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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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/hex.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>#include <linux/security.h>#include <linux/lsm_hooks.h>#include <linux/freezer.h>#include <linux/pid_namespace.h>#include <net/netns/generic.h>#include <net/ip.h>#include <net/ipv6.h>#include <linux/sctp.h>#include <linux/overflow.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 1static int audit_initialized = AUDIT_UNINITIALIZED;
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;
/* Number of modules that provide a security context. List of lsms that provide a security context */static u32 audit_subj_secctx_cnt;static u32 audit_obj_secctx_cnt;static const struct lsm_id *audit_subj_lsms[MAX_LSM_COUNT];static const struct lsm_id *audit_obj_lsms[MAX_LSM_COUNT];
/** * struct audit_net - audit private network namespace data * @sk: communication socket */struct audit_net { struct sock *sk;};
/** * struct auditd_connection - kernel/auditd connection state * @pid: auditd PID * @portid: netlink portid * @net: the associated network namespace * @rcu: RCU head * * Description: * This struct is RCU protected; you must either hold the RCU lock for reading * or the associated spinlock for writing. */struct auditd_connection { struct pid *pid; u32 portid; struct net *net; struct rcu_head rcu;};static struct auditd_connection __rcu *auditd_conn;static DEFINE_SPINLOCK(auditd_conn_lock);
/* If audit_rate_limit is non-zero, limit the rate of sending audit records * to that number per second. This prevents DoS attacks, but results in * audit records being dropped. */static 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. */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] 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);
/* 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];
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; /* the skb for audit_log functions */ struct sk_buff_head skb_list; /* formatted skbs, ready to send */ struct audit_context *ctx; /* NULL or associated context */ struct audit_stamp stamp; /* audit stamp for these records */ gfp_t gfp_mask;};
struct audit_reply { __u32 portid; struct net *net; struct sk_buff *skb;};
/** * 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_cfg_lsm - Identify a security module as providing a secctx. * @lsmid: LSM identity * @flags: which contexts are provided * * Description: * Increments the count of the security modules providing a secctx. * If the LSM id is already in the list leave it alone. */void audit_cfg_lsm(const struct lsm_id *lsmid, int flags){ int i;
if (flags & AUDIT_CFG_LSM_SECCTX_SUBJECT) { for (i = 0 ; i < audit_subj_secctx_cnt; i++) if (audit_subj_lsms[i] == lsmid) return; audit_subj_lsms[audit_subj_secctx_cnt++] = lsmid; } if (flags & AUDIT_CFG_LSM_SECCTX_OBJECT) { for (i = 0 ; i < audit_obj_secctx_cnt; i++) if (audit_obj_lsms[i] == lsmid) return; audit_obj_lsms[audit_obj_secctx_cnt++] = lsmid; }}
/** * audit_get_sk - Return the audit socket for the given network namespace * @net: the destination network namespace * * Description: * Returns the sock pointer if valid, NULL otherwise. The caller must ensure * that a reference is held for the network namespace while the sock is in use. */static struct sock *audit_get_sk(const struct net *net){ struct audit_net *aunet;
if (!net) return NULL;
aunet = net_generic(net, audit_net_id); return aunet->sk;}
void audit_panic(const char *message){ switch (audit_failure) { 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; static int messages; static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; int retval = 0;
if (!audit_rate_limit) return 1;
spin_lock_irqsave(&lock, flags); if (++messages < audit_rate_limit) { retval = 1; } else { now = jiffies; if (time_after(now, last_check + 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; 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 (time_after(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 * @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, struct sk_buff *skb, bool *ack){ unsigned long flags; struct auditd_connection *ac_old, *ac_new; struct nlmsghdr *nlh;
if (!pid || !net) return -EINVAL;
ac_new = kzalloc_obj(*ac_new); if (!ac_new) return -ENOMEM; ac_new->pid = get_pid(pid); ac_new->portid = portid; ac_new->net = get_net(net);
/* send the ack now to avoid a race with the queue backlog */ if (*ack) { nlh = nlmsg_hdr(skb); netlink_ack(skb, nlh, 0, NULL); *ack = false; }
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_printk_skb - Print the audit record to the ring buffer * @skb: audit record * * Whatever the reason, this packet may not make it to the auditd connection * so write it via printk so the information isn't completely lost. */static void kauditd_printk_skb(struct sk_buff *skb){ 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 * @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, __always_unused int error){ /* put the record back in the queue */ skb_queue_tail(&audit_hold_queue, skb);}
/** * kauditd_hold_skb - Queue an audit record, waiting for auditd * @skb: audit record * @error: error code * * 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, 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) 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 in the hold queue, queue the message */ if (!audit_backlog_limit || skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { skb_queue_tail(&audit_hold_queue, skb); return; }
/* we have no other options - drop the message */ audit_log_lost("kauditd hold queue overflow");drop: kfree_skb(skb);}
/** * kauditd_retry_skb - Queue an audit record, attempt to send again to auditd * @skb: audit record * @error: error code (unused) * * Description: * Not as serious as kauditd_hold_skb() as we still have a connected auditd, * but for some reason we are having problems sending it audit records so * queue the given record and attempt to resend. */static void kauditd_retry_skb(struct sk_buff *skb, __always_unused int error){ if (!audit_backlog_limit || skb_queue_len(&audit_retry_queue) < audit_backlog_limit) { skb_queue_tail(&audit_retry_queue, skb); return; }
/* we have to drop the record, send it via printk as a last effort */ kauditd_printk_skb(skb); audit_log_lost("kauditd retry queue overflow"); kfree_skb(skb);}
/** * auditd_reset - Disconnect the auditd connection * @ac: auditd connection state * * Description: * Break the auditd/kauditd connection and move all the queued records into the * hold queue in case auditd reconnects. It is important to note that the @ac * pointer should never be dereferenced inside this function as it may be NULL * or invalid, you can only compare the memory address! If @ac is NULL then * the connection will always be reset. */static void auditd_reset(const struct auditd_connection *ac){ unsigned long flags; struct sk_buff *skb; struct auditd_connection *ac_old;
/* if it isn't already broken, break the connection */ spin_lock_irqsave(&auditd_conn_lock, flags); ac_old = rcu_dereference_protected(auditd_conn, lockdep_is_held(&auditd_conn_lock)); if (ac && ac != ac_old) { /* someone already registered a new auditd connection */ spin_unlock_irqrestore(&auditd_conn_lock, flags); return; } rcu_assign_pointer(auditd_conn, NULL); spin_unlock_irqrestore(&auditd_conn_lock, flags);
if (ac_old) call_rcu(&ac_old->rcu, auditd_conn_free);
/* flush the retry queue to the hold queue, but don't touch the main * queue since we need to process that normally for multicast */ while ((skb = skb_dequeue(&audit_retry_queue))) kauditd_hold_skb(skb, -ECONNREFUSED);}
/** * auditd_send_unicast_skb - Send a record via unicast to auditd * @skb: audit record * * Description: * Send a skb to the audit daemon, returns positive/zero values on success and * negative values on failure; in all cases the skb will be consumed by this * function. If the send results in -ECONNREFUSED the connection with auditd * will be reset. This function may sleep so callers should not hold any locks * where this would cause a problem. */static int auditd_send_unicast_skb(struct sk_buff *skb){ int rc; u32 portid; struct net *net; struct sock *sk; struct auditd_connection *ac;
/* NOTE: we can't call netlink_unicast while in the RCU section so * take a reference to the network namespace and grab local * copies of the namespace, the sock, and the portid; the * namespace and sock aren't going to go away while we hold a * reference and if the portid does become invalid after the RCU * section netlink_unicast() should safely return an error */
rcu_read_lock(); ac = rcu_dereference(auditd_conn); if (!ac) { rcu_read_unlock(); kfree_skb(skb); rc = -ECONNREFUSED; goto err; } net = get_net(ac->net); sk = audit_get_sk(net); portid = ac->portid; rcu_read_unlock();
rc = netlink_unicast(sk, skb, portid, 0); put_net(net); if (rc < 0) goto err;
return rc;
err: if (ac && rc == -ECONNREFUSED) auditd_reset(ac); return rc;}
/** * kauditd_send_queue - Helper for kauditd_thread to flush skb queues * @sk: the sending sock * @portid: the netlink destination * @queue: the skb queue to process * @retry_limit: limit on number of netlink unicast failures * @skb_hook: per-skb hook for additional processing * @err_hook: hook called if the skb fails the netlink unicast send * * Description: * Run through the given queue and attempt to send the audit records to auditd, * returns zero on success, negative values on failure. It is up to the caller * to ensure that the @sk is valid for the duration of this function. * */static int kauditd_send_queue(struct sock *sk, u32 portid, struct sk_buff_head *queue, unsigned int retry_limit, void (*skb_hook)(struct sk_buff *skb), void (*err_hook)(struct sk_buff *skb, int error)){ int rc = 0; struct sk_buff *skb = NULL; struct sk_buff *skb_tail; unsigned int failed = 0;
/* NOTE: kauditd_thread takes care of all our locking, we just use * the netlink info passed to us (e.g. sk and portid) */
skb_tail = skb_peek_tail(queue); while ((skb != skb_tail) && (skb = skb_dequeue(queue))) { /* call the skb_hook for each skb we touch */ if (skb_hook) (*skb_hook)(skb);
/* can we send to anyone via unicast? */ if (!sk) { if (err_hook) (*err_hook)(skb, -ECONNREFUSED); continue; }
retry: /* grab an extra skb reference in case of error */ skb_get(skb); rc = netlink_unicast(sk, skb, portid, 0); if (rc < 0) { /* send failed - try a few times unless fatal error */ if (++failed >= retry_limit || rc == -ECONNREFUSED || rc == -EPERM) { sk = NULL; if (err_hook) (*err_hook)(skb, rc); if (rc == -EAGAIN) rc = 0; /* continue to drain the queue */ continue; } else goto retry; } else { /* skb sent - drop the extra reference and continue */ consume_skb(skb); failed = 0; } }
return (rc >= 0 ? 0 : rc);}
/* * kauditd_send_multicast_skb - Send a record to any multicast listeners * @skb: audit record * * Description: * Write a multicast message to anyone listening in the initial network * namespace. This function doesn't consume an skb as might be expected since * it has to copy it anyways. */static void kauditd_send_multicast_skb(struct sk_buff *skb){ struct sk_buff *copy; struct sock *sock = audit_get_sk(&init_net); struct nlmsghdr *nlh;
/* NOTE: we are not taking an additional reference for init_net since * we don't have to worry about it going away */
if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG)) return;
/* * 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 (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 (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_lockless(&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;
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_obj(*reply); 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);}
static int is_audit_feature_set(int i){ return af.features & AUDIT_FEATURE_TO_MASK(i);}
static int audit_get_feature(struct sk_buff *skb){ u32 seq;
seq = nlmsg_hdr(skb)->nlmsg_seq;
audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
return 0;}
static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature, u32 old_lock, u32 new_lock, int res){ struct audit_buffer *ab;
if (audit_enabled == AUDIT_OFF) return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE); if (!ab) return; audit_log_task_info(ab); audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d", audit_feature_names[which], !!old_feature, !!new_feature, !!old_lock, !!new_lock, res); audit_log_end(ab);}
static int audit_set_feature(struct audit_features *uaf){ int i;
BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
/* if there is ever a version 2 we should handle that here */
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { u32 feature = AUDIT_FEATURE_TO_MASK(i); u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */ if (!(feature & uaf->mask)) continue;
old_feature = af.features & feature; new_feature = uaf->features & feature; new_lock = (uaf->lock | af.lock) & feature; old_lock = af.lock & feature;
/* are we changing a locked feature? */ if (old_lock && (new_feature != old_feature)) { audit_log_feature_change(i, old_feature, new_feature, old_lock, new_lock, 0); return -EPERM; } } /* nothing invalid, do the changes */ for (i = 0; i <= AUDIT_LAST_FEATURE; i++) { u32 feature = AUDIT_FEATURE_TO_MASK(i); u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */ if (!(feature & uaf->mask)) continue;
old_feature = af.features & feature; new_feature = uaf->features & feature; old_lock = af.lock & feature; new_lock = (uaf->lock | af.lock) & feature;
if (new_feature != old_feature) audit_log_feature_change(i, old_feature, new_feature, old_lock, new_lock, 1);
if (new_feature) af.features |= feature; else af.features &= ~feature; af.lock |= new_lock; }
return 0;}
static int audit_replace(struct pid *pid){ pid_t pvnr; struct sk_buff *skb;
pvnr = pid_vnr(pid); skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr)); if (!skb) return -ENOMEM; return auditd_send_unicast_skb(skb);}
static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh, bool *ack){ u32 seq; void *data; int data_len; int err; struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; struct audit_sig_info *sig_data; struct lsm_context lsmctx = { NULL, 0, 0 };
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_lockless(&audit_queue); s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL; s.backlog_wait_time = audit_backlog_wait_time; s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual); audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s)); break; } case AUDIT_SET: { 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_ALL) return -EINVAL; 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), skb, ack); if (audit_enabled != AUDIT_OFF) audit_log_config_change("audit_pid", new_pid, auditd_pid, err ? 0 : 1); if (err) return err;
/* try to process any backlog */ wake_up_interruptible(&kauditd_wait); } else { if (audit_enabled != AUDIT_OFF) audit_log_config_change("audit_pid", new_pid, auditd_pid, 1);
/* unregister the auditd connection */ auditd_reset(NULL); } } if (s.mask & AUDIT_STATUS_RATE_LIMIT) { err = audit_set_rate_limit(s.rate_limit); if (err < 0) return err; } if (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; } if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) { u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
audit_log_config_change("backlog_wait_time_actual", 0, actual, 1); return actual; } break; } case AUDIT_GET_FEATURE: err = audit_get_feature(skb); if (err) return err; break; case AUDIT_SET_FEATURE: if (data_len < sizeof(struct audit_features)) return -EINVAL; err = audit_set_feature(data); if (err) return err; break; case AUDIT_USER: case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG: case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2: if (!audit_enabled && msg_type != AUDIT_USER_AVC) return 0; /* exit early if there isn't at least one character to print */ if (data_len < 2) return -EINVAL;
err = audit_filter(msg_type, AUDIT_FILTER_USER); if (err == 1) { /* match or error */ char *str = data;
err = 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 (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: if (audit_enabled == AUDIT_LOCKED) return -EPERM; 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;
if (audit_enabled == AUDIT_LOCKED) return -EPERM; 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: 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_flex(*sig_data, ctx, lsmctx.len); if (!sig_data) { 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 (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, struct_size(sig_data, ctx, lsmctx.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; bool ack; /* * 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)) { ack = nlh->nlmsg_flags & NLM_F_ACK; err = audit_receive_msg(skb, nlh, &ack);
/* send an ack if the user asked for one and audit_receive_msg * didn't already do it, or if there was an error. */ if (ack || err) netlink_ack(skb, nlh, err, NULL);
nlh = nlmsg_next(nlh, &len); } audit_ctl_unlock();
/* can't block with the ctrl lock, so penalize the sender now */ if (audit_backlog_limit && (skb_queue_len_lockless(&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_multicast_bind(struct net *net, int group){ int err = 0;
if (!capable(CAP_AUDIT_READ)) err = -EPERM; audit_log_multicast(group, "connect", err); return err;}
static void audit_multicast_unbind(struct net *net, int group){ audit_log_multicast(group, "disconnect", 0);}
static int __net_init audit_net_init(struct net *net){ struct netlink_kernel_cfg cfg = { .input = audit_receive, .bind = audit_multicast_bind, .unbind = audit_multicast_unbind, .flags = NL_CFG_F_NONROOT_RECV, .groups = AUDIT_NLGRP_MAX, };
struct audit_net *aunet = net_generic(net, audit_net_id);
aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg); if (aunet->sk == NULL) { audit_panic("cannot initialize netlink socket in namespace"); return -ENOMEM; } /* limit the timeout in case auditd is blocked/stopped */ aunet->sk->sk_sndtimeo = HZ / 10;
return 0;}
static void __net_exit audit_net_exit(struct net *net){ struct audit_net *aunet = net_generic(net, audit_net_id);
/* NOTE: you would think that we would want to check the auditd * connection and potentially reset it here if it lives in this * namespace, but since the auditd connection tracking struct holds a * reference to this namespace (see auditd_set()) we are only ever * going to get here after that connection has been released */
netlink_kernel_release(aunet->sk);}
static struct pernet_operations audit_net_ops __net_initdata = { .init = audit_net_init, .exit = audit_net_exit, .id = &audit_net_id, .size = sizeof(struct audit_net),};
/* Initialize audit support at boot time. */static int __init audit_init(void){ int i;
if (audit_initialized == AUDIT_DISABLED) return 0;
audit_buffer_cache = KMEM_CACHE(audit_buffer, SLAB_PANIC);
skb_queue_head_init(&audit_queue); skb_queue_head_init(&audit_retry_queue); skb_queue_head_init(&audit_hold_queue);
for (i = 0; i < AUDIT_INODE_BUCKETS; i++) INIT_LIST_HEAD(&audit_inode_hash[i]);
mutex_init(&audit_cmd_mutex.lock); audit_cmd_mutex.owner = NULL;
pr_info("initializing netlink subsys (%s)\n", str_enabled_disabled(audit_default)); register_pernet_subsys(&audit_net_ops);
audit_initialized = AUDIT_INITIALIZED;
kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd"); if (IS_ERR(kauditd_task)) { int err = PTR_ERR(kauditd_task); panic("audit: failed to start the kauditd thread (%d)\n", err); }
audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "state=initialized audit_enabled=%u res=1", audit_enabled);
return 0;}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){ struct sk_buff *skb;
if (!ab) return;
while ((skb = skb_dequeue(&ab->skb_list))) kfree_skb(skb); kmem_cache_free(audit_buffer_cache, ab);}
static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, gfp_t gfp_mask, int type){ struct audit_buffer *ab;
ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask); 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;
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_inc_return(&serial);}
static inline void audit_get_stamp(struct audit_context *ctx, struct audit_stamp *stamp){ if (!ctx || !auditsc_get_stamp(ctx, stamp)) { ktime_get_coarse_real_ts64(&stamp->ctime); stamp->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;
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, although we do penalize the sender * later in audit_receive() when it is safe to block */ if (!(auditd_test_task(current) || audit_ctl_owner_current())) { long stime = audit_backlog_wait_time;
while (audit_backlog_limit && (skb_queue_len_lockless(&audit_queue) > audit_backlog_limit)) { /* wake kauditd to try and flush the queue */ wake_up_interruptible(&kauditd_wait);
/* sleep if we are allowed and we haven't exhausted our * backlog wait limit */ if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) { long rtime = stime;
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&audit_backlog_wait, &wait); set_current_state(TASK_UNINTERRUPTIBLE); stime = schedule_timeout(rtime); atomic_add(rtime - stime, &audit_backlog_wait_time_actual); remove_wait_queue(&audit_backlog_wait, &wait); } else { if (audit_rate_check() && printk_ratelimit()) pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n", skb_queue_len_lockless(&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, &ab->stamp); /* cancel dummy context to enable supporting records */ if (ctx) ctx->dummy = 0; audit_log_format(ab, "audit(%llu.%03lu:%u): ", (unsigned long long)ab->stamp.ctime.tv_sec, ab->stamp.ctime.tv_nsec/1000000, ab->stamp.serial);
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 __printf(2, 0)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 int, 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 avail; size_t i, new_len; unsigned char *ptr; struct sk_buff *skb;
if (!ab) return;
BUG_ON(!ab->skb); skb = ab->skb; avail = skb_tailroom(skb);
if (check_shl_overflow(len, 1, &new_len)) { audit_log_format(ab, "?"); return; }
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 * @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, * 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_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_format(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)");}
/** * 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){ WARN_ON(ab->skb != skb_peek(&ab->skb_list));
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);
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;}
/** * 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){ ab->skb = skb_peek(&ab->skb_list);}
/** * 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. */int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop){ struct lsm_context ctx; char *space = ""; int error; int i;
security_current_getlsmprop_subj(prop); if (!lsmprop_is_set(prop)) return 0;
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; } 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, "%ssubj_%s=%s", space, audit_subj_lsms[i]->name, ctx.context); space = " "; security_release_secctx(&ctx); } } audit_buffer_aux_end(ab); return 0;
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){ struct lsm_prop prop;
security_current_getlsmprop_subj(&prop); return audit_log_subj_ctx(ab, &prop);}EXPORT_SYMBOL(audit_log_task_context);
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_buffer_aux_end(ab); return error;
error_path: audit_panic("error in audit_log_obj_ctx"); return error;}
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_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_path_denied(int type, const char *operation){ struct audit_buffer *ab;
if (!audit_enabled) return;
/* Generate log with subject, operation, outcome. */ ab = audit_log_start(audit_context(), GFP_KERNEL, type); 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);}
int audit_log_nf_skb(struct audit_buffer *ab, const struct sk_buff *skb, u8 nfproto){ /* find the IP protocol in the case of NFPROTO_BRIDGE */ if (nfproto == NFPROTO_BRIDGE) { switch (eth_hdr(skb)->h_proto) { case htons(ETH_P_IP): nfproto = NFPROTO_IPV4; break; case htons(ETH_P_IPV6): nfproto = NFPROTO_IPV6; break; default: goto unknown_proto; } }
switch (nfproto) { case NFPROTO_IPV4: { struct iphdr iph; const struct iphdr *ih;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(iph), &iph); if (!ih) return -ENOMEM;
switch (ih->protocol) { case IPPROTO_TCP: { struct tcphdr _tcph; const struct tcphdr *th;
th = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_tcph), &_tcph); if (!th) return -ENOMEM;
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, ih->protocol, ntohs(th->source), ntohs(th->dest)); break; } case IPPROTO_UDP: case IPPROTO_UDPLITE: { struct udphdr _udph; const struct udphdr *uh;
uh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_udph), &_udph); if (!uh) return -ENOMEM;
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, ih->protocol, ntohs(uh->source), ntohs(uh->dest)); break; } case IPPROTO_SCTP: { struct sctphdr _sctph; const struct sctphdr *sh;
sh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_sctph), &_sctph); if (!sh) return -ENOMEM;
audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, ih->protocol, ntohs(sh->source), ntohs(sh->dest)); break; } default: audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu", &ih->saddr, &ih->daddr, ih->protocol); }
break; } case NFPROTO_IPV6: { struct ipv6hdr iph; const struct ipv6hdr *ih; u8 nexthdr; __be16 frag_off;
ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(iph), &iph); if (!ih) return -ENOMEM;
nexthdr = ih->nexthdr; ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(iph), &nexthdr, &frag_off);
switch (nexthdr) { case IPPROTO_TCP: { struct tcphdr _tcph; const struct tcphdr *th;
th = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_tcph), &_tcph); if (!th) return -ENOMEM;
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, nexthdr, ntohs(th->source), ntohs(th->dest)); break; } case IPPROTO_UDP: case IPPROTO_UDPLITE: { struct udphdr _udph; const struct udphdr *uh;
uh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_udph), &_udph); if (!uh) return -ENOMEM;
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, nexthdr, ntohs(uh->source), ntohs(uh->dest)); break; } case IPPROTO_SCTP: { struct sctphdr _sctph; const struct sctphdr *sh;
sh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_sctph), &_sctph); if (!sh) return -ENOMEM;
audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu", &ih->saddr, &ih->daddr, nexthdr, ntohs(sh->source), ntohs(sh->dest)); break; } default: audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu", &ih->saddr, &ih->daddr, nexthdr); }
break; } default: goto unknown_proto; }
return 0;
unknown_proto: audit_log_format(ab, " saddr=? daddr=? proto=?"); return -EPFNOSUPPORT;}EXPORT_SYMBOL(audit_log_nf_skb);
/* global counter which is incremented every time something logs in */static atomic_t session_id = ATOMIC_INIT(0);
static int audit_set_loginuid_perm(kuid_t loginuid){ /* if we are unset, we don't need privs */ if (!audit_loginuid_set(current)) return 0; /* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/ if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE)) return -EPERM; /* it is set, you need permission */ if (!capable(CAP_AUDIT_CONTROL)) return -EPERM; /* reject if this is not an unset and we don't allow that */ if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID) && uid_valid(loginuid)) return -EPERM; return 0;}
static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid, unsigned int oldsessionid, unsigned int sessionid, int rc){ struct audit_buffer *ab; uid_t uid, oldloginuid, loginuid; struct tty_struct *tty;
if (!audit_enabled) return;
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN); if (!ab) return;
uid = from_kuid(&init_user_ns, task_uid(current)); oldloginuid = from_kuid(&init_user_ns, koldloginuid); loginuid = from_kuid(&init_user_ns, kloginuid); tty = audit_get_tty();
audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid); audit_log_task_context(ab); audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d", oldloginuid, loginuid, tty ? tty_name(tty) : "(none)", oldsessionid, sessionid, !rc); audit_put_tty(tty); audit_log_end(ab);}
/** * audit_set_loginuid - set current task's loginuid * @loginuid: loginuid value * * Returns 0. * * Called (set) from fs/proc/base.c::proc_loginuid_write(). */int audit_set_loginuid(kuid_t loginuid){ unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET; kuid_t oldloginuid; int rc;
oldloginuid = audit_get_loginuid(current); oldsessionid = audit_get_sessionid(current);
rc = audit_set_loginuid_perm(loginuid); if (rc) goto out;
/* are we setting or clearing? */ if (uid_valid(loginuid)) { sessionid = (unsigned int)atomic_inc_return(&session_id); if (unlikely(sessionid == AUDIT_SID_UNSET)) sessionid = (unsigned int)atomic_inc_return(&session_id); }
current->sessionid = sessionid; current->loginuid = loginuid;out: audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc); return rc;}
/** * audit_signal_info - record signal info for shutting down audit subsystem * @sig: signal value * @t: task being signaled * * If the audit subsystem is being terminated, record the task (pid) * and uid that is doing that. */int audit_signal_info(int sig, struct task_struct *t){ kuid_t uid = current_uid(), auid;
if (auditd_test_task(t) && (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2)) { audit_sig_pid = task_tgid_nr(current); auid = audit_get_loginuid(current); if (uid_valid(auid)) audit_sig_uid = auid; else audit_sig_uid = uid; security_current_getlsmprop_subj(&audit_sig_lsm); }
return audit_signal_info_syscall(t);}
/** * __audit_log_end - enqueue one audit record * @skb: the buffer to send */static void __audit_log_end(struct sk_buff *skb){ struct nlmsghdr *nlh;
if (audit_rate_check()) { /* setup the netlink header, see the comments in * kauditd_send_multicast_skb() for length quirks */ nlh = nlmsg_hdr(skb); nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
/* queue the netlink packet */ skb_queue_tail(&audit_queue, skb); } else { audit_log_lost("rate limit exceeded"); kfree_skb(skb); }}
/** * audit_log_end - end one audit record * @ab: the audit_buffer * * We can not do a netlink send inside an irq context because it blocks (last * arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a * queue and a kthread is scheduled to remove them from the queue outside the * irq context. May be called in any context. */void audit_log_end(struct audit_buffer *ab){ struct sk_buff *skb;
if (!ab) return;
while ((skb = skb_dequeue(&ab->skb_list))) __audit_log_end(skb);
/* poke the kauditd thread */ wake_up_interruptible(&kauditd_wait);
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);