diff options
Diffstat (limited to 'kernel/audit.c')
| -rw-r--r-- | kernel/audit.c | 123 |
1 files changed, 79 insertions, 44 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index ef35166fdc29..d321e251d32b 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -79,6 +79,8 @@ static int audit_rate_limit; /* Number of outstanding audit_buffers allowed. */ static int audit_backlog_limit = 64; +static int audit_backlog_wait_time = 60 * HZ; +static int audit_backlog_wait_overflow = 0; /* The identity of the user shutting down the audit system. */ uid_t audit_sig_uid = -1; @@ -106,18 +108,12 @@ static LIST_HEAD(audit_freelist); static struct sk_buff_head audit_skb_queue; static struct task_struct *kauditd_task; static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); - -/* 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. */ -static LIST_HEAD(audit_tsklist); -static LIST_HEAD(audit_entlist); -static LIST_HEAD(audit_extlist); +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 */ -static DECLARE_MUTEX(audit_netlink_sem); +DECLARE_MUTEX(audit_netlink_sem); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting * audit records. Since printk uses a 1024 byte buffer, this buffer @@ -137,6 +133,7 @@ struct audit_buffer { struct list_head list; struct sk_buff *skb; /* formatted skb ready to send */ struct audit_context *ctx; /* NULL or associated context */ + int gfp_mask; }; static void audit_set_pid(struct audit_buffer *ab, pid_t pid) @@ -233,7 +230,7 @@ static int audit_set_rate_limit(int limit, uid_t loginuid) { int old = audit_rate_limit; audit_rate_limit = limit; - audit_log(NULL, AUDIT_CONFIG_CHANGE, + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "audit_rate_limit=%d old=%d by auid=%u", audit_rate_limit, old, loginuid); return old; @@ -243,7 +240,7 @@ static int audit_set_backlog_limit(int limit, uid_t loginuid) { int old = audit_backlog_limit; audit_backlog_limit = limit; - audit_log(NULL, AUDIT_CONFIG_CHANGE, + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "audit_backlog_limit=%d old=%d by auid=%u", audit_backlog_limit, old, loginuid); return old; @@ -255,7 +252,7 @@ static int audit_set_enabled(int state, uid_t loginuid) if (state != 0 && state != 1) return -EINVAL; audit_enabled = state; - audit_log(NULL, AUDIT_CONFIG_CHANGE, + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "audit_enabled=%d old=%d by auid=%u", audit_enabled, old, loginuid); return old; @@ -269,7 +266,7 @@ static int audit_set_failure(int state, uid_t loginuid) && state != AUDIT_FAIL_PANIC) return -EINVAL; audit_failure = state; - audit_log(NULL, AUDIT_CONFIG_CHANGE, + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "audit_failure=%d old=%d by auid=%u", audit_failure, old, loginuid); return old; @@ -281,6 +278,7 @@ int kauditd_thread(void *dummy) while (1) { skb = skb_dequeue(&audit_skb_queue); + wake_up(&audit_backlog_wait); if (skb) { if (audit_pid) { int err = netlink_unicast(audit_sock, skb, audit_pid, 0); @@ -290,7 +288,7 @@ int kauditd_thread(void *dummy) audit_pid = 0; } } else { - printk(KERN_ERR "%s\n", skb->data + NLMSG_SPACE(0)); + printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0)); kfree_skb(skb); } } else { @@ -423,7 +421,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (status_get->mask & AUDIT_STATUS_PID) { int old = audit_pid; audit_pid = status_get->pid; - audit_log(NULL, AUDIT_CONFIG_CHANGE, + audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE, "audit_pid=%d old=%d by auid=%u", audit_pid, old, loginuid); } @@ -435,15 +433,21 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) break; case AUDIT_USER: case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG: - ab = audit_log_start(NULL, msg_type); - if (!ab) - break; /* audit_panic has been called */ - audit_log_format(ab, - "user pid=%d uid=%u auid=%u" - " msg='%.1024s'", - pid, uid, loginuid, (char *)data); - audit_set_pid(ab, pid); - audit_log_end(ab); + if (!audit_enabled && msg_type != AUDIT_USER_AVC) + return 0; + + err = audit_filter_user(&NETLINK_CB(skb), msg_type); + if (err == 1) { + err = 0; + ab = audit_log_start(NULL, GFP_KERNEL, msg_type); + if (ab) { + audit_log_format(ab, + "user pid=%d uid=%u auid=%u msg='%.1024s'", + pid, uid, loginuid, (char *)data); + audit_set_pid(ab, pid); + audit_log_end(ab); + } + } break; case AUDIT_ADD: case AUDIT_DEL: @@ -522,7 +526,7 @@ static int __init audit_init(void) skb_queue_head_init(&audit_skb_queue); audit_initialized = 1; audit_enabled = audit_default; - audit_log(NULL, AUDIT_KERNEL, "initialized"); + audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); return 0; } __initcall(audit_init); @@ -560,7 +564,7 @@ static void audit_buffer_free(struct audit_buffer *ab) } static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, - int gfp_mask, int type) + unsigned int __nocast gfp_mask, int type) { unsigned long flags; struct audit_buffer *ab = NULL; @@ -586,6 +590,7 @@ static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, goto err; ab->ctx = ctx; + ab->gfp_mask = gfp_mask; nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0)); nlh->nlmsg_type = type; nlh->nlmsg_flags = 0; @@ -605,26 +610,27 @@ err: * (timestamp,serial) tuple is unique for each syscall and is live from * syscall entry to syscall exit. * - * Atomic values are only guaranteed to be 24-bit, so we count down. - * * NOTE: Another possibility is to store the formatted records off the * audit context (for those records that have a context), and emit them * all at syscall exit. However, this could delay the reporting of * significant errors until syscall exit (or never, if the system * halts). */ + unsigned int audit_serial(void) { - static atomic_t serial = ATOMIC_INIT(0xffffff); - unsigned int a, b; + static spinlock_t serial_lock = SPIN_LOCK_UNLOCKED; + static unsigned int serial = 0; + unsigned long flags; + unsigned int ret; + + spin_lock_irqsave(&serial_lock, flags); do { - a = atomic_read(&serial); - if (atomic_dec_and_test(&serial)) - atomic_set(&serial, 0xffffff); - b = atomic_read(&serial); - } while (b != a - 1); + ret = ++serial; + } while (unlikely(!ret)); + spin_unlock_irqrestore(&serial_lock, flags); - return 0xffffff - b; + return ret; } static inline void audit_get_stamp(struct audit_context *ctx, @@ -644,17 +650,43 @@ static inline void audit_get_stamp(struct audit_context *ctx, * syscall, then the syscall is marked as auditable and an audit record * will be written at syscall exit. If there is no associated task, tsk * should be NULL. */ -struct audit_buffer *audit_log_start(struct audit_context *ctx, int type) + +struct audit_buffer *audit_log_start(struct audit_context *ctx, int gfp_mask, + int type) { struct audit_buffer *ab = NULL; struct timespec t; unsigned int serial; + int reserve; + unsigned long timeout_start = jiffies; if (!audit_initialized) return NULL; - if (audit_backlog_limit - && skb_queue_len(&audit_skb_queue) > audit_backlog_limit) { + if (gfp_mask & __GFP_WAIT) + reserve = 0; + else + reserve = 5; /* Allow atomic callers to go up to five + entries over the normal backlog limit */ + + while (audit_backlog_limit + && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) { + if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time + && time_before(jiffies, timeout_start + audit_backlog_wait_time)) { + + /* Wait for auditd to drain the queue a little */ + DECLARE_WAITQUEUE(wait, current); + set_current_state(TASK_INTERRUPTIBLE); + add_wait_queue(&audit_backlog_wait, &wait); + + if (audit_backlog_limit && + skb_queue_len(&audit_skb_queue) > audit_backlog_limit) + schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies); + + __set_current_state(TASK_RUNNING); + remove_wait_queue(&audit_backlog_wait, &wait); + continue; + } if (audit_rate_check()) printk(KERN_WARNING "audit: audit_backlog=%d > " @@ -662,10 +694,12 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, int type) skb_queue_len(&audit_skb_queue), audit_backlog_limit); audit_log_lost("backlog limit exceeded"); + audit_backlog_wait_time = audit_backlog_wait_overflow; + wake_up(&audit_backlog_wait); return NULL; } - ab = audit_buffer_alloc(ctx, GFP_ATOMIC, type); + ab = audit_buffer_alloc(ctx, gfp_mask, type); if (!ab) { audit_log_lost("out of memory in audit_log_start"); return NULL; @@ -689,7 +723,7 @@ static inline int audit_expand(struct audit_buffer *ab, int extra) { struct sk_buff *skb = ab->skb; int ret = pskb_expand_head(skb, skb_headroom(skb), extra, - GFP_ATOMIC); + ab->gfp_mask); if (ret < 0) { audit_log_lost("out of memory in audit_expand"); return 0; @@ -808,7 +842,7 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix, audit_log_format(ab, " %s", prefix); /* We will allow 11 spaces for ' (deleted)' to be appended */ - path = kmalloc(PATH_MAX+11, GFP_KERNEL); + path = kmalloc(PATH_MAX+11, ab->gfp_mask); if (!path) { audit_log_format(ab, "<no memory>"); return; @@ -840,7 +874,7 @@ void audit_log_end(struct audit_buffer *ab) ab->skb = NULL; wake_up_interruptible(&kauditd_wait); } else { - printk("%s\n", ab->skb->data + NLMSG_SPACE(0)); + printk(KERN_NOTICE "%s\n", ab->skb->data + NLMSG_SPACE(0)); } } audit_buffer_free(ab); @@ -849,12 +883,13 @@ void audit_log_end(struct audit_buffer *ab) /* Log an audit record. This is a convenience function that calls * audit_log_start, audit_log_vformat, and audit_log_end. It may be * called in any context. */ -void audit_log(struct audit_context *ctx, int type, const char *fmt, ...) +void audit_log(struct audit_context *ctx, int gfp_mask, int type, + const char *fmt, ...) { struct audit_buffer *ab; va_list args; - ab = audit_log_start(ctx, type); + ab = audit_log_start(ctx, gfp_mask, type); if (ab) { va_start(args, fmt); audit_log_vformat(ab, fmt, args); |