AppArmor is masking the capabilities returned by capget against the
capabilities mask in the profile. This is wrong, in complain mode the
profile has effectively all capabilities, as the profile restrictions are
not being enforced, merely tested against to determine if an access is
known by the profile.
This can result in the wrong behavior of security conscience applications
like sshd which examine their capability set, and change their behavior
accordingly. In this case because of the masked capability set being
returned sshd fails due to DAC checks, even when the profile is in complain
mode.
Kernels affected: 2.6.36 - 3.0.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Affected kernels 2.6.36 - 3.0
AppArmor may do a GFP_KERNEL memory allocation with task_lock(tsk->group_leader);
held when called from security_task_setrlimit. This will only occur when the
task's current policy has been replaced, and the task's creds have not been
updated before entering the LSM security_task_setrlimit() hook.
BUG: sleeping function called from invalid context at mm/slub.c:847
in_atomic(): 1, irqs_disabled(): 0, pid: 1583, name: cupsd
2 locks held by cupsd/1583:
#0: (tasklist_lock){.+.+.+}, at: [<ffffffff8104dafa>] do_prlimit+0x61/0x189
#1: (&(&p->alloc_lock)->rlock){+.+.+.}, at: [<ffffffff8104db2d>]
do_prlimit+0x94/0x189
Pid: 1583, comm: cupsd Not tainted 3.0.0-rc2-git1 #7
Call Trace:
[<ffffffff8102ebf2>] __might_sleep+0x10d/0x112
[<ffffffff810e6f46>] slab_pre_alloc_hook.isra.49+0x2d/0x33
[<ffffffff810e7bc4>] kmem_cache_alloc+0x22/0x132
[<ffffffff8105b6e6>] prepare_creds+0x35/0xe4
[<ffffffff811c0675>] aa_replace_current_profile+0x35/0xb2
[<ffffffff811c4d2d>] aa_current_profile+0x45/0x4c
[<ffffffff811c4d4d>] apparmor_task_setrlimit+0x19/0x3a
[<ffffffff811beaa5>] security_task_setrlimit+0x11/0x13
[<ffffffff8104db6b>] do_prlimit+0xd2/0x189
[<ffffffff8104dea9>] sys_setrlimit+0x3b/0x48
[<ffffffff814062bb>] system_call_fastpath+0x16/0x1b
Signed-off-by: John Johansen <john.johansen@canonical.com>
Reported-by: Miles Lane <miles.lane@gmail.com>
Cc: stable@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
When invalid parameters are passed to apparmor_setprocattr a NULL deref
oops occurs when it tries to record an audit message. This is because
it is passing NULL for the profile parameter for aa_audit. But aa_audit
now requires that the profile passed is not NULL.
Fix this by passing the current profile on the task that is trying to
setprocattr.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Cc: stable@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
- Introduce ns_capable to test for a capability in a non-default
user namespace.
- Teach cap_capable to handle capabilities in a non-default
user namespace.
The motivation is to get to the unprivileged creation of new
namespaces. It looks like this gets us 90% of the way there, with
only potential uid confusion issues left.
I still need to handle getting all caps after creation but otherwise I
think I have a good starter patch that achieves all of your goals.
Changelog:
11/05/2010: [serge] add apparmor
12/14/2010: [serge] fix capabilities to created user namespaces
Without this, if user serge creates a user_ns, he won't have
capabilities to the user_ns he created. THis is because we
were first checking whether his effective caps had the caps
he needed and returning -EPERM if not, and THEN checking whether
he was the creator. Reverse those checks.
12/16/2010: [serge] security_real_capable needs ns argument in !security case
01/11/2011: [serge] add task_ns_capable helper
01/11/2011: [serge] add nsown_capable() helper per Bastian Blank suggestion
02/16/2011: [serge] fix a logic bug: the root user is always creator of
init_user_ns, but should not always have capabilities to
it! Fix the check in cap_capable().
02/21/2011: Add the required user_ns parameter to security_capable,
fixing a compile failure.
02/23/2011: Convert some macros to functions as per akpm comments. Some
couldn't be converted because we can't easily forward-declare
them (they are inline if !SECURITY, extern if SECURITY). Add
a current_user_ns function so we can use it in capability.h
without #including cred.h. Move all forward declarations
together to the top of the #ifdef __KERNEL__ section, and use
kernel-doc format.
02/23/2011: Per dhowells, clean up comment in cap_capable().
02/23/2011: Per akpm, remove unreachable 'return -EPERM' in cap_capable.
(Original written and signed off by Eric; latest, modified version
acked by him)
[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: export current_user_ns() for ecryptfs]
[serge.hallyn@canonical.com: remove unneeded extra argument in selinux's task_has_capability]
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>
Acked-by: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
set_init_cxt() allocted sizeof(struct aa_task_cxt) bytes for cxt,
if register_security() failed, it will cause memory leak.
Signed-off-by: Zhitong Wang <zhitong.wangzt@alibaba-inc.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2.6.36 introduced the abilitiy to specify the task that is having its
rlimits set. Update mediation to ensure that confined tasks can only
set their own group_leader as expected by current policy.
Add TODO note about extending policy to support setting other tasks
rlimits.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
After rlimits tree was merged we get the following errors:
security/apparmor/lsm.c:663:2: warning: initialization from incompatible pointer type
It is because AppArmor was merged in the meantime, but uses the old
prototype. So fix it by adding struct task_struct as a first parameter
of apparmor_task_setrlimit.
NOTE that this is ONLY a compilation warning fix (and crashes caused
by that). It needs proper handling in AppArmor depending on who is the
'task'.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
Fixes these build errors:
security/apparmor/lsm.c:701: error: 'param_ops_aabool' undeclared here (not in a function)
security/apparmor/lsm.c:721: error: 'param_ops_aalockpolicy' undeclared here (not in a function)
security/apparmor/lsm.c:729: error: 'param_ops_aauint' undeclared here (not in a function)
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Remove extraneous path_truncate arguments from the AppArmor hook,
as they've been removed from the LSM API.
Signed-off-by: James Morris <jmorris@namei.org>
AppArmor hooks to interface with the LSM, module parameters and module
initialization.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
John Johansen