When an AUDIT_GET_FEATURE message is sent from userspace to the kernel, it
should reply with a message tagged as an AUDIT_GET_FEATURE type with a struct
audit_feature.  The current reply is a message tagged as an AUDIT_GET
type with a struct audit_feature.

This appears to have been a cut-and-paste-eo in commit b0fed402.
Reported-by: NSteve Grubb <sgrubb@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Report:
	Looking at your example code in
	http://people.redhat.com/rbriggs/audit-multicast-listen/audit-multicast-listen.c,
	it seems that nlmsg_len field in the received messages is supposed to
	contain the length of the header + payload, but it is always set to the
	size of the header only, i.e. 16. The example program works, because
	the printf format specifies the minimum width, not "precision", so it
	simply prints out the payload until the first zero byte. This isn't too
	much of a problem, but precludes the use of recvmmsg, iiuc?

	(gdb) p *(struct nlmsghdr*)nlh
	$14 = {nlmsg_len = 16, nlmsg_type = 1100, nlmsg_flags = 0, nlmsg_seq = 0, nlmsg_pid = 9910}

The only time nlmsg_len would have been updated was at audit_buffer_alloc()
inside audit_log_start() and never updated after.  It should arguably be done
in audit_log_vformat(), but would be more efficient in audit_log_end().
Reported-by: NZbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Since there is already a primitive to do this operation in the atomic_t, use it
to simplify audit_serial().
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Use kernel.h definition.

Cc: Eric Paris <eparis@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

audit_log_fcaps() isn't used outside kernel/audit.c.  Reduce its scope.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

audit_net_id isn't used outside kernel/audit.c.  Reduce its scope.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
Use #include <linux/types.h> instead of <asm/types.h>
Signed-off-by: NPaul McQuade <paulmcquad@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It is possible by passing a netlink socket to a more privileged
executable and then to fool that executable into writing to the socket
data that happens to be valid netlink message to do something that
privileged executable did not intend to do.

To keep this from happening replace bare capable and ns_capable calls
with netlink_capable, netlink_net_calls and netlink_ns_capable calls.
Which act the same as the previous calls except they verify that the
opener of the socket had the desired permissions as well.
Reported-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Test first to see if there are any userspace multicast listeners bound to the
socket before starting the multicast send work.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a netlink multicast socket with one group to kaudit for "best-effort"
delivery to read-only userspace clients such as systemd, in addition to the
existing bidirectional unicast auditd userspace client.

Currently, auditd is intended to use the CAP_AUDIT_CONTROL and CAP_AUDIT_WRITE
capabilities, but actually uses CAP_NET_ADMIN.  The CAP_AUDIT_READ capability
is added for use by read-only AUDIT_NLGRP_READLOG netlink multicast group
clients to the kaudit subsystem.

This will safely give access to services such as systemd to consume audit logs
while ensuring write access remains restricted for integrity.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Register a netlink per-protocol bind fuction for audit to check userspace
process capabilities before allowing a multicast group connection.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It its possible to configure your PAM stack to refuse login if audit
messages (about the login) were unable to be sent.  This is common in
many distros and thus normal configuration of many containers.  The PAM
modules determine if audit is enabled/disabled in the kernel based on
the return value from sending an audit message on the netlink socket.
If userspace gets back ECONNREFUSED it believes audit is disabled in the
kernel.  If it gets any other error else it refuses to let the login
proceed.

Just about ever since the introduction of namespaces the kernel audit
subsystem has returned EPERM if the task sending a message was not in
the init user or pid namespace.  So many forms of containers have never
worked if audit was enabled in the kernel.

BUT if the container was not in net_init then the kernel network code
would send ECONNREFUSED (instead of the audit code sending EPERM).  Thus
by pure accident/dumb luck/bug if an admin configured the PAM stack to
reject all logins that didn't talk to audit, but then ran the login
untility in the non-init_net namespace, it would work!! Clearly this was
a bug, but it is a bug some people expected.

With the introduction of network namespace support in 3.14-rc1 the two
bugs stopped cancelling each other out.  Now, containers in the
non-init_net namespace refused to let users log in (just like PAM was
configfured!) Obviously some people were not happy that what used to let
users log in, now didn't!

This fix is kinda hacky.  We return ECONNREFUSED for all non-init
relevant namespaces.  That means that not only will the old broken
non-init_net setups continue to work, now the broken non-init_pid or
non-init_user setups will 'work'.  They don't really work, since audit
isn't logging things.  But it's what most users want.

In 3.15 we should have patches to support not only the non-init_net
(3.14) namespace but also the non-init_pid and non-init_user namespace.
So all will be right in the world.  This just opens the doors wide open
on 3.14 and hopefully makes users happy, if not the audit system...
Reported-by: NAndre Tomt <andre@tomt.net>
Reported-by: NAdam Richter <adam_richter2004@yahoo.com>
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Conflicts:
	kernel/audit.c

It its possible to configure your PAM stack to refuse login if audit
messages (about the login) were unable to be sent.  This is common in
many distros and thus normal configuration of many containers.  The PAM
modules determine if audit is enabled/disabled in the kernel based on
the return value from sending an audit message on the netlink socket.
If userspace gets back ECONNREFUSED it believes audit is disabled in the
kernel.  If it gets any other error else it refuses to let the login
proceed.

Just about ever since the introduction of namespaces the kernel audit
subsystem has returned EPERM if the task sending a message was not in
the init user or pid namespace.  So many forms of containers have never
worked if audit was enabled in the kernel.

BUT if the container was not in net_init then the kernel network code
would send ECONNREFUSED (instead of the audit code sending EPERM).  Thus
by pure accident/dumb luck/bug if an admin configured the PAM stack to
reject all logins that didn't talk to audit, but then ran the login
untility in the non-init_net namespace, it would work!! Clearly this was
a bug, but it is a bug some people expected.

With the introduction of network namespace support in 3.14-rc1 the two
bugs stopped cancelling each other out.  Now, containers in the
non-init_net namespace refused to let users log in (just like PAM was
configfured!) Obviously some people were not happy that what used to let
users log in, now didn't!

This fix is kinda hacky.  We return ECONNREFUSED for all non-init
relevant namespaces.  That means that not only will the old broken
non-init_net setups continue to work, now the broken non-init_pid or
non-init_user setups will 'work'.  They don't really work, since audit
isn't logging things.  But it's what most users want.

In 3.15 we should have patches to support not only the non-init_net
(3.14) namespace but also the non-init_pid and non-init_user namespace.
So all will be right in the world.  This just opens the doors wide open
on 3.14 and hopefully makes users happy, if not the audit system...
Reported-by: NAndre Tomt <andre@tomt.net>
Reported-by: NAdam Richter <adam_richter2004@yahoo.com>
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL)

The rcu_assign_pointer() ensures that the initialization of a structure
is carried out before storing a pointer to that structure.
And in the case of the NULL pointer, there is no structure to initialize.
So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL)
Signed-off-by: NMonam Agarwal <monamagarwal123@gmail.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

Calling audit_log_lost with a \n in the format string leads to extra
newlines in dmesg.  That function will eventually call audit_panic which
uses pr_err with an explicit \n included.  Just make these calls match the
others that lack \n.
Reported-by: NJonathan Kamens <jik@kamens.brookline.ma.us>
Signed-off-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Still only permit the audit logging daemon and control to operate from the
initial PID namespace, but allow processes to log from another PID namespace.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
(informed by ebiederman's c776b5d2)
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

Store and log all PIDs with reference to the initial PID namespace and
use the access functions task_pid_nr() and task_tgid_nr() for task->pid
and task->tgid.

Cc: "Eric W. Biederman" <ebiederm@xmission.com>
(informed by ebiederman's c776b5d2)
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

sys_getppid() returns the parent pid of the current process in its own pid
namespace.  Since audit filters are based in the init pid namespace, a process
could avoid a filter or trigger an unintended one by being in an alternate pid
namespace or log meaningless information.

Switch to task_ppid_nr() for PPIDs to anchor all audit filters in the
init_pid_ns.

(informed by ebiederman's 6c621b7e)
Cc: stable@vger.kernel.org
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>

In perverse cases of file descriptor passing the current network
namespace of a process and the network namespace of a socket used by
that socket may differ.  Therefore use the network namespace of the
appropiate socket to ensure replies always go to the appropiate
socket.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

While reading through 3.14-rc1 I found a pretty siginficant mishandling
of network namespaces in the recent audit changes.

In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller.  This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a pid_t
(including the caller's network namespace changing, pid wraparound, and
the pid simply not being present).
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

The kbuild test robot reported:
> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git for-next
> head:   6f285b19
> commit: 6f285b19 [2/2] audit: Send replies in the proper network namespace.
> reproduce: make htmldocs
>
> >> Warning(kernel/audit.c:575): No description found for parameter 'request_skb'
> >> Warning(kernel/audit.c:575): Excess function parameter 'portid' description in 'audit_send_reply'
> >> Warning(kernel/auditfilter.c:1074): No description found for parameter 'request_skb'
> >> Warning(kernel/auditfilter.c:1074): Excess function parameter 'portid' description in 'audit_list_rules_s

Which was caused by my failure to update the kdoc annotations when I
updated the functions.  Fix that small oversight now.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

In perverse cases of file descriptor passing the current network
namespace of a process and the network namespace of a socket used by
that socket may differ.  Therefore use the network namespace of the
appropiate socket to ensure replies always go to the appropiate
socket.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

In struct audit_netlink_list and audit_reply add a reference to the
network namespace of the caller and remove the userspace pid of the
caller.  This cleanly remembers the callers network namespace, and
removes a huge class of races and nasty failure modes that can occur
when attempting to relook up the callers network namespace from a
pid_t (including the caller's network namespace changing, pid
wraparound, and the pid simply not being present).
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Fixup caught by checkpatch.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

A message about creating the audit socket might be fine at startup, but
a pr_info for every single network namespace created on a system isn't
useful.
Signed-off-by: NEric Paris <eparis@redhat.com>

The equivalent uapi struct uses __u32 so make the kernel
uses u32 too.

This can prevent some oddities where the limit is
logged/emitted as a negative value.

Convert kstrtol to kstrtouint to disallow negative values.
Signed-off-by: NJoe Perches <joe@perches.com>
[eparis: do not remove static from audit_default declaration]

Add pr_fmt to prefix "audit: " to output
Convert printk(KERN_<LEVEL> to pr_<level>
Coalesce formats
Use pr_cont
Move a brace after switch
Signed-off-by: NJoe Perches <joe@perches.com>

Using the generic kernel function causes the
object size to increase with gcc 4.8.1.

$ size kernel/audit.o*
   text	   data	    bss	    dec	    hex	filename
  18577	   6079	   8436	  33092	   8144	kernel/audit.o.new
  18579	   6015	   8420	  33014	   80f6	kernel/audit.o.old

Unsigned...

An admin is likely to want to see old and new values next to each other.
Putting all of the old values followed by all of the new values is just
hard to read as a human.
Signed-off-by: NEric Paris <eparis@redhat.com>

We can simplify the AUDIT_TTY_SET code to only grab the spin_lock one
time.  We need to determine if the new values are valid and if so, set
the new values at the same time we grab the old onces.  While we are
here get rid of 'res' and just use err.
Signed-off-by: NEric Paris <eparis@redhat.com>

If userspace specified that it was setting values via the mask we do not
need a second check to see if they also set the version field high
enough to understand those values.  (clearly if they set the mask they
knew those values).
Signed-off-by: NEric Paris <eparis@redhat.com>

Give names to the audit versions.  Just something for a userspace
programmer to know what the version provides.
Signed-off-by: NEric Paris <eparis@redhat.com>

We had some craziness with signed to unsigned long casting which appears
wholely unnecessary.  Just use signed long.  Even though 2 values of the
math equation are unsigned longs the result is expected to be a signed
long.  So why keep casting the result to signed long?  Just make it
signed long and use it.

We also remove the needless "timeout" variable.  We already have the
stack "sleep_time" variable.  Just use that...
Signed-off-by: NEric Paris <eparis@redhat.com>

Add task information to the log when changing a feature state.
Signed-off-by: NEric Paris <eparis@redhat.com>

NETLINK_CB(skb).sk is the socket of user space process,
netlink_unicast in kauditd_send_skb wants the kernel
side socket. Since the sk_state of audit netlink socket
is not NETLINK_CONNECTED, so the netlink_getsockbyportid
doesn't return -ECONNREFUSED.

And the socket of userspace process can be released anytime,
so the audit_sock may point to invalid socket.

this patch sets the audit_sock to the kernel side audit
netlink socket.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

print the error message and then return -ENOMEM.
Signed-off-by: NGao feng <gaofeng@cn.fujitsu.com>
Acked-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

An error on an AUDIT_NEVER rule disabled logging on that rule.
On error on AUDIT_NEVER rules, log.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

The backlog cannot be consumed when audit_log_start is running on auditd
even if audit_log_start calls wait_for_auditd to consume it.
The situation is the deadlock because only auditd can consume the backlog.
If the other process needs to send the backlog, it can be also stopped
by the deadlock.

So, audit_log_start running on auditd should not stop.

You can see the deadlock with the following reproducer:
 # auditctl -a exit,always -S all
 # reboot
Signed-off-by: NToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Reviewed-by: gaofeng@cn.fujitsu.com
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>

We do not need to hold the audit_cmd_mutex for this family of cases.  The
possible exception to this is the call to audit_filter_user(), so drop the lock
immediately after.  To help in fixing the race we are trying to avoid, make
sure that nothing called by audit_filter_user() calls audit_log_start().  In
particular, watch out for *_audit_rule_match().

This fix will take care of systemd and anything USING audit.  It still means
that we could race with something configuring audit and auditd shutting down.
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Reported-by: toshi.okajima@jp.fujitsu.com
Tested-by: toshi.okajima@jp.fujitsu.com
Signed-off-by: NEric Paris <eparis@redhat.com>

Right now the sessionid value in the kernel is a combination of u32,
int, and unsigned int.  Just use unsigned int throughout.
Signed-off-by: NEric Paris <eparis@redhat.com>
Signed-off-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NEric Paris <eparis@redhat.com>