diff options
Diffstat (limited to 'kernel/audit.c')
| -rw-r--r-- | kernel/audit.c | 2363 |
1 files changed, 1652 insertions, 711 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index 91e53d04b6a9..26a332ffb1b8 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* audit.c -- Auditing support * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. * System-call specific features have moved to auditsc.c @@ -5,20 +6,6 @@ * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. * All Rights Reserved. * - * 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 - * * Written by Rickard E. (Rik) Faith <faith@redhat.com> * * Goals: 1) Integrate fully with Security Modules. @@ -38,11 +25,15 @@ * 6) Support low-overhead kernel-based filtering to minimize the * information that must be passed to user-space. * - * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ + * Audit userspace, documentation, tests, and bug/issue trackers: + * https://github.com/linux-audit */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/file.h> #include <linux/init.h> -#include <asm/types.h> +#include <linux/types.h> #include <linux/atomic.h> #include <linux/mm.h> #include <linux/export.h> @@ -51,19 +42,22 @@ #include <linux/kthread.h> #include <linux/kernel.h> #include <linux/syscalls.h> +#include <linux/spinlock.h> +#include <linux/rcupdate.h> +#include <linux/mutex.h> +#include <linux/gfp.h> +#include <linux/pid.h> #include <linux/audit.h> #include <net/sock.h> #include <net/netlink.h> #include <linux/skbuff.h> -#ifdef CONFIG_SECURITY #include <linux/security.h> -#endif -#include <net/netlink.h> +#include <linux/lsm_hooks.h> #include <linux/freezer.h> -#include <linux/tty.h> #include <linux/pid_namespace.h> +#include <net/netns/generic.h> #include "audit.h" @@ -72,44 +66,72 @@ #define AUDIT_DISABLED -1 #define AUDIT_UNINITIALIZED 0 #define AUDIT_INITIALIZED 1 -static int audit_initialized; +static int audit_initialized = AUDIT_UNINITIALIZED; -#define AUDIT_OFF 0 -#define AUDIT_ON 1 -#define AUDIT_LOCKED 2 -int audit_enabled; -int audit_ever_enabled; +u32 audit_enabled = AUDIT_OFF; +bool audit_ever_enabled = !!AUDIT_OFF; EXPORT_SYMBOL_GPL(audit_enabled); /* Default state when kernel boots without any parameters. */ -static int audit_default; +static u32 audit_default = AUDIT_OFF; /* If auditing cannot proceed, audit_failure selects what happens. */ -static int audit_failure = AUDIT_FAIL_PRINTK; +static u32 audit_failure = AUDIT_FAIL_PRINTK; -/* - * If audit records are to be written to the netlink socket, audit_pid - * contains the pid of the auditd process and audit_nlk_portid contains - * the portid to use to send netlink messages to that process. +/* private audit network namespace index */ +static unsigned int audit_net_id; + +/* Number of modules that provide a security context. + List of lsms that provide a security context */ +static u32 audit_subj_secctx_cnt; +static u32 audit_obj_secctx_cnt; +static const struct lsm_id *audit_subj_lsms[MAX_LSM_COUNT]; +static const struct lsm_id *audit_obj_lsms[MAX_LSM_COUNT]; + +/** + * struct audit_net - audit private network namespace data + * @sk: communication socket + */ +struct audit_net { + struct sock *sk; +}; + +/** + * struct auditd_connection - kernel/auditd connection state + * @pid: auditd PID + * @portid: netlink portid + * @net: the associated network namespace + * @rcu: RCU head + * + * Description: + * This struct is RCU protected; you must either hold the RCU lock for reading + * or the associated spinlock for writing. */ -int audit_pid; -static int audit_nlk_portid; +struct auditd_connection { + struct pid *pid; + u32 portid; + struct net *net; + struct rcu_head rcu; +}; +static struct auditd_connection __rcu *auditd_conn; +static DEFINE_SPINLOCK(auditd_conn_lock); /* 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; +static u32 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; +/* Number of outstanding audit_buffers allowed. + * When set to zero, this means unlimited. */ +static u32 audit_backlog_limit = 64; +#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ) +static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME; /* The identity of the user shutting down the audit system. */ -kuid_t audit_sig_uid = INVALID_UID; -pid_t audit_sig_pid = -1; -u32 audit_sig_sid = 0; +static kuid_t audit_sig_uid = INVALID_UID; +static pid_t audit_sig_pid = -1; +static struct lsm_prop audit_sig_lsm; /* Records can be lost in several ways: 0) [suppressed in audit_alloc] @@ -118,79 +140,211 @@ u32 audit_sig_sid = 0; 3) suppressed due to audit_rate_limit 4) suppressed due to audit_backlog_limit */ -static atomic_t audit_lost = ATOMIC_INIT(0); +static atomic_t audit_lost = ATOMIC_INIT(0); -/* The netlink socket. */ -static struct sock *audit_sock; +/* Monotonically increasing sum of time the kernel has spent + * waiting while the backlog limit is exceeded. + */ +static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0); /* 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). */ -static DEFINE_SPINLOCK(audit_freelist_lock); -static int audit_freelist_count; -static LIST_HEAD(audit_freelist); +static struct kmem_cache *audit_buffer_cache; + +/* queue msgs to send via kauditd_task */ +static struct sk_buff_head audit_queue; +/* queue msgs due to temporary unicast send problems */ +static struct sk_buff_head audit_retry_queue; +/* queue msgs waiting for new auditd connection */ +static struct sk_buff_head audit_hold_queue; -static struct sk_buff_head audit_skb_queue; -/* queue of skbs to send to auditd when/if it comes back */ -static struct sk_buff_head audit_skb_hold_queue; +/* queue servicing thread */ static struct task_struct *kauditd_task; static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); + +/* waitqueue for callers who are blocked on the audit backlog */ static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); -/* Serialize requests from userspace. */ -DEFINE_MUTEX(audit_cmd_mutex); +static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION, + .mask = -1, + .features = 0, + .lock = 0,}; + +static char *audit_feature_names[2] = { + "only_unset_loginuid", + "loginuid_immutable", +}; + +/** + * struct audit_ctl_mutex - serialize requests from userspace + * @lock: the mutex used for locking + * @owner: the task which owns the lock + * + * Description: + * This is the lock struct used to ensure we only process userspace requests + * in an orderly fashion. We can't simply use a mutex/lock here because we + * need to track lock ownership so we don't end up blocking the lock owner in + * audit_log_start() or similar. + */ +static struct audit_ctl_mutex { + struct mutex lock; + void *owner; +} 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 * should be at least that large. */ #define AUDIT_BUFSIZ 1024 -/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the - * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ -#define AUDIT_MAXFREE (2*NR_CPUS) - /* The audit_buffer is used when formatting an audit record. The caller * locks briefly to get the record off the freelist or to allocate the * buffer, and locks briefly to send the buffer to the netlink layer or * to place it on a transmit queue. Multiple audit_buffers can be in * use simultaneously. */ struct audit_buffer { - struct list_head list; - struct sk_buff *skb; /* formatted skb ready to send */ + struct sk_buff *skb; /* the skb for audit_log functions */ + struct sk_buff_head skb_list; /* formatted skbs, ready to send */ struct audit_context *ctx; /* NULL or associated context */ + struct audit_stamp stamp; /* audit stamp for these records */ gfp_t gfp_mask; }; struct audit_reply { - int pid; + __u32 portid; + struct net *net; struct sk_buff *skb; }; -static void audit_set_pid(struct audit_buffer *ab, pid_t pid) +/** + * auditd_test_task - Check to see if a given task is an audit daemon + * @task: the task to check + * + * Description: + * Return 1 if the task is a registered audit daemon, 0 otherwise. + */ +int auditd_test_task(struct task_struct *task) { - if (ab) { - struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); - nlh->nlmsg_pid = pid; + int rc; + struct auditd_connection *ac; + + rcu_read_lock(); + ac = rcu_dereference(auditd_conn); + rc = (ac && ac->pid == task_tgid(task) ? 1 : 0); + rcu_read_unlock(); + + return rc; +} + +/** + * audit_ctl_lock - Take the audit control lock + */ +void audit_ctl_lock(void) +{ + mutex_lock(&audit_cmd_mutex.lock); + audit_cmd_mutex.owner = current; +} + +/** + * audit_ctl_unlock - Drop the audit control lock + */ +void audit_ctl_unlock(void) +{ + audit_cmd_mutex.owner = NULL; + mutex_unlock(&audit_cmd_mutex.lock); +} + +/** + * audit_ctl_owner_current - Test to see if the current task owns the lock + * + * Description: + * Return true if the current task owns the audit control lock, false if it + * doesn't own the lock. + */ +static bool audit_ctl_owner_current(void) +{ + return (current == audit_cmd_mutex.owner); +} + +/** + * auditd_pid_vnr - Return the auditd PID relative to the namespace + * + * Description: + * Returns the PID in relation to the namespace, 0 on failure. + */ +static pid_t auditd_pid_vnr(void) +{ + pid_t pid; + const struct auditd_connection *ac; + + rcu_read_lock(); + ac = rcu_dereference(auditd_conn); + if (!ac || !ac->pid) + pid = 0; + else + pid = pid_vnr(ac->pid); + rcu_read_unlock(); + + return pid; +} + +/** + * audit_cfg_lsm - Identify a security module as providing a secctx. + * @lsmid: LSM identity + * @flags: which contexts are provided + * + * Description: + * Increments the count of the security modules providing a secctx. + * If the LSM id is already in the list leave it alone. + */ +void audit_cfg_lsm(const struct lsm_id *lsmid, int flags) +{ + int i; + + if (flags & AUDIT_CFG_LSM_SECCTX_SUBJECT) { + for (i = 0 ; i < audit_subj_secctx_cnt; i++) + if (audit_subj_lsms[i] == lsmid) + return; + audit_subj_lsms[audit_subj_secctx_cnt++] = lsmid; + } + if (flags & AUDIT_CFG_LSM_SECCTX_OBJECT) { + for (i = 0 ; i < audit_obj_secctx_cnt; i++) + if (audit_obj_lsms[i] == lsmid) + return; + audit_obj_lsms[audit_obj_secctx_cnt++] = lsmid; } } +/** + * audit_get_sk - Return the audit socket for the given network namespace + * @net: the destination network namespace + * + * Description: + * Returns the sock pointer if valid, NULL otherwise. The caller must ensure + * that a reference is held for the network namespace while the sock is in use. + */ +static struct sock *audit_get_sk(const struct net *net) +{ + struct audit_net *aunet; + + if (!net) + return NULL; + + aunet = net_generic(net, audit_net_id); + return aunet->sk; +} + void audit_panic(const char *message) { - switch (audit_failure) - { + switch (audit_failure) { case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: if (printk_ratelimit()) - printk(KERN_ERR "audit: %s\n", message); + pr_err("%s\n", message); break; case AUDIT_FAIL_PANIC: - /* test audit_pid since printk is always losey, why bother? */ - if (audit_pid) - panic("audit: %s\n", message); + panic("audit: %s\n", message); break; } } @@ -202,18 +356,17 @@ static inline int audit_rate_check(void) static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; - unsigned long elapsed; int retval = 0; - if (!audit_rate_limit) return 1; + if (!audit_rate_limit) + return 1; spin_lock_irqsave(&lock, flags); if (++messages < audit_rate_limit) { retval = 1; } else { - now = jiffies; - elapsed = now - last_check; - if (elapsed > HZ) { + now = jiffies; + if (time_after(now, last_check + HZ)) { last_check = now; messages = 0; retval = 1; @@ -247,7 +400,7 @@ void audit_log_lost(const char *message) if (!print) { spin_lock_irqsave(&lock, flags); now = jiffies; - if (now - last_msg > HZ) { + if (time_after(now, last_msg + HZ)) { print = 1; last_msg = now; } @@ -256,9 +409,7 @@ void audit_log_lost(const char *message) if (print) { if (printk_ratelimit()) - printk(KERN_WARNING - "audit: audit_lost=%d audit_rate_limit=%d " - "audit_backlog_limit=%d\n", + pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", atomic_read(&audit_lost), audit_rate_limit, audit_backlog_limit); @@ -266,16 +417,16 @@ void audit_log_lost(const char *message) } } -static int audit_log_config_change(char *function_name, int new, int old, +static int audit_log_config_change(char *function_name, u32 new, u32 old, int allow_changes) { struct audit_buffer *ab; int rc = 0; - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return rc; - audit_log_format(ab, "%s=%d old=%d", function_name, new, old); + audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old); audit_log_session_info(ab); rc = audit_log_task_context(ab); if (rc) @@ -285,9 +436,10 @@ static int audit_log_config_change(char *function_name, int new, int old, return rc; } -static int audit_do_config_change(char *function_name, int *to_change, int new) +static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) { - int allow_changes, rc = 0, old = *to_change; + int allow_changes, rc = 0; + u32 old = *to_change; /* check if we are locked */ if (audit_enabled == AUDIT_LOCKED) @@ -310,20 +462,26 @@ static int audit_do_config_change(char *function_name, int *to_change, int new) return rc; } -static int audit_set_rate_limit(int limit) +static int audit_set_rate_limit(u32 limit) { return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit); } -static int audit_set_backlog_limit(int limit) +static int audit_set_backlog_limit(u32 limit) { return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); } -static int audit_set_enabled(int state) +static int audit_set_backlog_wait_time(u32 timeout) +{ + return audit_do_config_change("audit_backlog_wait_time", + &audit_backlog_wait_time, timeout); +} + +static int audit_set_enabled(u32 state) { int rc; - if (state < AUDIT_OFF || state > AUDIT_LOCKED) + if (state > AUDIT_LOCKED) return -EINVAL; rc = audit_do_config_change("audit_enabled", &audit_enabled, state); @@ -333,7 +491,7 @@ static int audit_set_enabled(int state) return rc; } -static int audit_set_failure(int state) +static int audit_set_failure(u32 state) { if (state != AUDIT_FAIL_SILENT && state != AUDIT_FAIL_PRINTK @@ -343,151 +501,477 @@ static int audit_set_failure(int state) return audit_do_config_change("audit_failure", &audit_failure, state); } -/* - * Queue skbs to be sent to auditd when/if it comes back. These skbs should - * already have been sent via prink/syslog and so if these messages are dropped - * it is not a huge concern since we already passed the audit_log_lost() - * notification and stuff. This is just nice to get audit messages during - * boot before auditd is running or messages generated while auditd is stopped. - * This only holds messages is audit_default is set, aka booting with audit=1 - * or building your kernel that way. +/** + * auditd_conn_free - RCU helper to release an auditd connection struct + * @rcu: RCU head + * + * Description: + * Drop any references inside the auditd connection tracking struct and free + * the memory. */ -static void audit_hold_skb(struct sk_buff *skb) +static void auditd_conn_free(struct rcu_head *rcu) { - if (audit_default && - skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) - skb_queue_tail(&audit_skb_hold_queue, skb); - else - kfree_skb(skb); + struct auditd_connection *ac; + + ac = container_of(rcu, struct auditd_connection, rcu); + put_pid(ac->pid); + put_net(ac->net); + kfree(ac); } -/* - * For one reason or another this nlh isn't getting delivered to the userspace - * audit daemon, just send it to printk. +/** + * auditd_set - Set/Reset the auditd connection state + * @pid: auditd PID + * @portid: auditd netlink portid + * @net: auditd network namespace pointer + * @skb: the netlink command from the audit daemon + * @ack: netlink ack flag, cleared if ack'd here + * + * Description: + * This function will obtain and drop network namespace references as + * necessary. Returns zero on success, negative values on failure. */ -static void audit_printk_skb(struct sk_buff *skb) +static int auditd_set(struct pid *pid, u32 portid, struct net *net, + struct sk_buff *skb, bool *ack) { - struct nlmsghdr *nlh = nlmsg_hdr(skb); - char *data = nlmsg_data(nlh); + unsigned long flags; + struct auditd_connection *ac_old, *ac_new; + struct nlmsghdr *nlh; - if (nlh->nlmsg_type != AUDIT_EOE) { - if (printk_ratelimit()) - printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); - else - audit_log_lost("printk limit exceeded\n"); + if (!pid || !net) + return -EINVAL; + + ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL); + if (!ac_new) + return -ENOMEM; + ac_new->pid = get_pid(pid); + ac_new->portid = portid; + ac_new->net = get_net(net); + + /* send the ack now to avoid a race with the queue backlog */ + if (*ack) { + nlh = nlmsg_hdr(skb); + netlink_ack(skb, nlh, 0, NULL); + *ack = false; } - audit_hold_skb(skb); + spin_lock_irqsave(&auditd_conn_lock, flags); + ac_old = rcu_dereference_protected(auditd_conn, + lockdep_is_held(&auditd_conn_lock)); + rcu_assign_pointer(auditd_conn, ac_new); + spin_unlock_irqrestore(&auditd_conn_lock, flags); + + if (ac_old) + call_rcu(&ac_old->rcu, auditd_conn_free); + + return 0; } -static void kauditd_send_skb(struct sk_buff *skb) +/** + * kauditd_printk_skb - Print the audit record to the ring buffer + * @skb: audit record + * + * Whatever the reason, this packet may not make it to the auditd connection + * so write it via printk so the information isn't completely lost. + */ +static void kauditd_printk_skb(struct sk_buff *skb) { - int err; - /* take a reference in case we can't send it and we want to hold it */ - skb_get(skb); - err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); - if (err < 0) { - BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ - printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); - audit_log_lost("auditd disappeared\n"); - audit_pid = 0; - /* we might get lucky and get this in the next auditd */ - audit_hold_skb(skb); - } else - /* drop the extra reference if sent ok */ - consume_skb(skb); + struct nlmsghdr *nlh = nlmsg_hdr(skb); + char *data = nlmsg_data(nlh); + + if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit()) + pr_notice("type=%d %s\n", nlh->nlmsg_type, data); } -/* - * flush_hold_queue - empty the hold queue if auditd appears +/** + * kauditd_rehold_skb - Handle a audit record send failure in the hold queue + * @skb: audit record + * @error: error code (unused) * - * If auditd just started, drain the queue of messages already - * sent to syslog/printk. Remember loss here is ok. We already - * called audit_log_lost() if it didn't go out normally. so the - * race between the skb_dequeue and the next check for audit_pid - * doesn't matter. + * Description: + * This should only be used by the kauditd_thread when it fails to flush the + * hold queue. + */ +static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error) +{ + /* put the record back in the queue */ + skb_queue_tail(&audit_hold_queue, skb); +} + +/** + * kauditd_hold_skb - Queue an audit record, waiting for auditd + * @skb: audit record + * @error: error code * - * If you ever find kauditd to be too slow we can get a perf win - * by doing our own locking and keeping better track if there - * are messages in this queue. I don't see the need now, but - * in 5 years when I want to play with this again I'll see this - * note and still have no friggin idea what i'm thinking today. + * Description: + * Queue the audit record, waiting for an instance of auditd. When this + * function is called we haven't given up yet on sending the record, but things + * are not looking good. The first thing we want to do is try to write the + * record via printk and then see if we want to try and hold on to the record + * and queue it, if we have room. If we want to hold on to the record, but we + * don't have room, record a record lost message. */ -static void flush_hold_queue(void) +static void kauditd_hold_skb(struct sk_buff *skb, int error) { - struct sk_buff *skb; + /* at this point it is uncertain if we will ever send this to auditd so + * try to send the message via printk before we go any further */ + kauditd_printk_skb(skb); + + /* can we just silently drop the message? */ + if (!audit_default) + goto drop; + + /* the hold queue is only for when the daemon goes away completely, + * not -EAGAIN failures; if we are in a -EAGAIN state requeue the + * record on the retry queue unless it's full, in which case drop it + */ + if (error == -EAGAIN) { + if (!audit_backlog_limit || + skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { + skb_queue_tail(&audit_retry_queue, skb); + return; + } + audit_log_lost("kauditd retry queue overflow"); + goto drop; + } - if (!audit_default || !audit_pid) + /* if we have room in the hold queue, queue the message */ + if (!audit_backlog_limit || + skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { + skb_queue_tail(&audit_hold_queue, skb); return; + } + + /* we have no other options - drop the message */ + audit_log_lost("kauditd hold queue overflow"); +drop: + kfree_skb(skb); +} - skb = skb_dequeue(&audit_skb_hold_queue); - if (likely(!skb)) +/** + * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd + * @skb: audit record + * @error: error code (unused) + * + * Description: + * Not as serious as kauditd_hold_skb() as we still have a connected auditd, + * but for some reason we are having problems sending it audit records so + * queue the given record and attempt to resend. + */ +static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error) +{ + if (!audit_backlog_limit || + skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { + skb_queue_tail(&audit_retry_queue, skb); return; + } - while (skb && audit_pid) { - kauditd_send_skb(skb); - skb = skb_dequeue(&audit_skb_hold_queue); + /* we have to drop the record, send it via printk as a last effort */ + kauditd_printk_skb(skb); + audit_log_lost("kauditd retry queue overflow"); + kfree_skb(skb); +} + +/** + * auditd_reset - Disconnect the auditd connection + * @ac: auditd connection state + * + * Description: + * Break the auditd/kauditd connection and move all the queued records into the + * hold queue in case auditd reconnects. It is important to note that the @ac + * pointer should never be dereferenced inside this function as it may be NULL + * or invalid, you can only compare the memory address! If @ac is NULL then + * the connection will always be reset. + */ +static void auditd_reset(const struct auditd_connection *ac) +{ + unsigned long flags; + struct sk_buff *skb; + struct auditd_connection *ac_old; + + /* if it isn't already broken, break the connection */ + spin_lock_irqsave(&auditd_conn_lock, flags); + ac_old = rcu_dereference_protected(auditd_conn, + lockdep_is_held(&auditd_conn_lock)); + if (ac && ac != ac_old) { + /* someone already registered a new auditd connection */ + spin_unlock_irqrestore(&auditd_conn_lock, flags); + return; } + rcu_assign_pointer(auditd_conn, NULL); + spin_unlock_irqrestore(&auditd_conn_lock, flags); + + if (ac_old) + call_rcu(&ac_old->rcu, auditd_conn_free); + + /* flush the retry queue to the hold queue, but don't touch the main + * queue since we need to process that normally for multicast */ + while ((skb = skb_dequeue(&audit_retry_queue))) + kauditd_hold_skb(skb, -ECONNREFUSED); +} + +/** + * auditd_send_unicast_skb - Send a record via unicast to auditd + * @skb: audit record + * + * Description: + * Send a skb to the audit daemon, returns positive/zero values on success and + * negative values on failure; in all cases the skb will be consumed by this + * function. If the send results in -ECONNREFUSED the connection with auditd + * will be reset. This function may sleep so callers should not hold any locks + * where this would cause a problem. + */ +static int auditd_send_unicast_skb(struct sk_buff *skb) +{ + int rc; + u32 portid; + struct net *net; + struct sock *sk; + struct auditd_connection *ac; + + /* NOTE: we can't call netlink_unicast while in the RCU section so + * take a reference to the network namespace and grab local + * copies of the namespace, the sock, and the portid; the + * namespace and sock aren't going to go away while we hold a + * reference and if the portid does become invalid after the RCU + * section netlink_unicast() should safely return an error */ + + rcu_read_lock(); + ac = rcu_dereference(auditd_conn); + if (!ac) { + rcu_read_unlock(); + kfree_skb(skb); + rc = -ECONNREFUSED; + goto err; + } + net = get_net(ac->net); + sk = audit_get_sk(net); + portid = ac->portid; + rcu_read_unlock(); + + rc = netlink_unicast(sk, skb, portid, 0); + put_net(net); + if (rc < 0) + goto err; + + return rc; + +err: + if (ac && rc == -ECONNREFUSED) + auditd_reset(ac); + return rc; +} + +/** + * kauditd_send_queue - Helper for kauditd_thread to flush skb queues + * @sk: the sending sock + * @portid: the netlink destination + * @queue: the skb queue to process + * @retry_limit: limit on number of netlink unicast failures + * @skb_hook: per-skb hook for additional processing + * @err_hook: hook called if the skb fails the netlink unicast send + * + * Description: + * Run through the given queue and attempt to send the audit records to auditd, + * returns zero on success, negative values on failure. It is up to the caller + * to ensure that the @sk is valid for the duration of this function. + * + */ +static int kauditd_send_queue(struct sock *sk, u32 portid, + struct sk_buff_head *queue, + unsigned int retry_limit, + void (*skb_hook)(struct sk_buff *skb), + void (*err_hook)(struct sk_buff *skb, int error)) +{ + int rc = 0; + struct sk_buff *skb = NULL; + struct sk_buff *skb_tail; + unsigned int failed = 0; + + /* NOTE: kauditd_thread takes care of all our locking, we just use + * the netlink info passed to us (e.g. sk and portid) */ + + skb_tail = skb_peek_tail(queue); + while ((skb != skb_tail) && (skb = skb_dequeue(queue))) { + /* call the skb_hook for each skb we touch */ + if (skb_hook) + (*skb_hook)(skb); + + /* can we send to anyone via unicast? */ + if (!sk) { + if (err_hook) + (*err_hook)(skb, -ECONNREFUSED); + continue; + } + +retry: + /* grab an extra skb reference in case of error */ + skb_get(skb); + rc = netlink_unicast(sk, skb, portid, 0); + if (rc < 0) { + /* send failed - try a few times unless fatal error */ + if (++failed >= retry_limit || + rc == -ECONNREFUSED || rc == -EPERM) { + sk = NULL; + if (err_hook) + (*err_hook)(skb, rc); + if (rc == -EAGAIN) + rc = 0; + /* continue to drain the queue */ + continue; + } else + goto retry; + } else { + /* skb sent - drop the extra reference and continue */ + consume_skb(skb); + failed = 0; + } + } + + return (rc >= 0 ? 0 : rc); +} + +/* + * kauditd_send_multicast_skb - Send a record to any multicast listeners + * @skb: audit record + * + * Description: + * Write a multicast message to anyone listening in the initial network + * namespace. This function doesn't consume an skb as might be expected since + * it has to copy it anyways. + */ +static void kauditd_send_multicast_skb(struct sk_buff *skb) +{ + struct sk_buff *copy; + struct sock *sock = audit_get_sk(&init_net); + struct nlmsghdr *nlh; + + /* NOTE: we are not taking an additional reference for init_net since + * we don't have to worry about it going away */ + + if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) + return; /* - * if auditd just disappeared but we - * dequeued an skb we need to drop ref + * The seemingly wasteful skb_copy() rather than bumping the refcount + * using skb_get() is necessary because non-standard mods are made to + * the skb by the original kaudit unicast socket send routine. The + * existing auditd daemon assumes this breakage. Fixing this would + * require co-ordinating a change in the established protocol between + * the kaudit kernel subsystem and the auditd userspace code. There is + * no reason for new multicast clients to continue with this + * non-compliance. */ - if (skb) - consume_skb(skb); + copy = skb_copy(skb, GFP_KERNEL); + if (!copy) + return; + nlh = nlmsg_hdr(copy); + nlh->nlmsg_len = skb->len; + + nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL); } +/** + * kauditd_thread - Worker thread to send audit records to userspace + * @dummy: unused + */ static int kauditd_thread(void *dummy) { + int rc; + u32 portid = 0; + struct net *net = NULL; + struct sock *sk = NULL; + struct auditd_connection *ac; + +#define UNICAST_RETRIES 5 + set_freezable(); while (!kthread_should_stop()) { - struct sk_buff *skb; - DECLARE_WAITQUEUE(wait, current); - - flush_hold_queue(); + /* NOTE: see the lock comments in auditd_send_unicast_skb() */ + rcu_read_lock(); + ac = rcu_dereference(auditd_conn); + if (!ac) { + rcu_read_unlock(); + goto main_queue; + } + net = get_net(ac->net); + sk = audit_get_sk(net); + portid = ac->portid; + rcu_read_unlock(); + + /* attempt to flush the hold queue */ + rc = kauditd_send_queue(sk, portid, + &audit_hold_queue, UNICAST_RETRIES, + NULL, kauditd_rehold_skb); + if (rc < 0) { + sk = NULL; + auditd_reset(ac); + goto main_queue; + } - skb = skb_dequeue(&audit_skb_queue); - wake_up(&audit_backlog_wait); - if (skb) { - if (audit_pid) - kauditd_send_skb(skb); - else - audit_printk_skb(skb); - continue; + /* attempt to flush the retry queue */ + rc = kauditd_send_queue(sk, portid, + &audit_retry_queue, UNICAST_RETRIES, + NULL, kauditd_hold_skb); + if (rc < 0) { + sk = NULL; + auditd_reset(ac); + goto main_queue; } - set_current_state(TASK_INTERRUPTIBLE); - add_wait_queue(&kauditd_wait, &wait); - if (!skb_queue_len(&audit_skb_queue)) { - try_to_freeze(); - schedule(); +main_queue: + /* process the main queue - do the multicast send and attempt + * unicast, dump failed record sends to the retry queue; if + * sk == NULL due to previous failures we will just do the + * multicast send and move the record to the hold queue */ + rc = kauditd_send_queue(sk, portid, &audit_queue, 1, + kauditd_send_multicast_skb, + (sk ? + kauditd_retry_skb : kauditd_hold_skb)); + if (ac && rc < 0) + auditd_reset(ac); + sk = NULL; + + /* drop our netns reference, no auditd sends past this line */ + if (net) { + put_net(net); + net = NULL; } - __set_current_state(TASK_RUNNING); - remove_wait_queue(&kauditd_wait, &wait); + /* we have processed all the queues so wake everyone */ + wake_up(&audit_backlog_wait); + + /* NOTE: we want to wake up if there is anything on the queue, + * regardless of if an auditd is connected, as we need to + * do the multicast send and rotate records from the + * main queue to the retry/hold queues */ + wait_event_freezable(kauditd_wait, + (skb_queue_len(&audit_queue) ? 1 : 0)); } + return 0; } -int audit_send_list(void *_dest) +int audit_send_list_thread(void *_dest) { struct audit_netlink_list *dest = _dest; - int pid = dest->pid; struct sk_buff *skb; + struct sock *sk = audit_get_sk(dest->net); /* wait for parent to finish and send an ACK */ - mutex_lock(&audit_cmd_mutex); - mutex_unlock(&audit_cmd_mutex); + audit_ctl_lock(); + audit_ctl_unlock(); while ((skb = __skb_dequeue(&dest->q)) != NULL) - netlink_unicast(audit_sock, skb, pid, 0); + netlink_unicast(sk, skb, dest->portid, 0); + put_net(dest->net); kfree(dest); return 0; } -struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, +struct sk_buff *audit_make_reply(int seq, int type, int done, int multi, const void *payload, int size) { struct sk_buff *skb; @@ -500,7 +984,7 @@ struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, if (!skb) return NULL; - nlh = nlmsg_put(skb, pid, seq, t, size, flags); + nlh = nlmsg_put(skb, 0, seq, t, size, flags); if (!nlh) goto out_kfree_skb; data = nlmsg_data(nlh); @@ -512,22 +996,35 @@ out_kfree_skb: return NULL; } +static void audit_free_reply(struct audit_reply *reply) +{ + if (!reply) + return; + + kfree_skb(reply->skb); + if (reply->net) + put_net(reply->net); + kfree(reply); +} + static int audit_send_reply_thread(void *arg) { struct audit_reply *reply = (struct audit_reply *)arg; - mutex_lock(&audit_cmd_mutex); - mutex_unlock(&audit_cmd_mutex); + audit_ctl_lock(); + audit_ctl_unlock(); /* Ignore failure. It'll only happen if the sender goes away, because our timeout is set to infinite. */ - netlink_unicast(audit_sock, reply->skb, reply->pid, 0); - kfree(reply); + netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0); + reply->skb = NULL; + audit_free_reply(reply); return 0; } + /** * audit_send_reply - send an audit reply message via netlink - * @pid: process id to send reply to + * @request_skb: skb of request we are replying to (used to target the reply) * @seq: sequence number * @type: audit message type * @done: done (last) flag @@ -535,33 +1032,32 @@ static int audit_send_reply_thread(void *arg) * @payload: payload data * @size: payload size * - * Allocates an skb, builds the netlink message, and sends it to the pid. - * No failure notifications. + * Allocates a skb, builds the netlink message, and sends it to the port id. */ -static void audit_send_reply(int pid, int seq, int type, int done, int multi, - const void *payload, int size) +static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, + int multi, const void *payload, int size) { - struct sk_buff *skb; struct task_struct *tsk; - struct audit_reply *reply = kmalloc(sizeof(struct audit_reply), - GFP_KERNEL); + struct audit_reply *reply; + reply = kzalloc(sizeof(*reply), GFP_KERNEL); if (!reply) return; - skb = audit_make_reply(pid, seq, type, done, multi, payload, size); - if (!skb) - goto out; - - reply->pid = pid; - reply->skb = skb; + reply->skb = audit_make_reply(seq, type, done, multi, payload, size); + if (!reply->skb) + goto err; + reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk)); + reply->portid = NETLINK_CB(request_skb).portid; tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply"); - if (!IS_ERR(tsk)) - return; - kfree_skb(skb); -out: - kfree(reply); + if (IS_ERR(tsk)) + goto err; + + return; + +err: + audit_free_reply(reply); } /* @@ -572,10 +1068,19 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) { int err = 0; - /* Only support the initial namespaces for now. */ - if ((current_user_ns() != &init_user_ns) || - (task_active_pid_ns(current) != &init_pid_ns)) - return -EPERM; + /* Only support initial user namespace for now. */ + /* + * We return ECONNREFUSED because it tricks userspace into thinking + * that audit was not configured into the kernel. Lots of users + * configure their PAM stack (because that's what the distro does) + * to reject login if unable to send messages to audit. If we return + * ECONNREFUSED the PAM stack thinks the kernel does not have audit + * configured in and will let login proceed. If we return EPERM + * userspace will reject all logins. This should be removed when we + * support non init namespaces!! + */ + if (current_user_ns() != &init_user_ns) + return -ECONNREFUSED; switch (msg_type) { case AUDIT_LIST: @@ -584,6 +1089,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) return -EOPNOTSUPP; case AUDIT_GET: case AUDIT_SET: + case AUDIT_GET_FEATURE: + case AUDIT_SET_FEATURE: case AUDIT_LIST_RULES: case AUDIT_ADD_RULE: case AUDIT_DEL_RULE: @@ -592,13 +1099,18 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) case AUDIT_TTY_SET: case AUDIT_TRIM: case AUDIT_MAKE_EQUIV: - if (!capable(CAP_AUDIT_CONTROL)) + /* Only support auditd and auditctl in initial pid namespace + * for now. */ + if (task_active_pid_ns(current) != &init_pid_ns) + return -EPERM; + + if (!netlink_capable(skb, 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 (!capable(CAP_AUDIT_WRITE)) + if (!netlink_capable(skb, CAP_AUDIT_WRITE)) err = -EPERM; break; default: /* bad msg */ @@ -608,154 +1120,358 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) return err; } -static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) +static void audit_log_common_recv_msg(struct audit_context *context, + struct audit_buffer **ab, u16 msg_type) { - int rc = 0; uid_t uid = from_kuid(&init_user_ns, current_uid()); + pid_t pid = task_tgid_nr(current); - if (!audit_enabled) { + if (!audit_enabled && msg_type != AUDIT_USER_AVC) { *ab = NULL; - return rc; + return; } - *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); + *ab = audit_log_start(context, GFP_KERNEL, msg_type); if (unlikely(!*ab)) - return rc; - audit_log_format(*ab, "pid=%d uid=%u", task_tgid_vnr(current), uid); + return; + audit_log_format(*ab, "pid=%d uid=%u ", pid, uid); audit_log_session_info(*ab); audit_log_task_context(*ab); +} - return rc; +static inline void audit_log_user_recv_msg(struct audit_buffer **ab, + u16 msg_type) +{ + audit_log_common_recv_msg(NULL, ab, msg_type); +} + +static int is_audit_feature_set(int i) +{ + return af.features & AUDIT_FEATURE_TO_MASK(i); +} + +static int audit_get_feature(struct sk_buff *skb) +{ + u32 seq; + + seq = nlmsg_hdr(skb)->nlmsg_seq; + + audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af)); + + return 0; } -static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) +static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, + u32 old_lock, u32 new_lock, int res) +{ + struct audit_buffer *ab; + + if (audit_enabled == AUDIT_OFF) + return; + + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE); + if (!ab) + return; + audit_log_task_info(ab); + audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", + audit_feature_names[which], !!old_feature, !!new_feature, + !!old_lock, !!new_lock, res); + audit_log_end(ab); +} + +static int audit_set_feature(struct audit_features *uaf) +{ + int i; + + BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); + + /* if there is ever a version 2 we should handle that here */ + + for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { + u32 feature = AUDIT_FEATURE_TO_MASK(i); + u32 old_feature, new_feature, old_lock, new_lock; + + /* if we are not changing this feature, move along */ + if (!(feature & uaf->mask)) + continue; + + old_feature = af.features & feature; + new_feature = uaf->features & feature; + new_lock = (uaf->lock | af.lock) & feature; + old_lock = af.lock & feature; + + /* are we changing a locked feature? */ + if (old_lock && (new_feature != old_feature)) { + audit_log_feature_change(i, old_feature, new_feature, + old_lock, new_lock, 0); + return -EPERM; + } + } + /* nothing invalid, do the changes */ + for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { + u32 feature = AUDIT_FEATURE_TO_MASK(i); + u32 old_feature, new_feature, old_lock, new_lock; + + /* if we are not changing this feature, move along */ + if (!(feature & uaf->mask)) + continue; + + old_feature = af.features & feature; + new_feature = uaf->features & feature; + old_lock = af.lock & feature; + new_lock = (uaf->lock | af.lock) & feature; + + if (new_feature != old_feature) + audit_log_feature_change(i, old_feature, new_feature, + old_lock, new_lock, 1); + + if (new_feature) + af.features |= feature; + else + af.features &= ~feature; + af.lock |= new_lock; + } + + return 0; +} + +static int audit_replace(struct pid *pid) +{ + pid_t pvnr; + struct sk_buff *skb; + + pvnr = pid_vnr(pid); + skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); + if (!skb) + return -ENOMEM; + return auditd_send_unicast_skb(skb); +} + +static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, + bool *ack) { u32 seq; void *data; - struct audit_status *status_get, status_set; + int data_len; int err; struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; struct audit_sig_info *sig_data; - char *ctx = NULL; - u32 len; + struct lsm_context lsmctx = { NULL, 0, 0 }; err = audit_netlink_ok(skb, msg_type); if (err) return err; - /* 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)) { - err = PTR_ERR(kauditd_task); - kauditd_task = NULL; - return err; - } - } seq = nlh->nlmsg_seq; data = nlmsg_data(nlh); + data_len = nlmsg_len(nlh); switch (msg_type) { - case AUDIT_GET: - status_set.enabled = audit_enabled; - status_set.failure = audit_failure; - status_set.pid = audit_pid; - status_set.rate_limit = audit_rate_limit; - status_set.backlog_limit = audit_backlog_limit; - status_set.lost = atomic_read(&audit_lost); - status_set.backlog = skb_queue_len(&audit_skb_queue); - audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_GET, 0, 0, - &status_set, sizeof(status_set)); + case AUDIT_GET: { + struct audit_status s; + memset(&s, 0, sizeof(s)); + s.enabled = audit_enabled; + s.failure = audit_failure; + /* NOTE: use pid_vnr() so the PID is relative to the current + * namespace */ + s.pid = auditd_pid_vnr(); + s.rate_limit = audit_rate_limit; + s.backlog_limit = audit_backlog_limit; + s.lost = atomic_read(&audit_lost); + s.backlog = skb_queue_len(&audit_queue); + s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; + s.backlog_wait_time = audit_backlog_wait_time; + s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual); + audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); break; - case AUDIT_SET: - if (nlh->nlmsg_len < sizeof(struct audit_status)) - return -EINVAL; - status_get = (struct audit_status *)data; - if (status_get->mask & AUDIT_STATUS_ENABLED) { - err = audit_set_enabled(status_get->enabled); + } + case AUDIT_SET: { + struct audit_status s; + memset(&s, 0, sizeof(s)); + /* guard against past and future API changes */ + memcpy(&s, data, min_t(size_t, sizeof(s), data_len)); + if (s.mask & AUDIT_STATUS_ENABLED) { + err = audit_set_enabled(s.enabled); if (err < 0) return err; } - if (status_get->mask & AUDIT_STATUS_FAILURE) { - err = audit_set_failure(status_get->failure); + if (s.mask & AUDIT_STATUS_FAILURE) { + err = audit_set_failure(s.failure); if (err < 0) return err; } - if (status_get->mask & AUDIT_STATUS_PID) { - int new_pid = status_get->pid; + if (s.mask & AUDIT_STATUS_PID) { + /* NOTE: we are using the vnr PID functions below + * because the s.pid value is relative to the + * namespace of the caller; at present this + * doesn't matter much since you can really only + * run auditd from the initial pid namespace, but + * something to keep in mind if this changes */ + pid_t new_pid = s.pid; + pid_t auditd_pid; + struct pid *req_pid = task_tgid(current); + + /* Sanity check - PID values must match. Setting + * pid to 0 is how auditd ends auditing. */ + if (new_pid && (new_pid != pid_vnr(req_pid))) + return -EINVAL; + + /* test the auditd connection */ + audit_replace(req_pid); + + auditd_pid = auditd_pid_vnr(); + if (auditd_pid) { + /* replacing a healthy auditd is not allowed */ + if (new_pid) { + audit_log_config_change("audit_pid", + new_pid, auditd_pid, 0); + return -EEXIST; + } + /* only current auditd can unregister itself */ + if (pid_vnr(req_pid) != auditd_pid) { + audit_log_config_change("audit_pid", + new_pid, auditd_pid, 0); + return -EACCES; + } + } - if (audit_enabled != AUDIT_OFF) - audit_log_config_change("audit_pid", new_pid, audit_pid, 1); - audit_pid = new_pid; - audit_nlk_portid = NETLINK_CB(skb).portid; + if (new_pid) { + /* register a new auditd connection */ + err = auditd_set(req_pid, + NETLINK_CB(skb).portid, + sock_net(NETLINK_CB(skb).sk), + skb, ack); + if (audit_enabled != AUDIT_OFF) + audit_log_config_change("audit_pid", + new_pid, + auditd_pid, + err ? 0 : 1); + if (err) + return err; + + /* try to process any backlog */ + wake_up_interruptible(&kauditd_wait); + } else { + if (audit_enabled != AUDIT_OFF) + audit_log_config_change("audit_pid", + new_pid, + auditd_pid, 1); + + /* unregister the auditd connection */ + auditd_reset(NULL); + } + } + if (s.mask & AUDIT_STATUS_RATE_LIMIT) { + err = audit_set_rate_limit(s.rate_limit); + if (err < 0) + return err; } - if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) { - err = audit_set_rate_limit(status_get->rate_limit); + if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { + err = audit_set_backlog_limit(s.backlog_limit); if (err < 0) return err; } - if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) - err = audit_set_backlog_limit(status_get->backlog_limit); + if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) { + if (sizeof(s) > (size_t)nlh->nlmsg_len) + return -EINVAL; + if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME) + return -EINVAL; + err = audit_set_backlog_wait_time(s.backlog_wait_time); + if (err < 0) + return err; + } + if (s.mask == AUDIT_STATUS_LOST) { + u32 lost = atomic_xchg(&audit_lost, 0); + + audit_log_config_change("lost", 0, lost, 1); + return lost; + } + if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) { + u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0); + + audit_log_config_change("backlog_wait_time_actual", 0, actual, 1); + return actual; + } + break; + } + case AUDIT_GET_FEATURE: + err = audit_get_feature(skb); + if (err) + return err; + break; + case AUDIT_SET_FEATURE: + if (data_len < sizeof(struct audit_features)) + return -EINVAL; + err = audit_set_feature(data); + if (err) + return err; 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; + /* exit early if there isn't at least one character to print */ + if (data_len < 2) + return -EINVAL; + + err = audit_filter(msg_type, AUDIT_FILTER_USER); + if (err == 1) { /* match or error */ + char *str = data; - err = audit_filter_user(msg_type); - if (err == 1) { err = 0; if (msg_type == AUDIT_USER_TTY) { - err = tty_audit_push_current(); + err = tty_audit_push(); if (err) break; } - audit_log_common_recv_msg(&ab, msg_type); - if (msg_type != AUDIT_USER_TTY) - audit_log_format(ab, " msg='%.1024s'", - (char *)data); - else { - int size; - + audit_log_user_recv_msg(&ab, msg_type); + if (msg_type != AUDIT_USER_TTY) { + /* ensure NULL termination */ + str[data_len - 1] = '\0'; + audit_log_format(ab, " msg='%.*s'", + AUDIT_MESSAGE_TEXT_MAX, + str); + } else { audit_log_format(ab, " data="); - size = nlmsg_len(nlh); - if (size > 0 && - ((unsigned char *)data)[size - 1] == '\0') - size--; - audit_log_n_untrustedstring(ab, data, size); + if (str[data_len - 1] == '\0') + data_len--; + audit_log_n_untrustedstring(ab, str, data_len); } - audit_set_pid(ab, NETLINK_CB(skb).portid); audit_log_end(ab); } break; case AUDIT_ADD_RULE: case AUDIT_DEL_RULE: - if (nlmsg_len(nlh) < sizeof(struct audit_rule_data)) + if (data_len < sizeof(struct audit_rule_data)) return -EINVAL; if (audit_enabled == AUDIT_LOCKED) { - audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); - audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled); + audit_log_common_recv_msg(audit_context(), &ab, + AUDIT_CONFIG_CHANGE); + audit_log_format(ab, " op=%s audit_enabled=%d res=0", + msg_type == AUDIT_ADD_RULE ? + "add_rule" : "remove_rule", + audit_enabled); audit_log_end(ab); return -EPERM; } - /* fallthrough */ + err = audit_rule_change(msg_type, seq, data, data_len); + break; case AUDIT_LIST_RULES: - err = audit_receive_filter(msg_type, NETLINK_CB(skb).portid, - seq, data, nlmsg_len(nlh)); + err = audit_list_rules_send(skb, seq); break; case AUDIT_TRIM: audit_trim_trees(); - audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); + audit_log_common_recv_msg(audit_context(), &ab, + AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=trim res=1"); audit_log_end(ab); break; case AUDIT_MAKE_EQUIV: { void *bufp = data; u32 sizes[2]; - size_t msglen = nlmsg_len(nlh); + size_t msglen = data_len; char *old, *new; err = -EINVAL; @@ -778,8 +1494,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) /* OK, here comes... */ err = audit_tag_tree(old, new); - audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE); - + audit_log_common_recv_msg(audit_context(), &ab, + AUDIT_CONFIG_CHANGE); audit_log_format(ab, " op=make_equiv old="); audit_log_untrustedstring(ab, old); audit_log_format(ab, " new="); @@ -791,56 +1507,70 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) break; } case AUDIT_SIGNAL_INFO: - len = 0; - if (audit_sig_sid) { - err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); - if (err) + if (lsmprop_is_set(&audit_sig_lsm)) { + err = security_lsmprop_to_secctx(&audit_sig_lsm, + &lsmctx, LSM_ID_UNDEF); + if (err < 0) return err; } - sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); + sig_data = kmalloc(struct_size(sig_data, ctx, lsmctx.len), + GFP_KERNEL); if (!sig_data) { - if (audit_sig_sid) - security_release_secctx(ctx, len); + if (lsmprop_is_set(&audit_sig_lsm)) + security_release_secctx(&lsmctx); return -ENOMEM; } sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid); sig_data->pid = audit_sig_pid; - if (audit_sig_sid) { - memcpy(sig_data->ctx, ctx, len); - security_release_secctx(ctx, len); + if (lsmprop_is_set(&audit_sig_lsm)) { + memcpy(sig_data->ctx, lsmctx.context, lsmctx.len); + security_release_secctx(&lsmctx); } - audit_send_reply(NETLINK_CB(skb).portid, seq, AUDIT_SIGNAL_INFO, - 0, 0, sig_data, sizeof(*sig_data) + len); + audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, + sig_data, struct_size(sig_data, ctx, + lsmctx.len)); kfree(sig_data); break; case AUDIT_TTY_GET: { struct audit_tty_status s; - struct task_struct *tsk = current; + unsigned int t; - spin_lock(&tsk->sighand->siglock); - s.enabled = tsk->signal->audit_tty != 0; - s.log_passwd = tsk->signal->audit_tty_log_passwd; - spin_unlock(&tsk->sighand->siglock); + t = READ_ONCE(current->signal->audit_tty); + s.enabled = t & AUDIT_TTY_ENABLE; + s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); - audit_send_reply(NETLINK_CB(skb).portid, seq, - AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); + audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); break; } case AUDIT_TTY_SET: { - struct audit_tty_status s; - struct task_struct *tsk = current; + struct audit_tty_status s, old; + struct audit_buffer *ab; + unsigned int t; memset(&s, 0, sizeof(s)); /* guard against past and future API changes */ - memcpy(&s, data, min(sizeof(s), (size_t)nlh->nlmsg_len)); + memcpy(&s, data, min_t(size_t, sizeof(s), data_len)); + /* check if new data is valid */ if ((s.enabled != 0 && s.enabled != 1) || (s.log_passwd != 0 && s.log_passwd != 1)) - return -EINVAL; + err = -EINVAL; - spin_lock(&tsk->sighand->siglock); - tsk->signal->audit_tty = s.enabled; - tsk->signal->audit_tty_log_passwd = s.log_passwd; - spin_unlock(&tsk->sighand->siglock); + if (err) + t = READ_ONCE(current->signal->audit_tty); + else { + t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD); + t = xchg(¤t->signal->audit_tty, t); + } + old.enabled = t & AUDIT_TTY_ENABLE; + old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); + + audit_log_common_recv_msg(audit_context(), &ab, + AUDIT_CONFIG_CHANGE); + audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d" + " old-log_passwd=%d new-log_passwd=%d res=%d", + old.enabled, s.enabled, old.log_passwd, + s.log_passwd, !err); + audit_log_end(ab); break; } default: @@ -851,13 +1581,17 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) return err < 0 ? err : 0; } -/* - * Get message from skb. Each message is processed by audit_receive_msg. - * Malformed skbs with wrong length are discarded silently. +/** + * audit_receive - receive messages from a netlink control socket + * @skb: the message buffer + * + * Parse the provided skb and deal with any messages that may be present, + * malformed skbs are discarded. */ -static void audit_receive_skb(struct sk_buff *skb) +static void audit_receive(struct sk_buff *skb) { struct nlmsghdr *nlh; + bool ack; /* * len MUST be signed for nlmsg_next to be able to dec it below 0 * if the nlmsg_len was not aligned @@ -868,140 +1602,251 @@ static void audit_receive_skb(struct sk_buff *skb) nlh = nlmsg_hdr(skb); len = skb->len; + audit_ctl_lock(); while (nlmsg_ok(nlh, len)) { - err = audit_receive_msg(skb, nlh); - /* if err or if this message says it wants a response */ - if (err || (nlh->nlmsg_flags & NLM_F_ACK)) - netlink_ack(skb, nlh, err); + ack = nlh->nlmsg_flags & NLM_F_ACK; + err = audit_receive_msg(skb, nlh, &ack); + + /* send an ack if the user asked for one and audit_receive_msg + * didn't already do it, or if there was an error. */ + if (ack || err) + netlink_ack(skb, nlh, err, NULL); nlh = nlmsg_next(nlh, &len); } + audit_ctl_unlock(); + + /* can't block with the ctrl lock, so penalize the sender now */ + if (audit_backlog_limit && + (skb_queue_len(&audit_queue) > audit_backlog_limit)) { + DECLARE_WAITQUEUE(wait, current); + + /* wake kauditd to try and flush the queue */ + wake_up_interruptible(&kauditd_wait); + + add_wait_queue_exclusive(&audit_backlog_wait, &wait); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_timeout(audit_backlog_wait_time); + remove_wait_queue(&audit_backlog_wait, &wait); + } } -/* Receive messages from netlink socket. */ -static void audit_receive(struct sk_buff *skb) +/* Log information about who is connecting to the audit multicast socket */ +static void audit_log_multicast(int group, const char *op, int err) { - mutex_lock(&audit_cmd_mutex); - audit_receive_skb(skb); - mutex_unlock(&audit_cmd_mutex); + const struct cred *cred; + struct tty_struct *tty; + char comm[sizeof(current->comm)]; + struct audit_buffer *ab; + + if (!audit_enabled) + return; + + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER); + if (!ab) + return; + + cred = current_cred(); + tty = audit_get_tty(); + audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u", + task_tgid_nr(current), + from_kuid(&init_user_ns, cred->uid), + from_kuid(&init_user_ns, audit_get_loginuid(current)), + tty ? tty_name(tty) : "(none)", + audit_get_sessionid(current)); + audit_put_tty(tty); + audit_log_task_context(ab); /* subj= */ + audit_log_format(ab, " comm="); + audit_log_untrustedstring(ab, get_task_comm(comm, current)); + audit_log_d_path_exe(ab, current->mm); /* exe= */ + audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err); + audit_log_end(ab); } -/* Initialize audit support at boot time. */ -static int __init audit_init(void) +/* Run custom bind function on netlink socket group connect or bind requests. */ +static int audit_multicast_bind(struct net *net, int group) +{ + int err = 0; + + if (!capable(CAP_AUDIT_READ)) + err = -EPERM; + audit_log_multicast(group, "connect", err); + return err; +} + +static void audit_multicast_unbind(struct net *net, int group) +{ + audit_log_multicast(group, "disconnect", 0); +} + +static int __net_init audit_net_init(struct net *net) { - int i; struct netlink_kernel_cfg cfg = { .input = audit_receive, + .bind = audit_multicast_bind, + .unbind = audit_multicast_unbind, + .flags = NL_CFG_F_NONROOT_RECV, + .groups = AUDIT_NLGRP_MAX, }; + struct audit_net *aunet = net_generic(net, audit_net_id); + + aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); + if (aunet->sk == NULL) { + audit_panic("cannot initialize netlink socket in namespace"); + return -ENOMEM; + } + /* limit the timeout in case auditd is blocked/stopped */ + aunet->sk->sk_sndtimeo = HZ / 10; + + return 0; +} + +static void __net_exit audit_net_exit(struct net *net) +{ + struct audit_net *aunet = net_generic(net, audit_net_id); + + /* NOTE: you would think that we would want to check the auditd + * connection and potentially reset it here if it lives in this + * namespace, but since the auditd connection tracking struct holds a + * reference to this namespace (see auditd_set()) we are only ever + * going to get here after that connection has been released */ + + netlink_kernel_release(aunet->sk); +} + +static struct pernet_operations audit_net_ops __net_initdata = { + .init = audit_net_init, + .exit = audit_net_exit, + .id = &audit_net_id, + .size = sizeof(struct audit_net), +}; + +/* Initialize audit support at boot time. */ +static int __init audit_init(void) +{ + int i; + if (audit_initialized == AUDIT_DISABLED) return 0; - printk(KERN_INFO "audit: initializing netlink socket (%s)\n", - audit_default ? "enabled" : "disabled"); - audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, &cfg); - if (!audit_sock) - audit_panic("cannot initialize netlink socket"); - else - audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; - - skb_queue_head_init(&audit_skb_queue); - skb_queue_head_init(&audit_skb_hold_queue); - audit_initialized = AUDIT_INITIALIZED; - audit_enabled = audit_default; - audit_ever_enabled |= !!audit_default; + audit_buffer_cache = KMEM_CACHE(audit_buffer, SLAB_PANIC); - audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized"); + skb_queue_head_init(&audit_queue); + skb_queue_head_init(&audit_retry_queue); + skb_queue_head_init(&audit_hold_queue); for (i = 0; i < AUDIT_INODE_BUCKETS; i++) INIT_LIST_HEAD(&audit_inode_hash[i]); + mutex_init(&audit_cmd_mutex.lock); + audit_cmd_mutex.owner = NULL; + + pr_info("initializing netlink subsys (%s)\n", + str_enabled_disabled(audit_default)); + register_pernet_subsys(&audit_net_ops); + + audit_initialized = AUDIT_INITIALIZED; + + kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); + if (IS_ERR(kauditd_task)) { + int err = PTR_ERR(kauditd_task); + panic("audit: failed to start the kauditd thread (%d)\n", err); + } + + audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, + "state=initialized audit_enabled=%u res=1", + audit_enabled); + return 0; } -__initcall(audit_init); +postcore_initcall(audit_init); -/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */ +/* + * Process kernel command-line parameter at boot time. + * audit={0|off} or audit={1|on}. + */ static int __init audit_enable(char *str) { - audit_default = !!simple_strtol(str, NULL, 0); - if (!audit_default) + if (!strcasecmp(str, "off") || !strcmp(str, "0")) + audit_default = AUDIT_OFF; + else if (!strcasecmp(str, "on") || !strcmp(str, "1")) + audit_default = AUDIT_ON; + else { + pr_err("audit: invalid 'audit' parameter value (%s)\n", str); + audit_default = AUDIT_ON; + } + + if (audit_default == AUDIT_OFF) audit_initialized = AUDIT_DISABLED; + if (audit_set_enabled(audit_default)) + pr_err("audit: error setting audit state (%d)\n", + audit_default); - printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled"); + pr_info("%s\n", audit_default ? + "enabled (after initialization)" : "disabled (until reboot)"); - if (audit_initialized == AUDIT_INITIALIZED) { - audit_enabled = audit_default; - audit_ever_enabled |= !!audit_default; - } else if (audit_initialized == AUDIT_UNINITIALIZED) { - printk(" (after initialization)"); - } else { - printk(" (until reboot)"); + return 1; +} +__setup("audit=", audit_enable); + +/* Process kernel command-line parameter at boot time. + * audit_backlog_limit=<n> */ +static int __init audit_backlog_limit_set(char *str) +{ + u32 audit_backlog_limit_arg; + + pr_info("audit_backlog_limit: "); + if (kstrtouint(str, 0, &audit_backlog_limit_arg)) { + pr_cont("using default of %u, unable to parse %s\n", + audit_backlog_limit, str); + return 1; } - printk("\n"); + + audit_backlog_limit = audit_backlog_limit_arg; + pr_cont("%d\n", audit_backlog_limit); return 1; } - -__setup("audit=", audit_enable); +__setup("audit_backlog_limit=", audit_backlog_limit_set); static void audit_buffer_free(struct audit_buffer *ab) { - unsigned long flags; + struct sk_buff *skb; if (!ab) return; - if (ab->skb) - kfree_skb(ab->skb); - - spin_lock_irqsave(&audit_freelist_lock, flags); - if (audit_freelist_count > AUDIT_MAXFREE) - kfree(ab); - else { - audit_freelist_count++; - list_add(&ab->list, &audit_freelist); - } - spin_unlock_irqrestore(&audit_freelist_lock, flags); + while ((skb = skb_dequeue(&ab->skb_list))) + kfree_skb(skb); + kmem_cache_free(audit_buffer_cache, ab); } -static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx, - gfp_t gfp_mask, int type) +static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, + gfp_t gfp_mask, int type) { - unsigned long flags; - struct audit_buffer *ab = NULL; - struct nlmsghdr *nlh; + struct audit_buffer *ab; - spin_lock_irqsave(&audit_freelist_lock, flags); - if (!list_empty(&audit_freelist)) { - ab = list_entry(audit_freelist.next, - struct audit_buffer, list); - list_del(&ab->list); - --audit_freelist_count; - } - spin_unlock_irqrestore(&audit_freelist_lock, flags); + ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); + if (!ab) + return NULL; - if (!ab) { - ab = kmalloc(sizeof(*ab), gfp_mask); - if (!ab) - goto err; - } - - ab->ctx = ctx; - ab->gfp_mask = gfp_mask; + skb_queue_head_init(&ab->skb_list); ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); if (!ab->skb) goto err; - nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0); - if (!nlh) - goto out_kfree_skb; + skb_queue_tail(&ab->skb_list, ab->skb); + + if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) + goto err; + + ab->ctx = ctx; + ab->gfp_mask = gfp_mask; return ab; -out_kfree_skb: - kfree_skb(ab->skb); - ab->skb = NULL; err: audit_buffer_free(ab); return NULL; @@ -1026,54 +1871,20 @@ err: */ unsigned int audit_serial(void) { - static DEFINE_SPINLOCK(serial_lock); - static unsigned int serial = 0; - - unsigned long flags; - unsigned int ret; + static atomic_t serial = ATOMIC_INIT(0); - spin_lock_irqsave(&serial_lock, flags); - do { - ret = ++serial; - } while (unlikely(!ret)); - spin_unlock_irqrestore(&serial_lock, flags); - - return ret; + return atomic_inc_return(&serial); } static inline void audit_get_stamp(struct audit_context *ctx, - struct timespec *t, unsigned int *serial) + struct audit_stamp *stamp) { - if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { - *t = CURRENT_TIME; - *serial = audit_serial(); + if (!ctx || !auditsc_get_stamp(ctx, stamp)) { + ktime_get_coarse_real_ts64(&stamp->ctime); + stamp->serial = audit_serial(); } } -/* - * Wait for auditd to drain the queue a little - */ -static void wait_for_auditd(unsigned long sleep_time) -{ - DECLARE_WAITQUEUE(wait, current); - set_current_state(TASK_UNINTERRUPTIBLE); - add_wait_queue(&audit_backlog_wait, &wait); - - if (audit_backlog_limit && - skb_queue_len(&audit_skb_queue) > audit_backlog_limit) - schedule_timeout(sleep_time); - - __set_current_state(TASK_RUNNING); - remove_wait_queue(&audit_backlog_wait, &wait); -} - -/* 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 tsk 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, tsk - * should be NULL. */ - /** * audit_log_start - obtain an audit buffer * @ctx: audit_context (may be NULL) @@ -1092,45 +1903,53 @@ static void wait_for_auditd(unsigned long sleep_time) struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type) { - struct audit_buffer *ab = NULL; - struct timespec t; - unsigned int uninitialized_var(serial); - int reserve; - unsigned long timeout_start = jiffies; + struct audit_buffer *ab; if (audit_initialized != AUDIT_INITIALIZED) return NULL; - if (unlikely(audit_filter_type(type))) + if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE))) return NULL; - 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) { - unsigned long sleep_time; - - sleep_time = timeout_start + audit_backlog_wait_time - - jiffies; - if ((long)sleep_time > 0) - wait_for_auditd(sleep_time); - continue; + /* NOTE: don't ever fail/sleep on these two conditions: + * 1. auditd generated record - since we need auditd to drain the + * queue; also, when we are checking for auditd, compare PIDs using + * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() + * using a PID anchored in the caller's namespace + * 2. generator holding the audit_cmd_mutex - we don't want to block + * while holding the mutex, although we do penalize the sender + * later in audit_receive() when it is safe to block + */ + if (!(auditd_test_task(current) || audit_ctl_owner_current())) { + long stime = audit_backlog_wait_time; + + while (audit_backlog_limit && + (skb_queue_len(&audit_queue) > audit_backlog_limit)) { + /* wake kauditd to try and flush the queue */ + wake_up_interruptible(&kauditd_wait); + + /* sleep if we are allowed and we haven't exhausted our + * backlog wait limit */ + if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) { + long rtime = stime; + + DECLARE_WAITQUEUE(wait, current); + + add_wait_queue_exclusive(&audit_backlog_wait, + &wait); + set_current_state(TASK_UNINTERRUPTIBLE); + stime = schedule_timeout(rtime); + atomic_add(rtime - stime, &audit_backlog_wait_time_actual); + remove_wait_queue(&audit_backlog_wait, &wait); + } else { + if (audit_rate_check() && printk_ratelimit()) + pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", + skb_queue_len(&audit_queue), + audit_backlog_limit); + audit_log_lost("backlog limit exceeded"); + return NULL; + } } - if (audit_rate_check() && printk_ratelimit()) - printk(KERN_WARNING - "audit: audit_backlog=%d > " - "audit_backlog_limit=%d\n", - 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_mask, type); @@ -1139,10 +1958,15 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, return NULL; } - audit_get_stamp(ab->ctx, &t, &serial); + audit_get_stamp(ab->ctx, &ab->stamp); + /* cancel dummy context to enable supporting records */ + if (ctx) + ctx->dummy = 0; + audit_log_format(ab, "audit(%llu.%03lu:%u): ", + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); - audit_log_format(ab, "audit(%lu.%03lu:%u): ", - t.tv_sec, t.tv_nsec/1000000, serial); return ab; } @@ -1176,8 +2000,8 @@ static inline int audit_expand(struct audit_buffer *ab, int extra) * 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. */ -static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, - va_list args) +static __printf(2, 0) +void audit_log_vformat(struct audit_buffer *ab, const char *fmt, va_list args) { int len, avail; struct sk_buff *skb; @@ -1234,7 +2058,7 @@ void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) } /** - * audit_log_hex - convert a buffer to hex and append it to the audit skb + * audit_log_n_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 @@ -1250,7 +2074,6 @@ void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, int i, avail, new_len; unsigned char *ptr; struct sk_buff *skb; - static const unsigned char *hex = "0123456789ABCDEF"; if (!ab) return; @@ -1268,10 +2091,8 @@ void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, } ptr = skb_tail_pointer(skb); - for (i=0; i<len; i++) { - *ptr++ = hex[(buf[i] & 0xF0)>>4]; /* Upper nibble */ - *ptr++ = hex[buf[i] & 0x0F]; /* Lower nibble */ - } + for (i = 0; i < len; i++) + ptr = hex_byte_pack_upper(ptr, buf[i]); *ptr = 0; skb_put(skb, len << 1); /* new string is twice the old string */ } @@ -1313,21 +2134,21 @@ void audit_log_n_string(struct audit_buffer *ab, const char *string, * @string: string to be checked * @len: max length of the string to check */ -int audit_string_contains_control(const char *string, size_t len) +bool audit_string_contains_control(const char *string, size_t len) { const unsigned char *p; for (p = string; p < (const unsigned char *)string + len; p++) { if (*p == '"' || *p < 0x21 || *p > 0x7e) - return 1; + return true; } - return 0; + return false; } /** * audit_log_n_untrustedstring - log a string that may contain random characters * @ab: audit_buffer - * @len: length of string (not including trailing null) * @string: string to be logged + * @len: length of string (not including trailing null) * * This code will escape a string that is passed to it if the string * contains a control character, unprintable character, double quote mark, @@ -1371,13 +2192,13 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix, /* We will allow 11 spaces for ' (deleted)' to be appended */ pathname = kmalloc(PATH_MAX+11, ab->gfp_mask); if (!pathname) { - audit_log_string(ab, "<no_memory>"); + audit_log_format(ab, "\"<no_memory>\""); return; } p = d_path(path, pathname, PATH_MAX+11); if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */ /* FIXME: can we save some information here? */ - audit_log_string(ab, "<too_long>"); + audit_log_format(ab, "\"<too_long>\""); } else audit_log_untrustedstring(ab, p); kfree(pathname); @@ -1385,10 +2206,10 @@ void audit_log_d_path(struct audit_buffer *ab, const char *prefix, void audit_log_session_info(struct audit_buffer *ab) { - u32 sessionid = audit_get_sessionid(current); + unsigned int sessionid = audit_get_sessionid(current); uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current)); - audit_log_format(ab, " auid=%u ses=%u\n", auid, sessionid); + audit_log_format(ab, "auid=%u ses=%u", auid, sessionid); } void audit_log_key(struct audit_buffer *ab, char *key) @@ -1400,200 +2221,233 @@ void audit_log_key(struct audit_buffer *ab, char *key) audit_log_format(ab, "(null)"); } -void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap) -{ - int i; - - audit_log_format(ab, " %s=", prefix); - CAP_FOR_EACH_U32(i) { - audit_log_format(ab, "%08x", - cap->cap[(_KERNEL_CAPABILITY_U32S-1) - i]); - } -} - -void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) -{ - kernel_cap_t *perm = &name->fcap.permitted; - kernel_cap_t *inh = &name->fcap.inheritable; - int log = 0; - - if (!cap_isclear(*perm)) { - audit_log_cap(ab, "cap_fp", perm); - log = 1; - } - if (!cap_isclear(*inh)) { - audit_log_cap(ab, "cap_fi", inh); - log = 1; - } - - if (log) - audit_log_format(ab, " cap_fe=%d cap_fver=%x", - name->fcap.fE, name->fcap_ver); -} - -static inline int audit_copy_fcaps(struct audit_names *name, - const struct dentry *dentry) +/** + * audit_buffer_aux_new - Add an aux record buffer to the skb list + * @ab: audit_buffer + * @type: message type + * + * Aux records are allocated and added to the skb list of + * the "main" record. The ab->skb is reset to point to the + * aux record on its creation. When the aux record in complete + * ab->skb has to be reset to point to the "main" record. + * This allows the audit_log_ functions to be ignorant of + * which kind of record it is logging to. It also avoids adding + * special data for aux records. + * + * On success ab->skb will point to the new aux record. + * Returns 0 on success, -ENOMEM should allocation fail. + */ +static int audit_buffer_aux_new(struct audit_buffer *ab, int type) { - struct cpu_vfs_cap_data caps; - int rc; - - if (!dentry) - return 0; + WARN_ON(ab->skb != skb_peek(&ab->skb_list)); - rc = get_vfs_caps_from_disk(dentry, &caps); - if (rc) - return rc; + ab->skb = nlmsg_new(AUDIT_BUFSIZ, ab->gfp_mask); + if (!ab->skb) + goto err; + if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) + goto err; + skb_queue_tail(&ab->skb_list, ab->skb); - name->fcap.permitted = caps.permitted; - name->fcap.inheritable = caps.inheritable; - name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE); - name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >> - VFS_CAP_REVISION_SHIFT; + audit_log_format(ab, "audit(%llu.%03lu:%u): ", + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); return 0; + +err: + kfree_skb(ab->skb); + ab->skb = skb_peek(&ab->skb_list); + return -ENOMEM; } -/* Copy inode data into an audit_names. */ -void audit_copy_inode(struct audit_names *name, const struct dentry *dentry, - const struct inode *inode) +/** + * audit_buffer_aux_end - Switch back to the "main" record from an aux record + * @ab: audit_buffer + * + * Restores the "main" audit record to ab->skb. + */ +static void audit_buffer_aux_end(struct audit_buffer *ab) { - name->ino = inode->i_ino; - name->dev = inode->i_sb->s_dev; - name->mode = inode->i_mode; - name->uid = inode->i_uid; - name->gid = inode->i_gid; - name->rdev = inode->i_rdev; - security_inode_getsecid(inode, &name->osid); - audit_copy_fcaps(name, dentry); + ab->skb = skb_peek(&ab->skb_list); } /** - * audit_log_name - produce AUDIT_PATH record from struct audit_names - * @context: audit_context for the task - * @n: audit_names structure with reportable details - * @path: optional path to report instead of audit_names->name - * @record_num: record number to report when handling a list of names - * @call_panic: optional pointer to int that will be updated if secid fails + * audit_log_subj_ctx - Add LSM subject information + * @ab: audit_buffer + * @prop: LSM subject properties. + * + * Add a subj= field and, if necessary, a AUDIT_MAC_TASK_CONTEXTS record. */ -void audit_log_name(struct audit_context *context, struct audit_names *n, - struct path *path, int record_num, int *call_panic) +int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop) { - struct audit_buffer *ab; - ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH); - if (!ab) - return; + struct lsm_context ctx; + char *space = ""; + int error; + int i; - audit_log_format(ab, "item=%d", record_num); + security_current_getlsmprop_subj(prop); + if (!lsmprop_is_set(prop)) + return 0; - if (path) - audit_log_d_path(ab, " name=", path); - else if (n->name) { - switch (n->name_len) { - case AUDIT_NAME_FULL: - /* log the full path */ - audit_log_format(ab, " name="); - audit_log_untrustedstring(ab, n->name->name); - break; - case 0: - /* name was specified as a relative path and the - * directory component is the cwd */ - audit_log_d_path(ab, " name=", &context->pwd); - break; - default: - /* log the name's directory component */ - audit_log_format(ab, " name="); - audit_log_n_untrustedstring(ab, n->name->name, - n->name_len); + if (audit_subj_secctx_cnt < 2) { + error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF); + if (error < 0) { + if (error != -EINVAL) + goto error_path; + return 0; } - } else - audit_log_format(ab, " name=(null)"); - - if (n->ino != (unsigned long)-1) { - audit_log_format(ab, " inode=%lu" - " dev=%02x:%02x mode=%#ho" - " ouid=%u ogid=%u rdev=%02x:%02x", - n->ino, - MAJOR(n->dev), - MINOR(n->dev), - n->mode, - from_kuid(&init_user_ns, n->uid), - from_kgid(&init_user_ns, n->gid), - MAJOR(n->rdev), - MINOR(n->rdev)); + audit_log_format(ab, " subj=%s", ctx.context); + security_release_secctx(&ctx); + return 0; } - if (n->osid != 0) { - char *ctx = NULL; - u32 len; - if (security_secid_to_secctx( - n->osid, &ctx, &len)) { - audit_log_format(ab, " osid=%u", n->osid); - if (call_panic) - *call_panic = 2; + /* Multiple LSMs provide contexts. Include an aux record. */ + audit_log_format(ab, " subj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_TASK_CONTEXTS); + if (error) + goto error_path; + + for (i = 0; i < audit_subj_secctx_cnt; i++) { + error = security_lsmprop_to_secctx(prop, &ctx, + audit_subj_lsms[i]->id); + if (error < 0) { + /* + * Don't print anything. An LSM like BPF could + * claim to support contexts, but only do so under + * certain conditions. + */ + if (error == -EOPNOTSUPP) + continue; + if (error != -EINVAL) + audit_panic("error in audit_log_subj_ctx"); } else { - audit_log_format(ab, " obj=%s", ctx); - security_release_secctx(ctx, len); + audit_log_format(ab, "%ssubj_%s=%s", space, + audit_subj_lsms[i]->name, ctx.context); + space = " "; + security_release_secctx(&ctx); } } + audit_buffer_aux_end(ab); + return 0; - audit_log_fcaps(ab, n); - audit_log_end(ab); +error_path: + audit_panic("error in audit_log_subj_ctx"); + return error; } +EXPORT_SYMBOL(audit_log_subj_ctx); int audit_log_task_context(struct audit_buffer *ab) { - char *ctx = NULL; - unsigned len; - int error; - u32 sid; + struct lsm_prop prop; - security_task_getsecid(current, &sid); - if (!sid) - return 0; + security_current_getlsmprop_subj(&prop); + return audit_log_subj_ctx(ab, &prop); +} +EXPORT_SYMBOL(audit_log_task_context); - error = security_secid_to_secctx(sid, &ctx, &len); - if (error) { - if (error != -EINVAL) - goto error_path; +int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop) +{ + int i; + int rc; + int error = 0; + char *space = ""; + struct lsm_context ctx; + + if (audit_obj_secctx_cnt < 2) { + error = security_lsmprop_to_secctx(prop, &ctx, LSM_ID_UNDEF); + if (error < 0) { + if (error != -EINVAL) + goto error_path; + return error; + } + audit_log_format(ab, " obj=%s", ctx.context); + security_release_secctx(&ctx); return 0; } + audit_log_format(ab, " obj=?"); + error = audit_buffer_aux_new(ab, AUDIT_MAC_OBJ_CONTEXTS); + if (error) + goto error_path; + + for (i = 0; i < audit_obj_secctx_cnt; i++) { + rc = security_lsmprop_to_secctx(prop, &ctx, + audit_obj_lsms[i]->id); + if (rc < 0) { + audit_log_format(ab, "%sobj_%s=?", space, + audit_obj_lsms[i]->name); + if (rc != -EINVAL) + audit_panic("error in audit_log_obj_ctx"); + error = rc; + } else { + audit_log_format(ab, "%sobj_%s=%s", space, + audit_obj_lsms[i]->name, ctx.context); + security_release_secctx(&ctx); + } + space = " "; + } - audit_log_format(ab, " subj=%s", ctx); - security_release_secctx(ctx, len); - return 0; + audit_buffer_aux_end(ab); + return error; error_path: - audit_panic("error in audit_log_task_context"); + audit_panic("error in audit_log_obj_ctx"); return error; } -EXPORT_SYMBOL(audit_log_task_context); -void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) +void audit_log_d_path_exe(struct audit_buffer *ab, + struct mm_struct *mm) +{ + struct file *exe_file; + + if (!mm) + goto out_null; + + exe_file = get_mm_exe_file(mm); + if (!exe_file) + goto out_null; + + audit_log_d_path(ab, " exe=", &exe_file->f_path); + fput(exe_file); + return; +out_null: + audit_log_format(ab, " exe=(null)"); +} + +struct tty_struct *audit_get_tty(void) +{ + struct tty_struct *tty = NULL; + unsigned long flags; + + spin_lock_irqsave(¤t->sighand->siglock, flags); + if (current->signal) + tty = tty_kref_get(current->signal->tty); + spin_unlock_irqrestore(¤t->sighand->siglock, flags); + return tty; +} + +void audit_put_tty(struct tty_struct *tty) +{ + tty_kref_put(tty); +} + +void audit_log_task_info(struct audit_buffer *ab) { const struct cred *cred; - char name[sizeof(tsk->comm)]; - struct mm_struct *mm = tsk->mm; - char *tty; + char comm[sizeof(current->comm)]; + struct tty_struct *tty; if (!ab) return; - /* tsk == current */ cred = current_cred(); - - spin_lock_irq(&tsk->sighand->siglock); - if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name) - tty = tsk->signal->tty->name; - else - tty = "(none)"; - spin_unlock_irq(&tsk->sighand->siglock); - + tty = audit_get_tty(); audit_log_format(ab, - " ppid=%ld pid=%d auid=%u uid=%u gid=%u" + " ppid=%d pid=%d auid=%u uid=%u gid=%u" " euid=%u suid=%u fsuid=%u" - " egid=%u sgid=%u fsgid=%u ses=%u tty=%s", - sys_getppid(), - tsk->pid, - from_kuid(&init_user_ns, audit_get_loginuid(tsk)), + " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", + task_ppid_nr(current), + task_tgid_nr(current), + from_kuid(&init_user_ns, audit_get_loginuid(current)), from_kuid(&init_user_ns, cred->uid), from_kgid(&init_user_ns, cred->gid), from_kuid(&init_user_ns, cred->euid), @@ -1602,81 +2456,194 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) from_kgid(&init_user_ns, cred->egid), from_kgid(&init_user_ns, cred->sgid), from_kgid(&init_user_ns, cred->fsgid), - audit_get_sessionid(tsk), tty); - - get_task_comm(name, tsk); + tty ? tty_name(tty) : "(none)", + audit_get_sessionid(current)); + audit_put_tty(tty); audit_log_format(ab, " comm="); - audit_log_untrustedstring(ab, name); - - if (mm) { - down_read(&mm->mmap_sem); - if (mm->exe_file) - audit_log_d_path(ab, " exe=", &mm->exe_file->f_path); - up_read(&mm->mmap_sem); - } + audit_log_untrustedstring(ab, get_task_comm(comm, current)); + audit_log_d_path_exe(ab, current->mm); audit_log_task_context(ab); } EXPORT_SYMBOL(audit_log_task_info); /** - * audit_log_link_denied - report a link restriction denial - * @operation: specific link opreation - * @link: the path that triggered the restriction + * audit_log_path_denied - report a path restriction denial + * @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc) + * @operation: specific operation name */ -void audit_log_link_denied(const char *operation, struct path *link) +void audit_log_path_denied(int type, const char *operation) { struct audit_buffer *ab; - struct audit_names *name; - name = kzalloc(sizeof(*name), GFP_NOFS); - if (!name) + if (!audit_enabled) return; - /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ - ab = audit_log_start(current->audit_context, GFP_KERNEL, - AUDIT_ANOM_LINK); + /* Generate log with subject, operation, outcome. */ + ab = audit_log_start(audit_context(), GFP_KERNEL, type); if (!ab) - goto out; + return; audit_log_format(ab, "op=%s", operation); - audit_log_task_info(ab, current); + audit_log_task_info(ab); audit_log_format(ab, " res=0"); audit_log_end(ab); +} - /* Generate AUDIT_PATH record with object. */ - name->type = AUDIT_TYPE_NORMAL; - audit_copy_inode(name, link->dentry, link->dentry->d_inode); - audit_log_name(current->audit_context, name, link, 0, NULL); +/* global counter which is incremented every time something logs in */ +static atomic_t session_id = ATOMIC_INIT(0); + +static int audit_set_loginuid_perm(kuid_t loginuid) +{ + /* if we are unset, we don't need privs */ + if (!audit_loginuid_set(current)) + return 0; + /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/ + if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE)) + return -EPERM; + /* it is set, you need permission */ + if (!capable(CAP_AUDIT_CONTROL)) + return -EPERM; + /* reject if this is not an unset and we don't allow that */ + if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID) + && uid_valid(loginuid)) + return -EPERM; + return 0; +} + +static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, + unsigned int oldsessionid, + unsigned int sessionid, int rc) +{ + struct audit_buffer *ab; + uid_t uid, oldloginuid, loginuid; + struct tty_struct *tty; + + if (!audit_enabled) + return; + + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN); + if (!ab) + return; + + uid = from_kuid(&init_user_ns, task_uid(current)); + oldloginuid = from_kuid(&init_user_ns, koldloginuid); + loginuid = from_kuid(&init_user_ns, kloginuid); + tty = audit_get_tty(); + + audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid); + audit_log_task_context(ab); + audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d", + oldloginuid, loginuid, tty ? tty_name(tty) : "(none)", + oldsessionid, sessionid, !rc); + audit_put_tty(tty); + audit_log_end(ab); +} + +/** + * audit_set_loginuid - set current task's loginuid + * @loginuid: loginuid value + * + * Returns 0. + * + * Called (set) from fs/proc/base.c::proc_loginuid_write(). + */ +int audit_set_loginuid(kuid_t loginuid) +{ + unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET; + kuid_t oldloginuid; + int rc; + + oldloginuid = audit_get_loginuid(current); + oldsessionid = audit_get_sessionid(current); + + rc = audit_set_loginuid_perm(loginuid); + if (rc) + goto out; + + /* are we setting or clearing? */ + if (uid_valid(loginuid)) { + sessionid = (unsigned int)atomic_inc_return(&session_id); + if (unlikely(sessionid == AUDIT_SID_UNSET)) + sessionid = (unsigned int)atomic_inc_return(&session_id); + } + + current->sessionid = sessionid; + current->loginuid = loginuid; out: - kfree(name); + audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc); + return rc; +} + +/** + * audit_signal_info - record signal info for shutting down audit subsystem + * @sig: signal value + * @t: task being signaled + * + * If the audit subsystem is being terminated, record the task (pid) + * and uid that is doing that. + */ +int audit_signal_info(int sig, struct task_struct *t) +{ + kuid_t uid = current_uid(), auid; + + if (auditd_test_task(t) && + (sig == SIGTERM || sig == SIGHUP || + sig == SIGUSR1 || sig == SIGUSR2)) { + audit_sig_pid = task_tgid_nr(current); + auid = audit_get_loginuid(current); + if (uid_valid(auid)) + audit_sig_uid = auid; + else + audit_sig_uid = uid; + security_current_getlsmprop_subj(&audit_sig_lsm); + } + + return audit_signal_info_syscall(t); +} + +/** + * __audit_log_end - enqueue one audit record + * @skb: the buffer to send + */ +static void __audit_log_end(struct sk_buff *skb) +{ + struct nlmsghdr *nlh; + + if (audit_rate_check()) { + /* setup the netlink header, see the comments in + * kauditd_send_multicast_skb() for length quirks */ + nlh = nlmsg_hdr(skb); + nlh->nlmsg_len = skb->len - NLMSG_HDRLEN; + + /* queue the netlink packet */ + skb_queue_tail(&audit_queue, skb); + } else { + audit_log_lost("rate limit exceeded"); + kfree_skb(skb); + } } /** * 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. + * We can not do a netlink send inside an irq context because it blocks (last + * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a + * queue and a kthread is scheduled to remove them from the queue outside the + * irq context. May be called in any context. */ void audit_log_end(struct audit_buffer *ab) { + struct sk_buff *skb; + if (!ab) return; - if (!audit_rate_check()) { - audit_log_lost("rate limit exceeded"); - } else { - struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); - nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN; - if (audit_pid) { - skb_queue_tail(&audit_skb_queue, ab->skb); - wake_up_interruptible(&kauditd_wait); - } else { - audit_printk_skb(ab->skb); - } - ab->skb = NULL; - } + while ((skb = skb_dequeue(&ab->skb_list))) + __audit_log_end(skb); + + /* poke the kauditd thread */ + wake_up_interruptible(&kauditd_wait); + audit_buffer_free(ab); } @@ -1707,32 +2674,6 @@ void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, } } -#ifdef CONFIG_SECURITY -/** - * audit_log_secctx - Converts and logs SELinux context - * @ab: audit_buffer - * @secid: security number - * - * This is a helper function that calls security_secid_to_secctx to convert - * secid to secctx and then adds the (converted) SELinux context to the audit - * log by calling audit_log_format, thus also preventing leak of internal secid - * to userspace. If secid cannot be converted audit_panic is called. - */ -void audit_log_secctx(struct audit_buffer *ab, u32 secid) -{ - u32 len; - char *secctx; - - if (security_secid_to_secctx(secid, &secctx, &len)) { - audit_panic("Cannot convert secid to context"); - } else { - audit_log_format(ab, " obj=%s", secctx); - security_release_secctx(secctx, len); - } -} -EXPORT_SYMBOL(audit_log_secctx); -#endif - EXPORT_SYMBOL(audit_log_start); EXPORT_SYMBOL(audit_log_end); EXPORT_SYMBOL(audit_log_format); |