1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* audit_fsnotify.c -- tracking inodes 3 * 4 * Copyright 2003-2009,2014-2015 Red Hat, Inc. 5 * Copyright 2005 Hewlett-Packard Development Company, L.P. 6 * Copyright 2005 IBM Corporation 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/audit.h> 11 #include <linux/kthread.h> 12 #include <linux/mutex.h> 13 #include <linux/fs.h> 14 #include <linux/fsnotify_backend.h> 15 #include <linux/namei.h> 16 #include <linux/netlink.h> 17 #include <linux/sched.h> 18 #include <linux/slab.h> 19 #include <linux/security.h> 20 #include "audit.h" 21 22 /* 23 * this mark lives on the parent directory of the inode in question. 24 * but dev, ino, and path are about the child 25 */ 26 struct audit_fsnotify_mark { 27 dev_t dev; /* associated superblock device */ 28 unsigned long ino; /* associated inode number */ 29 char *path; /* insertion path */ 30 struct fsnotify_mark mark; /* fsnotify mark on the inode */ 31 struct audit_krule *rule; 32 }; 33 34 /* fsnotify handle. */ 35 static struct fsnotify_group *audit_fsnotify_group; 36 37 /* fsnotify events we care about. */ 38 #define AUDIT_FS_EVENTS (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\ 39 FS_MOVE_SELF) 40 41 static void audit_fsnotify_mark_free(struct audit_fsnotify_mark *audit_mark) 42 { 43 kfree(audit_mark->path); 44 kfree(audit_mark); 45 } 46 47 static void audit_fsnotify_free_mark(struct fsnotify_mark *mark) 48 { 49 struct audit_fsnotify_mark *audit_mark; 50 51 audit_mark = container_of(mark, struct audit_fsnotify_mark, mark); 52 audit_fsnotify_mark_free(audit_mark); 53 } 54 55 char *audit_mark_path(struct audit_fsnotify_mark *mark) 56 { 57 return mark->path; 58 } 59 60 int audit_mark_compare(struct audit_fsnotify_mark *mark, unsigned long ino, dev_t dev) 61 { 62 if (mark->ino == AUDIT_INO_UNSET) 63 return 0; 64 return (mark->ino == ino) && (mark->dev == dev); 65 } 66 67 static void audit_update_mark(struct audit_fsnotify_mark *audit_mark, 68 const struct inode *inode) 69 { 70 audit_mark->dev = inode ? inode->i_sb->s_dev : AUDIT_DEV_UNSET; 71 audit_mark->ino = inode ? inode->i_ino : AUDIT_INO_UNSET; 72 } 73 74 struct audit_fsnotify_mark *audit_alloc_mark(struct audit_krule *krule, char *pathname, int len) 75 { 76 struct audit_fsnotify_mark *audit_mark; 77 struct path path; 78 struct dentry *dentry; 79 struct inode *inode; 80 int ret; 81 82 if (pathname[0] != '/' || pathname[len-1] == '/') 83 return ERR_PTR(-EINVAL); 84 85 dentry = kern_path_locked(pathname, &path); 86 if (IS_ERR(dentry)) 87 return (void *)dentry; /* returning an error */ 88 inode = path.dentry->d_inode; 89 inode_unlock(inode); 90 91 audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL); 92 if (unlikely(!audit_mark)) { 93 audit_mark = ERR_PTR(-ENOMEM); 94 goto out; 95 } 96 97 fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group); 98 audit_mark->mark.mask = AUDIT_FS_EVENTS; 99 audit_mark->path = pathname; 100 audit_update_mark(audit_mark, dentry->d_inode); 101 audit_mark->rule = krule; 102 103 ret = fsnotify_add_inode_mark(&audit_mark->mark, inode, true); 104 if (ret < 0) { 105 fsnotify_put_mark(&audit_mark->mark); 106 audit_mark = ERR_PTR(ret); 107 } 108 out: 109 dput(dentry); 110 path_put(&path); 111 return audit_mark; 112 } 113 114 static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op) 115 { 116 struct audit_buffer *ab; 117 struct audit_krule *rule = audit_mark->rule; 118 119 if (!audit_enabled) 120 return; 121 ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE); 122 if (unlikely(!ab)) 123 return; 124 audit_log_session_info(ab); 125 audit_log_format(ab, " op=%s path=", op); 126 audit_log_untrustedstring(ab, audit_mark->path); 127 audit_log_key(ab, rule->filterkey); 128 audit_log_format(ab, " list=%d res=1", rule->listnr); 129 audit_log_end(ab); 130 } 131 132 void audit_remove_mark(struct audit_fsnotify_mark *audit_mark) 133 { 134 fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group); 135 fsnotify_put_mark(&audit_mark->mark); 136 } 137 138 void audit_remove_mark_rule(struct audit_krule *krule) 139 { 140 struct audit_fsnotify_mark *mark = krule->exe; 141 142 audit_remove_mark(mark); 143 } 144 145 static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark) 146 { 147 struct audit_krule *rule = audit_mark->rule; 148 struct audit_entry *entry = container_of(rule, struct audit_entry, rule); 149 150 audit_mark_log_rule_change(audit_mark, "autoremove_rule"); 151 audit_del_rule(entry); 152 } 153 154 /* Update mark data in audit rules based on fsnotify events. */ 155 static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask, 156 struct inode *inode, struct inode *dir, 157 const struct qstr *dname, u32 cookie) 158 { 159 struct audit_fsnotify_mark *audit_mark; 160 161 audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark); 162 163 if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group) || 164 WARN_ON_ONCE(!inode)) 165 return 0; 166 167 if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) { 168 if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL)) 169 return 0; 170 audit_update_mark(audit_mark, inode); 171 } else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) { 172 audit_autoremove_mark_rule(audit_mark); 173 } 174 175 return 0; 176 } 177 178 static const struct fsnotify_ops audit_mark_fsnotify_ops = { 179 .handle_inode_event = audit_mark_handle_event, 180 .free_mark = audit_fsnotify_free_mark, 181 }; 182 183 static int __init audit_fsnotify_init(void) 184 { 185 audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops); 186 if (IS_ERR(audit_fsnotify_group)) { 187 audit_fsnotify_group = NULL; 188 audit_panic("cannot create audit fsnotify group"); 189 } 190 return 0; 191 } 192 device_initcall(audit_fsnotify_init); 193