diff options
Diffstat (limited to 'kernel/audit.c')
| -rw-r--r-- | kernel/audit.c | 175 |
1 files changed, 140 insertions, 35 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index 0a813d2883e..04fe2e301b6 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -52,6 +52,7 @@ #include <linux/audit.h> #include <net/sock.h> +#include <net/netlink.h> #include <linux/skbuff.h> #include <linux/netlink.h> @@ -72,7 +73,7 @@ static int audit_failure = AUDIT_FAIL_PRINTK; * contains the (non-zero) pid. */ int audit_pid; -/* If audit_limit is non-zero, limit the rate of sending audit records +/* If audit_rate_limit is non-zero, limit the rate of sending audit records * to that number per second. This prevents DoS attacks, but results in * audit records being dropped. */ static int audit_rate_limit; @@ -102,7 +103,7 @@ static struct sock *audit_sock; * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of * being placed on the freelist). */ static DEFINE_SPINLOCK(audit_freelist_lock); -static int audit_freelist_count = 0; +static int audit_freelist_count; static LIST_HEAD(audit_freelist); static struct sk_buff_head audit_skb_queue; @@ -113,7 +114,7 @@ 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 */ -DECLARE_MUTEX(audit_netlink_sem); +DEFINE_MUTEX(audit_netlink_mutex); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting * audit records. Since printk uses a 1024 byte buffer, this buffer @@ -142,7 +143,7 @@ static void audit_set_pid(struct audit_buffer *ab, pid_t pid) nlh->nlmsg_pid = pid; } -static void audit_panic(const char *message) +void audit_panic(const char *message) { switch (audit_failure) { @@ -186,8 +187,14 @@ static inline int audit_rate_check(void) return retval; } -/* Emit at least 1 message per second, even if audit_rate_check is - * throttling. */ +/** + * audit_log_lost - conditionally log lost audit message event + * @message: the message stating reason for lost audit message + * + * Emit at least 1 message per second, even if audit_rate_check is + * throttling. + * Always increment the lost messages counter. +*/ void audit_log_lost(const char *message) { static unsigned long last_msg = 0; @@ -218,7 +225,6 @@ void audit_log_lost(const char *message) audit_backlog_limit); audit_panic(message); } - } static int audit_set_rate_limit(int limit, uid_t loginuid) @@ -300,8 +306,22 @@ static int kauditd_thread(void *dummy) remove_wait_queue(&kauditd_wait, &wait); } } + return 0; } +/** + * audit_send_reply - send an audit reply message via netlink + * @pid: process id to send reply to + * @seq: sequence number + * @type: audit message type + * @done: done (last) flag + * @multi: multi-part message flag + * @payload: payload data + * @size: payload size + * + * Allocates an skb, builds the netlink message, and sends it to the pid. + * No failure notifications. + */ void audit_send_reply(int pid, int seq, int type, int done, int multi, void *payload, int size) { @@ -342,15 +362,19 @@ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type) switch (msg_type) { case AUDIT_GET: case AUDIT_LIST: + case AUDIT_LIST_RULES: case AUDIT_SET: case AUDIT_ADD: + case AUDIT_ADD_RULE: case AUDIT_DEL: + case AUDIT_DEL_RULE: case AUDIT_SIGNAL_INFO: if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL)) err = -EPERM; break; case AUDIT_USER: case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG: + case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2: if (!cap_raised(eff_cap, CAP_AUDIT_WRITE)) err = -EPERM; break; @@ -376,7 +400,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) if (err) return err; - /* As soon as there's any sign of userspace auditd, start kauditd to talk to it */ + /* As soon as there's any sign of userspace auditd, + * start kauditd to talk to it */ if (!kauditd_task) kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); if (IS_ERR(kauditd_task)) { @@ -430,6 +455,7 @@ 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: + case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2: if (!audit_enabled && msg_type != AUDIT_USER_AVC) return 0; @@ -448,12 +474,23 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) break; case AUDIT_ADD: case AUDIT_DEL: - if (nlh->nlmsg_len < sizeof(struct audit_rule)) + if (nlmsg_len(nlh) < sizeof(struct audit_rule)) return -EINVAL; /* fallthrough */ case AUDIT_LIST: err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, - uid, seq, data, loginuid); + uid, seq, data, nlmsg_len(nlh), + loginuid); + break; + case AUDIT_ADD_RULE: + case AUDIT_DEL_RULE: + if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) + return -EINVAL; + /* fallthrough */ + case AUDIT_LIST_RULES: + err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, + uid, seq, data, nlmsg_len(nlh), + loginuid); break; case AUDIT_SIGNAL_INFO: sig_data.uid = audit_sig_uid; @@ -469,9 +506,11 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) return err < 0 ? err : 0; } -/* Get message from skb (based on rtnetlink_rcv_skb). Each message is +/* + * Get message from skb (based on rtnetlink_rcv_skb). Each message is * processed by audit_receive_msg. Malformed skbs with wrong length are - * discarded silently. */ + * discarded silently. + */ static void audit_receive_skb(struct sk_buff *skb) { int err; @@ -499,14 +538,14 @@ static void audit_receive(struct sock *sk, int length) struct sk_buff *skb; unsigned int qlen; - down(&audit_netlink_sem); + mutex_lock(&audit_netlink_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); } - up(&audit_netlink_sem); + mutex_unlock(&audit_netlink_mutex); } @@ -519,8 +558,9 @@ static int __init audit_init(void) THIS_MODULE); if (!audit_sock) audit_panic("cannot initialize netlink socket"); + else + audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; - audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; skb_queue_head_init(&audit_skb_queue); audit_initialized = 1; audit_enabled = audit_default; @@ -600,7 +640,10 @@ err: return NULL; } -/* Compute a serial number for the audit record. Audit records are +/** + * audit_serial - compute a serial number for the audit record + * + * Compute a serial number for the audit record. Audit records are * written to user-space as soon as they are generated, so a complete * audit record may be written in several pieces. The timestamp of the * record and this serial number are used by the user-space tools to @@ -612,8 +655,8 @@ err: * 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). */ - + * halts). + */ unsigned int audit_serial(void) { static spinlock_t serial_lock = SPIN_LOCK_UNLOCKED; @@ -649,6 +692,21 @@ static inline void audit_get_stamp(struct audit_context *ctx, * will be written at syscall exit. If there is no associated task, tsk * should be NULL. */ +/** + * audit_log_start - obtain an audit buffer + * @ctx: audit_context (may be NULL) + * @gfp_mask: type of allocation + * @type: audit message type + * + * Returns audit_buffer pointer on success or NULL on error. + * + * Obtain an audit buffer. This routine does locking to obtain the + * audit buffer, but then no locking is required for calls to + * audit_log_*format. If the task (ctx) is a task that is currently in a + * syscall, then the syscall is marked as auditable and an audit record + * will be written at syscall exit. If there is no associated task, then + * task context (ctx) should be NULL. + */ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type) { @@ -661,6 +719,9 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, if (!audit_initialized) return NULL; + if (unlikely(audit_filter_type(type))) + return NULL; + if (gfp_mask & __GFP_WAIT) reserve = 0; else @@ -713,6 +774,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, /** * audit_expand - expand skb in the audit buffer * @ab: audit_buffer + * @extra: space to add at tail of the skb * * Returns 0 (no space) on failed expansion, or available space if * successful. @@ -729,10 +791,12 @@ static inline int audit_expand(struct audit_buffer *ab, int extra) return skb_tailroom(skb); } -/* Format an audit message into the audit buffer. If there isn't enough +/* + * Format an audit message into the audit buffer. If there isn't enough * room in the audit buffer, more room will be allocated and vsnprint * will be called a second time. Currently, we assume that a printk - * can't format message larger than 1024 bytes, so we don't either. */ + * can't format message larger than 1024 bytes, so we don't either. + */ static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, va_list args) { @@ -757,7 +821,8 @@ static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, /* The printk buffer is 1024 bytes long, so if we get * here and AUDIT_BUFSIZ is at least 1024, then we can * log everything that printk could have logged. */ - avail = audit_expand(ab, max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); + avail = audit_expand(ab, + max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); if (!avail) goto out; len = vsnprintf(skb->tail, avail, fmt, args2); @@ -768,8 +833,14 @@ out: return; } -/* Format a message into the audit buffer. All the work is done in - * audit_log_vformat. */ +/** + * audit_log_format - format a message into the audit buffer. + * @ab: audit_buffer + * @fmt: format string + * @...: optional parameters matching @fmt string + * + * All the work is done in audit_log_vformat. + */ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) { va_list args; @@ -781,9 +852,18 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) va_end(args); } -/* This function will take the passed buf and convert it into a string of - * ascii hex digits. The new string is placed onto the skb. */ -void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, +/** + * audit_log_hex - convert a buffer to hex and append it to the audit skb + * @ab: the audit_buffer + * @buf: buffer to convert to hex + * @len: length of @buf to be converted + * + * No return value; failure to expand is silently ignored. + * + * This function will take the passed buf and convert it into a string of + * ascii hex digits. The new string is placed onto the skb. + */ +void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, size_t len) { int i, avail, new_len; @@ -812,10 +892,16 @@ void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, skb_put(skb, len << 1); /* new string is twice the old string */ } -/* This code will escape a string that is passed to it if the string - * contains a control character, unprintable character, double quote mark, +/** + * audit_log_unstrustedstring - log a string that may contain random characters + * @ab: audit_buffer + * @string: string to be logged + * + * This code will escape a string that is passed to it if the string + * contains a control character, unprintable character, double quote mark, * or a space. Unescaped strings will start and end with a double quote mark. - * Strings that are escaped are printed in hex (2 digits per char). */ + * Strings that are escaped are printed in hex (2 digits per char). + */ void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) { const unsigned char *p = string; @@ -854,10 +940,15 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix, kfree(path); } -/* The netlink_* functions cannot be called inside an irq context, so - * the audit buffer is places on a queue and a tasklet is scheduled to +/** + * audit_log_end - end one audit record + * @ab: the audit_buffer + * + * The netlink_* functions cannot be called inside an irq context, so + * the audit buffer is placed on a queue and a tasklet is scheduled to * remove them from the queue outside the irq context. May be called in - * any context. */ + * any context. + */ void audit_log_end(struct audit_buffer *ab) { if (!ab) @@ -878,9 +969,18 @@ void audit_log_end(struct audit_buffer *ab) audit_buffer_free(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. */ +/** + * audit_log - Log an audit record + * @ctx: audit context + * @gfp_mask: type of allocation + * @type: audit message type + * @fmt: format string to use + * @...: variable parameters matching the format string + * + * 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, gfp_t gfp_mask, int type, const char *fmt, ...) { @@ -895,3 +995,8 @@ void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, audit_log_end(ab); } } + +EXPORT_SYMBOL(audit_log_start); +EXPORT_SYMBOL(audit_log_end); +EXPORT_SYMBOL(audit_log_format); +EXPORT_SYMBOL(audit_log); |