/* auditfilter.c -- filtering of audit events * * Copyright 2003-2004 Red Hat, Inc. * Copyright 2005 Hewlett-Packard Development Company, L.P. * Copyright 2005 IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/kernel.h> #include <linux/audit.h> #include <linux/kthread.h> #include <linux/mutex.h> #include <linux/fs.h> #include <linux/namei.h> #include <linux/netlink.h> #include <linux/sched.h> #include <linux/inotify.h> #include <linux/selinux.h> #include "audit.h" /* * Locking model: * * audit_filter_mutex: * Synchronizes writes and blocking reads of audit's filterlist * data. Rcu is used to traverse the filterlist and access * contents of structs audit_entry, audit_watch and opaque * selinux rules during filtering. If modified, these structures * must be copied and replace their counterparts in the filterlist. * An audit_parent struct is not accessed during filtering, so may * be written directly provided audit_filter_mutex is held. */ /* * Reference counting: * * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED * event. Each audit_watch holds a reference to its associated parent. * * audit_watch: if added to lists, lifetime is from audit_init_watch() to * audit_remove_watch(). Additionally, an audit_watch may exist * temporarily to assist in searching existing filter data. Each * audit_krule holds a reference to its associated watch. */ struct audit_parent { struct list_head ilist; /* entry in inotify registration list */ struct list_head watches; /* associated watches */ struct inotify_watch wdata; /* inotify watch data */ unsigned flags; /* status flags */ }; /* * audit_parent status flags: * * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to * a filesystem event to ensure we're adding audit watches to a valid parent. * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot * receive them while we have nameidata, but must be used for IN_MOVE_SELF which * we can receive while holding nameidata. */ #define AUDIT_PARENT_INVALID 0x001 /* Audit filter lists, defined in <linux/audit.h> */ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { LIST_HEAD_INIT(audit_filter_list[0]), LIST_HEAD_INIT(audit_filter_list[1]), LIST_HEAD_INIT(audit_filter_list[2]), LIST_HEAD_INIT(audit_filter_list[3]), LIST_HEAD_INIT(audit_filter_list[4]), LIST_HEAD_INIT(audit_filter_list[5]), #if AUDIT_NR_FILTERS != 6 #error Fix audit_filter_list initialiser #endif }; static DEFINE_MUTEX(audit_filter_mutex); /* Inotify handle */ extern struct inotify_handle *audit_ih; /* Inotify events we care about. */ #define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF void audit_free_parent(struct inotify_watch *i_watch) { struct audit_parent *parent; parent = container_of(i_watch, struct audit_parent, wdata); WARN_ON(!list_empty(&parent->watches)); kfree(parent); } static inline void audit_get_watch(struct audit_watch *watch) { atomic_inc(&watch->count); } static void audit_put_watch(struct audit_watch *watch) { if (atomic_dec_and_test(&watch->count)) { WARN_ON(watch->parent); WARN_ON(!list_empty(&watch->rules)); kfree(watch->path); kfree(watch); } } static void audit_remove_watch(struct audit_watch *watch) { list_del(&watch->wlist); put_inotify_watch(&watch->parent->wdata); watch->parent = NULL; audit_put_watch(watch); /* match initial get */ } static inline void audit_free_rule(struct audit_entry *e) { int i; /* some rules don't have associated watches */ if (e->rule.watch) audit_put_watch(e->rule.watch); if (e->rule.fields) for (i = 0; i < e->rule.field_count; i++) { struct audit_field *f = &e->rule.fields[i]; kfree(f->se_str); selinux_audit_rule_free(f->se_rule); } kfree(e->rule.fields); kfree(e->rule.filterkey); kfree(e); } static inline void audit_free_rule_rcu(struct rcu_head *head) { struct audit_entry *e = container_of(head, struct audit_entry, rcu); audit_free_rule(e); } /* Initialize a parent watch entry. */ static struct audit_parent *audit_init_parent(struct nameidata *ndp) { struct audit_parent *parent; s32 wd; parent = kzalloc(sizeof(*parent), GFP_KERNEL); if (unlikely(!parent)) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&parent->watches); parent->flags = 0; inotify_init_watch(&parent->wdata); /* grab a ref so inotify watch hangs around until we take audit_filter_mutex */ get_inotify_watch(&parent->wdata); wd = inotify_add_watch(audit_ih, &parent->wdata, ndp->dentry->d_inode, AUDIT_IN_WATCH); if (wd < 0) { audit_free_parent(&parent->wdata); return ERR_PTR(wd); } return parent; } /* Initialize a watch entry. */ static struct audit_watch *audit_init_watch(char *path) { struct audit_watch *watch; watch = kzalloc(sizeof(*watch), GFP_KERNEL); if (unlikely(!watch)) return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&watch->rules); atomic_set(&watch->count, 1); watch->path = path; watch->dev = (dev_t)-1; watch->ino = (unsigned long)-1; return watch; } /* Initialize an audit filterlist entry. */ static inline struct audit_entry *audit_init_entry(u32 field_count) { struct audit_entry *entry; struct audit_field *fields; entry = kzalloc(sizeof(*entry), GFP_KERNEL); if (unlikely(!entry)) return NULL; fields = kzalloc(sizeof(*fields) * field_count, GFP_KERNEL); if (unlikely(!fields)) { kfree(entry); return NULL; } entry->rule.fields = fields; return entry; } /* Unpack a filter field's string representation from user-space * buffer. */ static char *audit_unpack_string(void **bufp, size_t *remain, size_t len) { char *str; if (!*bufp || (len == 0) || (len > *remain)) return ERR_PTR(-EINVAL); /* Of the currently implemented string fields, PATH_MAX * defines the longest valid length. */ if (len > PATH_MAX) return ERR_PTR(-ENAMETOOLONG); str = kmalloc(len + 1, GFP_KERNEL); if (unlikely(!str)) return ERR_PTR(-ENOMEM); memcpy(str, *bufp, len); str[len] = 0; *bufp += len; *remain -= len; return str; } /* Translate an inode field to kernel respresentation. */ static inline int audit_to_inode(struct audit_krule *krule, struct audit_field *f) { if (krule->listnr != AUDIT_FILTER_EXIT || krule->watch || krule->inode_f) return -EINVAL; krule->inode_f = f; return 0; } /* Translate a watch string to kernel respresentation. */ static int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op) { struct audit_watch *watch; if (!audit_ih) return -EOPNOTSUPP; if (path[0] != '/' || path[len-1] == '/' || krule->listnr != AUDIT_FILTER_EXIT || op & ~AUDIT_EQUAL || krule->inode_f || krule->watch) /* 1 inode # per rule, for hash */ return -EINVAL; watch = audit_init_watch(path); if (unlikely(IS_ERR(watch))) return PTR_ERR(watch); audit_get_watch(watch); krule->watch = watch; return 0; } static __u32 *classes[AUDIT_SYSCALL_CLASSES]; int __init audit_register_class(int class, unsigned *list) { __u32 *p = kzalloc(AUDIT_BITMASK_SIZE * sizeof(__u32), GFP_KERNEL); if (!p) return -ENOMEM; while (*list != ~0U) { unsigned n = *list++; if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) { kfree(p); return -EINVAL; } p[AUDIT_WORD(n)] |= AUDIT_BIT(n); } if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) { kfree(p); return -EINVAL; } classes[class] = p; return 0; } int audit_match_class(int class, unsigned syscall) { if (unlikely(syscall >= AUDIT_BITMASK_SIZE * sizeof(__u32))) return 0; if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class])) return 0; return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall); } /* Common user-space to kernel rule translation. */ static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) { unsigned listnr; struct audit_entry *entry; int i, err; err = -EINVAL; listnr = rule->flags & ~AUDIT_FILTER_PREPEND; switch(listnr) { default: goto exit_err; case AUDIT_FILTER_USER: case AUDIT_FILTER_TYPE: #ifdef CONFIG_AUDITSYSCALL case AUDIT_FILTER_ENTRY: case AUDIT_FILTER_EXIT: case AUDIT_FILTER_TASK: #endif ; } if (unlikely(rule->action == AUDIT_POSSIBLE)) { printk(KERN_ERR "AUDIT_POSSIBLE is deprecated\n"); goto exit_err; } if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS) goto exit_err; if (rule->field_count > AUDIT_MAX_FIELDS) goto exit_err; err = -ENOMEM; entry = audit_init_entry(rule->field_count); if (!entry) goto exit_err; entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND; entry->rule.listnr = listnr; entry->rule.action = rule->action; entry->rule.field_count = rule->field_count; for (i = 0; i < AUDIT_BITMASK_SIZE; i++) entry->rule.mask[i] = rule->mask[i]; for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) { int bit = AUDIT_BITMASK_SIZE * 32 - i - 1; __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)]; __u32 *class; if (!(*p & AUDIT_BIT(bit))) continue; *p &= ~AUDIT_BIT(bit); class = classes[i]; if (class) { int j; for (j = 0; j < AUDIT_BITMASK_SIZE; j++) entry->rule.mask[j] |= class[j]; } } return entry; exit_err: return ERR_PTR(err); } /* Translate struct audit_rule to kernel's rule respresentation. * Exists for backward compatibility with userspace. */ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) { struct audit_entry *entry; struct audit_field *f; int err = 0; int i; entry = audit_to_entry_common(rule); if (IS_ERR(entry)) goto exit_nofree; for (i = 0; i < rule->field_count; i++) { struct audit_field *f = &entry->rule.fields[i]; f->op = rule->fields[i] & (AUDIT_NEGATE|AUDIT_OPERATORS); f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); f->val = rule->values[i]; err = -EINVAL; switch(f->type) { default: goto exit_free; case AUDIT_PID: case AUDIT_UID: case AUDIT_EUID: case AUDIT_SUID: case AUDIT_FSUID: case AUDIT_GID: case AUDIT_EGID: case AUDIT_SGID: case AUDIT_FSGID: case AUDIT_LOGINUID: case AUDIT_PERS: case AUDIT_ARCH: case AUDIT_MSGTYPE: case AUDIT_PPID: case AUDIT_DEVMAJOR: case AUDIT_DEVMINOR: case AUDIT_EXIT: case AUDIT_SUCCESS: case AUDIT_ARG0: case AUDIT_ARG1: case AUDIT_ARG2: case AUDIT_ARG3: break; case AUDIT_PERM: if (f->val & ~15) goto exit_free; break; case AUDIT_INODE: err = audit_to_inode(&entry->rule, f); if (err) goto exit_free; break; } entry->rule.vers_ops = (f->op & AUDIT_OPERATORS) ? 2 : 1; /* Support for legacy operators where * AUDIT_NEGATE bit signifies != and otherwise assumes == */ if (f->op & AUDIT_NEGATE) f->op = AUDIT_NOT_EQUAL; else if (!f->op) f->op = AUDIT_EQUAL; else if (f->op == AUDIT_OPERATORS) { err = -EINVAL; goto exit_free; } } f = entry->rule.inode_f; if (f) { switch(f->op) { case AUDIT_NOT_EQUAL: entry->rule.inode_f = NULL; case AUDIT_EQUAL: break; default: err = -EINVAL; goto exit_free; } } exit_nofree: return entry; exit_free: audit_free_rule(entry); return ERR_PTR(err); } /* Translate struct audit_rule_data to kernel's rule respresentation. */ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, size_t datasz) { int err = 0; struct audit_entry *entry; struct audit_field *f; void *bufp; size_t remain = datasz - sizeof(struct audit_rule_data); int i; char *str; entry = audit_to_entry_common((struct audit_rule *)data); if (IS_ERR(entry)) goto exit_nofree; bufp = data->buf; entry->rule.vers_ops = 2; for (i = 0; i < data->field_count; i++) { struct audit_field *f = &entry->rule.fields[i]; err = -EINVAL; if (!(data->fieldflags[i] & AUDIT_OPERATORS) || data->fieldflags[i] & ~AUDIT_OPERATORS) goto exit_free; f->op = data->fieldflags[i] & AUDIT_OPERATORS; f->type = data->fields[i]; f->val = data->values[i]; f->se_str = NULL; f->se_rule = NULL; switch(f->type) { case AUDIT_PID: case AUDIT_UID: case AUDIT_EUID: case AUDIT_SUID: case AUDIT_FSUID: case AUDIT_GID: case AUDIT_EGID: case AUDIT_SGID: case AUDIT_FSGID: case AUDIT_LOGINUID: case AUDIT_PERS: case AUDIT_ARCH: case AUDIT_MSGTYPE: case AUDIT_PPID: case AUDIT_DEVMAJOR: case AUDIT_DEVMINOR: case AUDIT_EXIT: case AUDIT_SUCCESS: case AUDIT_ARG0: case AUDIT_ARG1: case AUDIT_ARG2: case AUDIT_ARG3: break; case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: case AUDIT_SUBJ_SEN: case AUDIT_SUBJ_CLR: case AUDIT_OBJ_USER: case AUDIT_OBJ_ROLE: case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: str = audit_unpack_string(&bufp, &remain, f->val); if (IS_ERR(str)) goto exit_free; entry->rule.buflen += f->val; err = selinux_audit_rule_init(f->type, f->op, str, &f->se_rule); /* Keep currently invalid fields around in case they * become valid after a policy reload. */ if (err == -EINVAL) { printk(KERN_WARNING "audit rule for selinux " "\'%s\' is invalid\n", str); err = 0; } if (err) { kfree(str); goto exit_free; } else f->se_str = str; break; case AUDIT_WATCH: str = audit_unpack_string(&bufp, &remain, f->val); if (IS_ERR(str)) goto exit_free; entry->rule.buflen += f->val; err = audit_to_watch(&entry->rule, str, f->val, f->op); if (err) { kfree(str); goto exit_free; } break; case AUDIT_INODE: err = audit_to_inode(&entry->rule, f); if (err) goto exit_free; break; case AUDIT_FILTERKEY: err = -EINVAL; if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) goto exit_free; str = audit_unpack_string(&bufp, &remain, f->val); if (IS_ERR(str)) goto exit_free; entry->rule.buflen += f->val; entry->rule.filterkey = str; break; case AUDIT_PERM: if (f->val & ~15) goto exit_free; break; default: goto exit_free; } } f = entry->rule.inode_f; if (f) { switch(f->op) { case AUDIT_NOT_EQUAL: entry->rule.inode_f = NULL; case AUDIT_EQUAL: break; default: err = -EINVAL; goto exit_free; } } exit_nofree: return entry; exit_free: audit_free_rule(entry); return ERR_PTR(err); } /* Pack a filter field's string representation into data block. */ static inline size_t audit_pack_string(void **bufp, char *str) { size_t len = strlen(str); memcpy(*bufp, str, len); *bufp += len; return len; } /* Translate kernel rule respresentation to struct audit_rule. * Exists for backward compatibility with userspace. */ static struct audit_rule *audit_krule_to_rule(struct audit_krule *krule) { struct audit_rule *rule; int i; rule = kmalloc(sizeof(*rule), GFP_KERNEL); if (unlikely(!rule)) return NULL; memset(rule, 0, sizeof(*rule)); rule->flags = krule->flags | krule->listnr; rule->action = krule->action; rule->field_count = krule->field_count; for (i = 0; i < rule->field_count; i++) { rule->values[i] = krule->fields[i].val; rule->fields[i] = krule->fields[i].type; if (krule->vers_ops == 1) { if (krule->fields[i].op & AUDIT_NOT_EQUAL) rule->fields[i] |= AUDIT_NEGATE; } else { rule->fields[i] |= krule->fields[i].op; } } for (i = 0; i < AUDIT_BITMASK_SIZE; i++) rule->mask[i] = krule->mask[i]; return rule; } /* Translate kernel rule respresentation to struct audit_rule_data. */ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) { struct audit_rule_data *data; void *bufp; int i; data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); if (unlikely(!data)) return NULL; memset(data, 0, sizeof(*data)); data->flags = krule->flags | krule->listnr; data->action = krule->action; data->field_count = krule->field_count; bufp = data->buf; for (i = 0; i < data->field_count; i++) { struct audit_field *f = &krule->fields[i]; data->fields[i] = f->type; data->fieldflags[i] = f->op; switch(f->type) { case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: case AUDIT_SUBJ_SEN: case AUDIT_SUBJ_CLR: case AUDIT_OBJ_USER: case AUDIT_OBJ_ROLE: case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: data->buflen += data->values[i] = audit_pack_string(&bufp, f->se_str); break; case AUDIT_WATCH: data->buflen += data->values[i] = audit_pack_string(&bufp, krule->watch->path); break; case AUDIT_FILTERKEY: data->buflen += data->values[i] = audit_pack_string(&bufp, krule->filterkey); break; default: data->values[i] = f->val; } } for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; return data; } /* Compare two rules in kernel format. Considered success if rules * don't match. */ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) { int i; if (a->flags != b->flags || a->listnr != b->listnr || a->action != b->action || a->field_count != b->field_count) return 1; for (i = 0; i < a->field_count; i++) { if (a->fields[i].type != b->fields[i].type || a->fields[i].op != b->fields[i].op) return 1; switch(a->fields[i].type) { case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: case AUDIT_SUBJ_SEN: case AUDIT_SUBJ_CLR: case AUDIT_OBJ_USER: case AUDIT_OBJ_ROLE: case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: if (strcmp(a->fields[i].se_str, b->fields[i].se_str)) return 1; break; case AUDIT_WATCH: if (strcmp(a->watch->path, b->watch->path)) return 1; break; case AUDIT_FILTERKEY: /* both filterkeys exist based on above type compare */ if (strcmp(a->filterkey, b->filterkey)) return 1; break; default: if (a->fields[i].val != b->fields[i].val) return 1; } } for (i = 0; i < AUDIT_BITMASK_SIZE; i++) if (a->mask[i] != b->mask[i]) return 1; return 0; } /* Duplicate the given audit watch. The new watch's rules list is initialized * to an empty list and wlist is undefined. */ static struct audit_watch *audit_dupe_watch(struct audit_watch *old) { char *path; struct audit_watch *new; path = kstrdup(old->path, GFP_KERNEL); if (unlikely(!path)) return ERR_PTR(-ENOMEM); new = audit_init_watch(path); if (unlikely(IS_ERR(new))) { kfree(path); goto out; } new->dev = old->dev; new->ino = old->ino; get_inotify_watch(&old->parent->wdata); new->parent = old->parent; out: return new; } /* Duplicate selinux field information. The se_rule is opaque, so must be * re-initialized. */ static inline int audit_dupe_selinux_field(struct audit_field *df, struct audit_field *sf) { int ret = 0; char *se_str; /* our own copy of se_str */ se_str = kstrdup(sf->se_str, GFP_KERNEL); if (unlikely(IS_ERR(se_str))) return -ENOMEM; df->se_str = se_str; /* our own (refreshed) copy of se_rule */ ret = selinux_audit_rule_init(df->type, df->op, df->se_str, &df->se_rule); /* Keep currently invalid fields around in case they * become valid after a policy reload. */ if (ret == -EINVAL) { printk(KERN_WARNING "audit rule for selinux \'%s\' is " "invalid\n", df->se_str); ret = 0; } return ret; } /* Duplicate an audit rule. This will be a deep copy with the exception * of the watch - that pointer is carried over. The selinux specific fields * will be updated in the copy. The point is to be able to replace the old * rule with the new rule in the filterlist, then free the old rule. * The rlist element is undefined; list manipulations are handled apart from * the initial copy. */ static struct audit_entry *audit_dupe_rule(struct audit_krule *old, struct audit_watch *watch) { u32 fcount = old->field_count; struct audit_entry *entry; struct audit_krule *new; char *fk; int i, err = 0; entry = audit_init_entry(fcount); if (unlikely(!entry)) return ERR_PTR(-ENOMEM); new = &entry->rule; new->vers_ops = old->vers_ops; new->flags = old->flags; new->listnr = old->listnr; new->action = old->action; for (i = 0; i < AUDIT_BITMASK_SIZE; i++) new->mask[i] = old->mask[i]; new->buflen = old->buflen; new->inode_f = old->inode_f; new->watch = NULL; new->field_count = old->field_count; memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); /* deep copy this information, updating the se_rule fields, because * the originals will all be freed when the old rule is freed. */ for (i = 0; i < fcount; i++) { switch (new->fields[i].type) { case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: case AUDIT_SUBJ_SEN: case AUDIT_SUBJ_CLR: case AUDIT_OBJ_USER: case AUDIT_OBJ_ROLE: case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: err = audit_dupe_selinux_field(&new->fields[i], &old->fields[i]); break; case AUDIT_FILTERKEY: fk = kstrdup(old->filterkey, GFP_KERNEL); if (unlikely(!fk)) err = -ENOMEM; else new->filterkey = fk; } if (err) { audit_free_rule(entry); return ERR_PTR(err); } } if (watch) { audit_get_watch(watch); new->watch = watch; } return entry; } /* Update inode info in audit rules based on filesystem event. */ static void audit_update_watch(struct audit_parent *parent, const char *dname, dev_t dev, unsigned long ino, unsigned invalidating) { struct audit_watch *owatch, *nwatch, *nextw; struct audit_krule *r, *nextr; struct audit_entry *oentry, *nentry; struct audit_buffer *ab; mutex_lock(&audit_filter_mutex); list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) { if (audit_compare_dname_path(dname, owatch->path, NULL)) continue; /* If the update involves invalidating rules, do the inode-based * filtering now, so we don't omit records. */ if (invalidating && audit_filter_inodes(current, current->audit_context) == AUDIT_RECORD_CONTEXT) audit_set_auditable(current->audit_context); nwatch = audit_dupe_watch(owatch); if (unlikely(IS_ERR(nwatch))) { mutex_unlock(&audit_filter_mutex); audit_panic("error updating watch, skipping"); return; } nwatch->dev = dev; nwatch->ino = ino; list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) { oentry = container_of(r, struct audit_entry, rule); list_del(&oentry->rule.rlist); list_del_rcu(&oentry->list); nentry = audit_dupe_rule(&oentry->rule, nwatch); if (unlikely(IS_ERR(nentry))) audit_panic("error updating watch, removing"); else { int h = audit_hash_ino((u32)ino); list_add(&nentry->rule.rlist, &nwatch->rules); list_add_rcu(&nentry->list, &audit_inode_hash[h]); } call_rcu(&oentry->rcu, audit_free_rule_rcu); } ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); audit_log_format(ab, "audit updated rules specifying path="); audit_log_untrustedstring(ab, owatch->path); audit_log_format(ab, " with dev=%u ino=%lu\n", dev, ino); audit_log_end(ab); audit_remove_watch(owatch); goto add_watch_to_parent; /* event applies to a single watch */ } mutex_unlock(&audit_filter_mutex); return; add_watch_to_parent: list_add(&nwatch->wlist, &parent->watches); mutex_unlock(&audit_filter_mutex); return; } /* Remove all watches & rules associated with a parent that is going away. */ static void audit_remove_parent_watches(struct audit_parent *parent) { struct audit_watch *w, *nextw; struct audit_krule *r, *nextr; struct audit_entry *e; struct audit_buffer *ab; mutex_lock(&audit_filter_mutex); parent->flags |= AUDIT_PARENT_INVALID; list_for_each_entry_safe(w, nextw, &parent->watches, wlist) { list_for_each_entry_safe(r, nextr, &w->rules, rlist) { e = container_of(r, struct audit_entry, rule); ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); audit_log_format(ab, "audit implicitly removed rule path="); audit_log_untrustedstring(ab, w->path); if (r->filterkey) { audit_log_format(ab, " key="); audit_log_untrustedstring(ab, r->filterkey); } else audit_log_format(ab, " key=(null)"); audit_log_format(ab, " list=%d", r->listnr); audit_log_end(ab); list_del(&r->rlist); list_del_rcu(&e->list); call_rcu(&e->rcu, audit_free_rule_rcu); } audit_remove_watch(w); } mutex_unlock(&audit_filter_mutex); } /* Unregister inotify watches for parents on in_list. * Generates an IN_IGNORED event. */ static void audit_inotify_unregister(struct list_head *in_list) { struct audit_parent *p, *n; list_for_each_entry_safe(p, n, in_list, ilist) { list_del(&p->ilist); inotify_rm_watch(audit_ih, &p->wdata); /* the put matching the get in audit_do_del_rule() */ put_inotify_watch(&p->wdata); } } /* Find an existing audit rule. * Caller must hold audit_filter_mutex to prevent stale rule data. */ static struct audit_entry *audit_find_rule(struct audit_entry *entry, struct list_head *list) { struct audit_entry *e, *found = NULL; int h; if (entry->rule.watch) { /* we don't know the inode number, so must walk entire hash */ for (h = 0; h < AUDIT_INODE_BUCKETS; h++) { list = &audit_inode_hash[h]; list_for_each_entry(e, list, list) if (!audit_compare_rule(&entry->rule, &e->rule)) { found = e; goto out; } } goto out; } list_for_each_entry(e, list, list) if (!audit_compare_rule(&entry->rule, &e->rule)) { found = e; goto out; } out: return found; } /* Get path information necessary for adding watches. */ static int audit_get_nd(char *path, struct nameidata **ndp, struct nameidata **ndw) { struct nameidata *ndparent, *ndwatch; int err; ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL); if (unlikely(!ndparent)) return -ENOMEM; ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL); if (unlikely(!ndwatch)) { kfree(ndparent); return -ENOMEM; } err = path_lookup(path, LOOKUP_PARENT, ndparent); if (err) { kfree(ndparent); kfree(ndwatch); return err; } err = path_lookup(path, 0, ndwatch); if (err) { kfree(ndwatch); ndwatch = NULL; } *ndp = ndparent; *ndw = ndwatch; return 0; } /* Release resources used for watch path information. */ static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw) { if (ndp) { path_release(ndp); kfree(ndp); } if (ndw) { path_release(ndw); kfree(ndw); } } /* Associate the given rule with an existing parent inotify_watch. * Caller must hold audit_filter_mutex. */ static void audit_add_to_parent(struct audit_krule *krule, struct audit_parent *parent) { struct audit_watch *w, *watch = krule->watch; int watch_found = 0; list_for_each_entry(w, &parent->watches, wlist) { if (strcmp(watch->path, w->path)) continue; watch_found = 1; /* put krule's and initial refs to temporary watch */ audit_put_watch(watch); audit_put_watch(watch); audit_get_watch(w); krule->watch = watch = w; break; } if (!watch_found) { get_inotify_watch(&parent->wdata); watch->parent = parent; list_add(&watch->wlist, &parent->watches); } list_add(&krule->rlist, &watch->rules); } /* Find a matching watch entry, or add this one. * Caller must hold audit_filter_mutex. */ static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp, struct nameidata *ndw) { struct audit_watch *watch = krule->watch; struct inotify_watch *i_watch; struct audit_parent *parent; int ret = 0; /* update watch filter fields */ if (ndw) { watch->dev = ndw->dentry->d_inode->i_sb->s_dev; watch->ino = ndw->dentry->d_inode->i_ino; } /* The audit_filter_mutex must not be held during inotify calls because * we hold it during inotify event callback processing. If an existing * inotify watch is found, inotify_find_watch() grabs a reference before * returning. */ mutex_unlock(&audit_filter_mutex); if (inotify_find_watch(audit_ih, ndp->dentry->d_inode, &i_watch) < 0) { parent = audit_init_parent(ndp); if (IS_ERR(parent)) { /* caller expects mutex locked */ mutex_lock(&audit_filter_mutex); return PTR_ERR(parent); } } else parent = container_of(i_watch, struct audit_parent, wdata); mutex_lock(&audit_filter_mutex); /* parent was moved before we took audit_filter_mutex */ if (parent->flags & AUDIT_PARENT_INVALID) ret = -ENOENT; else audit_add_to_parent(krule, parent); /* match get in audit_init_parent or inotify_find_watch */ put_inotify_watch(&parent->wdata); return ret; } /* Add rule to given filterlist if not a duplicate. */ static inline int audit_add_rule(struct audit_entry *entry, struct list_head *list) { struct audit_entry *e; struct audit_field *inode_f = entry->rule.inode_f; struct audit_watch *watch = entry->rule.watch; struct nameidata *ndp, *ndw; int h, err, putnd_needed = 0; #ifdef CONFIG_AUDITSYSCALL int dont_count = 0; /* If either of these, don't count towards total */ if (entry->rule.listnr == AUDIT_FILTER_USER || entry->rule.listnr == AUDIT_FILTER_TYPE) dont_count = 1; #endif if (inode_f) { h = audit_hash_ino(inode_f->val); list = &audit_inode_hash[h]; } mutex_lock(&audit_filter_mutex); e = audit_find_rule(entry, list); mutex_unlock(&audit_filter_mutex); if (e) { err = -EEXIST; goto error; } /* Avoid calling path_lookup under audit_filter_mutex. */ if (watch) { err = audit_get_nd(watch->path, &ndp, &ndw); if (err) goto error; putnd_needed = 1; } mutex_lock(&audit_filter_mutex); if (watch) { /* audit_filter_mutex is dropped and re-taken during this call */ err = audit_add_watch(&entry->rule, ndp, ndw); if (err) { mutex_unlock(&audit_filter_mutex); goto error; } h = audit_hash_ino((u32)watch->ino); list = &audit_inode_hash[h]; } if (entry->rule.flags & AUDIT_FILTER_PREPEND) { list_add_rcu(&entry->list, list); entry->rule.flags &= ~AUDIT_FILTER_PREPEND; } else { list_add_tail_rcu(&entry->list, list); } #ifdef CONFIG_AUDITSYSCALL if (!dont_count) audit_n_rules++; #endif mutex_unlock(&audit_filter_mutex); if (putnd_needed) audit_put_nd(ndp, ndw); return 0; error: if (putnd_needed) audit_put_nd(ndp, ndw); if (watch) audit_put_watch(watch); /* tmp watch, matches initial get */ return err; } /* Remove an existing rule from filterlist. */ static inline int audit_del_rule(struct audit_entry *entry, struct list_head *list) { struct audit_entry *e; struct audit_field *inode_f = entry->rule.inode_f; struct audit_watch *watch, *tmp_watch = entry->rule.watch; LIST_HEAD(inotify_list); int h, ret = 0; #ifdef CONFIG_AUDITSYSCALL int dont_count = 0; /* If either of these, don't count towards total */ if (entry->rule.listnr == AUDIT_FILTER_USER || entry->rule.listnr == AUDIT_FILTER_TYPE) dont_count = 1; #endif if (inode_f) { h = audit_hash_ino(inode_f->val); list = &audit_inode_hash[h]; } mutex_lock(&audit_filter_mutex); e = audit_find_rule(entry, list); if (!e) { mutex_unlock(&audit_filter_mutex); ret = -ENOENT; goto out; } watch = e->rule.watch; if (watch) { struct audit_parent *parent = watch->parent; list_del(&e->rule.rlist); if (list_empty(&watch->rules)) { audit_remove_watch(watch); if (list_empty(&parent->watches)) { /* Put parent on the inotify un-registration * list. Grab a reference before releasing * audit_filter_mutex, to be released in * audit_inotify_unregister(). */ list_add(&parent->ilist, &inotify_list); get_inotify_watch(&parent->wdata); } } } list_del_rcu(&e->list); call_rcu(&e->rcu, audit_free_rule_rcu); #ifdef CONFIG_AUDITSYSCALL if (!dont_count) audit_n_rules--; #endif mutex_unlock(&audit_filter_mutex); if (!list_empty(&inotify_list)) audit_inotify_unregister(&inotify_list); out: if (tmp_watch) audit_put_watch(tmp_watch); /* match initial get */ return ret; } /* List rules using struct audit_rule. Exists for backward * compatibility with userspace. */ static void audit_list(int pid, int seq, struct sk_buff_head *q) { struct sk_buff *skb; struct audit_entry *entry; int i; /* This is a blocking read, so use audit_filter_mutex instead of rcu * iterator to sync with list writers. */ for (i=0; i<AUDIT_NR_FILTERS; i++) { list_for_each_entry(entry, &audit_filter_list[i], list) { struct audit_rule *rule; rule = audit_krule_to_rule(&entry->rule); if (unlikely(!rule)) break; skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, rule, sizeof(*rule)); if (skb) skb_queue_tail(q, skb); kfree(rule); } } for (i = 0; i < AUDIT_INODE_BUCKETS; i++) { list_for_each_entry(entry, &audit_inode_hash[i], list) { struct audit_rule *rule; rule = audit_krule_to_rule(&entry->rule); if (unlikely(!rule)) break; skb = audit_make_reply(pid, seq, AUDIT_LIST, 0, 1, rule, sizeof(*rule)); if (skb) skb_queue_tail(q, skb); kfree(rule); } } skb = audit_make_reply(pid, seq, AUDIT_LIST, 1, 1, NULL, 0); if (skb) skb_queue_tail(q, skb); } /* List rules using struct audit_rule_data. */ static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) { struct sk_buff *skb; struct audit_entry *e; int i; /* This is a blocking read, so use audit_filter_mutex instead of rcu * iterator to sync with list writers. */ for (i=0; i<AUDIT_NR_FILTERS; i++) { list_for_each_entry(e, &audit_filter_list[i], list) { struct audit_rule_data *data; data = audit_krule_to_data(&e->rule); if (unlikely(!data)) break; skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, data, sizeof(*data) + data->buflen); if (skb) skb_queue_tail(q, skb); kfree(data); } } for (i=0; i< AUDIT_INODE_BUCKETS; i++) { list_for_each_entry(e, &audit_inode_hash[i], list) { struct audit_rule_data *data; data = audit_krule_to_data(&e->rule); if (unlikely(!data)) break; skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, data, sizeof(*data) + data->buflen); if (skb) skb_queue_tail(q, skb); kfree(data); } } skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); if (skb) skb_queue_tail(q, skb); } /* Log rule additions and removals */ static void audit_log_rule_change(uid_t loginuid, u32 sid, char *action, struct audit_krule *rule, int res) { struct audit_buffer *ab; ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (!ab) return; audit_log_format(ab, "auid=%u", loginuid); if (sid) { char *ctx = NULL; u32 len; if (selinux_sid_to_string(sid, &ctx, &len)) audit_log_format(ab, " ssid=%u", sid); else audit_log_format(ab, " subj=%s", ctx); kfree(ctx); } audit_log_format(ab, " %s rule key=", action); if (rule->filterkey) audit_log_untrustedstring(ab, rule->filterkey); else audit_log_format(ab, "(null)"); audit_log_format(ab, " list=%d res=%d", rule->listnr, res); audit_log_end(ab); } /** * audit_receive_filter - apply all rules to the specified message type * @type: audit message type * @pid: target pid for netlink audit messages * @uid: target uid for netlink audit messages * @seq: netlink audit message sequence (serial) number * @data: payload data * @datasz: size of payload data * @loginuid: loginuid of sender * @sid: SE Linux Security ID of sender */ int audit_receive_filter(int type, int pid, int uid, int seq, void *data, size_t datasz, uid_t loginuid, u32 sid) { struct task_struct *tsk; struct audit_netlink_list *dest; int err = 0; struct audit_entry *entry; switch (type) { case AUDIT_LIST: case AUDIT_LIST_RULES: /* We can't just spew out the rules here because we might fill * the available socket buffer space and deadlock waiting for * auditctl to read from it... which isn't ever going to * happen if we're actually running in the context of auditctl * trying to _send_ the stuff */ dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); if (!dest) return -ENOMEM; dest->pid = pid; skb_queue_head_init(&dest->q); mutex_lock(&audit_filter_mutex); if (type == AUDIT_LIST) audit_list(pid, seq, &dest->q); else audit_list_rules(pid, seq, &dest->q); mutex_unlock(&audit_filter_mutex); tsk = kthread_run(audit_send_list, dest, "audit_send_list"); if (IS_ERR(tsk)) { skb_queue_purge(&dest->q); kfree(dest); err = PTR_ERR(tsk); } break; case AUDIT_ADD: case AUDIT_ADD_RULE: if (type == AUDIT_ADD) entry = audit_rule_to_entry(data); else entry = audit_data_to_entry(data, datasz); if (IS_ERR(entry)) return PTR_ERR(entry); err = audit_add_rule(entry, &audit_filter_list[entry->rule.listnr]); audit_log_rule_change(loginuid, sid, "add", &entry->rule, !err); if (err) audit_free_rule(entry); break; case AUDIT_DEL: case AUDIT_DEL_RULE: if (type == AUDIT_DEL) entry = audit_rule_to_entry(data); else entry = audit_data_to_entry(data, datasz); if (IS_ERR(entry)) return PTR_ERR(entry); err = audit_del_rule(entry, &audit_filter_list[entry->rule.listnr]); audit_log_rule_change(loginuid, sid, "remove", &entry->rule, !err); audit_free_rule(entry); break; default: return -EINVAL; } return err; } int audit_comparator(const u32 left, const u32 op, const u32 right) { switch (op) { case AUDIT_EQUAL: return (left == right); case AUDIT_NOT_EQUAL: return (left != right); case AUDIT_LESS_THAN: return (left < right); case AUDIT_LESS_THAN_OR_EQUAL: return (left <= right); case AUDIT_GREATER_THAN: return (left > right); case AUDIT_GREATER_THAN_OR_EQUAL: return (left >= right); } BUG(); return 0; } /* Compare given dentry name with last component in given path, * return of 0 indicates a match. */ int audit_compare_dname_path(const char *dname, const char *path, int *dirlen) { int dlen, plen; const char *p; if (!dname || !path) return 1; dlen = strlen(dname); plen = strlen(path); if (plen < dlen) return 1; /* disregard trailing slashes */ p = path + plen - 1; while ((*p == '/') && (p > path)) p--; /* find last path component */ p = p - dlen + 1; if (p < path) return 1; else if (p > path) { if (*--p != '/') return 1; else p++; } /* return length of path's directory component */ if (dirlen) *dirlen = p - path; return strncmp(p, dname, dlen); } static int audit_filter_user_rules(struct netlink_skb_parms *cb, struct audit_krule *rule, enum audit_state *state) { int i; for (i = 0; i < rule->field_count; i++) { struct audit_field *f = &rule->fields[i]; int result = 0; switch (f->type) { case AUDIT_PID: result = audit_comparator(cb->creds.pid, f->op, f->val); break; case AUDIT_UID: result = audit_comparator(cb->creds.uid, f->op, f->val); break; case AUDIT_GID: result = audit_comparator(cb->creds.gid, f->op, f->val); break; case AUDIT_LOGINUID: result = audit_comparator(cb->loginuid, f->op, f->val); break; } if (!result) return 0; } switch (rule->action) { case AUDIT_NEVER: *state = AUDIT_DISABLED; break; case AUDIT_ALWAYS: *state = AUDIT_RECORD_CONTEXT; break; } return 1; } int audit_filter_user(struct netlink_skb_parms *cb, int type) { struct audit_entry *e; enum audit_state state; int ret = 1; rcu_read_lock(); list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_USER], list) { if (audit_filter_user_rules(cb, &e->rule, &state)) { if (state == AUDIT_DISABLED) ret = 0; break; } } rcu_read_unlock(); return ret; /* Audit by default */ } int audit_filter_type(int type) { struct audit_entry *e; int result = 0; rcu_read_lock(); if (list_empty(&audit_filter_list[AUDIT_FILTER_TYPE])) goto unlock_and_return; list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TYPE], list) { int i; for (i = 0; i < e->rule.field_count; i++) { struct audit_field *f = &e->rule.fields[i]; if (f->type == AUDIT_MSGTYPE) { result = audit_comparator(type, f->op, f->val); if (!result) break; } } if (result) goto unlock_and_return; } unlock_and_return: rcu_read_unlock(); return result; } /* Check to see if the rule contains any selinux fields. Returns 1 if there are selinux fields specified in the rule, 0 otherwise. */ static inline int audit_rule_has_selinux(struct audit_krule *rule) { int i; for (i = 0; i < rule->field_count; i++) { struct audit_field *f = &rule->fields[i]; switch (f->type) { case AUDIT_SUBJ_USER: case AUDIT_SUBJ_ROLE: case AUDIT_SUBJ_TYPE: case AUDIT_SUBJ_SEN: case AUDIT_SUBJ_CLR: case AUDIT_OBJ_USER: case AUDIT_OBJ_ROLE: case AUDIT_OBJ_TYPE: case AUDIT_OBJ_LEV_LOW: case AUDIT_OBJ_LEV_HIGH: return 1; } } return 0; } /* This function will re-initialize the se_rule field of all applicable rules. * It will traverse the filter lists serarching for rules that contain selinux * specific filter fields. When such a rule is found, it is copied, the * selinux field is re-initialized, and the old rule is replaced with the * updated rule. */ int selinux_audit_rule_update(void) { struct audit_entry *entry, *n, *nentry; struct audit_watch *watch; int i, err = 0; /* audit_filter_mutex synchronizes the writers */ mutex_lock(&audit_filter_mutex); for (i = 0; i < AUDIT_NR_FILTERS; i++) { list_for_each_entry_safe(entry, n, &audit_filter_list[i], list) { if (!audit_rule_has_selinux(&entry->rule)) continue; watch = entry->rule.watch; nentry = audit_dupe_rule(&entry->rule, watch); if (unlikely(IS_ERR(nentry))) { /* save the first error encountered for the * return value */ if (!err) err = PTR_ERR(nentry); audit_panic("error updating selinux filters"); if (watch) list_del(&entry->rule.rlist); list_del_rcu(&entry->list); } else { if (watch) { list_add(&nentry->rule.rlist, &watch->rules); list_del(&entry->rule.rlist); } list_replace_rcu(&entry->list, &nentry->list); } call_rcu(&entry->rcu, audit_free_rule_rcu); } } mutex_unlock(&audit_filter_mutex); return err; } /* Update watch data in audit rules based on inotify events. */ void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask, u32 cookie, const char *dname, struct inode *inode) { struct audit_parent *parent; parent = container_of(i_watch, struct audit_parent, wdata); if (mask & (IN_CREATE|IN_MOVED_TO) && inode) audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0); else if (mask & (IN_DELETE|IN_MOVED_FROM)) audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1); /* inotify automatically removes the watch and sends IN_IGNORED */ else if (mask & (IN_DELETE_SELF|IN_UNMOUNT)) audit_remove_parent_watches(parent); /* inotify does not remove the watch, so remove it manually */ else if(mask & IN_MOVE_SELF) { audit_remove_parent_watches(parent); inotify_remove_watch_locked(audit_ih, i_watch); } else if (mask & IN_IGNORED) put_inotify_watch(i_watch); }