 203ac13ac6fSEric W. Biederman } 204ac13ac6fSEric W. Biederman } 205e0d04529SEric W. Biederman 2068425d6aaSEric W. Biederman static void erase_header(struct ctl_table_header *head) 2078425d6aaSEric W. Biederman { 208ac13ac6fSEric W. Biederman struct ctl_table *entry; 209ac13ac6fSEric W. Biederman for (entry = head->ctl_table; entry->procname; entry++) 210ac13ac6fSEric W. Biederman erase_entry(head, entry); 2118425d6aaSEric W. Biederman } 2128425d6aaSEric W. Biederman 2130e47c99dSEric W. Biederman static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) 2148425d6aaSEric W. Biederman { 215ac13ac6fSEric W. Biederman struct ctl_table *entry; 2160e47c99dSEric W. Biederman int err; 2170e47c99dSEric W. Biederman 218f9bd6733SEric W. Biederman /* Is this a permanently empty directory? */ 219f9bd6733SEric W. Biederman if (is_empty_dir(&dir->header)) 220f9bd6733SEric W. Biederman return -EROFS; 221f9bd6733SEric W. Biederman 222f9bd6733SEric W. Biederman /* Am I creating a permanently empty directory? */ 223f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) { 224f9bd6733SEric W. Biederman if (!RB_EMPTY_ROOT(&dir->root)) 225f9bd6733SEric W. Biederman return -EINVAL; 226f9bd6733SEric W. Biederman set_empty_dir(dir); 227f9bd6733SEric W. Biederman } 228f9bd6733SEric W. Biederman 2290e47c99dSEric W. Biederman dir->header.nreg++; 2307ec66d06SEric W. Biederman header->parent = dir; 2310e47c99dSEric W. Biederman err = insert_links(header); 2320e47c99dSEric W. Biederman if (err) 2330e47c99dSEric W. Biederman goto fail_links; 234ac13ac6fSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 235ac13ac6fSEric W. Biederman err = insert_entry(header, entry); 236ac13ac6fSEric W. Biederman if (err) 237ac13ac6fSEric W. Biederman goto fail; 238ac13ac6fSEric W. Biederman } 2390e47c99dSEric W. Biederman return 0; 240ac13ac6fSEric W. Biederman fail: 241ac13ac6fSEric W. Biederman erase_header(header); 242ac13ac6fSEric W. Biederman put_links(header); 2430e47c99dSEric W. Biederman fail_links: 244f9bd6733SEric W. Biederman if (header->ctl_table == sysctl_mount_point) 245f9bd6733SEric W. Biederman clear_empty_dir(dir); 2460e47c99dSEric W. Biederman header->parent = NULL; 2470e47c99dSEric W. Biederman drop_sysctl_table(&dir->header); 2480e47c99dSEric W. Biederman return err; 2498425d6aaSEric W. Biederman } 2508425d6aaSEric W. Biederman 2511f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2521f87f0b5SEric W. Biederman static int use_table(struct ctl_table_header *p) 2531f87f0b5SEric W. Biederman { 2541f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2551f87f0b5SEric W. Biederman return 0; 2561f87f0b5SEric W. Biederman p->used++; 2571f87f0b5SEric W. Biederman return 1; 2581f87f0b5SEric W. Biederman } 2591f87f0b5SEric W. Biederman 2601f87f0b5SEric W. Biederman /* called under sysctl_lock */ 2611f87f0b5SEric W. Biederman static void unuse_table(struct ctl_table_header *p) 2621f87f0b5SEric W. Biederman { 2631f87f0b5SEric W. Biederman if (!--p->used) 2641f87f0b5SEric W. Biederman if (unlikely(p->unregistering)) 2651f87f0b5SEric W. Biederman complete(p->unregistering); 2661f87f0b5SEric W. Biederman } 2671f87f0b5SEric W. Biederman 268f90f3cafSEric W. Biederman static void proc_sys_invalidate_dcache(struct ctl_table_header *head) 269d6cffbbeSKonstantin Khlebnikov { 270f90f3cafSEric W. Biederman proc_invalidate_siblings_dcache(&head->inodes, &sysctl_lock); 271d6cffbbeSKonstantin Khlebnikov } 272d6cffbbeSKonstantin Khlebnikov 2731f87f0b5SEric W. Biederman /* called under sysctl_lock, will reacquire if has to wait */ 2741f87f0b5SEric W. Biederman static void start_unregistering(struct ctl_table_header *p) 2751f87f0b5SEric W. Biederman { 2761f87f0b5SEric W. Biederman /* 2771f87f0b5SEric W. Biederman * if p->used is 0, nobody will ever touch that entry again; 2781f87f0b5SEric W. Biederman * we'll eliminate all paths to it before dropping sysctl_lock 2791f87f0b5SEric W. Biederman */ 2801f87f0b5SEric W. Biederman if (unlikely(p->used)) { 2811f87f0b5SEric W. Biederman struct completion wait; 2821f87f0b5SEric W. Biederman init_completion(&wait); 2831f87f0b5SEric W. Biederman p->unregistering = &wait; 2841f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 2851f87f0b5SEric W. Biederman wait_for_completion(&wait); 2861f87f0b5SEric W. Biederman } else { 2871f87f0b5SEric W. Biederman /* anything non-NULL; we'll never dereference it */ 2881f87f0b5SEric W. Biederman p->unregistering = ERR_PTR(-EINVAL); 289ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 2901f87f0b5SEric W. Biederman } 2911f87f0b5SEric W. Biederman /* 292f90f3cafSEric W. Biederman * Invalidate dentries for unregistered sysctls: namespaced sysctls 293d6cffbbeSKonstantin Khlebnikov * can have duplicate names and contaminate dcache very badly. 294d6cffbbeSKonstantin Khlebnikov */ 295f90f3cafSEric W. Biederman proc_sys_invalidate_dcache(p); 296d6cffbbeSKonstantin Khlebnikov /* 2971f87f0b5SEric W. Biederman * do not remove from the list until nobody holds it; walking the 2981f87f0b5SEric W. Biederman * list in do_sysctl() relies on that. 2991f87f0b5SEric W. Biederman */ 300ace0c791SEric W. Biederman spin_lock(&sysctl_lock); 3018425d6aaSEric W. Biederman erase_header(p); 3021f87f0b5SEric W. Biederman } 3031f87f0b5SEric W. Biederman 3041f87f0b5SEric W. Biederman static struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head) 3051f87f0b5SEric W. Biederman { 306ab4a1f24SPrasad Joshi BUG_ON(!head); 3071f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3081f87f0b5SEric W. Biederman if (!use_table(head)) 3091f87f0b5SEric W. Biederman head = ERR_PTR(-ENOENT); 3101f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3111f87f0b5SEric W. Biederman return head; 3121f87f0b5SEric W. Biederman } 3131f87f0b5SEric W. Biederman 3141f87f0b5SEric W. Biederman static void sysctl_head_finish(struct ctl_table_header *head) 3151f87f0b5SEric W. Biederman { 3161f87f0b5SEric W. Biederman if (!head) 3171f87f0b5SEric W. Biederman return; 3181f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 3191f87f0b5SEric W. Biederman unuse_table(head); 3201f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 3211f87f0b5SEric W. Biederman } 3221f87f0b5SEric W. Biederman 3231f87f0b5SEric W. Biederman static struct ctl_table_set * 32413bcc6a2SEric W. Biederman lookup_header_set(struct ctl_table_root *root) 3251f87f0b5SEric W. Biederman { 3261f87f0b5SEric W. Biederman struct ctl_table_set *set = &root->default_set; 3271f87f0b5SEric W. Biederman if (root->lookup) 32813bcc6a2SEric W. Biederman set = root->lookup(root); 3291f87f0b5SEric W. Biederman return set; 3301f87f0b5SEric W. Biederman } 3311f87f0b5SEric W. Biederman 332076c3eedSEric W. Biederman static struct ctl_table *lookup_entry(struct ctl_table_header **phead, 3337ec66d06SEric W. Biederman struct ctl_dir *dir, 334076c3eedSEric W. Biederman const char *name, int namelen) 335076c3eedSEric W. Biederman { 336076c3eedSEric W. Biederman struct ctl_table_header *head; 337076c3eedSEric W. Biederman struct ctl_table *entry; 338076c3eedSEric W. Biederman 339076c3eedSEric W. Biederman spin_lock(&sysctl_lock); 3400e47c99dSEric W. Biederman entry = find_entry(&head, dir, name, namelen); 341076c3eedSEric W. Biederman if (entry && use_table(head)) 342076c3eedSEric W. Biederman *phead = head; 343076c3eedSEric W. Biederman else 344076c3eedSEric W. Biederman entry = NULL; 345076c3eedSEric W. Biederman spin_unlock(&sysctl_lock); 346076c3eedSEric W. Biederman return entry; 347076c3eedSEric W. Biederman } 348076c3eedSEric W. Biederman 349ac13ac6fSEric W. Biederman static struct ctl_node *first_usable_entry(struct rb_node *node) 3501f87f0b5SEric W. Biederman { 351ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3521f87f0b5SEric W. Biederman 353ac13ac6fSEric W. Biederman for (;node; node = rb_next(node)) { 354ac13ac6fSEric W. Biederman ctl_node = rb_entry(node, struct ctl_node, node); 355ac13ac6fSEric W. Biederman if (use_table(ctl_node->header)) 356ac13ac6fSEric W. Biederman return ctl_node; 3571f87f0b5SEric W. Biederman } 3581f87f0b5SEric W. Biederman return NULL; 3591f87f0b5SEric W. Biederman } 3601f87f0b5SEric W. Biederman 3617ec66d06SEric W. Biederman static void first_entry(struct ctl_dir *dir, 3626a75ce16SEric W. Biederman struct ctl_table_header **phead, struct ctl_table **pentry) 3631f87f0b5SEric W. Biederman { 364ac13ac6fSEric W. Biederman struct ctl_table_header *head = NULL; 3657ec66d06SEric W. Biederman struct ctl_table *entry = NULL; 366ac13ac6fSEric W. Biederman struct ctl_node *ctl_node; 3676a75ce16SEric W. Biederman 3686a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 369ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_first(&dir->root)); 3706a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 371ac13ac6fSEric W. Biederman if (ctl_node) { 372ac13ac6fSEric W. Biederman head = ctl_node->header; 373ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 374ac13ac6fSEric W. Biederman } 3756a75ce16SEric W. Biederman *phead = head; 3766a75ce16SEric W. Biederman *pentry = entry; 3776a75ce16SEric W. Biederman } 3786a75ce16SEric W. Biederman 3797ec66d06SEric W. Biederman static void next_entry(struct ctl_table_header **phead, struct ctl_table **pentry) 3806a75ce16SEric W. Biederman { 3816a75ce16SEric W. Biederman struct ctl_table_header *head = *phead; 3826a75ce16SEric W. Biederman struct ctl_table *entry = *pentry; 383ac13ac6fSEric W. Biederman struct ctl_node *ctl_node = &head->node[entry - head->ctl_table]; 3846a75ce16SEric W. Biederman 3856a75ce16SEric W. Biederman spin_lock(&sysctl_lock); 3866a75ce16SEric W. Biederman unuse_table(head); 387ac13ac6fSEric W. Biederman 388ac13ac6fSEric W. Biederman ctl_node = first_usable_entry(rb_next(&ctl_node->node)); 3896a75ce16SEric W. Biederman spin_unlock(&sysctl_lock); 390ac13ac6fSEric W. Biederman head = NULL; 391ac13ac6fSEric W. Biederman if (ctl_node) { 392ac13ac6fSEric W. Biederman head = ctl_node->header; 393ac13ac6fSEric W. Biederman entry = &head->ctl_table[ctl_node - head->node]; 3946a75ce16SEric W. Biederman } 3956a75ce16SEric W. Biederman *phead = head; 3966a75ce16SEric W. Biederman *pentry = entry; 3971f87f0b5SEric W. Biederman } 3981f87f0b5SEric W. Biederman 3991f87f0b5SEric W. Biederman /* 4001f87f0b5SEric W. Biederman * sysctl_perm does NOT grant the superuser all rights automatically, because 4011f87f0b5SEric W. Biederman * some sysctl variables are readonly even to root. 4021f87f0b5SEric W. Biederman */ 4031f87f0b5SEric W. Biederman 4041f87f0b5SEric W. Biederman static int test_perm(int mode, int op) 4051f87f0b5SEric W. Biederman { 406091bd3eaSEric W. Biederman if (uid_eq(current_euid(), GLOBAL_ROOT_UID)) 4071f87f0b5SEric W. Biederman mode >>= 6; 408091bd3eaSEric W. Biederman else if (in_egroup_p(GLOBAL_ROOT_GID)) 4091f87f0b5SEric W. Biederman mode >>= 3; 4101f87f0b5SEric W. Biederman if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0) 4111f87f0b5SEric W. Biederman return 0; 4121f87f0b5SEric W. Biederman return -EACCES; 4131f87f0b5SEric W. Biederman } 4141f87f0b5SEric W. Biederman 41573f7ef43SEric W. Biederman static int sysctl_perm(struct ctl_table_header *head, struct ctl_table *table, int op) 4161f87f0b5SEric W. Biederman { 41773f7ef43SEric W. Biederman struct ctl_table_root *root = head->root; 4181f87f0b5SEric W. Biederman int mode; 4191f87f0b5SEric W. Biederman 4201f87f0b5SEric W. Biederman if (root->permissions) 42173f7ef43SEric W. Biederman mode = root->permissions(head, table); 4221f87f0b5SEric W. Biederman else 4231f87f0b5SEric W. Biederman mode = table->mode; 4241f87f0b5SEric W. Biederman 4251f87f0b5SEric W. Biederman return test_perm(mode, op); 4261f87f0b5SEric W. Biederman } 4271f87f0b5SEric W. Biederman 4289043476fSAl Viro static struct inode *proc_sys_make_inode(struct super_block *sb, 4299043476fSAl Viro struct ctl_table_header *head, struct ctl_table *table) 43077b14db5SEric W. Biederman { 431e79c6a4fSDmitry Torokhov struct ctl_table_root *root = head->root; 43277b14db5SEric W. Biederman struct inode *inode; 4339043476fSAl Viro struct proc_inode *ei; 43477b14db5SEric W. Biederman 4359043476fSAl Viro inode = new_inode(sb); 43677b14db5SEric W. Biederman if (!inode) 437ea5751ccSIvan Delalande return ERR_PTR(-ENOMEM); 43877b14db5SEric W. Biederman 43985fe4025SChristoph Hellwig inode->i_ino = get_next_ino(); 44085fe4025SChristoph Hellwig 44177b14db5SEric W. Biederman ei = PROC_I(inode); 4429043476fSAl Viro 443d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 444ace0c791SEric W. Biederman if (unlikely(head->unregistering)) { 445ace0c791SEric W. Biederman spin_unlock(&sysctl_lock); 446ace0c791SEric W. Biederman iput(inode); 447ea5751ccSIvan Delalande return ERR_PTR(-ENOENT); 448ace0c791SEric W. Biederman } 449ace0c791SEric W. Biederman ei->sysctl = head; 450ace0c791SEric W. Biederman ei->sysctl_entry = table; 4510afa5ca8SEric W. Biederman hlist_add_head_rcu(&ei->sibling_inodes, &head->inodes); 452d6cffbbeSKonstantin Khlebnikov head->count++; 453d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 454d6cffbbeSKonstantin Khlebnikov 455078cd827SDeepa Dinamani inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); 4569043476fSAl Viro inode->i_mode = table->mode; 4577ec66d06SEric W. Biederman if (!S_ISDIR(table->mode)) { 4589043476fSAl Viro inode->i_mode |= S_IFREG; 45977b14db5SEric W. Biederman inode->i_op = &proc_sys_inode_operations; 46077b14db5SEric W. Biederman inode->i_fop = &proc_sys_file_operations; 4619043476fSAl Viro } else { 4629043476fSAl Viro inode->i_mode |= S_IFDIR; 4639043476fSAl Viro inode->i_op = &proc_sys_dir_operations; 4649043476fSAl Viro inode->i_fop = &proc_sys_dir_file_operations; 465f9bd6733SEric W. Biederman if (is_empty_dir(head)) 466f9bd6733SEric W. Biederman make_empty_dir_inode(inode); 4679043476fSAl Viro } 468e79c6a4fSDmitry Torokhov 469e79c6a4fSDmitry Torokhov if (root->set_ownership) 470e79c6a4fSDmitry Torokhov root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); 4715ec27ec7SRadoslaw Burny else { 4725ec27ec7SRadoslaw Burny inode->i_uid = GLOBAL_ROOT_UID; 4735ec27ec7SRadoslaw Burny inode->i_gid = GLOBAL_ROOT_GID; 4745ec27ec7SRadoslaw Burny } 475e79c6a4fSDmitry Torokhov 47677b14db5SEric W. Biederman return inode; 47777b14db5SEric W. Biederman } 47877b14db5SEric W. Biederman 479d6cffbbeSKonstantin Khlebnikov void proc_sys_evict_inode(struct inode *inode, struct ctl_table_header *head) 480d6cffbbeSKonstantin Khlebnikov { 481d6cffbbeSKonstantin Khlebnikov spin_lock(&sysctl_lock); 4820afa5ca8SEric W. Biederman hlist_del_init_rcu(&PROC_I(inode)->sibling_inodes); 483d6cffbbeSKonstantin Khlebnikov if (!--head->count) 484d6cffbbeSKonstantin Khlebnikov kfree_rcu(head, rcu); 485d6cffbbeSKonstantin Khlebnikov spin_unlock(&sysctl_lock); 486d6cffbbeSKonstantin Khlebnikov } 487d6cffbbeSKonstantin Khlebnikov 48881324364SAdrian Bunk static struct ctl_table_header *grab_header(struct inode *inode) 48977b14db5SEric W. Biederman { 4903cc3e046SEric W. Biederman struct ctl_table_header *head = PROC_I(inode)->sysctl; 4913cc3e046SEric W. Biederman if (!head) 4920e47c99dSEric W. Biederman head = &sysctl_table_root.default_set.dir.header; 4933cc3e046SEric W. Biederman return sysctl_head_grab(head); 49477b14db5SEric W. Biederman } 49577b14db5SEric W. Biederman 49677b14db5SEric W. Biederman static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, 49700cd8dd3SAl Viro unsigned int flags) 49877b14db5SEric W. Biederman { 4999043476fSAl Viro struct ctl_table_header *head = grab_header(dir); 5009043476fSAl Viro struct ctl_table_header *h = NULL; 501dc12e909SAl Viro const struct qstr *name = &dentry->d_name; 5029043476fSAl Viro struct ctl_table *p; 50377b14db5SEric W. Biederman struct inode *inode; 5049043476fSAl Viro struct dentry *err = ERR_PTR(-ENOENT); 5057ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 5060e47c99dSEric W. Biederman int ret; 50777b14db5SEric W. Biederman 5089043476fSAl Viro if (IS_ERR(head)) 5099043476fSAl Viro return ERR_CAST(head); 5109043476fSAl Viro 5117ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 5129043476fSAl Viro 5137ec66d06SEric W. Biederman p = lookup_entry(&h, ctl_dir, name->name, name->len); 5149043476fSAl Viro if (!p) 51577b14db5SEric W. Biederman goto out; 51677b14db5SEric W. Biederman 5174e757320SEric W. Biederman if (S_ISLNK(p->mode)) { 51813bcc6a2SEric W. Biederman ret = sysctl_follow_link(&h, &p); 5190e47c99dSEric W. Biederman err = ERR_PTR(ret); 5200e47c99dSEric W. Biederman if (ret) 5210e47c99dSEric W. Biederman goto out; 5224e757320SEric W. Biederman } 5230e47c99dSEric W. Biederman 5249043476fSAl Viro inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); 525ea5751ccSIvan Delalande if (IS_ERR(inode)) { 526ea5751ccSIvan Delalande err = ERR_CAST(inode); 52777b14db5SEric W. Biederman goto out; 528ea5751ccSIvan Delalande } 52977b14db5SEric W. Biederman 530fb045adbSNick Piggin d_set_d_op(dentry, &proc_sys_dentry_operations); 531888e2b03SAl Viro err = d_splice_alias(inode, dentry); 53277b14db5SEric W. Biederman 53377b14db5SEric W. Biederman out: 5346bf61045SFrancesco Ruggeri if (h) 5356bf61045SFrancesco Ruggeri sysctl_head_finish(h); 53677b14db5SEric W. Biederman sysctl_head_finish(head); 53777b14db5SEric W. Biederman return err; 53877b14db5SEric W. Biederman } 53977b14db5SEric W. Biederman 5404bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_call_handler(struct kiocb *iocb, struct iov_iter *iter, 5414bd6a735SMatthew Wilcox (Oracle) int write) 54277b14db5SEric W. Biederman { 5434bd6a735SMatthew Wilcox (Oracle) struct inode *inode = file_inode(iocb->ki_filp); 5449043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 5459043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 5464bd6a735SMatthew Wilcox (Oracle) size_t count = iov_iter_count(iter); 5474bd6a735SMatthew Wilcox (Oracle) char *kbuf; 5482a2da53bSDavid Howells ssize_t error; 54977b14db5SEric W. Biederman 5509043476fSAl Viro if (IS_ERR(head)) 5519043476fSAl Viro return PTR_ERR(head); 55277b14db5SEric W. Biederman 55377b14db5SEric W. Biederman /* 55477b14db5SEric W. Biederman * At this point we know that the sysctl was not unregistered 55577b14db5SEric W. Biederman * and won't be until we finish. 55677b14db5SEric W. Biederman */ 55777b14db5SEric W. Biederman error = -EPERM; 55873f7ef43SEric W. Biederman if (sysctl_perm(head, table, write ? MAY_WRITE : MAY_READ)) 55977b14db5SEric W. Biederman goto out; 56077b14db5SEric W. Biederman 5619043476fSAl Viro /* if that can happen at all, it should be -EINVAL, not -EISDIR */ 5629043476fSAl Viro error = -EINVAL; 5639043476fSAl Viro if (!table->proc_handler) 5649043476fSAl Viro goto out; 5659043476fSAl Viro 566ef9d965bSChristoph Hellwig /* don't even try if the size is too large */ 567d4d80e69SMatthew Wilcox (Oracle) error = -ENOMEM; 568d4d80e69SMatthew Wilcox (Oracle) if (count >= KMALLOC_MAX_SIZE) 569d4d80e69SMatthew Wilcox (Oracle) goto out; 57045089437SJosef Bacik kbuf = kvzalloc(count + 1, GFP_KERNEL); 57132927393SChristoph Hellwig if (!kbuf) 57232927393SChristoph Hellwig goto out; 5734bd6a735SMatthew Wilcox (Oracle) 5744bd6a735SMatthew Wilcox (Oracle) if (write) { 5754bd6a735SMatthew Wilcox (Oracle) error = -EFAULT; 5764bd6a735SMatthew Wilcox (Oracle) if (!copy_from_iter_full(kbuf, count, iter)) 5774bd6a735SMatthew Wilcox (Oracle) goto out_free_buf; 5784bd6a735SMatthew Wilcox (Oracle) kbuf[count] = '\0'; 5794e63acdfSAndrey Ignatov } 5804e63acdfSAndrey Ignatov 58132927393SChristoph Hellwig error = BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, &kbuf, &count, 5824bd6a735SMatthew Wilcox (Oracle) &iocb->ki_pos); 58332927393SChristoph Hellwig if (error) 58432927393SChristoph Hellwig goto out_free_buf; 58532927393SChristoph Hellwig 58632927393SChristoph Hellwig /* careful: calling conventions are nasty here */ 5874bd6a735SMatthew Wilcox (Oracle) error = table->proc_handler(table, write, kbuf, &count, &iocb->ki_pos); 58832927393SChristoph Hellwig if (error) 58932927393SChristoph Hellwig goto out_free_buf; 59032927393SChristoph Hellwig 59132927393SChristoph Hellwig if (!write) { 59232927393SChristoph Hellwig error = -EFAULT; 5934bd6a735SMatthew Wilcox (Oracle) if (copy_to_iter(kbuf, count, iter) < count) 59432927393SChristoph Hellwig goto out_free_buf; 59532927393SChristoph Hellwig } 59632927393SChristoph Hellwig 5974e63acdfSAndrey Ignatov error = count; 59832927393SChristoph Hellwig out_free_buf: 59945089437SJosef Bacik kvfree(kbuf); 60077b14db5SEric W. Biederman out: 60177b14db5SEric W. Biederman sysctl_head_finish(head); 60277b14db5SEric W. Biederman 60377b14db5SEric W. Biederman return error; 60477b14db5SEric W. Biederman } 60577b14db5SEric W. Biederman 6064bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_read(struct kiocb *iocb, struct iov_iter *iter) 6077708bfb1SPavel Emelyanov { 6084bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 0); 6097708bfb1SPavel Emelyanov } 6107708bfb1SPavel Emelyanov 6114bd6a735SMatthew Wilcox (Oracle) static ssize_t proc_sys_write(struct kiocb *iocb, struct iov_iter *iter) 61277b14db5SEric W. Biederman { 6134bd6a735SMatthew Wilcox (Oracle) return proc_sys_call_handler(iocb, iter, 1); 61477b14db5SEric W. Biederman } 61577b14db5SEric W. Biederman 616f1ecf068SLucas De Marchi static int proc_sys_open(struct inode *inode, struct file *filp) 617f1ecf068SLucas De Marchi { 6184e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 619f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 620f1ecf068SLucas De Marchi 6214e474a00SLucas De Marchi /* sysctl was unregistered */ 6224e474a00SLucas De Marchi if (IS_ERR(head)) 6234e474a00SLucas De Marchi return PTR_ERR(head); 6244e474a00SLucas De Marchi 625f1ecf068SLucas De Marchi if (table->poll) 626f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 627f1ecf068SLucas De Marchi 6284e474a00SLucas De Marchi sysctl_head_finish(head); 6294e474a00SLucas De Marchi 630f1ecf068SLucas De Marchi return 0; 631f1ecf068SLucas De Marchi } 632f1ecf068SLucas De Marchi 633076ccb76SAl Viro static __poll_t proc_sys_poll(struct file *filp, poll_table *wait) 634f1ecf068SLucas De Marchi { 635496ad9aaSAl Viro struct inode *inode = file_inode(filp); 6364e474a00SLucas De Marchi struct ctl_table_header *head = grab_header(inode); 637f1ecf068SLucas De Marchi struct ctl_table *table = PROC_I(inode)->sysctl_entry; 638076ccb76SAl Viro __poll_t ret = DEFAULT_POLLMASK; 6394e474a00SLucas De Marchi unsigned long event; 6404e474a00SLucas De Marchi 6414e474a00SLucas De Marchi /* sysctl was unregistered */ 6424e474a00SLucas De Marchi if (IS_ERR(head)) 643a9a08845SLinus Torvalds return EPOLLERR | EPOLLHUP; 644f1ecf068SLucas De Marchi 645f1ecf068SLucas De Marchi if (!table->proc_handler) 646f1ecf068SLucas De Marchi goto out; 647f1ecf068SLucas De Marchi 648f1ecf068SLucas De Marchi if (!table->poll) 649f1ecf068SLucas De Marchi goto out; 650f1ecf068SLucas De Marchi 6514e474a00SLucas De Marchi event = (unsigned long)filp->private_data; 652f1ecf068SLucas De Marchi poll_wait(filp, &table->poll->wait, wait); 653f1ecf068SLucas De Marchi 654f1ecf068SLucas De Marchi if (event != atomic_read(&table->poll->event)) { 655f1ecf068SLucas De Marchi filp->private_data = proc_sys_poll_event(table->poll); 656a9a08845SLinus Torvalds ret = EPOLLIN | EPOLLRDNORM | EPOLLERR | EPOLLPRI; 657f1ecf068SLucas De Marchi } 658f1ecf068SLucas De Marchi 659f1ecf068SLucas De Marchi out: 6604e474a00SLucas De Marchi sysctl_head_finish(head); 6614e474a00SLucas De Marchi 662f1ecf068SLucas De Marchi return ret; 663f1ecf068SLucas De Marchi } 66477b14db5SEric W. Biederman 665f0c3b509SAl Viro static bool proc_sys_fill_cache(struct file *file, 666f0c3b509SAl Viro struct dir_context *ctx, 6679043476fSAl Viro struct ctl_table_header *head, 6689043476fSAl Viro struct ctl_table *table) 66977b14db5SEric W. Biederman { 670f0c3b509SAl Viro struct dentry *child, *dir = file->f_path.dentry; 67177b14db5SEric W. Biederman struct inode *inode; 67277b14db5SEric W. Biederman struct qstr qname; 67377b14db5SEric W. Biederman ino_t ino = 0; 67477b14db5SEric W. Biederman unsigned type = DT_UNKNOWN; 67577b14db5SEric W. Biederman 67677b14db5SEric W. Biederman qname.name = table->procname; 67777b14db5SEric W. Biederman qname.len = strlen(table->procname); 6788387ff25SLinus Torvalds qname.hash = full_name_hash(dir, qname.name, qname.len); 67977b14db5SEric W. Biederman 68077b14db5SEric W. Biederman child = d_lookup(dir, &qname); 68177b14db5SEric W. Biederman if (!child) { 68276aab3abSAl Viro DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq); 68376aab3abSAl Viro child = d_alloc_parallel(dir, &qname, &wq); 68476aab3abSAl Viro if (IS_ERR(child)) 68576aab3abSAl Viro return false; 68676aab3abSAl Viro if (d_in_lookup(child)) { 687888e2b03SAl Viro struct dentry *res; 6889043476fSAl Viro inode = proc_sys_make_inode(dir->d_sb, head, table); 689ea5751ccSIvan Delalande if (IS_ERR(inode)) { 69076aab3abSAl Viro d_lookup_done(child); 6919043476fSAl Viro dput(child); 692f0c3b509SAl Viro return false; 69376aab3abSAl Viro } 694fb045adbSNick Piggin d_set_d_op(child, &proc_sys_dentry_operations); 695888e2b03SAl Viro res = d_splice_alias(inode, child); 696888e2b03SAl Viro d_lookup_done(child); 697888e2b03SAl Viro if (unlikely(res)) { 698888e2b03SAl Viro if (IS_ERR(res)) { 699888e2b03SAl Viro dput(child); 700888e2b03SAl Viro return false; 701888e2b03SAl Viro } 702888e2b03SAl Viro dput(child); 703888e2b03SAl Viro child = res; 704888e2b03SAl Viro } 70577b14db5SEric W. Biederman } 70677b14db5SEric W. Biederman } 7072b0143b5SDavid Howells inode = d_inode(child); 70877b14db5SEric W. Biederman ino = inode->i_ino; 70977b14db5SEric W. Biederman type = inode->i_mode >> 12; 71077b14db5SEric W. Biederman dput(child); 711f0c3b509SAl Viro return dir_emit(ctx, qname.name, qname.len, ino, type); 7129043476fSAl Viro } 7139043476fSAl Viro 714f0c3b509SAl Viro static bool proc_sys_link_fill_cache(struct file *file, 715f0c3b509SAl Viro struct dir_context *ctx, 7160e47c99dSEric W. Biederman struct ctl_table_header *head, 7170e47c99dSEric W. Biederman struct ctl_table *table) 7180e47c99dSEric W. Biederman { 719f0c3b509SAl Viro bool ret = true; 720a0b0d1c3SDanilo Krummrich 7210e47c99dSEric W. Biederman head = sysctl_head_grab(head); 722a0b0d1c3SDanilo Krummrich if (IS_ERR(head)) 723a0b0d1c3SDanilo Krummrich return false; 7240e47c99dSEric W. Biederman 7250e47c99dSEric W. Biederman /* It is not an error if we can not follow the link ignore it */ 726835b94e0SDanilo Krummrich if (sysctl_follow_link(&head, &table)) 7270e47c99dSEric W. Biederman goto out; 7280e47c99dSEric W. Biederman 729f0c3b509SAl Viro ret = proc_sys_fill_cache(file, ctx, head, table); 7300e47c99dSEric W. Biederman out: 7310e47c99dSEric W. Biederman sysctl_head_finish(head); 7320e47c99dSEric W. Biederman return ret; 7330e47c99dSEric W. Biederman } 7340e47c99dSEric W. Biederman 735e5eea098SJoe Perches static int scan(struct ctl_table_header *head, struct ctl_table *table, 7369043476fSAl Viro unsigned long *pos, struct file *file, 737f0c3b509SAl Viro struct dir_context *ctx) 7389043476fSAl Viro { 739f0c3b509SAl Viro bool res; 7409043476fSAl Viro 741f0c3b509SAl Viro if ((*pos)++ < ctx->pos) 742f0c3b509SAl Viro return true; 7439043476fSAl Viro 7440e47c99dSEric W. Biederman if (unlikely(S_ISLNK(table->mode))) 745f0c3b509SAl Viro res = proc_sys_link_fill_cache(file, ctx, head, table); 7460e47c99dSEric W. Biederman else 747f0c3b509SAl Viro res = proc_sys_fill_cache(file, ctx, head, table); 7489043476fSAl Viro 749f0c3b509SAl Viro if (res) 750f0c3b509SAl Viro ctx->pos = *pos; 7516a75ce16SEric W. Biederman 7526a75ce16SEric W. Biederman return res; 75377b14db5SEric W. Biederman } 75477b14db5SEric W. Biederman 755f0c3b509SAl Viro static int proc_sys_readdir(struct file *file, struct dir_context *ctx) 75677b14db5SEric W. Biederman { 757f0c3b509SAl Viro struct ctl_table_header *head = grab_header(file_inode(file)); 7589043476fSAl Viro struct ctl_table_header *h = NULL; 7596a75ce16SEric W. Biederman struct ctl_table *entry; 7607ec66d06SEric W. Biederman struct ctl_dir *ctl_dir; 76177b14db5SEric W. Biederman unsigned long pos; 76277b14db5SEric W. Biederman 7639043476fSAl Viro if (IS_ERR(head)) 7649043476fSAl Viro return PTR_ERR(head); 7659043476fSAl Viro 7667ec66d06SEric W. Biederman ctl_dir = container_of(head, struct ctl_dir, header); 76777b14db5SEric W. Biederman 768f0c3b509SAl Viro if (!dir_emit_dots(file, ctx)) 76993362fa4SZhou Chengming goto out; 770f0c3b509SAl Viro 77177b14db5SEric W. Biederman pos = 2; 77277b14db5SEric W. Biederman 7737ec66d06SEric W. Biederman for (first_entry(ctl_dir, &h, &entry); h; next_entry(&h, &entry)) { 774f0c3b509SAl Viro if (!scan(h, entry, &pos, file, ctx)) { 7759043476fSAl Viro sysctl_head_finish(h); 7769043476fSAl Viro break; 77777b14db5SEric W. Biederman } 77877b14db5SEric W. Biederman } 77993362fa4SZhou Chengming out: 78077b14db5SEric W. Biederman sysctl_head_finish(head); 781f0c3b509SAl Viro return 0; 78277b14db5SEric W. Biederman } 78377b14db5SEric W. Biederman 784549c7297SChristian Brauner static int proc_sys_permission(struct user_namespace *mnt_userns, 785549c7297SChristian Brauner struct inode *inode, int mask) 78677b14db5SEric W. Biederman { 78777b14db5SEric W. Biederman /* 78877b14db5SEric W. Biederman * sysctl entries that are not writeable, 78977b14db5SEric W. Biederman * are _NOT_ writeable, capabilities or not. 79077b14db5SEric W. Biederman */ 791f696a365SMiklos Szeredi struct ctl_table_header *head; 792f696a365SMiklos Szeredi struct ctl_table *table; 79377b14db5SEric W. Biederman int error; 79477b14db5SEric W. Biederman 795f696a365SMiklos Szeredi /* Executable files are not allowed under /proc/sys/ */ 796f696a365SMiklos Szeredi if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) 797f696a365SMiklos Szeredi return -EACCES; 798f696a365SMiklos Szeredi 799f696a365SMiklos Szeredi head = grab_header(inode); 8009043476fSAl Viro if (IS_ERR(head)) 8019043476fSAl Viro return PTR_ERR(head); 80277b14db5SEric W. Biederman 803f696a365SMiklos Szeredi table = PROC_I(inode)->sysctl_entry; 8049043476fSAl Viro if (!table) /* global root - r-xr-xr-x */ 8059043476fSAl Viro error = mask & MAY_WRITE ? -EACCES : 0; 8069043476fSAl Viro else /* Use the permissions on the sysctl table entry */ 80773f7ef43SEric W. Biederman error = sysctl_perm(head, table, mask & ~MAY_NOT_BLOCK); 8089043476fSAl Viro 80977b14db5SEric W. Biederman sysctl_head_finish(head); 81077b14db5SEric W. Biederman return error; 81177b14db5SEric W. Biederman } 81277b14db5SEric W. Biederman 813549c7297SChristian Brauner static int proc_sys_setattr(struct user_namespace *mnt_userns, 814549c7297SChristian Brauner struct dentry *dentry, struct iattr *attr) 81577b14db5SEric W. Biederman { 8162b0143b5SDavid Howells struct inode *inode = d_inode(dentry); 81777b14db5SEric W. Biederman int error; 81877b14db5SEric W. Biederman 81977b14db5SEric W. Biederman if (attr->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) 82077b14db5SEric W. Biederman return -EPERM; 82177b14db5SEric W. Biederman 8222f221d6fSChristian Brauner error = setattr_prepare(&init_user_ns, dentry, attr); 8231025774cSChristoph Hellwig if (error) 82477b14db5SEric W. Biederman return error; 8251025774cSChristoph Hellwig 8262f221d6fSChristian Brauner setattr_copy(&init_user_ns, inode, attr); 8271025774cSChristoph Hellwig mark_inode_dirty(inode); 8281025774cSChristoph Hellwig return 0; 82977b14db5SEric W. Biederman } 83077b14db5SEric W. Biederman 831549c7297SChristian Brauner static int proc_sys_getattr(struct user_namespace *mnt_userns, 832549c7297SChristian Brauner const struct path *path, struct kstat *stat, 833a528d35eSDavid Howells u32 request_mask, unsigned int query_flags) 8349043476fSAl Viro { 835a528d35eSDavid Howells struct inode *inode = d_inode(path->dentry); 8369043476fSAl Viro struct ctl_table_header *head = grab_header(inode); 8379043476fSAl Viro struct ctl_table *table = PROC_I(inode)->sysctl_entry; 8389043476fSAl Viro 8399043476fSAl Viro if (IS_ERR(head)) 8409043476fSAl Viro return PTR_ERR(head); 8419043476fSAl Viro 8420d56a451SChristian Brauner generic_fillattr(&init_user_ns, inode, stat); 8439043476fSAl Viro if (table) 8449043476fSAl Viro stat->mode = (stat->mode & S_IFMT) | table->mode; 8459043476fSAl Viro 8469043476fSAl Viro sysctl_head_finish(head); 8479043476fSAl Viro return 0; 8489043476fSAl Viro } 8499043476fSAl Viro 85077b14db5SEric W. Biederman static const struct file_operations proc_sys_file_operations = { 851f1ecf068SLucas De Marchi .open = proc_sys_open, 852f1ecf068SLucas De Marchi .poll = proc_sys_poll, 8534bd6a735SMatthew Wilcox (Oracle) .read_iter = proc_sys_read, 8544bd6a735SMatthew Wilcox (Oracle) .write_iter = proc_sys_write, 8554bd6a735SMatthew Wilcox (Oracle) .splice_read = generic_file_splice_read, 8564bd6a735SMatthew Wilcox (Oracle) .splice_write = iter_file_splice_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); 1024153ee1c4SGeert Uytterhoeven pr_cont("%*.*s %ld\n", namelen, namelen, name, 1025153ee1c4SGeert Uytterhoeven 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 spin_lock(&sysctl_lock); 10580e47c99dSEric W. Biederman root = (*pentry)->data; 105913bcc6a2SEric W. Biederman set = lookup_header_set(root); 10600e47c99dSEric W. Biederman dir = xlate_dir(set, (*phead)->parent); 10610e47c99dSEric W. Biederman if (IS_ERR(dir)) 10620e47c99dSEric W. Biederman ret = PTR_ERR(dir); 10630e47c99dSEric W. Biederman else { 10640e47c99dSEric W. Biederman const char *procname = (*pentry)->procname; 10650e47c99dSEric W. Biederman head = NULL; 10660e47c99dSEric W. Biederman entry = find_entry(&head, dir, procname, strlen(procname)); 10670e47c99dSEric W. Biederman ret = -ENOENT; 10680e47c99dSEric W. Biederman if (entry && use_table(head)) { 10690e47c99dSEric W. Biederman unuse_table(*phead); 10700e47c99dSEric W. Biederman *phead = head; 10710e47c99dSEric W. Biederman *pentry = entry; 10720e47c99dSEric W. Biederman ret = 0; 10730e47c99dSEric W. Biederman } 10740e47c99dSEric W. Biederman } 10750e47c99dSEric W. Biederman 10760e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 10770e47c99dSEric W. Biederman return ret; 10780e47c99dSEric W. Biederman } 10790e47c99dSEric W. Biederman 10807c60c48fSEric W. Biederman static int sysctl_err(const char *path, struct ctl_table *table, char *fmt, ...) 10817c60c48fSEric W. Biederman { 10827c60c48fSEric W. Biederman struct va_format vaf; 10837c60c48fSEric W. Biederman va_list args; 10847c60c48fSEric W. Biederman 10857c60c48fSEric W. Biederman va_start(args, fmt); 10867c60c48fSEric W. Biederman vaf.fmt = fmt; 10877c60c48fSEric W. Biederman vaf.va = &args; 10887c60c48fSEric W. Biederman 108987ebdc00SAndrew Morton pr_err("sysctl table check failed: %s/%s %pV\n", 10907c60c48fSEric W. Biederman path, table->procname, &vaf); 10917c60c48fSEric W. Biederman 10927c60c48fSEric W. Biederman va_end(args); 10937c60c48fSEric W. Biederman return -EINVAL; 10947c60c48fSEric W. Biederman } 10957c60c48fSEric W. Biederman 10964f2fec00SLuis R. Rodriguez static int sysctl_check_table_array(const char *path, struct ctl_table *table) 10974f2fec00SLuis R. Rodriguez { 10984f2fec00SLuis R. Rodriguez int err = 0; 10994f2fec00SLuis R. Rodriguez 110061d9b56aSLuis R. Rodriguez if ((table->proc_handler == proc_douintvec) || 110161d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax)) { 11024f2fec00SLuis R. Rodriguez if (table->maxlen != sizeof(unsigned int)) 110364a11f3dSWaiman Long err |= sysctl_err(path, table, "array not allowed"); 11044f2fec00SLuis R. Rodriguez } 11054f2fec00SLuis R. Rodriguez 1106cb944413SEric Dumazet if (table->proc_handler == proc_dou8vec_minmax) { 1107cb944413SEric Dumazet if (table->maxlen != sizeof(u8)) 1108cb944413SEric Dumazet err |= sysctl_err(path, table, "array not allowed"); 1109cb944413SEric Dumazet } 1110cb944413SEric Dumazet 11114f2fec00SLuis R. Rodriguez return err; 11124f2fec00SLuis R. Rodriguez } 11134f2fec00SLuis R. Rodriguez 11147c60c48fSEric W. Biederman static int sysctl_check_table(const char *path, struct ctl_table *table) 11157c60c48fSEric W. Biederman { 11167c60c48fSEric W. Biederman int err = 0; 11177c60c48fSEric W. Biederman for (; table->procname; table++) { 11187c60c48fSEric W. Biederman if (table->child) 111989c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "Not a file"); 11207c60c48fSEric W. Biederman 11211f87f0b5SEric W. Biederman if ((table->proc_handler == proc_dostring) || 11221f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec) || 11231680a386SLiping Zhang (table->proc_handler == proc_douintvec) || 112461d9b56aSLuis R. Rodriguez (table->proc_handler == proc_douintvec_minmax) || 11251f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_minmax) || 1126cb944413SEric Dumazet (table->proc_handler == proc_dou8vec_minmax) || 11271f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_jiffies) || 11281f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_userhz_jiffies) || 11291f87f0b5SEric W. Biederman (table->proc_handler == proc_dointvec_ms_jiffies) || 11301f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_minmax) || 11311f87f0b5SEric W. Biederman (table->proc_handler == proc_doulongvec_ms_jiffies_minmax)) { 11321f87f0b5SEric W. Biederman if (!table->data) 113389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No data"); 11341f87f0b5SEric W. Biederman if (!table->maxlen) 113589c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No maxlen"); 11364f2fec00SLuis R. Rodriguez else 11374f2fec00SLuis R. Rodriguez err |= sysctl_check_table_array(path, table); 11381f87f0b5SEric W. Biederman } 11391f87f0b5SEric W. Biederman if (!table->proc_handler) 114089c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "No proc_handler"); 11417c60c48fSEric W. Biederman 11427c60c48fSEric W. Biederman if ((table->mode & (S_IRUGO|S_IWUGO)) != table->mode) 114389c5b53bSLuis R. Rodriguez err |= sysctl_err(path, table, "bogus .mode 0%o", 11447c60c48fSEric W. Biederman table->mode); 11451f87f0b5SEric W. Biederman } 11467c60c48fSEric W. Biederman return err; 11471f87f0b5SEric W. Biederman } 11481f87f0b5SEric W. Biederman 11490e47c99dSEric W. Biederman static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table *table, 11500e47c99dSEric W. Biederman struct ctl_table_root *link_root) 11510e47c99dSEric W. Biederman { 11520e47c99dSEric W. Biederman struct ctl_table *link_table, *entry, *link; 11530e47c99dSEric W. Biederman struct ctl_table_header *links; 1154ac13ac6fSEric W. Biederman struct ctl_node *node; 11550e47c99dSEric W. Biederman char *link_name; 11560e47c99dSEric W. Biederman int nr_entries, name_bytes; 11570e47c99dSEric W. Biederman 11580e47c99dSEric W. Biederman name_bytes = 0; 11590e47c99dSEric W. Biederman nr_entries = 0; 11600e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 11610e47c99dSEric W. Biederman nr_entries++; 11620e47c99dSEric W. Biederman name_bytes += strlen(entry->procname) + 1; 11630e47c99dSEric W. Biederman } 11640e47c99dSEric W. Biederman 11650e47c99dSEric W. Biederman links = kzalloc(sizeof(struct ctl_table_header) + 1166ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries + 11670e47c99dSEric W. Biederman sizeof(struct ctl_table)*(nr_entries + 1) + 11680e47c99dSEric W. Biederman name_bytes, 11690e47c99dSEric W. Biederman GFP_KERNEL); 11700e47c99dSEric W. Biederman 11710e47c99dSEric W. Biederman if (!links) 11720e47c99dSEric W. Biederman return NULL; 11730e47c99dSEric W. Biederman 1174ac13ac6fSEric W. Biederman node = (struct ctl_node *)(links + 1); 1175ac13ac6fSEric W. Biederman link_table = (struct ctl_table *)(node + nr_entries); 11760e47c99dSEric W. Biederman link_name = (char *)&link_table[nr_entries + 1]; 11770e47c99dSEric W. Biederman 11780e47c99dSEric W. Biederman for (link = link_table, entry = table; entry->procname; link++, entry++) { 11790e47c99dSEric W. Biederman int len = strlen(entry->procname) + 1; 11800e47c99dSEric W. Biederman memcpy(link_name, entry->procname, len); 11810e47c99dSEric W. Biederman link->procname = link_name; 11820e47c99dSEric W. Biederman link->mode = S_IFLNK|S_IRWXUGO; 11830e47c99dSEric W. Biederman link->data = link_root; 11840e47c99dSEric W. Biederman link_name += len; 11850e47c99dSEric W. Biederman } 1186ac13ac6fSEric W. Biederman init_header(links, dir->header.root, dir->header.set, node, link_table); 11870e47c99dSEric W. Biederman links->nreg = nr_entries; 11880e47c99dSEric W. Biederman 11890e47c99dSEric W. Biederman return links; 11900e47c99dSEric W. Biederman } 11910e47c99dSEric W. Biederman 11920e47c99dSEric W. Biederman static bool get_links(struct ctl_dir *dir, 11930e47c99dSEric W. Biederman struct ctl_table *table, struct ctl_table_root *link_root) 11940e47c99dSEric W. Biederman { 11950e47c99dSEric W. Biederman struct ctl_table_header *head; 11960e47c99dSEric W. Biederman struct ctl_table *entry, *link; 11970e47c99dSEric W. Biederman 11980e47c99dSEric W. Biederman /* Are there links available for every entry in table? */ 11990e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12000e47c99dSEric W. Biederman const char *procname = entry->procname; 12010e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12020e47c99dSEric W. Biederman if (!link) 12030e47c99dSEric W. Biederman return false; 12040e47c99dSEric W. Biederman if (S_ISDIR(link->mode) && S_ISDIR(entry->mode)) 12050e47c99dSEric W. Biederman continue; 12060e47c99dSEric W. Biederman if (S_ISLNK(link->mode) && (link->data == link_root)) 12070e47c99dSEric W. Biederman continue; 12080e47c99dSEric W. Biederman return false; 12090e47c99dSEric W. Biederman } 12100e47c99dSEric W. Biederman 12110e47c99dSEric W. Biederman /* The checks passed. Increase the registration count on the links */ 12120e47c99dSEric W. Biederman for (entry = table; entry->procname; entry++) { 12130e47c99dSEric W. Biederman const char *procname = entry->procname; 12140e47c99dSEric W. Biederman link = find_entry(&head, dir, procname, strlen(procname)); 12150e47c99dSEric W. Biederman head->nreg++; 12160e47c99dSEric W. Biederman } 12170e47c99dSEric W. Biederman return true; 12180e47c99dSEric W. Biederman } 12190e47c99dSEric W. Biederman 12200e47c99dSEric W. Biederman static int insert_links(struct ctl_table_header *head) 12210e47c99dSEric W. Biederman { 12220e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 12230e47c99dSEric W. Biederman struct ctl_dir *core_parent = NULL; 12240e47c99dSEric W. Biederman struct ctl_table_header *links; 12250e47c99dSEric W. Biederman int err; 12260e47c99dSEric W. Biederman 12270e47c99dSEric W. Biederman if (head->set == root_set) 12280e47c99dSEric W. Biederman return 0; 12290e47c99dSEric W. Biederman 12300e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, head->parent); 12310e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 12320e47c99dSEric W. Biederman return 0; 12330e47c99dSEric W. Biederman 12340e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) 12350e47c99dSEric W. Biederman return 0; 12360e47c99dSEric W. Biederman 12370e47c99dSEric W. Biederman core_parent->header.nreg++; 12380e47c99dSEric W. Biederman spin_unlock(&sysctl_lock); 12390e47c99dSEric W. Biederman 12400e47c99dSEric W. Biederman links = new_links(core_parent, head->ctl_table, head->root); 12410e47c99dSEric W. Biederman 12420e47c99dSEric W. Biederman spin_lock(&sysctl_lock); 12430e47c99dSEric W. Biederman err = -ENOMEM; 12440e47c99dSEric W. Biederman if (!links) 12450e47c99dSEric W. Biederman goto out; 12460e47c99dSEric W. Biederman 12470e47c99dSEric W. Biederman err = 0; 12480e47c99dSEric W. Biederman if (get_links(core_parent, head->ctl_table, head->root)) { 12490e47c99dSEric W. Biederman kfree(links); 12500e47c99dSEric W. Biederman goto out; 12510e47c99dSEric W. Biederman } 12520e47c99dSEric W. Biederman 12530e47c99dSEric W. Biederman err = insert_header(core_parent, links); 12540e47c99dSEric W. Biederman if (err) 12550e47c99dSEric W. Biederman kfree(links); 12560e47c99dSEric W. Biederman out: 12570e47c99dSEric W. Biederman drop_sysctl_table(&core_parent->header); 12580e47c99dSEric W. Biederman return err; 12590e47c99dSEric W. Biederman } 12600e47c99dSEric W. Biederman 12611f87f0b5SEric W. Biederman /** 1262f728019bSEric W. Biederman * __register_sysctl_table - register a leaf sysctl table 126360a47a2eSEric W. Biederman * @set: Sysctl tree to register on 12641f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 12651f87f0b5SEric W. Biederman * @table: the top-level table structure 12661f87f0b5SEric W. Biederman * 12671f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 12681f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 12691f87f0b5SEric W. Biederman * 12701f87f0b5SEric W. Biederman * The members of the &struct ctl_table structure are used as follows: 12711f87f0b5SEric W. Biederman * 12721f87f0b5SEric W. Biederman * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not 12731f87f0b5SEric W. Biederman * enter a sysctl file 12741f87f0b5SEric W. Biederman * 12751f87f0b5SEric W. Biederman * data - a pointer to data for use by proc_handler 12761f87f0b5SEric W. Biederman * 12771f87f0b5SEric W. Biederman * maxlen - the maximum size in bytes of the data 12781f87f0b5SEric W. Biederman * 1279f728019bSEric W. Biederman * mode - the file permissions for the /proc/sys file 12801f87f0b5SEric W. Biederman * 1281f728019bSEric W. Biederman * child - must be %NULL. 12821f87f0b5SEric W. Biederman * 12831f87f0b5SEric W. Biederman * proc_handler - the text handler routine (described below) 12841f87f0b5SEric W. Biederman * 12851f87f0b5SEric W. Biederman * extra1, extra2 - extra pointers usable by the proc handler routines 12861f87f0b5SEric W. Biederman * 12871f87f0b5SEric W. Biederman * Leaf nodes in the sysctl tree will be represented by a single file 12881f87f0b5SEric W. Biederman * under /proc; non-leaf nodes will be represented by directories. 12891f87f0b5SEric W. Biederman * 1290f728019bSEric W. Biederman * There must be a proc_handler routine for any terminal nodes. 1291f728019bSEric W. Biederman * Several default handlers are available to cover common cases - 12921f87f0b5SEric W. Biederman * 12931f87f0b5SEric W. Biederman * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(), 12941f87f0b5SEric W. Biederman * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 12951f87f0b5SEric W. Biederman * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax() 12961f87f0b5SEric W. Biederman * 12971f87f0b5SEric W. Biederman * It is the handler's job to read the input buffer from user memory 12981f87f0b5SEric W. Biederman * and process it. The handler should return 0 on success. 12991f87f0b5SEric W. Biederman * 13001f87f0b5SEric W. Biederman * This routine returns %NULL on a failure to register, and a pointer 13011f87f0b5SEric W. Biederman * to the table header on success. 13021f87f0b5SEric W. Biederman */ 13036e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_table( 130460a47a2eSEric W. Biederman struct ctl_table_set *set, 13056e9d5164SEric W. Biederman const char *path, struct ctl_table *table) 13061f87f0b5SEric W. Biederman { 130760a47a2eSEric W. Biederman struct ctl_table_root *root = set->dir.header.root; 13081f87f0b5SEric W. Biederman struct ctl_table_header *header; 13096e9d5164SEric W. Biederman const char *name, *nextname; 13107ec66d06SEric W. Biederman struct ctl_dir *dir; 1311ac13ac6fSEric W. Biederman struct ctl_table *entry; 1312ac13ac6fSEric W. Biederman struct ctl_node *node; 1313ac13ac6fSEric W. Biederman int nr_entries = 0; 13141f87f0b5SEric W. Biederman 1315ac13ac6fSEric W. Biederman for (entry = table; entry->procname; entry++) 1316ac13ac6fSEric W. Biederman nr_entries++; 1317ac13ac6fSEric W. Biederman 1318ac13ac6fSEric W. Biederman header = kzalloc(sizeof(struct ctl_table_header) + 1319ac13ac6fSEric W. Biederman sizeof(struct ctl_node)*nr_entries, GFP_KERNEL); 13201f87f0b5SEric W. Biederman if (!header) 13211f87f0b5SEric W. Biederman return NULL; 13221f87f0b5SEric W. Biederman 1323ac13ac6fSEric W. Biederman node = (struct ctl_node *)(header + 1); 1324ac13ac6fSEric W. Biederman init_header(header, root, set, node, table); 13257c60c48fSEric W. Biederman if (sysctl_check_table(path, table)) 13267c60c48fSEric W. Biederman goto fail; 13278d6ecfccSEric W. Biederman 13281f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 13290e47c99dSEric W. Biederman dir = &set->dir; 133060f126d9SEric W. Biederman /* Reference moved down the diretory tree get_subdir */ 13317ec66d06SEric W. Biederman dir->header.nreg++; 13327ec66d06SEric W. Biederman spin_unlock(&sysctl_lock); 13337ec66d06SEric W. Biederman 13347ec66d06SEric W. Biederman /* Find the directory for the ctl_table */ 13357ec66d06SEric W. Biederman for (name = path; name; name = nextname) { 13367ec66d06SEric W. Biederman int namelen; 13377ec66d06SEric W. Biederman nextname = strchr(name, '/'); 13387ec66d06SEric W. Biederman if (nextname) { 13397ec66d06SEric W. Biederman namelen = nextname - name; 13407ec66d06SEric W. Biederman nextname++; 13417ec66d06SEric W. Biederman } else { 13427ec66d06SEric W. Biederman namelen = strlen(name); 13437ec66d06SEric W. Biederman } 13447ec66d06SEric W. Biederman if (namelen == 0) 13451f87f0b5SEric W. Biederman continue; 13467ec66d06SEric W. Biederman 13470e47c99dSEric W. Biederman dir = get_subdir(dir, name, namelen); 13487ec66d06SEric W. Biederman if (IS_ERR(dir)) 13497ec66d06SEric W. Biederman goto fail; 13501f87f0b5SEric W. Biederman } 13510e47c99dSEric W. Biederman 13527ec66d06SEric W. Biederman spin_lock(&sysctl_lock); 13530e47c99dSEric W. Biederman if (insert_header(dir, header)) 13540e47c99dSEric W. Biederman goto fail_put_dir_locked; 13550e47c99dSEric W. Biederman 13567ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13571f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 13581f87f0b5SEric W. Biederman 13591f87f0b5SEric W. Biederman return header; 13600e47c99dSEric W. Biederman 13617ec66d06SEric W. Biederman fail_put_dir_locked: 13627ec66d06SEric W. Biederman drop_sysctl_table(&dir->header); 13637c60c48fSEric W. Biederman spin_unlock(&sysctl_lock); 13647c60c48fSEric W. Biederman fail: 13657c60c48fSEric W. Biederman kfree(header); 13667c60c48fSEric W. Biederman dump_stack(); 13677c60c48fSEric W. Biederman return NULL; 13681f87f0b5SEric W. Biederman } 13691f87f0b5SEric W. Biederman 1370fea478d4SEric W. Biederman /** 1371fea478d4SEric W. Biederman * register_sysctl - register a sysctl table 1372fea478d4SEric W. Biederman * @path: The path to the directory the sysctl table is in. 1373fea478d4SEric W. Biederman * @table: the table structure 1374fea478d4SEric W. Biederman * 1375fea478d4SEric W. Biederman * Register a sysctl table. @table should be a filled in ctl_table 1376fea478d4SEric W. Biederman * array. A completely 0 filled entry terminates the table. 1377fea478d4SEric W. Biederman * 1378fea478d4SEric W. Biederman * See __register_sysctl_table for more details. 1379fea478d4SEric W. Biederman */ 1380fea478d4SEric W. Biederman struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) 1381fea478d4SEric W. Biederman { 1382fea478d4SEric W. Biederman return __register_sysctl_table(&sysctl_table_root.default_set, 1383fea478d4SEric W. Biederman path, table); 1384fea478d4SEric W. Biederman } 1385fea478d4SEric W. Biederman EXPORT_SYMBOL(register_sysctl); 1386fea478d4SEric W. Biederman 1387*3ddd9a80SXiaoming Ni /** 1388*3ddd9a80SXiaoming Ni * __register_sysctl_init() - register sysctl table to path 1389*3ddd9a80SXiaoming Ni * @path: path name for sysctl base 1390*3ddd9a80SXiaoming Ni * @table: This is the sysctl table that needs to be registered to the path 1391*3ddd9a80SXiaoming Ni * @table_name: The name of sysctl table, only used for log printing when 1392*3ddd9a80SXiaoming Ni * registration fails 1393*3ddd9a80SXiaoming Ni * 1394*3ddd9a80SXiaoming Ni * The sysctl interface is used by userspace to query or modify at runtime 1395*3ddd9a80SXiaoming Ni * a predefined value set on a variable. These variables however have default 1396*3ddd9a80SXiaoming Ni * values pre-set. Code which depends on these variables will always work even 1397*3ddd9a80SXiaoming Ni * if register_sysctl() fails. If register_sysctl() fails you'd just loose the 1398*3ddd9a80SXiaoming Ni * ability to query or modify the sysctls dynamically at run time. Chances of 1399*3ddd9a80SXiaoming Ni * register_sysctl() failing on init are extremely low, and so for both reasons 1400*3ddd9a80SXiaoming Ni * this function does not return any error as it is used by initialization code. 1401*3ddd9a80SXiaoming Ni * 1402*3ddd9a80SXiaoming Ni * Context: Can only be called after your respective sysctl base path has been 1403*3ddd9a80SXiaoming Ni * registered. So for instance, most base directories are registered early on 1404*3ddd9a80SXiaoming Ni * init before init levels are processed through proc_sys_init() and 1405*3ddd9a80SXiaoming Ni * sysctl_init(). 1406*3ddd9a80SXiaoming Ni */ 1407*3ddd9a80SXiaoming Ni void __init __register_sysctl_init(const char *path, struct ctl_table *table, 1408*3ddd9a80SXiaoming Ni const char *table_name) 1409*3ddd9a80SXiaoming Ni { 1410*3ddd9a80SXiaoming Ni struct ctl_table_header *hdr = register_sysctl(path, table); 1411*3ddd9a80SXiaoming Ni 1412*3ddd9a80SXiaoming Ni if (unlikely(!hdr)) { 1413*3ddd9a80SXiaoming Ni pr_err("failed when register_sysctl %s to %s\n", table_name, path); 1414*3ddd9a80SXiaoming Ni return; 1415*3ddd9a80SXiaoming Ni } 1416*3ddd9a80SXiaoming Ni kmemleak_not_leak(hdr); 1417*3ddd9a80SXiaoming Ni } 1418*3ddd9a80SXiaoming Ni 14196e9d5164SEric W. Biederman static char *append_path(const char *path, char *pos, const char *name) 14206e9d5164SEric W. Biederman { 14216e9d5164SEric W. Biederman int namelen; 14226e9d5164SEric W. Biederman namelen = strlen(name); 14236e9d5164SEric W. Biederman if (((pos - path) + namelen + 2) >= PATH_MAX) 14246e9d5164SEric W. Biederman return NULL; 14256e9d5164SEric W. Biederman memcpy(pos, name, namelen); 14266e9d5164SEric W. Biederman pos[namelen] = '/'; 14276e9d5164SEric W. Biederman pos[namelen + 1] = '\0'; 14286e9d5164SEric W. Biederman pos += namelen + 1; 14296e9d5164SEric W. Biederman return pos; 14306e9d5164SEric W. Biederman } 14316e9d5164SEric W. Biederman 1432f728019bSEric W. Biederman static int count_subheaders(struct ctl_table *table) 1433f728019bSEric W. Biederman { 1434f728019bSEric W. Biederman int has_files = 0; 1435f728019bSEric W. Biederman int nr_subheaders = 0; 1436f728019bSEric W. Biederman struct ctl_table *entry; 1437f728019bSEric W. Biederman 1438f728019bSEric W. Biederman /* special case: no directory and empty directory */ 1439f728019bSEric W. Biederman if (!table || !table->procname) 1440f728019bSEric W. Biederman return 1; 1441f728019bSEric W. Biederman 1442f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1443f728019bSEric W. Biederman if (entry->child) 1444f728019bSEric W. Biederman nr_subheaders += count_subheaders(entry->child); 1445f728019bSEric W. Biederman else 1446f728019bSEric W. Biederman has_files = 1; 1447f728019bSEric W. Biederman } 1448f728019bSEric W. Biederman return nr_subheaders + has_files; 1449f728019bSEric W. Biederman } 1450f728019bSEric W. Biederman 1451f728019bSEric W. Biederman static int register_leaf_sysctl_tables(const char *path, char *pos, 145260a47a2eSEric W. Biederman struct ctl_table_header ***subheader, struct ctl_table_set *set, 1453f728019bSEric W. Biederman struct ctl_table *table) 1454f728019bSEric W. Biederman { 1455f728019bSEric W. Biederman struct ctl_table *ctl_table_arg = NULL; 1456f728019bSEric W. Biederman struct ctl_table *entry, *files; 1457f728019bSEric W. Biederman int nr_files = 0; 1458f728019bSEric W. Biederman int nr_dirs = 0; 1459f728019bSEric W. Biederman int err = -ENOMEM; 1460f728019bSEric W. Biederman 1461f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1462f728019bSEric W. Biederman if (entry->child) 1463f728019bSEric W. Biederman nr_dirs++; 1464f728019bSEric W. Biederman else 1465f728019bSEric W. Biederman nr_files++; 1466f728019bSEric W. Biederman } 1467f728019bSEric W. Biederman 1468f728019bSEric W. Biederman files = table; 1469f728019bSEric W. Biederman /* If there are mixed files and directories we need a new table */ 1470f728019bSEric W. Biederman if (nr_dirs && nr_files) { 1471f728019bSEric W. Biederman struct ctl_table *new; 14726396bb22SKees Cook files = kcalloc(nr_files + 1, sizeof(struct ctl_table), 1473f728019bSEric W. Biederman GFP_KERNEL); 1474f728019bSEric W. Biederman if (!files) 1475f728019bSEric W. Biederman goto out; 1476f728019bSEric W. Biederman 1477f728019bSEric W. Biederman ctl_table_arg = files; 1478f728019bSEric W. Biederman for (new = files, entry = table; entry->procname; entry++) { 1479f728019bSEric W. Biederman if (entry->child) 1480f728019bSEric W. Biederman continue; 1481f728019bSEric W. Biederman *new = *entry; 1482f728019bSEric W. Biederman new++; 1483f728019bSEric W. Biederman } 1484f728019bSEric W. Biederman } 1485f728019bSEric W. Biederman 1486f728019bSEric W. Biederman /* Register everything except a directory full of subdirectories */ 1487f728019bSEric W. Biederman if (nr_files || !nr_dirs) { 1488f728019bSEric W. Biederman struct ctl_table_header *header; 148960a47a2eSEric W. Biederman header = __register_sysctl_table(set, path, files); 1490f728019bSEric W. Biederman if (!header) { 1491f728019bSEric W. Biederman kfree(ctl_table_arg); 1492f728019bSEric W. Biederman goto out; 1493f728019bSEric W. Biederman } 1494f728019bSEric W. Biederman 1495f728019bSEric W. Biederman /* Remember if we need to free the file table */ 1496f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1497f728019bSEric W. Biederman **subheader = header; 1498f728019bSEric W. Biederman (*subheader)++; 1499f728019bSEric W. Biederman } 1500f728019bSEric W. Biederman 1501f728019bSEric W. Biederman /* Recurse into the subdirectories. */ 1502f728019bSEric W. Biederman for (entry = table; entry->procname; entry++) { 1503f728019bSEric W. Biederman char *child_pos; 1504f728019bSEric W. Biederman 1505f728019bSEric W. Biederman if (!entry->child) 1506f728019bSEric W. Biederman continue; 1507f728019bSEric W. Biederman 1508f728019bSEric W. Biederman err = -ENAMETOOLONG; 1509f728019bSEric W. Biederman child_pos = append_path(path, pos, entry->procname); 1510f728019bSEric W. Biederman if (!child_pos) 1511f728019bSEric W. Biederman goto out; 1512f728019bSEric W. Biederman 1513f728019bSEric W. Biederman err = register_leaf_sysctl_tables(path, child_pos, subheader, 151460a47a2eSEric W. Biederman set, entry->child); 1515f728019bSEric W. Biederman pos[0] = '\0'; 1516f728019bSEric W. Biederman if (err) 1517f728019bSEric W. Biederman goto out; 1518f728019bSEric W. Biederman } 1519f728019bSEric W. Biederman err = 0; 1520f728019bSEric W. Biederman out: 1521f728019bSEric W. Biederman /* On failure our caller will unregister all registered subheaders */ 1522f728019bSEric W. Biederman return err; 1523f728019bSEric W. Biederman } 1524f728019bSEric W. Biederman 15256e9d5164SEric W. Biederman /** 15266e9d5164SEric W. Biederman * __register_sysctl_paths - register a sysctl table hierarchy 152760a47a2eSEric W. Biederman * @set: Sysctl tree to register on 15286e9d5164SEric W. Biederman * @path: The path to the directory the sysctl table is in. 15296e9d5164SEric W. Biederman * @table: the top-level table structure 15306e9d5164SEric W. Biederman * 15316e9d5164SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 15326e9d5164SEric W. Biederman * array. A completely 0 filled entry terminates the table. 15336e9d5164SEric W. Biederman * 15346e9d5164SEric W. Biederman * See __register_sysctl_table for more details. 15356e9d5164SEric W. Biederman */ 15366e9d5164SEric W. Biederman struct ctl_table_header *__register_sysctl_paths( 153760a47a2eSEric W. Biederman struct ctl_table_set *set, 15386e9d5164SEric W. Biederman const struct ctl_path *path, struct ctl_table *table) 15396e9d5164SEric W. Biederman { 1540ec6a5266SEric W. Biederman struct ctl_table *ctl_table_arg = table; 1541f728019bSEric W. Biederman int nr_subheaders = count_subheaders(table); 1542f728019bSEric W. Biederman struct ctl_table_header *header = NULL, **subheaders, **subheader; 15436e9d5164SEric W. Biederman const struct ctl_path *component; 15446e9d5164SEric W. Biederman char *new_path, *pos; 15456e9d5164SEric W. Biederman 15466e9d5164SEric W. Biederman pos = new_path = kmalloc(PATH_MAX, GFP_KERNEL); 15476e9d5164SEric W. Biederman if (!new_path) 15486e9d5164SEric W. Biederman return NULL; 15496e9d5164SEric W. Biederman 15506e9d5164SEric W. Biederman pos[0] = '\0'; 15516e9d5164SEric W. Biederman for (component = path; component->procname; component++) { 15526e9d5164SEric W. Biederman pos = append_path(new_path, pos, component->procname); 15536e9d5164SEric W. Biederman if (!pos) 15546e9d5164SEric W. Biederman goto out; 15556e9d5164SEric W. Biederman } 1556ec6a5266SEric W. Biederman while (table->procname && table->child && !table[1].procname) { 1557ec6a5266SEric W. Biederman pos = append_path(new_path, pos, table->procname); 1558ec6a5266SEric W. Biederman if (!pos) 1559ec6a5266SEric W. Biederman goto out; 1560ec6a5266SEric W. Biederman table = table->child; 1561ec6a5266SEric W. Biederman } 1562f728019bSEric W. Biederman if (nr_subheaders == 1) { 156360a47a2eSEric W. Biederman header = __register_sysctl_table(set, new_path, table); 1564ec6a5266SEric W. Biederman if (header) 1565ec6a5266SEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1566f728019bSEric W. Biederman } else { 1567f728019bSEric W. Biederman header = kzalloc(sizeof(*header) + 1568f728019bSEric W. Biederman sizeof(*subheaders)*nr_subheaders, GFP_KERNEL); 1569f728019bSEric W. Biederman if (!header) 1570f728019bSEric W. Biederman goto out; 1571f728019bSEric W. Biederman 1572f728019bSEric W. Biederman subheaders = (struct ctl_table_header **) (header + 1); 1573f728019bSEric W. Biederman subheader = subheaders; 1574f728019bSEric W. Biederman header->ctl_table_arg = ctl_table_arg; 1575f728019bSEric W. Biederman 1576f728019bSEric W. Biederman if (register_leaf_sysctl_tables(new_path, pos, &subheader, 157760a47a2eSEric W. Biederman set, table)) 1578f728019bSEric W. Biederman goto err_register_leaves; 1579f728019bSEric W. Biederman } 1580f728019bSEric W. Biederman 15816e9d5164SEric W. Biederman out: 15826e9d5164SEric W. Biederman kfree(new_path); 15836e9d5164SEric W. Biederman return header; 1584f728019bSEric W. Biederman 1585f728019bSEric W. Biederman err_register_leaves: 1586f728019bSEric W. Biederman while (subheader > subheaders) { 1587f728019bSEric W. Biederman struct ctl_table_header *subh = *(--subheader); 1588f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1589f728019bSEric W. Biederman unregister_sysctl_table(subh); 1590f728019bSEric W. Biederman kfree(table); 1591f728019bSEric W. Biederman } 1592f728019bSEric W. Biederman kfree(header); 1593f728019bSEric W. Biederman header = NULL; 1594f728019bSEric W. Biederman goto out; 15956e9d5164SEric W. Biederman } 15966e9d5164SEric W. Biederman 15971f87f0b5SEric W. Biederman /** 15985b31a7dfSzhouchuangao * register_sysctl_paths - register a sysctl table hierarchy 15991f87f0b5SEric W. Biederman * @path: The path to the directory the sysctl table is in. 16001f87f0b5SEric W. Biederman * @table: the top-level table structure 16011f87f0b5SEric W. Biederman * 16021f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16031f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16041f87f0b5SEric W. Biederman * 16051f87f0b5SEric W. Biederman * See __register_sysctl_paths for more details. 16061f87f0b5SEric W. Biederman */ 16071f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path, 16081f87f0b5SEric W. Biederman struct ctl_table *table) 16091f87f0b5SEric W. Biederman { 161060a47a2eSEric W. Biederman return __register_sysctl_paths(&sysctl_table_root.default_set, 16111f87f0b5SEric W. Biederman path, table); 16121f87f0b5SEric W. Biederman } 16131f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_paths); 16141f87f0b5SEric W. Biederman 16151f87f0b5SEric W. Biederman /** 16161f87f0b5SEric W. Biederman * register_sysctl_table - register a sysctl table hierarchy 16171f87f0b5SEric W. Biederman * @table: the top-level table structure 16181f87f0b5SEric W. Biederman * 16191f87f0b5SEric W. Biederman * Register a sysctl table hierarchy. @table should be a filled in ctl_table 16201f87f0b5SEric W. Biederman * array. A completely 0 filled entry terminates the table. 16211f87f0b5SEric W. Biederman * 16221f87f0b5SEric W. Biederman * See register_sysctl_paths for more details. 16231f87f0b5SEric W. Biederman */ 16241f87f0b5SEric W. Biederman struct ctl_table_header *register_sysctl_table(struct ctl_table *table) 16251f87f0b5SEric W. Biederman { 16261f87f0b5SEric W. Biederman static const struct ctl_path null_path[] = { {} }; 16271f87f0b5SEric W. Biederman 16281f87f0b5SEric W. Biederman return register_sysctl_paths(null_path, table); 16291f87f0b5SEric W. Biederman } 16301f87f0b5SEric W. Biederman EXPORT_SYMBOL(register_sysctl_table); 16311f87f0b5SEric W. Biederman 16320e47c99dSEric W. Biederman static void put_links(struct ctl_table_header *header) 16330e47c99dSEric W. Biederman { 16340e47c99dSEric W. Biederman struct ctl_table_set *root_set = &sysctl_table_root.default_set; 16350e47c99dSEric W. Biederman struct ctl_table_root *root = header->root; 16360e47c99dSEric W. Biederman struct ctl_dir *parent = header->parent; 16370e47c99dSEric W. Biederman struct ctl_dir *core_parent; 16380e47c99dSEric W. Biederman struct ctl_table *entry; 16390e47c99dSEric W. Biederman 16400e47c99dSEric W. Biederman if (header->set == root_set) 16410e47c99dSEric W. Biederman return; 16420e47c99dSEric W. Biederman 16430e47c99dSEric W. Biederman core_parent = xlate_dir(root_set, parent); 16440e47c99dSEric W. Biederman if (IS_ERR(core_parent)) 16450e47c99dSEric W. Biederman return; 16460e47c99dSEric W. Biederman 16470e47c99dSEric W. Biederman for (entry = header->ctl_table; entry->procname; entry++) { 16480e47c99dSEric W. Biederman struct ctl_table_header *link_head; 16490e47c99dSEric W. Biederman struct ctl_table *link; 16500e47c99dSEric W. Biederman const char *name = entry->procname; 16510e47c99dSEric W. Biederman 16520e47c99dSEric W. Biederman link = find_entry(&link_head, core_parent, name, strlen(name)); 16530e47c99dSEric W. Biederman if (link && 16540e47c99dSEric W. Biederman ((S_ISDIR(link->mode) && S_ISDIR(entry->mode)) || 16550e47c99dSEric W. Biederman (S_ISLNK(link->mode) && (link->data == root)))) { 16560e47c99dSEric W. Biederman drop_sysctl_table(link_head); 16570e47c99dSEric W. Biederman } 16580e47c99dSEric W. Biederman else { 165987ebdc00SAndrew Morton pr_err("sysctl link missing during unregister: "); 16600e47c99dSEric W. Biederman sysctl_print_dir(parent); 1661153ee1c4SGeert Uytterhoeven pr_cont("%s\n", name); 16620e47c99dSEric W. Biederman } 16630e47c99dSEric W. Biederman } 16640e47c99dSEric W. Biederman } 16650e47c99dSEric W. Biederman 1666938aaa4fSEric W. Biederman static void drop_sysctl_table(struct ctl_table_header *header) 1667938aaa4fSEric W. Biederman { 16687ec66d06SEric W. Biederman struct ctl_dir *parent = header->parent; 16697ec66d06SEric W. Biederman 1670938aaa4fSEric W. Biederman if (--header->nreg) 1671938aaa4fSEric W. Biederman return; 1672938aaa4fSEric W. Biederman 167389189557SYueHaibing if (parent) { 16740e47c99dSEric W. Biederman put_links(header); 1675938aaa4fSEric W. Biederman start_unregistering(header); 167689189557SYueHaibing } 167789189557SYueHaibing 1678938aaa4fSEric W. Biederman if (!--header->count) 1679938aaa4fSEric W. Biederman kfree_rcu(header, rcu); 16807ec66d06SEric W. Biederman 16817ec66d06SEric W. Biederman if (parent) 16827ec66d06SEric W. Biederman drop_sysctl_table(&parent->header); 1683938aaa4fSEric W. Biederman } 1684938aaa4fSEric W. Biederman 16851f87f0b5SEric W. Biederman /** 16861f87f0b5SEric W. Biederman * unregister_sysctl_table - unregister a sysctl table hierarchy 16871f87f0b5SEric W. Biederman * @header: the header returned from register_sysctl_table 16881f87f0b5SEric W. Biederman * 16891f87f0b5SEric W. Biederman * Unregisters the sysctl table and all children. proc entries may not 16901f87f0b5SEric W. Biederman * actually be removed until they are no longer used by anyone. 16911f87f0b5SEric W. Biederman */ 16921f87f0b5SEric W. Biederman void unregister_sysctl_table(struct ctl_table_header * header) 16931f87f0b5SEric W. Biederman { 1694f728019bSEric W. Biederman int nr_subheaders; 16951f87f0b5SEric W. Biederman might_sleep(); 16961f87f0b5SEric W. Biederman 16971f87f0b5SEric W. Biederman if (header == NULL) 16981f87f0b5SEric W. Biederman return; 16991f87f0b5SEric W. Biederman 1700f728019bSEric W. Biederman nr_subheaders = count_subheaders(header->ctl_table_arg); 1701f728019bSEric W. Biederman if (unlikely(nr_subheaders > 1)) { 1702f728019bSEric W. Biederman struct ctl_table_header **subheaders; 1703f728019bSEric W. Biederman int i; 1704f728019bSEric W. Biederman 1705f728019bSEric W. Biederman subheaders = (struct ctl_table_header **)(header + 1); 1706f728019bSEric W. Biederman for (i = nr_subheaders -1; i >= 0; i--) { 1707f728019bSEric W. Biederman struct ctl_table_header *subh = subheaders[i]; 1708f728019bSEric W. Biederman struct ctl_table *table = subh->ctl_table_arg; 1709f728019bSEric W. Biederman unregister_sysctl_table(subh); 1710f728019bSEric W. Biederman kfree(table); 1711f728019bSEric W. Biederman } 1712f728019bSEric W. Biederman kfree(header); 1713f728019bSEric W. Biederman return; 1714f728019bSEric W. Biederman } 1715f728019bSEric W. Biederman 17161f87f0b5SEric W. Biederman spin_lock(&sysctl_lock); 1717938aaa4fSEric W. Biederman drop_sysctl_table(header); 17181f87f0b5SEric W. Biederman spin_unlock(&sysctl_lock); 17191f87f0b5SEric W. Biederman } 17201f87f0b5SEric W. Biederman EXPORT_SYMBOL(unregister_sysctl_table); 17211f87f0b5SEric W. Biederman 17220e47c99dSEric W. Biederman void setup_sysctl_set(struct ctl_table_set *set, 17239eb47c26SEric W. Biederman struct ctl_table_root *root, 17241f87f0b5SEric W. Biederman int (*is_seen)(struct ctl_table_set *)) 17251f87f0b5SEric W. Biederman { 17261347440dSDan Carpenter memset(set, 0, sizeof(*set)); 17270e47c99dSEric W. Biederman set->is_seen = is_seen; 1728ac13ac6fSEric W. Biederman init_header(&set->dir.header, root, set, NULL, root_table); 17291f87f0b5SEric W. Biederman } 17301f87f0b5SEric W. Biederman 173197324cd8SEric W. Biederman void retire_sysctl_set(struct ctl_table_set *set) 173297324cd8SEric W. Biederman { 1733ac13ac6fSEric W. Biederman WARN_ON(!RB_EMPTY_ROOT(&set->dir.root)); 173497324cd8SEric W. Biederman } 17351f87f0b5SEric W. Biederman 17361e0edd3fSAlexey Dobriyan int __init proc_sys_init(void) 173777b14db5SEric W. Biederman { 1738e1675231SAlexey Dobriyan struct proc_dir_entry *proc_sys_root; 1739e1675231SAlexey Dobriyan 174077b14db5SEric W. Biederman proc_sys_root = proc_mkdir("sys", NULL); 17419043476fSAl Viro proc_sys_root->proc_iops = &proc_sys_dir_operations; 1742d56c0d45SAlexey Dobriyan proc_sys_root->proc_dir_ops = &proc_sys_dir_file_operations; 174377b14db5SEric W. Biederman proc_sys_root->nlink = 0; 1744de4e83bdSEric W. Biederman 1745de4e83bdSEric W. Biederman return sysctl_init(); 174677b14db5SEric W. Biederman } 17473db978d4SVlastimil Babka 17480a477e1aSVlastimil Babka struct sysctl_alias { 17490a477e1aSVlastimil Babka const char *kernel_param; 17500a477e1aSVlastimil Babka const char *sysctl_param; 17510a477e1aSVlastimil Babka }; 17520a477e1aSVlastimil Babka 17530a477e1aSVlastimil Babka /* 17540a477e1aSVlastimil Babka * Historically some settings had both sysctl and a command line parameter. 17550a477e1aSVlastimil Babka * With the generic sysctl. parameter support, we can handle them at a single 17560a477e1aSVlastimil Babka * place and only keep the historical name for compatibility. This is not meant 17570a477e1aSVlastimil Babka * to add brand new aliases. When adding existing aliases, consider whether 17580a477e1aSVlastimil Babka * the possibly different moment of changing the value (e.g. from early_param 17590a477e1aSVlastimil Babka * to the moment do_sysctl_args() is called) is an issue for the specific 17600a477e1aSVlastimil Babka * parameter. 17610a477e1aSVlastimil Babka */ 17620a477e1aSVlastimil Babka static const struct sysctl_alias sysctl_aliases[] = { 1763f117955aSGuilherme G. Piccoli {"hardlockup_all_cpu_backtrace", "kernel.hardlockup_all_cpu_backtrace" }, 1764b467f3efSVlastimil Babka {"hung_task_panic", "kernel.hung_task_panic" }, 1765f117955aSGuilherme G. Piccoli {"numa_zonelist_order", "vm.numa_zonelist_order" }, 1766f117955aSGuilherme G. Piccoli {"softlockup_all_cpu_backtrace", "kernel.softlockup_all_cpu_backtrace" }, 1767f117955aSGuilherme G. Piccoli {"softlockup_panic", "kernel.softlockup_panic" }, 17680a477e1aSVlastimil Babka { } 17690a477e1aSVlastimil Babka }; 17700a477e1aSVlastimil Babka 17710a477e1aSVlastimil Babka static const char *sysctl_find_alias(char *param) 17720a477e1aSVlastimil Babka { 17730a477e1aSVlastimil Babka const struct sysctl_alias *alias; 17740a477e1aSVlastimil Babka 17750a477e1aSVlastimil Babka for (alias = &sysctl_aliases[0]; alias->kernel_param != NULL; alias++) { 17760a477e1aSVlastimil Babka if (strcmp(alias->kernel_param, param) == 0) 17770a477e1aSVlastimil Babka return alias->sysctl_param; 17780a477e1aSVlastimil Babka } 17790a477e1aSVlastimil Babka 17800a477e1aSVlastimil Babka return NULL; 17810a477e1aSVlastimil Babka } 17820a477e1aSVlastimil Babka 17833db978d4SVlastimil Babka /* Set sysctl value passed on kernel command line. */ 17843db978d4SVlastimil Babka static int process_sysctl_arg(char *param, char *val, 17853db978d4SVlastimil Babka const char *unused, void *arg) 17863db978d4SVlastimil Babka { 17873db978d4SVlastimil Babka char *path; 17883db978d4SVlastimil Babka struct vfsmount **proc_mnt = arg; 17893db978d4SVlastimil Babka struct file_system_type *proc_fs_type; 17903db978d4SVlastimil Babka struct file *file; 17913db978d4SVlastimil Babka int len; 17923db978d4SVlastimil Babka int err; 17933db978d4SVlastimil Babka loff_t pos = 0; 17943db978d4SVlastimil Babka ssize_t wret; 17953db978d4SVlastimil Babka 17960a477e1aSVlastimil Babka if (strncmp(param, "sysctl", sizeof("sysctl") - 1) == 0) { 17973db978d4SVlastimil Babka param += sizeof("sysctl") - 1; 17983db978d4SVlastimil Babka 17993db978d4SVlastimil Babka if (param[0] != '/' && param[0] != '.') 18003db978d4SVlastimil Babka return 0; 18013db978d4SVlastimil Babka 18023db978d4SVlastimil Babka param++; 18030a477e1aSVlastimil Babka } else { 18040a477e1aSVlastimil Babka param = (char *) sysctl_find_alias(param); 18050a477e1aSVlastimil Babka if (!param) 18060a477e1aSVlastimil Babka return 0; 18070a477e1aSVlastimil Babka } 18083db978d4SVlastimil Babka 1809697edcb0SXiaoming Ni if (!val) 1810697edcb0SXiaoming Ni return -EINVAL; 1811697edcb0SXiaoming Ni len = strlen(val); 1812697edcb0SXiaoming Ni if (len == 0) 1813697edcb0SXiaoming Ni return -EINVAL; 1814697edcb0SXiaoming Ni 18153db978d4SVlastimil Babka /* 18163db978d4SVlastimil Babka * To set sysctl options, we use a temporary mount of proc, look up the 18173db978d4SVlastimil Babka * respective sys/ file and write to it. To avoid mounting it when no 18183db978d4SVlastimil Babka * options were given, we mount it only when the first sysctl option is 18193db978d4SVlastimil Babka * found. Why not a persistent mount? There are problems with a 18203db978d4SVlastimil Babka * persistent mount of proc in that it forces userspace not to use any 18213db978d4SVlastimil Babka * proc mount options. 18223db978d4SVlastimil Babka */ 18233db978d4SVlastimil Babka if (!*proc_mnt) { 18243db978d4SVlastimil Babka proc_fs_type = get_fs_type("proc"); 18253db978d4SVlastimil Babka if (!proc_fs_type) { 18263db978d4SVlastimil Babka pr_err("Failed to find procfs to set sysctl from command line\n"); 18273db978d4SVlastimil Babka return 0; 18283db978d4SVlastimil Babka } 18293db978d4SVlastimil Babka *proc_mnt = kern_mount(proc_fs_type); 18303db978d4SVlastimil Babka put_filesystem(proc_fs_type); 18313db978d4SVlastimil Babka if (IS_ERR(*proc_mnt)) { 18323db978d4SVlastimil Babka pr_err("Failed to mount procfs to set sysctl from command line\n"); 18333db978d4SVlastimil Babka return 0; 18343db978d4SVlastimil Babka } 18353db978d4SVlastimil Babka } 18363db978d4SVlastimil Babka 18373db978d4SVlastimil Babka path = kasprintf(GFP_KERNEL, "sys/%s", param); 18383db978d4SVlastimil Babka if (!path) 18393db978d4SVlastimil Babka panic("%s: Failed to allocate path for %s\n", __func__, param); 18403db978d4SVlastimil Babka strreplace(path, '.', '/'); 18413db978d4SVlastimil Babka 1842ffb37ca3SAl Viro file = file_open_root_mnt(*proc_mnt, path, O_WRONLY, 0); 18433db978d4SVlastimil Babka if (IS_ERR(file)) { 18443db978d4SVlastimil Babka err = PTR_ERR(file); 18453db978d4SVlastimil Babka if (err == -ENOENT) 18463db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': parameter not found\n", 18473db978d4SVlastimil Babka param, val); 18483db978d4SVlastimil Babka else if (err == -EACCES) 18493db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': permission denied (read-only?)\n", 18503db978d4SVlastimil Babka param, val); 18513db978d4SVlastimil Babka else 18523db978d4SVlastimil Babka pr_err("Error %pe opening proc file to set sysctl parameter '%s=%s'\n", 18533db978d4SVlastimil Babka file, param, val); 18543db978d4SVlastimil Babka goto out; 18553db978d4SVlastimil Babka } 18563db978d4SVlastimil Babka wret = kernel_write(file, val, len, &pos); 18573db978d4SVlastimil Babka if (wret < 0) { 18583db978d4SVlastimil Babka err = wret; 18593db978d4SVlastimil Babka if (err == -EINVAL) 18603db978d4SVlastimil Babka pr_err("Failed to set sysctl parameter '%s=%s': invalid value\n", 18613db978d4SVlastimil Babka param, val); 18623db978d4SVlastimil Babka else 18633db978d4SVlastimil Babka pr_err("Error %pe writing to proc file to set sysctl parameter '%s=%s'\n", 18643db978d4SVlastimil Babka ERR_PTR(err), param, val); 18653db978d4SVlastimil Babka } else if (wret != len) { 18663db978d4SVlastimil Babka pr_err("Wrote only %zd bytes of %d writing to proc file %s to set sysctl parameter '%s=%s\n", 18673db978d4SVlastimil Babka wret, len, path, param, val); 18683db978d4SVlastimil Babka } 18693db978d4SVlastimil Babka 18703db978d4SVlastimil Babka err = filp_close(file, NULL); 18713db978d4SVlastimil Babka if (err) 18723db978d4SVlastimil Babka pr_err("Error %pe closing proc file to set sysctl parameter '%s=%s\n", 18733db978d4SVlastimil Babka ERR_PTR(err), param, val); 18743db978d4SVlastimil Babka out: 18753db978d4SVlastimil Babka kfree(path); 18763db978d4SVlastimil Babka return 0; 18773db978d4SVlastimil Babka } 18783db978d4SVlastimil Babka 18793db978d4SVlastimil Babka void do_sysctl_args(void) 18803db978d4SVlastimil Babka { 18813db978d4SVlastimil Babka char *command_line; 18823db978d4SVlastimil Babka struct vfsmount *proc_mnt = NULL; 18833db978d4SVlastimil Babka 18843db978d4SVlastimil Babka command_line = kstrdup(saved_command_line, GFP_KERNEL); 18853db978d4SVlastimil Babka if (!command_line) 18863db978d4SVlastimil Babka panic("%s: Failed to allocate copy of command line\n", __func__); 18873db978d4SVlastimil Babka 18883db978d4SVlastimil Babka parse_args("Setting sysctl args", command_line, 18893db978d4SVlastimil Babka NULL, 0, -1, -1, &proc_mnt, process_sysctl_arg); 18903db978d4SVlastimil Babka 18913db978d4SVlastimil Babka if (proc_mnt) 18923db978d4SVlastimil Babka kern_unmount(proc_mnt); 18933db978d4SVlastimil Babka 18943db978d4SVlastimil Babka kfree(command_line); 18953db978d4SVlastimil Babka } 1896