linux-toradex.git/kernel/audit.c, branch v3.14.3

AUDIT: Allow login in non-init namespaces

2014-03-31T00:02:53+00:00

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: Andre Tomt 
Reported-by: Adam Richter 
Signed-off-by: Eric Paris 
Signed-off-by: Linus Torvalds

audit: Update kdoc for audit_send_reply and audit_list_rules_send

2014-03-08T23:31:54+00:00

The kbuild test robot reported:
> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git for-next
> head:   6f285b19d09f72e801525f5eea1bdad22e559bf0
> commit: 6f285b19d09f72e801525f5eea1bdad22e559bf0 [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: "Eric W. Biederman"

audit: Send replies in the proper network namespace.

2014-03-01T03:44:55+00:00

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: "Eric W. Biederman"

audit: Use struct net not pid_t to remember the network namespce to reply in

2014-02-28T12:04:33+00:00

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: "Eric W. Biederman"

audit: fix location of __net_initdata for audit_net_ops

2014-01-17T22:14:32+00:00

Fixup caught by checkpatch.

Signed-off-by: Richard Guy Briggs 
Signed-off-by: Eric Paris

audit: remove pr_info for every network namespace

2014-01-17T22:04:38+00:00

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: Eric Paris

audit: Convert int limit uses to u32

2014-01-14T19:54:00+00:00

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: Joe Perches 
[eparis: do not remove static from audit_default declaration]

audit: Use more current logging style

2014-01-14T19:53:54+00:00

Add pr_fmt to prefix "audit: " to output
Convert printk(KERN_ to pr_
Coalesce formats
Use pr_cont
Move a brace after switch

Signed-off-by: Joe Perches

audit: Use hex_byte_pack_upper

2014-01-14T19:53:50+00:00

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...

audit: reorder AUDIT_TTY_SET arguments

2014-01-14T03:33:41+00:00

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: Eric Paris