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![Mel Gorman](/assets/img/avatar_default.png)
__GFP_WAIT has been used to identify atomic context in callers that hold spinlocks or are in interrupts. They are expected to be high priority and have access one of two watermarks lower than "min" which can be referred to as the "atomic reserve". __GFP_HIGH users get access to the first lower watermark and can be called the "high priority reserve". Over time, callers had a requirement to not block when fallback options were available. Some have abused __GFP_WAIT leading to a situation where an optimisitic allocation with a fallback option can access atomic reserves. This patch uses __GFP_ATOMIC to identify callers that are truely atomic, cannot sleep and have no alternative. High priority users continue to use __GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify callers that want to wake kswapd for background reclaim. __GFP_WAIT is redefined as a caller that is willing to enter direct reclaim and wake kswapd for background reclaim. This patch then converts a number of sites o __GFP_ATOMIC is used by callers that are high priority and have memory pools for those requests. GFP_ATOMIC uses this flag. o Callers that have a limited mempool to guarantee forward progress clear __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall into this category where kswapd will still be woken but atomic reserves are not used as there is a one-entry mempool to guarantee progress. o Callers that are checking if they are non-blocking should use the helper gfpflags_allow_blocking() where possible. This is because checking for __GFP_WAIT as was done historically now can trigger false positives. Some exceptions like dm-crypt.c exist where the code intent is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to flag manipulations. o Callers that built their own GFP flags instead of starting with GFP_KERNEL and friends now also need to specify __GFP_KSWAPD_RECLAIM. The first key hazard to watch out for is callers that removed __GFP_WAIT and was depending on access to atomic reserves for inconspicuous reasons. In some cases it may be appropriate for them to use __GFP_HIGH. The second key hazard is callers that assembled their own combination of GFP flags instead of starting with something like GFP_KERNEL. They may now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless if it's missed in most cases as other activity will wake kswapd. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2050 lines
53 KiB
C
2050 lines
53 KiB
C
/* audit.c -- Auditing support
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* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
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* System-call specific features have moved to auditsc.c
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*
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* Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Written by Rickard E. (Rik) Faith <faith@redhat.com>
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*
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* Goals: 1) Integrate fully with Security Modules.
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* 2) Minimal run-time overhead:
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* a) Minimal when syscall auditing is disabled (audit_enable=0).
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* b) Small when syscall auditing is enabled and no audit record
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* is generated (defer as much work as possible to record
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* generation time):
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* i) context is allocated,
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* ii) names from getname are stored without a copy, and
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* iii) inode information stored from path_lookup.
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* 3) Ability to disable syscall auditing at boot time (audit=0).
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* 4) Usable by other parts of the kernel (if audit_log* is called,
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* then a syscall record will be generated automatically for the
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* current syscall).
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* 5) Netlink interface to user-space.
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* 6) Support low-overhead kernel-based filtering to minimize the
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* information that must be passed to user-space.
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*
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* Example user-space utilities: http://people.redhat.com/sgrubb/audit/
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/file.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/atomic.h>
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#include <linux/mm.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/kthread.h>
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#include <linux/kernel.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <net/sock.h>
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#include <net/netlink.h>
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#include <linux/skbuff.h>
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#ifdef CONFIG_SECURITY
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#include <linux/security.h>
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#endif
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#include <linux/freezer.h>
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#include <linux/tty.h>
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#include <linux/pid_namespace.h>
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#include <net/netns/generic.h>
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#include "audit.h"
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/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
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* (Initialization happens after skb_init is called.) */
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#define AUDIT_DISABLED -1
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#define AUDIT_UNINITIALIZED 0
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#define AUDIT_INITIALIZED 1
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static int audit_initialized;
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#define AUDIT_OFF 0
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#define AUDIT_ON 1
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#define AUDIT_LOCKED 2
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u32 audit_enabled;
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u32 audit_ever_enabled;
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EXPORT_SYMBOL_GPL(audit_enabled);
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/* Default state when kernel boots without any parameters. */
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static u32 audit_default;
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/* If auditing cannot proceed, audit_failure selects what happens. */
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static u32 audit_failure = AUDIT_FAIL_PRINTK;
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/*
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* If audit records are to be written to the netlink socket, audit_pid
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* contains the pid of the auditd process and audit_nlk_portid contains
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* the portid to use to send netlink messages to that process.
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*/
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int audit_pid;
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static __u32 audit_nlk_portid;
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/* If audit_rate_limit is non-zero, limit the rate of sending audit records
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* to that number per second. This prevents DoS attacks, but results in
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* audit records being dropped. */
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static u32 audit_rate_limit;
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/* Number of outstanding audit_buffers allowed.
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* When set to zero, this means unlimited. */
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static u32 audit_backlog_limit = 64;
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#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
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static u32 audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME;
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static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
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static u32 audit_backlog_wait_overflow = 0;
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/* The identity of the user shutting down the audit system. */
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kuid_t audit_sig_uid = INVALID_UID;
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pid_t audit_sig_pid = -1;
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u32 audit_sig_sid = 0;
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/* Records can be lost in several ways:
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0) [suppressed in audit_alloc]
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1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
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2) out of memory in audit_log_move [alloc_skb]
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3) suppressed due to audit_rate_limit
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4) suppressed due to audit_backlog_limit
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*/
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static atomic_t audit_lost = ATOMIC_INIT(0);
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/* The netlink socket. */
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static struct sock *audit_sock;
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static int audit_net_id;
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/* Hash for inode-based rules */
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struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
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/* The audit_freelist is a list of pre-allocated audit buffers (if more
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* than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
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* being placed on the freelist). */
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static DEFINE_SPINLOCK(audit_freelist_lock);
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static int audit_freelist_count;
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static LIST_HEAD(audit_freelist);
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static struct sk_buff_head audit_skb_queue;
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/* queue of skbs to send to auditd when/if it comes back */
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static struct sk_buff_head audit_skb_hold_queue;
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static struct task_struct *kauditd_task;
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static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
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static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
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static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
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.mask = -1,
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.features = 0,
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.lock = 0,};
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static char *audit_feature_names[2] = {
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"only_unset_loginuid",
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"loginuid_immutable",
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};
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/* Serialize requests from userspace. */
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DEFINE_MUTEX(audit_cmd_mutex);
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/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
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* audit records. Since printk uses a 1024 byte buffer, this buffer
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* should be at least that large. */
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#define AUDIT_BUFSIZ 1024
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/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
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* audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
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#define AUDIT_MAXFREE (2*NR_CPUS)
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/* The audit_buffer is used when formatting an audit record. The caller
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* locks briefly to get the record off the freelist or to allocate the
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* buffer, and locks briefly to send the buffer to the netlink layer or
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* to place it on a transmit queue. Multiple audit_buffers can be in
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* use simultaneously. */
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struct audit_buffer {
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struct list_head list;
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struct sk_buff *skb; /* formatted skb ready to send */
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struct audit_context *ctx; /* NULL or associated context */
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gfp_t gfp_mask;
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};
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struct audit_reply {
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__u32 portid;
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struct net *net;
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struct sk_buff *skb;
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};
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static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
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{
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if (ab) {
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struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
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nlh->nlmsg_pid = portid;
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}
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}
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void audit_panic(const char *message)
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{
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switch (audit_failure) {
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case AUDIT_FAIL_SILENT:
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break;
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case AUDIT_FAIL_PRINTK:
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if (printk_ratelimit())
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pr_err("%s\n", message);
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break;
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case AUDIT_FAIL_PANIC:
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/* test audit_pid since printk is always losey, why bother? */
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if (audit_pid)
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panic("audit: %s\n", message);
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break;
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}
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}
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static inline int audit_rate_check(void)
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{
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static unsigned long last_check = 0;
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static int messages = 0;
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static DEFINE_SPINLOCK(lock);
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unsigned long flags;
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unsigned long now;
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unsigned long elapsed;
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int retval = 0;
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if (!audit_rate_limit) return 1;
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spin_lock_irqsave(&lock, flags);
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if (++messages < audit_rate_limit) {
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retval = 1;
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} else {
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now = jiffies;
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elapsed = now - last_check;
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if (elapsed > HZ) {
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last_check = now;
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messages = 0;
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retval = 1;
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}
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}
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spin_unlock_irqrestore(&lock, flags);
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return retval;
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}
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/**
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* audit_log_lost - conditionally log lost audit message event
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* @message: the message stating reason for lost audit message
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*
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* Emit at least 1 message per second, even if audit_rate_check is
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* throttling.
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* Always increment the lost messages counter.
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*/
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void audit_log_lost(const char *message)
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{
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static unsigned long last_msg = 0;
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static DEFINE_SPINLOCK(lock);
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unsigned long flags;
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unsigned long now;
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int print;
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atomic_inc(&audit_lost);
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print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
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if (!print) {
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spin_lock_irqsave(&lock, flags);
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now = jiffies;
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if (now - last_msg > HZ) {
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print = 1;
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last_msg = now;
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}
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spin_unlock_irqrestore(&lock, flags);
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}
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if (print) {
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if (printk_ratelimit())
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pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
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atomic_read(&audit_lost),
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audit_rate_limit,
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audit_backlog_limit);
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audit_panic(message);
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}
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}
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static int audit_log_config_change(char *function_name, u32 new, u32 old,
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int allow_changes)
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{
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struct audit_buffer *ab;
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int rc = 0;
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ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
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if (unlikely(!ab))
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return rc;
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audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
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audit_log_session_info(ab);
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rc = audit_log_task_context(ab);
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if (rc)
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allow_changes = 0; /* Something weird, deny request */
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audit_log_format(ab, " res=%d", allow_changes);
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audit_log_end(ab);
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return rc;
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}
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static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
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{
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int allow_changes, rc = 0;
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u32 old = *to_change;
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/* check if we are locked */
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if (audit_enabled == AUDIT_LOCKED)
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allow_changes = 0;
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else
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allow_changes = 1;
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if (audit_enabled != AUDIT_OFF) {
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rc = audit_log_config_change(function_name, new, old, allow_changes);
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if (rc)
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allow_changes = 0;
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}
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/* If we are allowed, make the change */
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if (allow_changes == 1)
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*to_change = new;
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/* Not allowed, update reason */
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else if (rc == 0)
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rc = -EPERM;
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return rc;
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}
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static int audit_set_rate_limit(u32 limit)
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{
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return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
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}
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static int audit_set_backlog_limit(u32 limit)
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{
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return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
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}
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static int audit_set_backlog_wait_time(u32 timeout)
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{
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return audit_do_config_change("audit_backlog_wait_time",
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&audit_backlog_wait_time_master, timeout);
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}
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static int audit_set_enabled(u32 state)
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{
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int rc;
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if (state > AUDIT_LOCKED)
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return -EINVAL;
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rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
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if (!rc)
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audit_ever_enabled |= !!state;
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return rc;
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}
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static int audit_set_failure(u32 state)
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{
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if (state != AUDIT_FAIL_SILENT
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&& state != AUDIT_FAIL_PRINTK
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&& state != AUDIT_FAIL_PANIC)
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return -EINVAL;
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return audit_do_config_change("audit_failure", &audit_failure, state);
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}
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/*
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* Queue skbs to be sent to auditd when/if it comes back. These skbs should
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* already have been sent via prink/syslog and so if these messages are dropped
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* it is not a huge concern since we already passed the audit_log_lost()
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* notification and stuff. This is just nice to get audit messages during
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* boot before auditd is running or messages generated while auditd is stopped.
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* This only holds messages is audit_default is set, aka booting with audit=1
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* or building your kernel that way.
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*/
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static void audit_hold_skb(struct sk_buff *skb)
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{
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if (audit_default &&
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(!audit_backlog_limit ||
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skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
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skb_queue_tail(&audit_skb_hold_queue, skb);
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else
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kfree_skb(skb);
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}
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/*
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* For one reason or another this nlh isn't getting delivered to the userspace
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* audit daemon, just send it to printk.
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*/
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static void audit_printk_skb(struct sk_buff *skb)
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{
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struct nlmsghdr *nlh = nlmsg_hdr(skb);
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char *data = nlmsg_data(nlh);
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if (nlh->nlmsg_type != AUDIT_EOE) {
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if (printk_ratelimit())
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pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
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else
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audit_log_lost("printk limit exceeded");
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}
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audit_hold_skb(skb);
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}
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static void kauditd_send_skb(struct sk_buff *skb)
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{
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int err;
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int attempts = 0;
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#define AUDITD_RETRIES 5
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restart:
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/* take a reference in case we can't send it and we want to hold it */
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skb_get(skb);
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err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
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if (err < 0) {
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pr_err("netlink_unicast sending to audit_pid=%d returned error: %d\n",
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audit_pid, err);
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if (audit_pid) {
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if (err == -ECONNREFUSED || err == -EPERM
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|| ++attempts >= AUDITD_RETRIES) {
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char s[32];
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snprintf(s, sizeof(s), "audit_pid=%d reset", audit_pid);
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audit_log_lost(s);
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audit_pid = 0;
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audit_sock = NULL;
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} else {
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pr_warn("re-scheduling(#%d) write to audit_pid=%d\n",
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attempts, audit_pid);
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set_current_state(TASK_INTERRUPTIBLE);
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schedule();
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__set_current_state(TASK_RUNNING);
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goto restart;
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}
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}
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/* we might get lucky and get this in the next auditd */
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audit_hold_skb(skb);
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} else
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/* drop the extra reference if sent ok */
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consume_skb(skb);
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}
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|
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/*
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* kauditd_send_multicast_skb - send the skb to multicast userspace listeners
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*
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* This function doesn't consume an skb as might be expected since it has to
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* copy it anyways.
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*/
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static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
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{
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struct sk_buff *copy;
|
|
struct audit_net *aunet = net_generic(&init_net, audit_net_id);
|
|
struct sock *sock = aunet->nlsk;
|
|
|
|
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_mask);
|
|
if (!copy)
|
|
return;
|
|
|
|
nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
|
|
}
|
|
|
|
/*
|
|
* flush_hold_queue - empty the hold queue if auditd appears
|
|
*
|
|
* If auditd just started, drain the queue of messages already
|
|
* sent to syslog/printk. Remember loss here is ok. We already
|
|
* called audit_log_lost() if it didn't go out normally. so the
|
|
* race between the skb_dequeue and the next check for audit_pid
|
|
* doesn't matter.
|
|
*
|
|
* If you ever find kauditd to be too slow we can get a perf win
|
|
* by doing our own locking and keeping better track if there
|
|
* are messages in this queue. I don't see the need now, but
|
|
* in 5 years when I want to play with this again I'll see this
|
|
* note and still have no friggin idea what i'm thinking today.
|
|
*/
|
|
static void flush_hold_queue(void)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
if (!audit_default || !audit_pid)
|
|
return;
|
|
|
|
skb = skb_dequeue(&audit_skb_hold_queue);
|
|
if (likely(!skb))
|
|
return;
|
|
|
|
while (skb && audit_pid) {
|
|
kauditd_send_skb(skb);
|
|
skb = skb_dequeue(&audit_skb_hold_queue);
|
|
}
|
|
|
|
/*
|
|
* if auditd just disappeared but we
|
|
* dequeued an skb we need to drop ref
|
|
*/
|
|
if (skb)
|
|
consume_skb(skb);
|
|
}
|
|
|
|
static int kauditd_thread(void *dummy)
|
|
{
|
|
set_freezable();
|
|
while (!kthread_should_stop()) {
|
|
struct sk_buff *skb;
|
|
|
|
flush_hold_queue();
|
|
|
|
skb = skb_dequeue(&audit_skb_queue);
|
|
|
|
if (skb) {
|
|
if (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit)
|
|
wake_up(&audit_backlog_wait);
|
|
if (audit_pid)
|
|
kauditd_send_skb(skb);
|
|
else
|
|
audit_printk_skb(skb);
|
|
continue;
|
|
}
|
|
|
|
wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int audit_send_list(void *_dest)
|
|
{
|
|
struct audit_netlink_list *dest = _dest;
|
|
struct sk_buff *skb;
|
|
struct net *net = dest->net;
|
|
struct audit_net *aunet = net_generic(net, audit_net_id);
|
|
|
|
/* wait for parent to finish and send an ACK */
|
|
mutex_lock(&audit_cmd_mutex);
|
|
mutex_unlock(&audit_cmd_mutex);
|
|
|
|
while ((skb = __skb_dequeue(&dest->q)) != NULL)
|
|
netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
|
|
|
|
put_net(net);
|
|
kfree(dest);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct sk_buff *audit_make_reply(__u32 portid, 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, portid, 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 int audit_send_reply_thread(void *arg)
|
|
{
|
|
struct audit_reply *reply = (struct audit_reply *)arg;
|
|
struct net *net = reply->net;
|
|
struct audit_net *aunet = net_generic(net, audit_net_id);
|
|
|
|
mutex_lock(&audit_cmd_mutex);
|
|
mutex_unlock(&audit_cmd_mutex);
|
|
|
|
/* Ignore failure. It'll only happen if the sender goes away,
|
|
because our timeout is set to infinite. */
|
|
netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
|
|
put_net(net);
|
|
kfree(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 an skb, builds the netlink message, and sends it to the port id.
|
|
* No failure notifications.
|
|
*/
|
|
static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
|
|
int multi, const void *payload, int size)
|
|
{
|
|
u32 portid = NETLINK_CB(request_skb).portid;
|
|
struct net *net = sock_net(NETLINK_CB(request_skb).sk);
|
|
struct sk_buff *skb;
|
|
struct task_struct *tsk;
|
|
struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
|
|
GFP_KERNEL);
|
|
|
|
if (!reply)
|
|
return;
|
|
|
|
skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
|
|
if (!skb)
|
|
goto out;
|
|
|
|
reply->net = get_net(net);
|
|
reply->portid = portid;
|
|
reply->skb = skb;
|
|
|
|
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
|
|
if (!IS_ERR(tsk))
|
|
return;
|
|
kfree_skb(skb);
|
|
out:
|
|
kfree(reply);
|
|
}
|
|
|
|
/*
|
|
* 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_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(NULL, 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);
|
|
}
|
|
|
|
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(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
|
|
audit_log_task_info(ab, current);
|
|
audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
|
|
audit_feature_names[which], !!old_feature, !!new_feature,
|
|
!!old_lock, !!new_lock, res);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
static int audit_set_feature(struct sk_buff *skb)
|
|
{
|
|
struct audit_features *uaf;
|
|
int i;
|
|
|
|
BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
|
|
uaf = nlmsg_data(nlmsg_hdr(skb));
|
|
|
|
/* if there is ever a version 2 we should handle that here */
|
|
|
|
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_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
|
{
|
|
u32 seq;
|
|
void *data;
|
|
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;
|
|
|
|
/* As soon as there's any sign of userspace auditd,
|
|
* start kauditd to talk to it */
|
|
if (!kauditd_task) {
|
|
kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
|
|
if (IS_ERR(kauditd_task)) {
|
|
err = PTR_ERR(kauditd_task);
|
|
kauditd_task = NULL;
|
|
return err;
|
|
}
|
|
}
|
|
seq = nlh->nlmsg_seq;
|
|
data = nlmsg_data(nlh);
|
|
|
|
switch (msg_type) {
|
|
case AUDIT_GET: {
|
|
struct audit_status s;
|
|
memset(&s, 0, sizeof(s));
|
|
s.enabled = audit_enabled;
|
|
s.failure = audit_failure;
|
|
s.pid = audit_pid;
|
|
s.rate_limit = audit_rate_limit;
|
|
s.backlog_limit = audit_backlog_limit;
|
|
s.lost = atomic_read(&audit_lost);
|
|
s.backlog = skb_queue_len(&audit_skb_queue);
|
|
s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
|
|
s.backlog_wait_time = audit_backlog_wait_time_master;
|
|
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), nlmsg_len(nlh)));
|
|
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) {
|
|
int new_pid = s.pid;
|
|
|
|
if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
|
|
return -EACCES;
|
|
if (audit_enabled != AUDIT_OFF)
|
|
audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
|
|
audit_pid = new_pid;
|
|
audit_nlk_portid = NETLINK_CB(skb).portid;
|
|
audit_sock = skb->sk;
|
|
}
|
|
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;
|
|
}
|
|
break;
|
|
}
|
|
case AUDIT_GET_FEATURE:
|
|
err = audit_get_feature(skb);
|
|
if (err)
|
|
return err;
|
|
break;
|
|
case AUDIT_SET_FEATURE:
|
|
err = audit_set_feature(skb);
|
|
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;
|
|
|
|
err = audit_filter_user(msg_type);
|
|
if (err == 1) { /* match or error */
|
|
err = 0;
|
|
if (msg_type == AUDIT_USER_TTY) {
|
|
err = tty_audit_push_current();
|
|
if (err)
|
|
break;
|
|
}
|
|
mutex_unlock(&audit_cmd_mutex);
|
|
audit_log_common_recv_msg(&ab, msg_type);
|
|
if (msg_type != AUDIT_USER_TTY)
|
|
audit_log_format(ab, " msg='%.*s'",
|
|
AUDIT_MESSAGE_TEXT_MAX,
|
|
(char *)data);
|
|
else {
|
|
int size;
|
|
|
|
audit_log_format(ab, " data=");
|
|
size = nlmsg_len(nlh);
|
|
if (size > 0 &&
|
|
((unsigned char *)data)[size - 1] == '\0')
|
|
size--;
|
|
audit_log_n_untrustedstring(ab, data, size);
|
|
}
|
|
audit_set_portid(ab, NETLINK_CB(skb).portid);
|
|
audit_log_end(ab);
|
|
mutex_lock(&audit_cmd_mutex);
|
|
}
|
|
break;
|
|
case AUDIT_ADD_RULE:
|
|
case AUDIT_DEL_RULE:
|
|
if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
|
|
return -EINVAL;
|
|
if (audit_enabled == AUDIT_LOCKED) {
|
|
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
|
|
audit_log_end(ab);
|
|
return -EPERM;
|
|
}
|
|
err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
|
|
seq, data, nlmsg_len(nlh));
|
|
break;
|
|
case AUDIT_LIST_RULES:
|
|
err = audit_list_rules_send(skb, seq);
|
|
break;
|
|
case AUDIT_TRIM:
|
|
audit_trim_trees();
|
|
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " op=trim res=1");
|
|
audit_log_end(ab);
|
|
break;
|
|
case AUDIT_MAKE_EQUIV: {
|
|
void *bufp = data;
|
|
u32 sizes[2];
|
|
size_t msglen = nlmsg_len(nlh);
|
|
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(&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;
|
|
struct task_struct *tsk = current;
|
|
|
|
spin_lock(&tsk->sighand->siglock);
|
|
s.enabled = tsk->signal->audit_tty;
|
|
s.log_passwd = tsk->signal->audit_tty_log_passwd;
|
|
spin_unlock(&tsk->sighand->siglock);
|
|
|
|
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 task_struct *tsk = current;
|
|
struct audit_buffer *ab;
|
|
|
|
memset(&s, 0, sizeof(s));
|
|
/* guard against past and future API changes */
|
|
memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
|
|
/* check if new data is valid */
|
|
if ((s.enabled != 0 && s.enabled != 1) ||
|
|
(s.log_passwd != 0 && s.log_passwd != 1))
|
|
err = -EINVAL;
|
|
|
|
spin_lock(&tsk->sighand->siglock);
|
|
old.enabled = tsk->signal->audit_tty;
|
|
old.log_passwd = tsk->signal->audit_tty_log_passwd;
|
|
if (!err) {
|
|
tsk->signal->audit_tty = s.enabled;
|
|
tsk->signal->audit_tty_log_passwd = s.log_passwd;
|
|
}
|
|
spin_unlock(&tsk->sighand->siglock);
|
|
|
|
audit_log_common_recv_msg(&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;
|
|
}
|
|
|
|
/*
|
|
* Get message from skb. Each message is processed by audit_receive_msg.
|
|
* Malformed skbs with wrong length are discarded silently.
|
|
*/
|
|
static void audit_receive_skb(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;
|
|
|
|
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);
|
|
|
|
nlh = nlmsg_next(nlh, &len);
|
|
}
|
|
}
|
|
|
|
/* Receive messages from netlink socket. */
|
|
static void audit_receive(struct sk_buff *skb)
|
|
{
|
|
mutex_lock(&audit_cmd_mutex);
|
|
audit_receive_skb(skb);
|
|
mutex_unlock(&audit_cmd_mutex);
|
|
}
|
|
|
|
/* 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->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
|
|
if (aunet->nlsk == NULL) {
|
|
audit_panic("cannot initialize netlink socket in namespace");
|
|
return -ENOMEM;
|
|
}
|
|
aunet->nlsk->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);
|
|
struct sock *sock = aunet->nlsk;
|
|
if (sock == audit_sock) {
|
|
audit_pid = 0;
|
|
audit_sock = NULL;
|
|
}
|
|
|
|
RCU_INIT_POINTER(aunet->nlsk, NULL);
|
|
synchronize_net();
|
|
netlink_kernel_release(sock);
|
|
}
|
|
|
|
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;
|
|
|
|
pr_info("initializing netlink subsys (%s)\n",
|
|
audit_default ? "enabled" : "disabled");
|
|
register_pernet_subsys(&audit_net_ops);
|
|
|
|
skb_queue_head_init(&audit_skb_queue);
|
|
skb_queue_head_init(&audit_skb_hold_queue);
|
|
audit_initialized = AUDIT_INITIALIZED;
|
|
audit_enabled = audit_default;
|
|
audit_ever_enabled |= !!audit_default;
|
|
|
|
audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
|
|
|
|
for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
|
|
INIT_LIST_HEAD(&audit_inode_hash[i]);
|
|
|
|
return 0;
|
|
}
|
|
__initcall(audit_init);
|
|
|
|
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
|
|
static int __init audit_enable(char *str)
|
|
{
|
|
audit_default = !!simple_strtol(str, NULL, 0);
|
|
if (!audit_default)
|
|
audit_initialized = AUDIT_DISABLED;
|
|
|
|
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)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
if (ab->skb)
|
|
kfree_skb(ab->skb);
|
|
|
|
spin_lock_irqsave(&audit_freelist_lock, flags);
|
|
if (audit_freelist_count > AUDIT_MAXFREE)
|
|
kfree(ab);
|
|
else {
|
|
audit_freelist_count++;
|
|
list_add(&ab->list, &audit_freelist);
|
|
}
|
|
spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
|
}
|
|
|
|
static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
|
|
gfp_t gfp_mask, int type)
|
|
{
|
|
unsigned long flags;
|
|
struct audit_buffer *ab = NULL;
|
|
struct nlmsghdr *nlh;
|
|
|
|
spin_lock_irqsave(&audit_freelist_lock, flags);
|
|
if (!list_empty(&audit_freelist)) {
|
|
ab = list_entry(audit_freelist.next,
|
|
struct audit_buffer, list);
|
|
list_del(&ab->list);
|
|
--audit_freelist_count;
|
|
}
|
|
spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
|
|
|
if (!ab) {
|
|
ab = kmalloc(sizeof(*ab), gfp_mask);
|
|
if (!ab)
|
|
goto err;
|
|
}
|
|
|
|
ab->ctx = ctx;
|
|
ab->gfp_mask = gfp_mask;
|
|
|
|
ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
|
|
if (!ab->skb)
|
|
goto err;
|
|
|
|
nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
|
|
if (!nlh)
|
|
goto out_kfree_skb;
|
|
|
|
return ab;
|
|
|
|
out_kfree_skb:
|
|
kfree_skb(ab->skb);
|
|
ab->skb = NULL;
|
|
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 timespec *t, unsigned int *serial)
|
|
{
|
|
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
|
|
*t = CURRENT_TIME;
|
|
*serial = audit_serial();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Wait for auditd to drain the queue a little
|
|
*/
|
|
static long wait_for_auditd(long sleep_time)
|
|
{
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
add_wait_queue_exclusive(&audit_backlog_wait, &wait);
|
|
|
|
if (audit_backlog_limit &&
|
|
skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
|
|
sleep_time = schedule_timeout(sleep_time);
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
remove_wait_queue(&audit_backlog_wait, &wait);
|
|
|
|
return sleep_time;
|
|
}
|
|
|
|
/**
|
|
* 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 = NULL;
|
|
struct timespec t;
|
|
unsigned int uninitialized_var(serial);
|
|
int reserve = 5; /* Allow atomic callers to go up to five
|
|
entries over the normal backlog limit */
|
|
unsigned long timeout_start = jiffies;
|
|
|
|
if (audit_initialized != AUDIT_INITIALIZED)
|
|
return NULL;
|
|
|
|
if (unlikely(audit_filter_type(type)))
|
|
return NULL;
|
|
|
|
if (gfp_mask & __GFP_DIRECT_RECLAIM) {
|
|
if (audit_pid && audit_pid == current->pid)
|
|
gfp_mask &= ~__GFP_DIRECT_RECLAIM;
|
|
else
|
|
reserve = 0;
|
|
}
|
|
|
|
while (audit_backlog_limit
|
|
&& skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
|
|
if (gfp_mask & __GFP_DIRECT_RECLAIM && audit_backlog_wait_time) {
|
|
long sleep_time;
|
|
|
|
sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
|
|
if (sleep_time > 0) {
|
|
sleep_time = wait_for_auditd(sleep_time);
|
|
if (sleep_time > 0)
|
|
continue;
|
|
}
|
|
}
|
|
if (audit_rate_check() && printk_ratelimit())
|
|
pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
|
|
skb_queue_len(&audit_skb_queue),
|
|
audit_backlog_limit);
|
|
audit_log_lost("backlog limit exceeded");
|
|
audit_backlog_wait_time = audit_backlog_wait_overflow;
|
|
wake_up(&audit_backlog_wait);
|
|
return NULL;
|
|
}
|
|
|
|
if (!reserve)
|
|
audit_backlog_wait_time = audit_backlog_wait_time_master;
|
|
|
|
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(%lu.%03lu:%u): ",
|
|
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_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)");
|
|
}
|
|
|
|
void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
|
|
{
|
|
int i;
|
|
|
|
audit_log_format(ab, " %s=", prefix);
|
|
CAP_FOR_EACH_U32(i) {
|
|
audit_log_format(ab, "%08x",
|
|
cap->cap[CAP_LAST_U32 - i]);
|
|
}
|
|
}
|
|
|
|
static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
|
|
{
|
|
kernel_cap_t *perm = &name->fcap.permitted;
|
|
kernel_cap_t *inh = &name->fcap.inheritable;
|
|
int log = 0;
|
|
|
|
if (!cap_isclear(*perm)) {
|
|
audit_log_cap(ab, "cap_fp", perm);
|
|
log = 1;
|
|
}
|
|
if (!cap_isclear(*inh)) {
|
|
audit_log_cap(ab, "cap_fi", inh);
|
|
log = 1;
|
|
}
|
|
|
|
if (log)
|
|
audit_log_format(ab, " cap_fe=%d cap_fver=%x",
|
|
name->fcap.fE, name->fcap_ver);
|
|
}
|
|
|
|
static inline int audit_copy_fcaps(struct audit_names *name,
|
|
const struct dentry *dentry)
|
|
{
|
|
struct cpu_vfs_cap_data caps;
|
|
int rc;
|
|
|
|
if (!dentry)
|
|
return 0;
|
|
|
|
rc = get_vfs_caps_from_disk(dentry, &caps);
|
|
if (rc)
|
|
return rc;
|
|
|
|
name->fcap.permitted = caps.permitted;
|
|
name->fcap.inheritable = caps.inheritable;
|
|
name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
|
|
name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
|
|
VFS_CAP_REVISION_SHIFT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Copy inode data into an audit_names. */
|
|
void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
|
|
const struct inode *inode)
|
|
{
|
|
name->ino = inode->i_ino;
|
|
name->dev = inode->i_sb->s_dev;
|
|
name->mode = inode->i_mode;
|
|
name->uid = inode->i_uid;
|
|
name->gid = inode->i_gid;
|
|
name->rdev = inode->i_rdev;
|
|
security_inode_getsecid(inode, &name->osid);
|
|
audit_copy_fcaps(name, dentry);
|
|
}
|
|
|
|
/**
|
|
* audit_log_name - produce AUDIT_PATH record from struct audit_names
|
|
* @context: audit_context for the task
|
|
* @n: audit_names structure with reportable details
|
|
* @path: optional path to report instead of audit_names->name
|
|
* @record_num: record number to report when handling a list of names
|
|
* @call_panic: optional pointer to int that will be updated if secid fails
|
|
*/
|
|
void audit_log_name(struct audit_context *context, struct audit_names *n,
|
|
struct path *path, int record_num, int *call_panic)
|
|
{
|
|
struct audit_buffer *ab;
|
|
ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
|
|
if (!ab)
|
|
return;
|
|
|
|
audit_log_format(ab, "item=%d", record_num);
|
|
|
|
if (path)
|
|
audit_log_d_path(ab, " name=", path);
|
|
else if (n->name) {
|
|
switch (n->name_len) {
|
|
case AUDIT_NAME_FULL:
|
|
/* log the full path */
|
|
audit_log_format(ab, " name=");
|
|
audit_log_untrustedstring(ab, n->name->name);
|
|
break;
|
|
case 0:
|
|
/* name was specified as a relative path and the
|
|
* directory component is the cwd */
|
|
audit_log_d_path(ab, " name=", &context->pwd);
|
|
break;
|
|
default:
|
|
/* log the name's directory component */
|
|
audit_log_format(ab, " name=");
|
|
audit_log_n_untrustedstring(ab, n->name->name,
|
|
n->name_len);
|
|
}
|
|
} else
|
|
audit_log_format(ab, " name=(null)");
|
|
|
|
if (n->ino != AUDIT_INO_UNSET)
|
|
audit_log_format(ab, " inode=%lu"
|
|
" dev=%02x:%02x mode=%#ho"
|
|
" ouid=%u ogid=%u rdev=%02x:%02x",
|
|
n->ino,
|
|
MAJOR(n->dev),
|
|
MINOR(n->dev),
|
|
n->mode,
|
|
from_kuid(&init_user_ns, n->uid),
|
|
from_kgid(&init_user_ns, n->gid),
|
|
MAJOR(n->rdev),
|
|
MINOR(n->rdev));
|
|
if (n->osid != 0) {
|
|
char *ctx = NULL;
|
|
u32 len;
|
|
if (security_secid_to_secctx(
|
|
n->osid, &ctx, &len)) {
|
|
audit_log_format(ab, " osid=%u", n->osid);
|
|
if (call_panic)
|
|
*call_panic = 2;
|
|
} else {
|
|
audit_log_format(ab, " obj=%s", ctx);
|
|
security_release_secctx(ctx, len);
|
|
}
|
|
}
|
|
|
|
/* log the audit_names record type */
|
|
audit_log_format(ab, " nametype=");
|
|
switch(n->type) {
|
|
case AUDIT_TYPE_NORMAL:
|
|
audit_log_format(ab, "NORMAL");
|
|
break;
|
|
case AUDIT_TYPE_PARENT:
|
|
audit_log_format(ab, "PARENT");
|
|
break;
|
|
case AUDIT_TYPE_CHILD_DELETE:
|
|
audit_log_format(ab, "DELETE");
|
|
break;
|
|
case AUDIT_TYPE_CHILD_CREATE:
|
|
audit_log_format(ab, "CREATE");
|
|
break;
|
|
default:
|
|
audit_log_format(ab, "UNKNOWN");
|
|
break;
|
|
}
|
|
|
|
audit_log_fcaps(ab, n);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
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)");
|
|
}
|
|
|
|
void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
|
|
{
|
|
const struct cred *cred;
|
|
char comm[sizeof(tsk->comm)];
|
|
char *tty;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
/* tsk == current */
|
|
cred = current_cred();
|
|
|
|
spin_lock_irq(&tsk->sighand->siglock);
|
|
if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
|
|
tty = tsk->signal->tty->name;
|
|
else
|
|
tty = "(none)";
|
|
spin_unlock_irq(&tsk->sighand->siglock);
|
|
|
|
audit_log_format(ab,
|
|
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
|
|
" euid=%u suid=%u fsuid=%u"
|
|
" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
|
|
task_ppid_nr(tsk),
|
|
task_pid_nr(tsk),
|
|
from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
|
|
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, audit_get_sessionid(tsk));
|
|
|
|
audit_log_format(ab, " comm=");
|
|
audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
|
|
|
|
audit_log_d_path_exe(ab, tsk->mm);
|
|
audit_log_task_context(ab);
|
|
}
|
|
EXPORT_SYMBOL(audit_log_task_info);
|
|
|
|
/**
|
|
* audit_log_link_denied - report a link restriction denial
|
|
* @operation: specific link operation
|
|
* @link: the path that triggered the restriction
|
|
*/
|
|
void audit_log_link_denied(const char *operation, struct path *link)
|
|
{
|
|
struct audit_buffer *ab;
|
|
struct audit_names *name;
|
|
|
|
name = kzalloc(sizeof(*name), GFP_NOFS);
|
|
if (!name)
|
|
return;
|
|
|
|
/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
|
|
ab = audit_log_start(current->audit_context, GFP_KERNEL,
|
|
AUDIT_ANOM_LINK);
|
|
if (!ab)
|
|
goto out;
|
|
audit_log_format(ab, "op=%s", operation);
|
|
audit_log_task_info(ab, current);
|
|
audit_log_format(ab, " res=0");
|
|
audit_log_end(ab);
|
|
|
|
/* Generate AUDIT_PATH record with object. */
|
|
name->type = AUDIT_TYPE_NORMAL;
|
|
audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
|
|
audit_log_name(current->audit_context, name, link, 0, NULL);
|
|
out:
|
|
kfree(name);
|
|
}
|
|
|
|
/**
|
|
* audit_log_end - end one audit record
|
|
* @ab: the audit_buffer
|
|
*
|
|
* netlink_unicast() cannot be called 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)
|
|
{
|
|
if (!ab)
|
|
return;
|
|
if (!audit_rate_check()) {
|
|
audit_log_lost("rate limit exceeded");
|
|
} else {
|
|
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
|
|
|
|
nlh->nlmsg_len = ab->skb->len;
|
|
kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
|
|
|
|
/*
|
|
* The original kaudit unicast socket sends up messages with
|
|
* nlmsg_len set to the payload length rather than the entire
|
|
* message length. This breaks the standard set by netlink.
|
|
* 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.
|
|
*/
|
|
nlh->nlmsg_len -= NLMSG_HDRLEN;
|
|
|
|
if (audit_pid) {
|
|
skb_queue_tail(&audit_skb_queue, ab->skb);
|
|
wake_up_interruptible(&kauditd_wait);
|
|
} else {
|
|
audit_printk_skb(ab->skb);
|
|
}
|
|
ab->skb = NULL;
|
|
}
|
|
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);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SECURITY
|
|
/**
|
|
* audit_log_secctx - Converts and logs SELinux context
|
|
* @ab: audit_buffer
|
|
* @secid: security number
|
|
*
|
|
* This is a helper function that calls security_secid_to_secctx to convert
|
|
* secid to secctx and then adds the (converted) SELinux context to the audit
|
|
* log by calling audit_log_format, thus also preventing leak of internal secid
|
|
* to userspace. If secid cannot be converted audit_panic is called.
|
|
*/
|
|
void audit_log_secctx(struct audit_buffer *ab, u32 secid)
|
|
{
|
|
u32 len;
|
|
char *secctx;
|
|
|
|
if (security_secid_to_secctx(secid, &secctx, &len)) {
|
|
audit_panic("Cannot convert secid to context");
|
|
} else {
|
|
audit_log_format(ab, " obj=%s", secctx);
|
|
security_release_secctx(secctx, len);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(audit_log_secctx);
|
|
#endif
|
|
|
|
EXPORT_SYMBOL(audit_log_start);
|
|
EXPORT_SYMBOL(audit_log_end);
|
|
EXPORT_SYMBOL(audit_log_format);
|
|
EXPORT_SYMBOL(audit_log);
|