diff options
| -rw-r--r-- | include/linux/audit.h | 1 | ||||
| -rw-r--r-- | init/Kconfig | 3 | ||||
| -rw-r--r-- | kernel/audit.c | 41 | ||||
| -rw-r--r-- | kernel/audit.h | 38 | ||||
| -rw-r--r-- | kernel/auditfilter.c | 785 | ||||
| -rw-r--r-- | kernel/auditsc.c | 124 |
6 files changed, 903 insertions, 89 deletions
diff --git a/include/linux/audit.h b/include/linux/audit.h index 7c8780b..c783275 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -165,6 +165,7 @@ #define AUDIT_INODE 102 #define AUDIT_EXIT 103 #define AUDIT_SUCCESS 104 /* exit >= 0; value ignored */ +#define AUDIT_WATCH 105 #define AUDIT_ARG0 200 #define AUDIT_ARG1 (AUDIT_ARG0+1) diff --git a/init/Kconfig b/init/Kconfig index 3b36a1d..c4d0fa6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -182,7 +182,8 @@ config AUDITSYSCALL help Enable low-overhead system-call auditing infrastructure that can be used independently or with another kernel subsystem, - such as SELinux. + such as SELinux. To use audit's filesystem watch feature, please + ensure that INOTIFY is configured. config IKCONFIG bool "Kernel .config support" diff --git a/kernel/audit.c b/kernel/audit.c index 0738a4b..0fbf1c1 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -56,6 +56,7 @@ #include <linux/skbuff.h> #include <linux/netlink.h> #include <linux/selinux.h> +#include <linux/inotify.h> #include "audit.h" @@ -103,6 +104,12 @@ static atomic_t audit_lost = ATOMIC_INIT(0); /* The netlink socket. */ static struct sock *audit_sock; +/* Inotify handle. */ +struct inotify_handle *audit_ih; + +/* Hash for inode-based rules */ +struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; + /* The audit_freelist is a list of pre-allocated audit buffers (if more * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of * being placed on the freelist). */ @@ -115,10 +122,8 @@ static struct task_struct *kauditd_task; static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); -/* The netlink socket is only to be read by 1 CPU, which lets us assume - * that list additions and deletions never happen simultaneously in - * auditsc.c */ -DEFINE_MUTEX(audit_netlink_mutex); +/* Serialize requests from userspace. */ +static DEFINE_MUTEX(audit_cmd_mutex); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting * audit records. Since printk uses a 1024 byte buffer, this buffer @@ -373,8 +378,8 @@ int audit_send_list(void *_dest) struct sk_buff *skb; /* wait for parent to finish and send an ACK */ - mutex_lock(&audit_netlink_mutex); - mutex_unlock(&audit_netlink_mutex); + mutex_lock(&audit_cmd_mutex); + mutex_unlock(&audit_cmd_mutex); while ((skb = __skb_dequeue(&dest->q)) != NULL) netlink_unicast(audit_sock, skb, pid, 0); @@ -665,20 +670,30 @@ static void audit_receive(struct sock *sk, int length) struct sk_buff *skb; unsigned int qlen; - mutex_lock(&audit_netlink_mutex); + mutex_lock(&audit_cmd_mutex); for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) { skb = skb_dequeue(&sk->sk_receive_queue); audit_receive_skb(skb); kfree_skb(skb); } - mutex_unlock(&audit_netlink_mutex); + mutex_unlock(&audit_cmd_mutex); } +#ifdef CONFIG_AUDITSYSCALL +static const struct inotify_operations audit_inotify_ops = { + .handle_event = audit_handle_ievent, + .destroy_watch = audit_free_parent, +}; +#endif /* Initialize audit support at boot time. */ static int __init audit_init(void) { +#ifdef CONFIG_AUDITSYSCALL + int i; +#endif + printk(KERN_INFO "audit: initializing netlink socket (%s)\n", audit_default ? "enabled" : "disabled"); audit_sock = netlink_kernel_create(NETLINK_AUDIT, 0, audit_receive, @@ -697,6 +712,16 @@ static int __init audit_init(void) selinux_audit_set_callback(&selinux_audit_rule_update); audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); + +#ifdef CONFIG_AUDITSYSCALL + audit_ih = inotify_init(&audit_inotify_ops); + if (IS_ERR(audit_ih)) + audit_panic("cannot initialize inotify handle"); + + for (i = 0; i < AUDIT_INODE_BUCKETS; i++) + INIT_LIST_HEAD(&audit_inode_hash[i]); +#endif + return 0; } __initcall(audit_init); diff --git a/kernel/audit.h b/kernel/audit.h index 52cb1e3..58fa44cb 100644 --- a/kernel/audit.h +++ b/kernel/audit.h @@ -19,7 +19,6 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ -#include <linux/mutex.h> #include <linux/fs.h> #include <linux/audit.h> #include <linux/skbuff.h> @@ -54,6 +53,18 @@ enum audit_state { }; /* Rule lists */ +struct audit_parent; + +struct audit_watch { + atomic_t count; /* reference count */ + char *path; /* insertion path */ + dev_t dev; /* associated superblock device */ + unsigned long ino; /* associated inode number */ + struct audit_parent *parent; /* associated parent */ + struct list_head wlist; /* entry in parent->watches list */ + struct list_head rules; /* associated rules */ +}; + struct audit_field { u32 type; u32 val; @@ -71,6 +82,9 @@ struct audit_krule { u32 buflen; /* for data alloc on list rules */ u32 field_count; struct audit_field *fields; + struct audit_field *inode_f; /* quick access to an inode field */ + struct audit_watch *watch; /* associated watch */ + struct list_head rlist; /* entry in audit_watch.rules list */ }; struct audit_entry { @@ -79,10 +93,18 @@ struct audit_entry { struct audit_krule rule; }; - extern int audit_pid; -extern int audit_comparator(const u32 left, const u32 op, const u32 right); +#define AUDIT_INODE_BUCKETS 32 +extern struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; + +static inline int audit_hash_ino(u32 ino) +{ + return (ino & (AUDIT_INODE_BUCKETS-1)); +} + +extern int audit_comparator(const u32 left, const u32 op, const u32 right); +extern int audit_compare_dname_path(const char *dname, const char *path); extern struct sk_buff * audit_make_reply(int pid, int seq, int type, int done, int multi, void *payload, int size); @@ -91,7 +113,6 @@ extern void audit_send_reply(int pid, int seq, int type, void *payload, int size); extern void audit_log_lost(const char *message); extern void audit_panic(const char *message); -extern struct mutex audit_netlink_mutex; struct audit_netlink_list { int pid; @@ -100,6 +121,10 @@ struct audit_netlink_list { int audit_send_list(void *); +struct inotify_watch; +extern void audit_free_parent(struct inotify_watch *); +extern void audit_handle_ievent(struct inotify_watch *, u32, u32, u32, + const char *, struct inode *); extern int selinux_audit_rule_update(void); #ifdef CONFIG_AUDITSYSCALL @@ -109,6 +134,11 @@ static inline void audit_signal_info(int sig, struct task_struct *t) if (unlikely(audit_pid && t->tgid == audit_pid)) __audit_signal_info(sig, t); } +extern enum audit_state audit_filter_inodes(struct task_struct *, + struct audit_context *); +extern void audit_set_auditable(struct audit_context *); #else #define audit_signal_info(s,t) +#define audit_filter_inodes(t,c) AUDIT_DISABLED +#define audit_set_auditable(c) #endif diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c index df9503d..03a6919 100644 --- a/kernel/auditfilter.c +++ b/kernel/auditfilter.c @@ -22,13 +22,59 @@ #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" -/* There are three lists of rules -- one to search at task creation - * time, one to search at syscall entry time, and another to search at - * syscall exit time. */ +/* + * 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]), @@ -41,9 +87,53 @@ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { #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]; @@ -60,6 +150,50 @@ static inline void audit_free_rule_rcu(struct rcu_head *head) 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) { @@ -107,6 +241,43 @@ static char *audit_unpack_string(void **bufp, size_t *remain, size_t 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; +} + /* Common user-space to kernel rule translation. */ static inline struct audit_entry *audit_to_entry_common(struct audit_rule *rule) { @@ -161,6 +332,7 @@ exit_err: 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; @@ -175,14 +347,23 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) f->type = rule->fields[i] & ~(AUDIT_NEGATE|AUDIT_OPERATORS); f->val = rule->values[i]; - if (f->type & AUDIT_UNUSED_BITS || - f->type == AUDIT_SE_USER || - f->type == AUDIT_SE_ROLE || - f->type == AUDIT_SE_TYPE || - f->type == AUDIT_SE_SEN || - f->type == AUDIT_SE_CLR) { - err = -EINVAL; + err = -EINVAL; + if (f->type & AUDIT_UNUSED_BITS) + goto exit_free; + + switch(f->type) { + case AUDIT_SE_USER: + case AUDIT_SE_ROLE: + case AUDIT_SE_TYPE: + case AUDIT_SE_SEN: + case AUDIT_SE_CLR: + case AUDIT_WATCH: goto exit_free; + 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; @@ -199,6 +380,18 @@ static struct audit_entry *audit_rule_to_entry(struct audit_rule *rule) } } + f = entry->rule.inode_f; + if (f) { + switch(f->op) { + case AUDIT_NOT_EQUAL: + entry->rule.inode_f = NULL; + case AUDIT_EQUAL: + break; + default: + goto exit_free; + } + } + exit_nofree: return entry; @@ -213,6 +406,7 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, { int err = 0; struct audit_entry *entry; + struct audit_field *f; void *bufp; size_t remain = datasz - sizeof(struct audit_rule_data); int i; @@ -263,6 +457,35 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, } 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; + } + } + + f = entry->rule.inode_f; + if (f) { + switch(f->op) { + case AUDIT_NOT_EQUAL: + entry->rule.inode_f = NULL; + case AUDIT_EQUAL: + break; + default: + goto exit_free; } } @@ -346,6 +569,10 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) 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; default: data->values[i] = f->val; } @@ -381,6 +608,10 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) 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; default: if (a->fields[i].val != b->fields[i].val) return 1; @@ -394,6 +625,32 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) 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, @@ -425,8 +682,11 @@ static inline int audit_dupe_selinux_field(struct audit_field *df, /* 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. */ -static struct audit_entry *audit_dupe_rule(struct audit_krule *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; @@ -445,6 +705,8 @@ static struct audit_entry *audit_dupe_rule(struct audit_krule *old) 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); @@ -466,21 +728,318 @@ static struct audit_entry *audit_dupe_rule(struct audit_krule *old) } } + if (watch) { + audit_get_watch(watch); + new->watch = watch; + } + return entry; } -/* Add rule to given filterlist if not a duplicate. Protected by - * audit_netlink_mutex. */ +/* 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)) + 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 watch="); + 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; + + 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); + list_del(&r->rlist); + list_del_rcu(&e->list); + call_rcu(&e->rcu, audit_free_rule_rcu); + + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, + "audit implicitly removed rule from list=%d\n", + AUDIT_FILTER_EXIT); + } + 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 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; + + 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; + } - /* Do not use the _rcu iterator here, since this is the only - * addition routine. */ - list_for_each_entry(e, list, list) { - if (!audit_compare_rule(&entry->rule, &e->rule)) - return -EEXIST; + /* 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) { @@ -488,27 +1047,77 @@ static inline int audit_add_rule(struct audit_entry *entry, } else { list_add_tail_rcu(&entry->list, list); } + mutex_unlock(&audit_filter_mutex); - return 0; + 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. Protected by - * audit_netlink_mutex. */ +/* 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; + + if (inode_f) { + h = audit_hash_ino(inode_f->val); + list = &audit_inode_hash[h]; + } - /* Do not use the _rcu iterator here, since this is the only - * deletion routine. */ - list_for_each_entry(e, list, list) { - if (!audit_compare_rule(&entry->rule, &e->rule)) { - list_del_rcu(&e->list); - call_rcu(&e->rcu, audit_free_rule_rcu); - return 0; + 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); + } } } - return -ENOENT; /* No matching rule */ + + list_del_rcu(&e->list); + call_rcu(&e->rcu, audit_free_rule_rcu); + + 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 @@ -519,8 +1128,8 @@ static void audit_list(int pid, int seq, struct sk_buff_head *q) struct audit_entry *entry; int i; - /* The *_rcu iterators not needed here because we are - always called with audit_netlink_mutex held. */ + /* 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; @@ -535,6 +1144,20 @@ static void audit_list(int pid, int seq, struct sk_buff_head *q) 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); @@ -547,8 +1170,8 @@ static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) struct audit_entry *e; int i; - /* The *_rcu iterators not needed here because we are - always called with audit_netlink_mutex held. */ + /* 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; @@ -557,7 +1180,21 @@ static void audit_list_rules(int pid, int seq, struct sk_buff_head *q) if (unlikely(!data)) break; skb = audit_make_reply(pid, seq, AUDIT_LIST_RULES, 0, 1, - data, sizeof(*data)); + 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); @@ -602,10 +1239,12 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data, 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)) { @@ -625,6 +1264,7 @@ int audit_receive_filter(int type, int pid, int uid, int seq, void *data, err = audit_add_rule(entry, &audit_filter_list[entry->rule.listnr]); + if (sid) { char *ctx = NULL; u32 len; @@ -705,7 +1345,39 @@ int audit_comparator(const u32 left, const u32 op, const u32 right) 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 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 strncmp(p, dname, dlen); +} static int audit_filter_user_rules(struct netlink_skb_parms *cb, struct audit_krule *rule, @@ -818,32 +1490,65 @@ static inline int audit_rule_has_selinux(struct audit_krule *rule) int selinux_audit_rule_update(void) { struct audit_entry *entry, *n, *nentry; + struct audit_watch *watch; int i, err = 0; - /* audit_netlink_mutex synchronizes the writers */ - mutex_lock(&audit_netlink_mutex); + /* 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; - nentry = audit_dupe_rule(&entry->rule); + 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_netlink_mutex); + 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); +} diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 14e295a4..174a3f6 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -200,12 +200,13 @@ struct audit_context { #endif }; - +/* Determine if any context name data matches a rule's watch data */ /* Compare a task_struct with an audit_rule. Return 1 on match, 0 * otherwise. */ static int audit_filter_rules(struct task_struct *tsk, struct audit_krule *rule, struct audit_context *ctx, + struct audit_names *name, enum audit_state *state) { int i, j, need_sid = 1; @@ -268,7 +269,10 @@ static int audit_filter_rules(struct task_struct *tsk, } break; case AUDIT_DEVMAJOR: - if (ctx) { + if (name) + result = audit_comparator(MAJOR(name->dev), + f->op, f->val); + else if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (audit_comparator(MAJOR(ctx->names[j].dev), f->op, f->val)) { ++result; @@ -278,7 +282,10 @@ static int audit_filter_rules(struct task_struct *tsk, } break; case AUDIT_DEVMINOR: - if (ctx) { + if (name) + result = audit_comparator(MINOR(name->dev), + f->op, f->val); + else if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (audit_comparator(MINOR(ctx->names[j].dev), f->op, f->val)) { ++result; @@ -288,7 +295,10 @@ static int audit_filter_rules(struct task_struct *tsk, } break; case AUDIT_INODE: - if (ctx) { + if (name) + result = (name->ino == f->val || + name->pino == f->val); + else if (ctx) { for (j = 0; j < ctx->name_count; j++) { if (audit_comparator(ctx->names[j].ino, f->op, f->val) || audit_comparator(ctx->names[j].pino, f->op, f->val)) { @@ -298,6 +308,12 @@ static int audit_filter_rules(struct task_struct *tsk, } } break; + case AUDIT_WATCH: + if (name && rule->watch->ino != (unsigned long)-1) + result = (name->dev == rule->watch->dev && + (name->ino == rule->watch->ino || + name->pino == rule->watch->ino)); + break; case AUDIT_LOGINUID: result = 0; if (ctx) @@ -354,7 +370,7 @@ static enum audit_state audit_filter_task(struct task_struct *tsk) rcu_read_lock(); list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_TASK], list) { - if (audit_filter_rules(tsk, &e->rule, NULL, &state)) { + if (audit_filter_rules(tsk, &e->rule, NULL, NULL, &state)) { rcu_read_unlock(); return state; } @@ -384,8 +400,9 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, int bit = AUDIT_BIT(ctx->major); list_for_each_entry_rcu(e, list, list) { - if ((e->rule.mask[word] & bit) == bit - && audit_filter_rules(tsk, &e->rule, ctx, &state)) { + if ((e->rule.mask[word] & bit) == bit && + audit_filter_rules(tsk, &e->rule, ctx, NULL, + &state)) { rcu_read_unlock(); return state; } @@ -395,6 +412,49 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk, return AUDIT_BUILD_CONTEXT; } +/* At syscall exit time, this filter is called if any audit_names[] have been + * collected during syscall processing. We only check rules in sublists at hash + * buckets applicable to the inode numbers in audit_names[]. + * Regarding audit_state, same rules apply as for audit_filter_syscall(). + */ +enum audit_state audit_filter_inodes(struct task_struct *tsk, + struct audit_context *ctx) +{ + int i; + struct audit_entry *e; + enum audit_state state; + + if (audit_pid && tsk->tgid == audit_pid) + return AUDIT_DISABLED; + + rcu_read_lock(); + for (i = 0; i < ctx->name_count; i++) { + int word = AUDIT_WORD(ctx->major); + int bit = AUDIT_BIT(ctx->major); + struct audit_names *n = &ctx->names[i]; + int h = audit_hash_ino((u32)n->ino); + struct list_head *list = &audit_inode_hash[h]; + + if (list_empty(list)) + continue; + + list_for_each_entry_rcu(e, list, list) { + if ((e->rule.mask[word] & bit) == bit && + audit_filter_rules(tsk, &e->rule, ctx, n, &state)) { + rcu_read_unlock(); + return state; + } + } + } + rcu_read_unlock(); + return AUDIT_BUILD_CONTEXT; +} + +void audit_set_auditable(struct audit_context *ctx) +{ + ctx->auditable = 1; +} + static inline struct audit_context *audit_get_context(struct task_struct *tsk, int return_valid, int return_code) @@ -408,11 +468,20 @@ static inline struct audit_context *audit_get_context(struct task_struct *tsk, if (context->in_syscall && !context->auditable) { enum audit_state state; + state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]); + if (state == AUDIT_RECORD_CONTEXT) { + context->auditable = 1; + goto get_context; + } + + state = audit_filter_inodes(tsk, context); if (state == AUDIT_RECORD_CONTEXT) context->auditable = 1; + } +get_context: context->pid = tsk->pid; context->ppid = sys_getppid(); /* sic. tsk == current in all cases */ context->uid = tsk->uid; @@ -1142,37 +1211,20 @@ void __audit_inode_child(const char *dname, const struct inode *inode, return; /* determine matching parent */ - if (dname) - for (idx = 0; idx < context->name_count; idx++) - if (context->names[idx].pino == pino) { - const char *n; - const char *name = context->names[idx].name; - int dlen = strlen(dname); - int nlen = name ? strlen(name) : 0; - - if (nlen < dlen) - continue; - - /* disregard trailing slashes */ - n = name + nlen - 1; - while ((*n == '/') && (n > name)) - n--; - - /* find last path component */ - n = n - dlen + 1; - if (n < name) - continue; - else if (n > name) { - if (*--n != '/') - continue; - else - n++; - } + if (!dname) + goto no_match; + for (idx = 0; idx < context->name_count; idx++) + if (context->names[idx].pino == pino) { + const char *name = context->names[idx].name; - if (strncmp(n, dname, dlen) == 0) - goto update_context; - } + if (!name) + continue; + + if (audit_compare_dname_path(dname, name) == 0) + goto update_context; + } +no_match: /* catch-all in case match not found */ idx = context->name_count++; context->names[idx].name = NULL; |
