diff options
Diffstat (limited to 'kernel/audit.c')
| -rw-r--r-- | kernel/audit.c | 1171 |
1 files changed, 741 insertions, 430 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index 6dd556931739..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. @@ -38,7 +25,8 @@ * 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 @@ -59,16 +47,14 @@ #include <linux/mutex.h> #include <linux/gfp.h> #include <linux/pid.h> -#include <linux/slab.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 <linux/lsm_hooks.h> #include <linux/freezer.h> #include <linux/pid_namespace.h> #include <net/netns/generic.h> @@ -80,18 +66,15 @@ #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 -u32 audit_enabled; -u32 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 u32 audit_default; +static u32 audit_default = AUDIT_OFF; /* If auditing cannot proceed, audit_failure selects what happens. */ static u32 audit_failure = AUDIT_FAIL_PRINTK; @@ -99,6 +82,13 @@ static u32 audit_failure = AUDIT_FAIL_PRINTK; /* 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 @@ -118,12 +108,13 @@ struct audit_net { * This struct is RCU protected; you must either hold the RCU lock for reading * or the associated spinlock for writing. */ -static struct auditd_connection { +struct auditd_connection { struct pid *pid; u32 portid; struct net *net; struct rcu_head rcu; -} *auditd_conn = NULL; +}; +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 @@ -138,9 +129,9 @@ static u32 audit_backlog_limit = 64; 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] @@ -151,6 +142,11 @@ u32 audit_sig_sid = 0; */ static atomic_t audit_lost = ATOMIC_INIT(0); +/* 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]; @@ -180,9 +176,21 @@ static char *audit_feature_names[2] = { "loginuid_immutable", }; - -/* Serialize requests from userspace. */ -DEFINE_MUTEX(audit_cmd_mutex); +/** + * 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 @@ -195,8 +203,10 @@ DEFINE_MUTEX(audit_cmd_mutex); * to place it on a transmit queue. Multiple audit_buffers can be in * use simultaneously. */ struct audit_buffer { - 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; }; @@ -227,6 +237,36 @@ int auditd_test_task(struct task_struct *task) } /** + * 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: @@ -249,6 +289,33 @@ static pid_t auditd_pid_vnr(void) } /** + * 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 * @@ -289,18 +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; @@ -334,7 +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; } @@ -357,10 +423,10 @@ static int audit_log_config_change(char *function_name, u32 new, u32 old, 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=%u old=%u", 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) @@ -443,30 +509,34 @@ static int audit_set_failure(u32 state) * Drop any references inside the auditd connection tracking struct and free * the memory. */ - static void auditd_conn_free(struct rcu_head *rcu) - { +static void auditd_conn_free(struct rcu_head *rcu) +{ struct auditd_connection *ac; ac = container_of(rcu, struct auditd_connection, rcu); put_pid(ac->pid); put_net(ac->net); kfree(ac); - } +} /** * 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 int auditd_set(struct pid *pid, u32 portid, struct net *net) +static int auditd_set(struct pid *pid, u32 portid, struct net *net, + struct sk_buff *skb, bool *ack) { unsigned long flags; struct auditd_connection *ac_old, *ac_new; + struct nlmsghdr *nlh; if (!pid || !net) return -EINVAL; @@ -478,6 +548,13 @@ static int auditd_set(struct pid *pid, u32 portid, struct net *net) 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; + } + spin_lock_irqsave(&auditd_conn_lock, flags); ac_old = rcu_dereference_protected(auditd_conn, lockdep_is_held(&auditd_conn_lock)); @@ -491,7 +568,7 @@ static int auditd_set(struct pid *pid, u32 portid, struct net *net) } /** - * kauditd_print_skb - Print the audit record to the ring buffer + * 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 @@ -509,20 +586,22 @@ static void kauditd_printk_skb(struct sk_buff *skb) /** * kauditd_rehold_skb - Handle a audit record send failure in the hold queue * @skb: audit record + * @error: error code (unused) * * 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) +static void kauditd_rehold_skb(struct sk_buff *skb, __always_unused int error) { - /* put the record back in the queue at the same place */ - skb_queue_head(&audit_hold_queue, skb); + /* 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 * * Description: * Queue the audit record, waiting for an instance of auditd. When this @@ -532,19 +611,31 @@ static void kauditd_rehold_skb(struct sk_buff *skb) * 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 kauditd_hold_skb(struct sk_buff *skb) +static void kauditd_hold_skb(struct sk_buff *skb, int error) { /* 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) { - kfree_skb(skb); - return; + 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 we have room, queue the message */ + /* 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); @@ -553,24 +644,32 @@ static void kauditd_hold_skb(struct sk_buff *skb) /* we have no other options - drop the message */ audit_log_lost("kauditd hold queue overflow"); +drop: kfree_skb(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) +static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error) { - /* NOTE: because records should only live in the retry queue for a - * short period of time, before either being sent or moved to the hold - * queue, we don't currently enforce a limit on this queue */ - skb_queue_tail(&audit_retry_queue, skb); + if (!audit_backlog_limit || + skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { + skb_queue_tail(&audit_retry_queue, skb); + return; + } + + /* 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); } /** @@ -608,7 +707,7 @@ static void auditd_reset(const struct auditd_connection *ac) /* 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); + kauditd_hold_skb(skb, -ECONNREFUSED); } /** @@ -682,16 +781,18 @@ 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)) + void (*err_hook)(struct sk_buff *skb, int error)) { int rc = 0; - struct sk_buff *skb; - static unsigned int failed = 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) */ - while ((skb = skb_dequeue(queue))) { + 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); @@ -699,36 +800,34 @@ static int kauditd_send_queue(struct sock *sk, u32 portid, /* can we send to anyone via unicast? */ if (!sk) { if (err_hook) - (*err_hook)(skb); + (*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) { - /* fatal failure for our queue flush attempt? */ + /* send failed - try a few times unless fatal error */ if (++failed >= retry_limit || rc == -ECONNREFUSED || rc == -EPERM) { - /* yes - error processing for the queue */ sk = NULL; if (err_hook) - (*err_hook)(skb); - if (!skb_hook) - goto out; - /* keep processing with the skb_hook */ + (*err_hook)(skb, rc); + if (rc == -EAGAIN) + rc = 0; + /* continue to drain the queue */ continue; } else - /* no - requeue to preserve ordering */ - skb_queue_head(queue, skb); + goto retry; } else { - /* it worked - drop the extra reference and continue */ + /* skb sent - drop the extra reference and continue */ consume_skb(skb); failed = 0; } } -out: return (rc >= 0 ? 0 : rc); } @@ -804,7 +903,7 @@ static int kauditd_thread(void *dummy) rc = kauditd_send_queue(sk, portid, &audit_hold_queue, UNICAST_RETRIES, NULL, kauditd_rehold_skb); - if (ac && rc < 0) { + if (rc < 0) { sk = NULL; auditd_reset(ac); goto main_queue; @@ -814,7 +913,7 @@ static int kauditd_thread(void *dummy) rc = kauditd_send_queue(sk, portid, &audit_retry_queue, UNICAST_RETRIES, NULL, kauditd_hold_skb); - if (ac && rc < 0) { + if (rc < 0) { sk = NULL; auditd_reset(ac); goto main_queue; @@ -853,15 +952,15 @@ main_queue: return 0; } -int audit_send_list(void *_dest) +int audit_send_list_thread(void *_dest) { struct audit_netlink_list *dest = _dest; 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(sk, skb, dest->portid, 0); @@ -897,19 +996,29 @@ 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; - struct sock *sk = audit_get_sk(reply->net); - 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(sk, reply->skb, reply->portid, 0); - put_net(reply->net); - kfree(reply); + netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0); + reply->skb = NULL; + audit_free_reply(reply); return 0; } @@ -923,35 +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 port id. - * No failure notifications. + * Allocates a skb, builds the netlink message, and sends it to the port id. */ static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done, int multi, const void *payload, int size) { - struct net *net = sock_net(NETLINK_CB(request_skb).sk); - 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(seq, type, done, multi, payload, size); - if (!skb) - goto out; - - reply->net = get_net(net); + 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; - reply->skb = skb; 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); } /* @@ -1014,7 +1120,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) return err; } -static void 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) { uid_t uid = from_kuid(&init_user_ns, current_uid()); pid_t pid = task_tgid_nr(current); @@ -1024,19 +1131,24 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) return; } - *ab = audit_log_start(NULL, GFP_KERNEL, msg_type); + *ab = audit_log_start(context, GFP_KERNEL, msg_type); if (unlikely(!*ab)) return; - audit_log_format(*ab, "pid=%d uid=%u", pid, uid); + audit_log_format(*ab, "pid=%d uid=%u ", pid, uid); audit_log_session_info(*ab); audit_log_task_context(*ab); } -int is_audit_feature_set(int i) +static inline void audit_log_user_recv_msg(struct audit_buffer **ab, + u16 msg_type) { - return af.features & AUDIT_FEATURE_TO_MASK(i); + 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) { @@ -1057,21 +1169,21 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature if (audit_enabled == AUDIT_OFF) return; - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE); - audit_log_task_info(ab, current); + 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 sk_buff *skb) +static int audit_set_feature(struct audit_features *uaf) { - struct audit_features *uaf; int i; BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names)); - uaf = nlmsg_data(nlmsg_hdr(skb)); /* if there is ever a version 2 we should handle that here */ @@ -1135,16 +1247,17 @@ static int audit_replace(struct pid *pid) return auditd_send_unicast_skb(skb); } -static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) +static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, + bool *ack) { u32 seq; void *data; + 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) @@ -1152,22 +1265,24 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) seq = nlh->nlmsg_seq; data = nlmsg_data(nlh); + data_len = nlmsg_len(nlh); switch (msg_type) { case AUDIT_GET: { struct audit_status s; memset(&s, 0, sizeof(s)); - s.enabled = audit_enabled; - s.failure = audit_failure; + 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.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; } @@ -1175,7 +1290,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 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), nlmsg_len(nlh))); + 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) @@ -1197,32 +1312,36 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) pid_t auditd_pid; struct pid *req_pid = task_tgid(current); - /* sanity check - PID values must match */ - if (new_pid != pid_vnr(req_pid)) + /* 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(); - /* only the current auditd can unregister itself */ - if ((!new_pid) && (new_pid != auditd_pid)) { - audit_log_config_change("audit_pid", new_pid, - auditd_pid, 0); - return -EACCES; - } - /* replacing a healthy auditd is not allowed */ - if (auditd_pid && new_pid) { - audit_log_config_change("audit_pid", new_pid, - auditd_pid, 0); - return -EEXIST; + 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 (new_pid) { /* register a new auditd connection */ err = auditd_set(req_pid, NETLINK_CB(skb).portid, - sock_net(NETLINK_CB(skb).sk)); + sock_net(NETLINK_CB(skb).sk), + skb, ack); if (audit_enabled != AUDIT_OFF) audit_log_config_change("audit_pid", new_pid, @@ -1268,6 +1387,12 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 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: @@ -1276,7 +1401,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) return err; break; case AUDIT_SET_FEATURE: - err = audit_set_feature(skb); + if (data_len < sizeof(struct audit_features)) + return -EINVAL; + err = audit_set_feature(data); if (err) return err; break; @@ -1285,58 +1412,66 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) 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 = 0; if (msg_type == AUDIT_USER_TTY) { err = tty_audit_push(); if (err) break; } - audit_log_common_recv_msg(&ab, msg_type); - if (msg_type != AUDIT_USER_TTY) + 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, - (char *)data); - else { - int size; - + 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_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; } - err = audit_rule_change(msg_type, seq, data, nlmsg_len(nlh)); + err = audit_rule_change(msg_type, seq, data, data_len); break; case AUDIT_LIST_RULES: 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; @@ -1359,8 +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="); @@ -1372,26 +1507,28 @@ 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(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, - sig_data, sizeof(*sig_data) + len); + sig_data, struct_size(sig_data, ctx, + lsmctx.len)); kfree(sig_data); break; case AUDIT_TTY_GET: { @@ -1412,7 +1549,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) memset(&s, 0, sizeof(s)); /* guard against past and future API changes */ - memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh))); + 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)) @@ -1427,7 +1564,8 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) old.enabled = t & AUDIT_TTY_ENABLE; old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); - 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=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, @@ -1450,9 +1588,10 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) * Parse the provided skb and deal with any messages that may be present, * malformed skbs are discarded. */ -static void audit_receive(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 @@ -1463,32 +1602,89 @@ static void audit_receive(struct sk_buff *skb) nlh = nlmsg_hdr(skb); len = skb->len; - mutex_lock(&audit_cmd_mutex); + 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)) + 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); } - mutex_unlock(&audit_cmd_mutex); + 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); + } +} + +/* Log information about who is connecting to the audit multicast socket */ +static void audit_log_multicast(int group, const char *op, int err) +{ + 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); } /* Run custom bind function on netlink socket group connect or bind requests. */ -static int audit_bind(struct net *net, int group) +static int audit_multicast_bind(struct net *net, int group) { + int err = 0; + if (!capable(CAP_AUDIT_READ)) - return -EPERM; + err = -EPERM; + audit_log_multicast(group, "connect", err); + return err; +} - return 0; +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) { struct netlink_kernel_cfg cfg = { .input = audit_receive, - .bind = audit_bind, + .bind = audit_multicast_bind, + .unbind = audit_multicast_unbind, .flags = NL_CFG_F_NONROOT_RECV, .groups = AUDIT_NLGRP_MAX, }; @@ -1500,7 +1696,8 @@ static int __net_init audit_net_init(struct net *net) audit_panic("cannot initialize netlink socket in namespace"); return -ENOMEM; } - aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; + /* limit the timeout in case auditd is blocked/stopped */ + aunet->sk->sk_sndtimeo = HZ / 10; return 0; } @@ -1533,9 +1730,7 @@ static int __init audit_init(void) if (audit_initialized == AUDIT_DISABLED) return 0; - audit_buffer_cache = kmem_cache_create("audit_buffer", - sizeof(struct audit_buffer), - 0, SLAB_PANIC, NULL); + audit_buffer_cache = KMEM_CACHE(audit_buffer, SLAB_PANIC); skb_queue_head_init(&audit_queue); skb_queue_head_init(&audit_retry_queue); @@ -1544,13 +1739,14 @@ static int __init audit_init(void) 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", - audit_default ? "enabled" : "disabled"); + str_enabled_disabled(audit_default)); register_pernet_subsys(&audit_net_ops); audit_initialized = AUDIT_INITIALIZED; - audit_enabled = audit_default; - audit_ever_enabled |= !!audit_default; kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); if (IS_ERR(kauditd_task)) { @@ -1564,14 +1760,28 @@ static int __init audit_init(void) 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); pr_info("%s\n", audit_default ? "enabled (after initialization)" : "disabled (until reboot)"); @@ -1602,10 +1812,13 @@ __setup("audit_backlog_limit=", audit_backlog_limit_set); static void audit_buffer_free(struct audit_buffer *ab) { + struct sk_buff *skb; + if (!ab) return; - kfree_skb(ab->skb); + while ((skb = skb_dequeue(&ab->skb_list))) + kfree_skb(skb); kmem_cache_free(audit_buffer_cache, ab); } @@ -1618,9 +1831,14 @@ static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, if (!ab) return NULL; + skb_queue_head_init(&ab->skb_list); + ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); if (!ab->skb) goto err; + + skb_queue_tail(&ab->skb_list, ab->skb); + if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) goto err; @@ -1655,15 +1873,15 @@ unsigned int audit_serial(void) { static atomic_t serial = ATOMIC_INIT(0); - return atomic_add_return(1, &serial); + return atomic_inc_return(&serial); } static inline void audit_get_stamp(struct audit_context *ctx, - struct timespec64 *t, unsigned int *serial) + struct audit_stamp *stamp) { - if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { - ktime_get_real_ts64(t); - *serial = audit_serial(); + if (!ctx || !auditsc_get_stamp(ctx, stamp)) { + ktime_get_coarse_real_ts64(&stamp->ctime); + stamp->serial = audit_serial(); } } @@ -1686,13 +1904,11 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type) { struct audit_buffer *ab; - struct timespec64 t; - unsigned int uninitialized_var(serial); if (audit_initialized != AUDIT_INITIALIZED) return NULL; - if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) + if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE))) return NULL; /* NOTE: don't ever fail/sleep on these two conditions: @@ -1701,9 +1917,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, * 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 */ - if (!(auditd_test_task(current) || - (current == __mutex_owner(&audit_cmd_mutex)))) { + * 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 && @@ -1714,12 +1931,15 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, /* 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(stime); + 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()) @@ -1738,9 +1958,14 @@ 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)t.tv_sec, t.tv_nsec/1000000, serial); + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); return ab; } @@ -1775,8 +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; @@ -1833,7 +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 @@ -1922,8 +2147,8 @@ bool audit_string_contains_control(const char *string, size_t len) /** * 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, @@ -1967,13 +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); @@ -1984,7 +2209,7 @@ void audit_log_session_info(struct audit_buffer *ab) 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", auid, sessionid); + audit_log_format(ab, "auid=%u ses=%u", auid, sessionid); } void audit_log_key(struct audit_buffer *ab, char *key) @@ -1996,179 +2221,178 @@ 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[CAP_LAST_U32 - i]); - } -} - -static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name) -{ - audit_log_cap(ab, "cap_fp", &name->fcap.permitted); - audit_log_cap(ab, "cap_fi", &name->fcap.inheritable); - 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; + WARN_ON(ab->skb != skb_peek(&ab->skb_list)); - if (!dentry) - return 0; - - 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, - 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, - const 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 != AUDIT_INO_UNSET) - 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)); - 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; + audit_log_format(ab, " subj=%s", ctx.context); + security_release_secctx(&ctx); + return 0; + } + /* 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; - /* log the audit_names record type */ - audit_log_format(ab, " nametype="); - switch(n->type) { - case AUDIT_TYPE_NORMAL: - audit_log_format(ab, "NORMAL"); - break; - case AUDIT_TYPE_PARENT: - audit_log_format(ab, "PARENT"); - break; - case AUDIT_TYPE_CHILD_DELETE: - audit_log_format(ab, "DELETE"); - break; - case AUDIT_TYPE_CHILD_CREATE: - audit_log_format(ab, "CREATE"); - break; - default: - audit_log_format(ab, "UNKNOWN"); - break; - } - - 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_d_path_exe(struct audit_buffer *ab, struct mm_struct *mm) @@ -2189,15 +2413,15 @@ out_null: audit_log_format(ab, " exe=(null)"); } -struct tty_struct *audit_get_tty(struct task_struct *tsk) +struct tty_struct *audit_get_tty(void) { struct tty_struct *tty = NULL; unsigned long flags; - spin_lock_irqsave(&tsk->sighand->siglock, flags); - if (tsk->signal) - tty = tty_kref_get(tsk->signal->tty); - spin_unlock_irqrestore(&tsk->sighand->siglock, 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; } @@ -2206,25 +2430,24 @@ void audit_put_tty(struct tty_struct *tty) tty_kref_put(tty); } -void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) +void audit_log_task_info(struct audit_buffer *ab) { const struct cred *cred; - char comm[sizeof(tsk->comm)]; + char comm[sizeof(current->comm)]; struct tty_struct *tty; if (!ab) return; - /* tsk == current */ cred = current_cred(); - tty = audit_get_tty(tsk); + tty = audit_get_tty(); audit_log_format(ab, " ppid=%d pid=%d auid=%u uid=%u gid=%u" " euid=%u suid=%u fsuid=%u" " egid=%u sgid=%u fsgid=%u tty=%s ses=%u", - task_ppid_nr(tsk), - task_tgid_nr(tsk), - from_kuid(&init_user_ns, audit_get_loginuid(tsk)), + 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), @@ -2234,45 +2457,169 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk) from_kgid(&init_user_ns, cred->sgid), from_kgid(&init_user_ns, cred->fsgid), tty ? tty_name(tty) : "(none)", - audit_get_sessionid(tsk)); + audit_get_sessionid(current)); audit_put_tty(tty); audit_log_format(ab, " comm="); - audit_log_untrustedstring(ab, get_task_comm(comm, tsk)); - audit_log_d_path_exe(ab, tsk->mm); + 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 operation - * @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, const 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); +} + +/* 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; - /* Generate AUDIT_PATH record with object. */ - name->type = AUDIT_TYPE_NORMAL; - audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry)); - audit_log_name(current->audit_context, name, link, 0, NULL); + /* 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); + } } /** @@ -2281,31 +2628,21 @@ out: * * 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 tasklet is scheduled to remove them from the queue outside the + * 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; - struct nlmsghdr *nlh; if (!ab) return; - if (audit_rate_check()) { - skb = ab->skb; - ab->skb = NULL; + while ((skb = skb_dequeue(&ab->skb_list))) + __audit_log_end(skb); - /* 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 and poke the kauditd thread */ - skb_queue_tail(&audit_queue, skb); - wake_up_interruptible(&kauditd_wait); - } else - audit_log_lost("rate limit exceeded"); + /* poke the kauditd thread */ + wake_up_interruptible(&kauditd_wait); audit_buffer_free(ab); } @@ -2337,32 +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); |