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 int ret; 80 81 if (pathname[0] != '/' || pathname[len-1] == '/') 82 return ERR_PTR(-EINVAL); 83 84 dentry = kern_path_parent(pathname, &path); 85 if (IS_ERR(dentry)) 86 return ERR_CAST(dentry); /* returning an error */ 87 if (d_really_is_negative(dentry)) { 88 audit_mark = ERR_PTR(-ENOENT); 89 goto out; 90 } 91 92 audit_mark = kzalloc(sizeof(*audit_mark), GFP_KERNEL); 93 if (unlikely(!audit_mark)) { 94 audit_mark = ERR_PTR(-ENOMEM); 95 goto out; 96 } 97 98 fsnotify_init_mark(&audit_mark->mark, audit_fsnotify_group); 99 audit_mark->mark.mask = AUDIT_FS_EVENTS; 100 audit_mark->path = pathname; 101 audit_update_mark(audit_mark, dentry->d_inode); 102 audit_mark->rule = krule; 103 104 ret = fsnotify_add_inode_mark(&audit_mark->mark, path.dentry->d_inode, 0); 105 if (ret < 0) { 106 audit_mark->path = NULL; 107 fsnotify_put_mark(&audit_mark->mark); 108 audit_mark = ERR_PTR(ret); 109 } 110 out: 111 dput(dentry); 112 path_put(&path); 113 return audit_mark; 114 } 115 116 static void audit_mark_log_rule_change(struct audit_fsnotify_mark *audit_mark, char *op) 117 { 118 struct audit_buffer *ab; 119 struct audit_krule *rule = audit_mark->rule; 120 121 if (!audit_enabled) 122 return; 123 ab = audit_log_start(audit_context(), GFP_NOFS, AUDIT_CONFIG_CHANGE); 124 if (unlikely(!ab)) 125 return; 126 audit_log_session_info(ab); 127 audit_log_format(ab, " op=%s path=", op); 128 audit_log_untrustedstring(ab, audit_mark->path); 129 audit_log_key(ab, rule->filterkey); 130 audit_log_format(ab, " list=%d res=1", rule->listnr); 131 audit_log_end(ab); 132 } 133 134 void audit_remove_mark(struct audit_fsnotify_mark *audit_mark) 135 { 136 fsnotify_destroy_mark(&audit_mark->mark, audit_fsnotify_group); 137 fsnotify_put_mark(&audit_mark->mark); 138 } 139 140 void audit_remove_mark_rule(struct audit_krule *krule) 141 { 142 struct audit_fsnotify_mark *mark = krule->exe; 143 144 audit_remove_mark(mark); 145 } 146 147 static void audit_autoremove_mark_rule(struct audit_fsnotify_mark *audit_mark) 148 { 149 struct audit_krule *rule = audit_mark->rule; 150 struct audit_entry *entry = container_of(rule, struct audit_entry, rule); 151 152 audit_mark_log_rule_change(audit_mark, "autoremove_rule"); 153 audit_del_rule(entry); 154 } 155 156 /* Update mark data in audit rules based on fsnotify events. */ 157 static int audit_mark_handle_event(struct fsnotify_mark *inode_mark, u32 mask, 158 struct inode *inode, struct inode *dir, 159 const struct qstr *dname, u32 cookie) 160 { 161 struct audit_fsnotify_mark *audit_mark; 162 163 audit_mark = container_of(inode_mark, struct audit_fsnotify_mark, mark); 164 165 if (WARN_ON_ONCE(inode_mark->group != audit_fsnotify_group)) 166 return 0; 167 168 if (mask & (FS_CREATE|FS_MOVED_TO|FS_DELETE|FS_MOVED_FROM)) { 169 if (audit_compare_dname_path(dname, audit_mark->path, AUDIT_NAME_FULL)) 170 return 0; 171 audit_update_mark(audit_mark, inode); 172 } else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF)) { 173 audit_autoremove_mark_rule(audit_mark); 174 } 175 176 return 0; 177 } 178 179 static const struct fsnotify_ops audit_mark_fsnotify_ops = { 180 .handle_inode_event = audit_mark_handle_event, 181 .free_mark = audit_fsnotify_free_mark, 182 }; 183 184 static int __init audit_fsnotify_init(void) 185 { 186 audit_fsnotify_group = fsnotify_alloc_group(&audit_mark_fsnotify_ops, 187 FSNOTIFY_GROUP_DUPS); 188 if (IS_ERR(audit_fsnotify_group)) { 189 audit_fsnotify_group = NULL; 190 audit_panic("cannot create audit fsnotify group"); 191 } 192 return 0; 193 } 194 device_initcall(audit_fsnotify_init); 195