| // 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 |
| * |
| * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. |
| * All Rights Reserved. |
| * |
| * Written by Rickard E. (Rik) Faith <faith@redhat.com> |
| * |
| * Goals: 1) Integrate fully with Security Modules. |
| * 2) Minimal run-time overhead: |
| * a) Minimal when syscall auditing is disabled (audit_enable=0). |
| * b) Small when syscall auditing is enabled and no audit record |
| * is generated (defer as much work as possible to record |
| * generation time): |
| * i) context is allocated, |
| * ii) names from getname are stored without a copy, and |
| * iii) inode information stored from path_lookup. |
| * 3) Ability to disable syscall auditing at boot time (audit=0). |
| * 4) Usable by other parts of the kernel (if audit_log* is called, |
| * then a syscall record will be generated automatically for the |
| * current syscall). |
| * 5) Netlink interface to user-space. |
| * 6) Support low-overhead kernel-based filtering to minimize the |
| * information that must be passed to user-space. |
| * |
| * 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 <linux/types.h> |
| #include <linux/atomic.h> |
| #include <linux/mm.h> |
| #include <linux/export.h> |
| #include <linux/slab.h> |
| #include <linux/err.h> |
| #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 <linux/freezer.h> |
| #include <linux/pid_namespace.h> |
| #include <net/netns/generic.h> |
| |
| #include "audit.h" |
| |
| /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. |
| * (Initialization happens after skb_init is called.) */ |
| #define AUDIT_DISABLED -1 |
| #define AUDIT_UNINITIALIZED 0 |
| #define AUDIT_INITIALIZED 1 |
| static int audit_initialized; |
| |
| 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 = AUDIT_OFF; |
| |
| /* If auditing cannot proceed, audit_failure selects what happens. */ |
| static u32 audit_failure = AUDIT_FAIL_PRINTK; |
| |
| /* private audit network namespace index */ |
| static unsigned int audit_net_id; |
| |
| /** |
| * 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. |
| */ |
| static struct auditd_connection { |
| struct pid *pid; |
| u32 portid; |
| struct net *net; |
| struct rcu_head rcu; |
| } *auditd_conn = NULL; |
| 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 u32 audit_rate_limit; |
| |
| /* 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; |
| |
| /* Records can be lost in several ways: |
| 0) [suppressed in audit_alloc] |
| 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] |
| 2) out of memory in audit_log_move [alloc_skb] |
| 3) suppressed due to audit_rate_limit |
| 4) suppressed due to audit_backlog_limit |
| */ |
| static atomic_t audit_lost = ATOMIC_INIT(0); |
| |
| /* Hash for inode-based rules */ |
| struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; |
| |
| 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; |
| |
| /* 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); |
| |
| 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 |
| |
| /* 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 sk_buff *skb; /* formatted skb ready to send */ |
| struct audit_context *ctx; /* NULL or associated context */ |
| gfp_t gfp_mask; |
| }; |
| |
| struct audit_reply { |
| __u32 portid; |
| struct net *net; |
| struct sk_buff *skb; |
| }; |
| |
| static struct kmem_cache *audit_task_cache; |
| |
| void __init audit_task_init(void) |
| { |
| audit_task_cache = kmem_cache_create("audit_task", |
| sizeof(struct audit_task_info), |
| 0, SLAB_PANIC, NULL); |
| } |
| |
| /** |
| * audit_alloc - allocate an audit info block for a task |
| * @tsk: task |
| * |
| * Call audit_alloc_syscall to filter on the task information and |
| * allocate a per-task audit context if necessary. This is called from |
| * copy_process, so no lock is needed. |
| */ |
| int audit_alloc(struct task_struct *tsk) |
| { |
| int ret = 0; |
| struct audit_task_info *info; |
| |
| info = kmem_cache_alloc(audit_task_cache, GFP_KERNEL); |
| if (!info) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| info->loginuid = audit_get_loginuid(current); |
| info->sessionid = audit_get_sessionid(current); |
| info->contid = audit_get_contid(current); |
| tsk->audit = info; |
| |
| ret = audit_alloc_syscall(tsk); |
| if (ret) { |
| tsk->audit = NULL; |
| kmem_cache_free(audit_task_cache, info); |
| } |
| out: |
| return ret; |
| } |
| |
| struct audit_task_info init_struct_audit = { |
| .loginuid = INVALID_UID, |
| .sessionid = AUDIT_SID_UNSET, |
| .contid = AUDIT_CID_UNSET, |
| #ifdef CONFIG_AUDITSYSCALL |
| .ctx = NULL, |
| #endif |
| }; |
| |
| /** |
| * audit_free - free per-task audit info |
| * @tsk: task whose audit info block to free |
| * |
| * Called from copy_process and do_exit |
| */ |
| void audit_free(struct task_struct *tsk) |
| { |
| struct audit_task_info *info = tsk->audit; |
| |
| audit_free_syscall(tsk); |
| /* Freeing the audit_task_info struct must be performed after |
| * audit_log_exit() due to need for loginuid and sessionid. |
| */ |
| info = tsk->audit; |
| tsk->audit = NULL; |
| kmem_cache_free(audit_task_cache, info); |
| } |
| |
| /** |
| * 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) |
| { |
| 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_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) { |
| case AUDIT_FAIL_SILENT: |
| break; |
| case AUDIT_FAIL_PRINTK: |
| if (printk_ratelimit()) |
| pr_err("%s\n", message); |
| break; |
| case AUDIT_FAIL_PANIC: |
| panic("audit: %s\n", message); |
| break; |
| } |
| } |
| |
| static inline int audit_rate_check(void) |
| { |
| static unsigned long last_check = 0; |
| static int messages = 0; |
| static DEFINE_SPINLOCK(lock); |
| unsigned long flags; |
| unsigned long now; |
| unsigned long elapsed; |
| int retval = 0; |
| |
| 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) { |
| last_check = now; |
| messages = 0; |
| retval = 1; |
| } |
| } |
| spin_unlock_irqrestore(&lock, flags); |
| |
| return retval; |
| } |
| |
| /** |
| * audit_log_lost - conditionally log lost audit message event |
| * @message: the message stating reason for lost audit message |
| * |
| * Emit at least 1 message per second, even if audit_rate_check is |
| * throttling. |
| * Always increment the lost messages counter. |
| */ |
| void audit_log_lost(const char *message) |
| { |
| static unsigned long last_msg = 0; |
| static DEFINE_SPINLOCK(lock); |
| unsigned long flags; |
| unsigned long now; |
| int print; |
| |
| atomic_inc(&audit_lost); |
| |
| print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); |
| |
| if (!print) { |
| spin_lock_irqsave(&lock, flags); |
| now = jiffies; |
| if (now - last_msg > HZ) { |
| print = 1; |
| last_msg = now; |
| } |
| spin_unlock_irqrestore(&lock, flags); |
| } |
| |
| if (print) { |
| if (printk_ratelimit()) |
| pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n", |
| atomic_read(&audit_lost), |
| audit_rate_limit, |
| audit_backlog_limit); |
| audit_panic(message); |
| } |
| } |
| |
| 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(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); |
| if (unlikely(!ab)) |
| return rc; |
| 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) |
| allow_changes = 0; /* Something weird, deny request */ |
| audit_log_format(ab, " res=%d", allow_changes); |
| audit_log_end(ab); |
| return rc; |
| } |
| |
| static int audit_do_config_change(char *function_name, u32 *to_change, u32 new) |
| { |
| int allow_changes, rc = 0; |
| u32 old = *to_change; |
| |
| /* check if we are locked */ |
| if (audit_enabled == AUDIT_LOCKED) |
| allow_changes = 0; |
| else |
| allow_changes = 1; |
| |
| if (audit_enabled != AUDIT_OFF) { |
| rc = audit_log_config_change(function_name, new, old, allow_changes); |
| if (rc) |
| allow_changes = 0; |
| } |
| |
| /* If we are allowed, make the change */ |
| if (allow_changes == 1) |
| *to_change = new; |
| /* Not allowed, update reason */ |
| else if (rc == 0) |
| rc = -EPERM; |
| return rc; |
| } |
| |
| 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(u32 limit) |
| { |
| return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit); |
| } |
| |
| 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_LOCKED) |
| return -EINVAL; |
| |
| rc = audit_do_config_change("audit_enabled", &audit_enabled, state); |
| if (!rc) |
| audit_ever_enabled |= !!state; |
| |
| return rc; |
| } |
| |
| static int audit_set_failure(u32 state) |
| { |
| if (state != AUDIT_FAIL_SILENT |
| && state != AUDIT_FAIL_PRINTK |
| && state != AUDIT_FAIL_PANIC) |
| return -EINVAL; |
| |
| return audit_do_config_change("audit_failure", &audit_failure, state); |
| } |
| |
| /** |
| * 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 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 |
| * |
| * 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) |
| { |
| unsigned long flags; |
| struct auditd_connection *ac_old, *ac_new; |
| |
| 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); |
| |
| 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; |
| } |
| |
| /** |
| * kauditd_print_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) |
| { |
| 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); |
| } |
| |
| /** |
| * kauditd_rehold_skb - Handle a audit record send failure in the hold queue |
| * @skb: audit record |
| * |
| * 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) |
| { |
| /* put the record back in the queue at the same place */ |
| skb_queue_head(&audit_hold_queue, skb); |
| } |
| |
| /** |
| * kauditd_hold_skb - Queue an audit record, waiting for auditd |
| * @skb: audit record |
| * |
| * 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 kauditd_hold_skb(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) { |
| kfree_skb(skb); |
| return; |
| } |
| |
| /* if we have room, 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"); |
| kfree_skb(skb); |
| } |
| |
| /** |
| * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd |
| * @skb: audit record |
| * |
| * 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) |
| { |
| /* 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); |
| } |
| |
| /** |
| * 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); |
| } |
| |
| /** |
| * 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 rc = 0; |
| struct sk_buff *skb; |
| static 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))) { |
| /* 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); |
| continue; |
| } |
| |
| /* 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? */ |
| 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 */ |
| continue; |
| } else |
| /* no - requeue to preserve ordering */ |
| skb_queue_head(queue, skb); |
| } else { |
| /* it worked - drop the extra reference and continue */ |
| consume_skb(skb); |
| failed = 0; |
| } |
| } |
| |
| out: |
| 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; |
| |
| /* |
| * 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. |
| */ |
| 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()) { |
| /* 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 (ac && rc < 0) { |
| sk = NULL; |
| auditd_reset(ac); |
| goto main_queue; |
| } |
| |
| /* attempt to flush the retry queue */ |
| rc = kauditd_send_queue(sk, portid, |
| &audit_retry_queue, UNICAST_RETRIES, |
| NULL, kauditd_hold_skb); |
| if (ac && rc < 0) { |
| sk = NULL; |
| auditd_reset(ac); |
| goto main_queue; |
| } |
| |
| 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; |
| } |
| |
| /* 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_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 */ |
| audit_ctl_lock(); |
| audit_ctl_unlock(); |
| |
| while ((skb = __skb_dequeue(&dest->q)) != NULL) |
| netlink_unicast(sk, skb, dest->portid, 0); |
| |
| put_net(dest->net); |
| kfree(dest); |
| |
| return 0; |
| } |
| |
| struct sk_buff *audit_make_reply(int seq, int type, int done, |
| int multi, const void *payload, int size) |
| { |
| struct sk_buff *skb; |
| struct nlmsghdr *nlh; |
| void *data; |
| int flags = multi ? NLM_F_MULTI : 0; |
| int t = done ? NLMSG_DONE : type; |
| |
| skb = nlmsg_new(size, GFP_KERNEL); |
| if (!skb) |
| return NULL; |
| |
| nlh = nlmsg_put(skb, 0, seq, t, size, flags); |
| if (!nlh) |
| goto out_kfree_skb; |
| data = nlmsg_data(nlh); |
| memcpy(data, payload, size); |
| return skb; |
| |
| out_kfree_skb: |
| kfree_skb(skb); |
| return NULL; |
| } |
| |
| static void audit_free_reply(struct audit_reply *reply) |
| { |
| if (!reply) |
| return; |
| |
| if (reply->skb) |
| 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; |
| |
| 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_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 |
| * @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 |
| * @multi: multi-part message flag |
| * @payload: payload data |
| * @size: payload size |
| * |
| * 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 task_struct *tsk; |
| struct audit_reply *reply; |
| |
| reply = kzalloc(sizeof(*reply), GFP_KERNEL); |
| if (!reply) |
| return; |
| |
| 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)) |
| goto err; |
| |
| return; |
| |
| err: |
| audit_free_reply(reply); |
| } |
| |
| /* |
| * Check for appropriate CAP_AUDIT_ capabilities on incoming audit |
| * control messages. |
| */ |
| static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) |
| { |
| int err = 0; |
| |
| /* 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: |
| case AUDIT_ADD: |
| case AUDIT_DEL: |
| 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: |
| case AUDIT_SIGNAL_INFO: |
| case AUDIT_TTY_GET: |
| case AUDIT_TTY_SET: |
| case AUDIT_TRIM: |
| case AUDIT_MAKE_EQUIV: |
| /* 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 (!netlink_capable(skb, CAP_AUDIT_WRITE)) |
| err = -EPERM; |
| break; |
| default: /* bad msg */ |
| err = -EINVAL; |
| } |
| |
| return err; |
| } |
| |
| 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); |
| |
| if (!audit_enabled && msg_type != AUDIT_USER_AVC) { |
| *ab = NULL; |
| return; |
| } |
| |
| *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_session_info(*ab); |
| audit_log_task_context(*ab); |
| } |
| |
| static inline void audit_log_user_recv_msg(struct audit_buffer **ab, |
| u16 msg_type) |
| { |
| audit_log_common_recv_msg(NULL, ab, msg_type); |
| } |
| |
| 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 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) |
| { |
| 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; |
| |
| err = audit_netlink_ok(skb, msg_type); |
| if (err) |
| return err; |
| |
| 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; |
| /* 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; |
| audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); |
| break; |
| } |
| 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 (s.mask & AUDIT_STATUS_FAILURE) { |
| err = audit_set_failure(s.failure); |
| if (err < 0) |
| return err; |
| } |
| 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 (new_pid) { |
| /* register a new auditd connection */ |
| err = auditd_set(req_pid, |
| NETLINK_CB(skb).portid, |
| sock_net(NETLINK_CB(skb).sk)); |
| 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 (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) { |
| err = audit_set_backlog_limit(s.backlog_limit); |
| if (err < 0) |
| return err; |
| } |
| 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; |
| } |
| 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 = 0; |
| if (msg_type == AUDIT_USER_TTY) { |
| err = tty_audit_push(); |
| if (err) |
| break; |
| } |
| 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="); |
| if (data_len > 0 && 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 (data_len < sizeof(struct audit_rule_data)) |
| return -EINVAL; |
| if (audit_enabled == AUDIT_LOCKED) { |
| 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, 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(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 = data_len; |
| char *old, *new; |
| |
| err = -EINVAL; |
| if (msglen < 2 * sizeof(u32)) |
| break; |
| memcpy(sizes, bufp, 2 * sizeof(u32)); |
| bufp += 2 * sizeof(u32); |
| msglen -= 2 * sizeof(u32); |
| old = audit_unpack_string(&bufp, &msglen, sizes[0]); |
| if (IS_ERR(old)) { |
| err = PTR_ERR(old); |
| break; |
| } |
| new = audit_unpack_string(&bufp, &msglen, sizes[1]); |
| if (IS_ERR(new)) { |
| err = PTR_ERR(new); |
| kfree(old); |
| break; |
| } |
| /* OK, here comes... */ |
| err = audit_tag_tree(old, new); |
| |
| 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="); |
| audit_log_untrustedstring(ab, new); |
| audit_log_format(ab, " res=%d", !err); |
| audit_log_end(ab); |
| kfree(old); |
| kfree(new); |
| break; |
| } |
| case AUDIT_SIGNAL_INFO: |
| len = 0; |
| if (audit_sig_sid) { |
| err = security_secid_to_secctx(audit_sig_sid, &ctx, &len); |
| if (err) |
| return err; |
| } |
| sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL); |
| if (!sig_data) { |
| if (audit_sig_sid) |
| security_release_secctx(ctx, len); |
| 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); |
| } |
| audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, |
| sig_data, sizeof(*sig_data) + len); |
| kfree(sig_data); |
| break; |
| case AUDIT_TTY_GET: { |
| struct audit_tty_status s; |
| unsigned int t; |
| |
| t = READ_ONCE(current->signal->audit_tty); |
| s.enabled = t & AUDIT_TTY_ENABLE; |
| s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD); |
| |
| audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s)); |
| break; |
| } |
| case AUDIT_TTY_SET: { |
| 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_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)) |
| err = -EINVAL; |
| |
| 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: |
| err = -EINVAL; |
| break; |
| } |
| |
| return err < 0 ? err : 0; |
| } |
| |
| /** |
| * 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(struct sk_buff *skb) |
| { |
| struct nlmsghdr *nlh; |
| /* |
| * len MUST be signed for nlmsg_next to be able to dec it below 0 |
| * if the nlmsg_len was not aligned |
| */ |
| int len; |
| int err; |
| |
| 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, NULL); |
| |
| nlh = nlmsg_next(nlh, &len); |
| } |
| audit_ctl_unlock(); |
| } |
| |
| /* Run custom bind function on netlink socket group connect or bind requests. */ |
| static int audit_bind(struct net *net, int group) |
| { |
| if (!capable(CAP_AUDIT_READ)) |
| return -EPERM; |
| |
| return 0; |
| } |
| |
| static int __net_init audit_net_init(struct net *net) |
| { |
| struct netlink_kernel_cfg cfg = { |
| .input = audit_receive, |
| .bind = audit_bind, |
| .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; |
| } |
| aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; |
| |
| 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; |
| |
| audit_buffer_cache = kmem_cache_create("audit_buffer", |
| sizeof(struct audit_buffer), |
| 0, SLAB_PANIC, NULL); |
| |
| 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", |
| audit_default ? "enabled" : "disabled"); |
| 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; |
| } |
| postcore_initcall(audit_init); |
| |
| /* |
| * Process kernel command-line parameter at boot time. |
| * audit={0|off} or audit={1|on}. |
| */ |
| static int __init audit_enable(char *str) |
| { |
| 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)"); |
| |
| 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; |
| } |
| |
| audit_backlog_limit = audit_backlog_limit_arg; |
| pr_cont("%d\n", audit_backlog_limit); |
| |
| return 1; |
| } |
| __setup("audit_backlog_limit=", audit_backlog_limit_set); |
| |
| static void audit_buffer_free(struct audit_buffer *ab) |
| { |
| if (!ab) |
| return; |
| |
| kfree_skb(ab->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) |
| { |
| struct audit_buffer *ab; |
| |
| ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); |
| if (!ab) |
| return NULL; |
| |
| ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask); |
| if (!ab->skb) |
| goto err; |
| if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0)) |
| goto err; |
| |
| ab->ctx = ctx; |
| ab->gfp_mask = gfp_mask; |
| |
| return ab; |
| |
| err: |
| audit_buffer_free(ab); |
| return NULL; |
| } |
| |
| /** |
| * audit_serial - compute a serial number for the audit record |
| * |
| * Compute a serial number for the audit record. Audit records are |
| * written to user-space as soon as they are generated, so a complete |
| * audit record may be written in several pieces. The timestamp of the |
| * record and this serial number are used by the user-space tools to |
| * determine which pieces belong to the same audit record. The |
| * (timestamp,serial) tuple is unique for each syscall and is live from |
| * syscall entry to syscall exit. |
| * |
| * NOTE: Another possibility is to store the formatted records off the |
| * audit context (for those records that have a context), and emit them |
| * all at syscall exit. However, this could delay the reporting of |
| * significant errors until syscall exit (or never, if the system |
| * halts). |
| */ |
| unsigned int audit_serial(void) |
| { |
| static atomic_t serial = ATOMIC_INIT(0); |
| |
| return atomic_add_return(1, &serial); |
| } |
| |
| static inline void audit_get_stamp(struct audit_context *ctx, |
| struct timespec64 *t, unsigned int *serial) |
| { |
| if (!ctx || !auditsc_get_stamp(ctx, t, serial)) { |
| ktime_get_coarse_real_ts64(t); |
| *serial = audit_serial(); |
| } |
| } |
| |
| /** |
| * audit_log_start - obtain an audit buffer |
| * @ctx: audit_context (may be NULL) |
| * @gfp_mask: type of allocation |
| * @type: audit message type |
| * |
| * Returns audit_buffer pointer on success or NULL on error. |
| * |
| * Obtain an audit buffer. This routine does locking to obtain the |
| * audit buffer, but then no locking is required for calls to |
| * audit_log_*format. If the task (ctx) is a task that is currently in a |
| * syscall, then the syscall is marked as auditable and an audit record |
| * will be written at syscall exit. If there is no associated task, then |
| * task context (ctx) should be NULL. |
| */ |
| struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, |
| int type) |
| { |
| 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_EXCLUDE))) |
| return NULL; |
| |
| /* 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 */ |
| 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)) { |
| DECLARE_WAITQUEUE(wait, current); |
| |
| add_wait_queue_exclusive(&audit_backlog_wait, |
| &wait); |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| stime = schedule_timeout(stime); |
| 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; |
| } |
| } |
| } |
| |
| ab = audit_buffer_alloc(ctx, gfp_mask, type); |
| if (!ab) { |
| audit_log_lost("out of memory in audit_log_start"); |
| return NULL; |
| } |
| |
| audit_get_stamp(ab->ctx, &t, &serial); |
| audit_log_format(ab, "audit(%llu.%03lu:%u): ", |
| (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial); |
| |
| return ab; |
| } |
| |
| /** |
| * audit_expand - expand skb in the audit buffer |
| * @ab: audit_buffer |
| * @extra: space to add at tail of the skb |
| * |
| * Returns 0 (no space) on failed expansion, or available space if |
| * successful. |
| */ |
| static inline int audit_expand(struct audit_buffer *ab, int extra) |
| { |
| struct sk_buff *skb = ab->skb; |
| int oldtail = skb_tailroom(skb); |
| int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask); |
| int newtail = skb_tailroom(skb); |
| |
| if (ret < 0) { |
| audit_log_lost("out of memory in audit_expand"); |
| return 0; |
| } |
| |
| skb->truesize += newtail - oldtail; |
| return newtail; |
| } |
| |
| /* |
| * Format an audit message into the audit buffer. If there isn't enough |
| * room in the audit buffer, more room will be allocated and vsnprint |
| * will be called a second time. Currently, we assume that a printk |
| * can't format message larger than 1024 bytes, so we don't either. |
| */ |
| static void audit_log_vformat(struct audit_buffer *ab, const char *fmt, |
| va_list args) |
| { |
| int len, avail; |
| struct sk_buff *skb; |
| va_list args2; |
| |
| if (!ab) |
| return; |
| |
| BUG_ON(!ab->skb); |
| skb = ab->skb; |
| avail = skb_tailroom(skb); |
| if (avail == 0) { |
| avail = audit_expand(ab, AUDIT_BUFSIZ); |
| if (!avail) |
| goto out; |
| } |
| va_copy(args2, args); |
| len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args); |
| if (len >= avail) { |
| /* The printk buffer is 1024 bytes long, so if we get |
| * here and AUDIT_BUFSIZ is at least 1024, then we can |
| * log everything that printk could have logged. */ |
| avail = audit_expand(ab, |
| max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail)); |
| if (!avail) |
| goto out_va_end; |
| len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2); |
| } |
| if (len > 0) |
| skb_put(skb, len); |
| out_va_end: |
| va_end(args2); |
| out: |
| return; |
| } |
| |
| /** |
| * audit_log_format - format a message into the audit buffer. |
| * @ab: audit_buffer |
| * @fmt: format string |
| * @...: optional parameters matching @fmt string |
| * |
| * All the work is done in audit_log_vformat. |
| */ |
| void audit_log_format(struct audit_buffer *ab, const char *fmt, ...) |
| { |
| va_list args; |
| |
| if (!ab) |
| return; |
| va_start(args, fmt); |
| audit_log_vformat(ab, fmt, args); |
| va_end(args); |
| } |
| |
| /** |
| * 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 |
| * |
| * No return value; failure to expand is silently ignored. |
| * |
| * This function will take the passed buf and convert it into a string of |
| * ascii hex digits. The new string is placed onto the skb. |
| */ |
| void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf, |
| size_t len) |
| { |
| int i, avail, new_len; |
| unsigned char *ptr; |
| struct sk_buff *skb; |
| |
| if (!ab) |
| return; |
| |
| BUG_ON(!ab->skb); |
| skb = ab->skb; |
| avail = skb_tailroom(skb); |
| new_len = len<<1; |
| if (new_len >= avail) { |
| /* Round the buffer request up to the next multiple */ |
| new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1); |
| avail = audit_expand(ab, new_len); |
| if (!avail) |
| return; |
| } |
| |
| ptr = skb_tail_pointer(skb); |
| 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 */ |
| } |
| |
| /* |
| * Format a string of no more than slen characters into the audit buffer, |
| * enclosed in quote marks. |
| */ |
| void audit_log_n_string(struct audit_buffer *ab, const char *string, |
| size_t slen) |
| { |
| int avail, new_len; |
| unsigned char *ptr; |
| struct sk_buff *skb; |
| |
| if (!ab) |
| return; |
| |
| BUG_ON(!ab->skb); |
| skb = ab->skb; |
| avail = skb_tailroom(skb); |
| new_len = slen + 3; /* enclosing quotes + null terminator */ |
| if (new_len > avail) { |
| avail = audit_expand(ab, new_len); |
| if (!avail) |
| return; |
| } |
| ptr = skb_tail_pointer(skb); |
| *ptr++ = '"'; |
| memcpy(ptr, string, slen); |
| ptr += slen; |
| *ptr++ = '"'; |
| *ptr = 0; |
| skb_put(skb, slen + 2); /* don't include null terminator */ |
| } |
| |
| /** |
| * audit_string_contains_control - does a string need to be logged in hex |
| * @string: string to be checked |
| * @len: max length of the string to check |
| */ |
| 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 true; |
| } |
| 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 |
| * |
| * This code will escape a string that is passed to it if the string |
| * contains a control character, unprintable character, double quote mark, |
| * or a space. Unescaped strings will start and end with a double quote mark. |
| * Strings that are escaped are printed in hex (2 digits per char). |
| * |
| * The caller specifies the number of characters in the string to log, which may |
| * or may not be the entire string. |
| */ |
| void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string, |
| size_t len) |
| { |
| if (audit_string_contains_control(string, len)) |
| audit_log_n_hex(ab, string, len); |
| else |
| audit_log_n_string(ab, string, len); |
| } |
| |
| /** |
| * audit_log_untrustedstring - log a string that may contain random characters |
| * @ab: audit_buffer |
| * @string: string to be logged |
| * |
| * Same as audit_log_n_untrustedstring(), except that strlen is used to |
| * determine string length. |
| */ |
| void audit_log_untrustedstring(struct audit_buffer *ab, const char *string) |
| { |
| audit_log_n_untrustedstring(ab, string, strlen(string)); |
| } |
| |
| /* This is a helper-function to print the escaped d_path */ |
| void audit_log_d_path(struct audit_buffer *ab, const char *prefix, |
| const struct path *path) |
| { |
| char *p, *pathname; |
| |
| if (prefix) |
| audit_log_format(ab, "%s", 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>"); |
| 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>"); |
| } else |
| audit_log_untrustedstring(ab, p); |
| kfree(pathname); |
| } |
| |
| 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); |
| } |
| |
| void audit_log_key(struct audit_buffer *ab, char *key) |
| { |
| audit_log_format(ab, " key="); |
| if (key) |
| audit_log_untrustedstring(ab, key); |
| else |
| audit_log_format(ab, "(null)"); |
| } |
| |
| int audit_log_task_context(struct audit_buffer *ab) |
| { |
| char *ctx = NULL; |
| unsigned len; |
| int error; |
| u32 sid; |
| |
| security_task_getsecid(current, &sid); |
| if (!sid) |
| return 0; |
| |
| error = security_secid_to_secctx(sid, &ctx, &len); |
| if (error) { |
| if (error != -EINVAL) |
| goto error_path; |
| return 0; |
| } |
| |
| audit_log_format(ab, " subj=%s", ctx); |
| security_release_secctx(ctx, len); |
| return 0; |
| |
| error_path: |
| audit_panic("error in audit_log_task_context"); |
| return error; |
| } |
| EXPORT_SYMBOL(audit_log_task_context); |
| |
| 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 comm[sizeof(current->comm)]; |
| struct tty_struct *tty; |
| |
| if (!ab) |
| return; |
| |
| cred = current_cred(); |
| 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(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), |
| from_kuid(&init_user_ns, cred->suid), |
| from_kuid(&init_user_ns, cred->fsuid), |
| from_kgid(&init_user_ns, cred->egid), |
| from_kgid(&init_user_ns, cred->sgid), |
| from_kgid(&init_user_ns, cred->fsgid), |
| tty ? tty_name(tty) : "(none)", |
| audit_get_sessionid(current)); |
| audit_put_tty(tty); |
| audit_log_format(ab, " comm="); |
| 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 |
| */ |
| void audit_log_link_denied(const char *operation) |
| { |
| struct audit_buffer *ab; |
| |
| if (!audit_enabled || audit_dummy_context()) |
| return; |
| |
| /* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */ |
| ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_ANOM_LINK); |
| if (!ab) |
| return; |
| audit_log_format(ab, "op=%s", operation); |
| 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; |
| |
| /* 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->audit->sessionid = sessionid; |
| current->audit->loginuid = loginuid; |
| out: |
| 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_task_getsecid(current, &audit_sig_sid); |
| } |
| |
| return audit_signal_info_syscall(t); |
| } |
| |
| /* |
| * audit_set_contid - set current task's audit contid |
| * @task: target task |
| * @contid: contid value |
| * |
| * Returns 0 on success, -EPERM on permission failure. |
| * |
| * Called (set) from fs/proc/base.c::proc_contid_write(). |
| */ |
| int audit_set_contid(struct task_struct *task, u64 contid) |
| { |
| u64 oldcontid; |
| int rc = 0; |
| struct audit_buffer *ab; |
| |
| task_lock(task); |
| /* Can't set if audit disabled */ |
| if (!task->audit) { |
| task_unlock(task); |
| return -ENOPROTOOPT; |
| } |
| oldcontid = audit_get_contid(task); |
| read_lock(&tasklist_lock); |
| /* Don't allow the audit containerid to be unset */ |
| if (!audit_contid_valid(contid)) |
| rc = -EINVAL; |
| /* if we don't have caps, reject */ |
| else if (!capable(CAP_AUDIT_CONTROL)) |
| rc = -EPERM; |
| /* if task has children or is not single-threaded, deny */ |
| else if (!list_empty(&task->children)) |
| rc = -EBUSY; |
| else if (!(thread_group_leader(task) && thread_group_empty(task))) |
| rc = -EALREADY; |
| /* if contid is already set, deny */ |
| else if (audit_contid_set(task)) |
| rc = -ECHILD; |
| read_unlock(&tasklist_lock); |
| if (!rc) |
| task->audit->contid = contid; |
| task_unlock(task); |
| |
| if (!audit_enabled) |
| return rc; |
| |
| ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONTAINER_OP); |
| if (!ab) |
| return rc; |
| |
| audit_log_format(ab, |
| "op=set opid=%d contid=%llu old-contid=%llu", |
| task_tgid_nr(task), contid, oldcontid); |
| audit_log_end(ab); |
| return rc; |
| } |
| |
| /** |
| * audit_log_end - end one audit record |
| * @ab: the audit_buffer |
| * |
| * 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 |
| * 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; |
| |
| /* 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"); |
| |
| audit_buffer_free(ab); |
| } |
| |
| /** |
| * audit_log - Log an audit record |
| * @ctx: audit context |
| * @gfp_mask: type of allocation |
| * @type: audit message type |
| * @fmt: format string to use |
| * @...: variable parameters matching the format string |
| * |
| * This is a convenience function that calls audit_log_start, |
| * audit_log_vformat, and audit_log_end. It may be called |
| * in any context. |
| */ |
| void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type, |
| const char *fmt, ...) |
| { |
| struct audit_buffer *ab; |
| va_list args; |
| |
| ab = audit_log_start(ctx, gfp_mask, type); |
| if (ab) { |
| va_start(args, fmt); |
| audit_log_vformat(ab, fmt, args); |
| va_end(args); |
| audit_log_end(ab); |
| } |
| } |
| |
| EXPORT_SYMBOL(audit_log_start); |
| EXPORT_SYMBOL(audit_log_end); |
| EXPORT_SYMBOL(audit_log_format); |
| EXPORT_SYMBOL(audit_log); |