linux-toradex.git/security, branch v2.6.34.15

Fix install_process_keyring error handling

2014-02-10T21:11:33+00:00

commit 27d6379894be4a81984da4d48002196a83939ca9 upstream.

Fix an incorrect error check that returns 1 for error instead of the
expected error code.

Signed-off-by: Andi Kleen 
Signed-off-by: David Howells 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker

keys: fix race with concurrent install_user_keyrings()

2014-02-10T21:11:15+00:00

commit 0da9dfdd2cd9889201bc6f6f43580c99165cd087 upstream.

This fixes CVE-2013-1792.

There is a race in install_user_keyrings() that can cause a NULL pointer
dereference when called concurrently for the same user if the uid and
uid-session keyrings are not yet created.  It might be possible for an
unprivileged user to trigger this by calling keyctl() from userspace in
parallel immediately after logging in.

Assume that we have two threads both executing lookup_user_key(), both
looking for KEY_SPEC_USER_SESSION_KEYRING.

	THREAD A			THREAD B
	===============================	===============================
					==>call install_user_keyrings();
	if (!cred->user->session_keyring)
	==>call install_user_keyrings()
					...
					user->uid_keyring = uid_keyring;
	if (user->uid_keyring)
		return 0;
	<==
	key = cred->user->session_keyring [== NULL]
					user->session_keyring = session_keyring;
	atomic_inc(&key->usage); [oops]

At the point thread A dereferences cred->user->session_keyring, thread B
hasn't updated user->session_keyring yet, but thread A assumes it is
populated because install_user_keyrings() returned ok.

The race window is really small but can be exploited if, for example,
thread B is interrupted or preempted after initializing uid_keyring, but
before doing setting session_keyring.

This couldn't be reproduced on a stock kernel.  However, after placing
systemtap probe on 'user->session_keyring = session_keyring;' that
introduced some delay, the kernel could be crashed reliably.

Fix this by checking both pointers before deciding whether to return.
Alternatively, the test could be done away with entirely as it is checked
inside the mutex - but since the mutex is global, that may not be the best
way.

Signed-off-by: David Howells 
Reported-by: Mateusz Guzik 
Signed-off-by: Andrew Morton 
Signed-off-by: James Morris 
Signed-off-by: Paul Gortmaker

KEYS: Fix a NULL pointer deref in the user-defined key type

2012-08-17T19:35:05+00:00

commit 9f35a33b8d06263a165efe3541d9aa0cdbd70b3b upstream.

Fix a NULL pointer deref in the user-defined key type whereby updating a
negative key into a fully instantiated key will cause an oops to occur
when the code attempts to free the non-existent old payload.

This results in an oops that looks something like the following:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [] __call_rcu+0x11/0x13e
  PGD 3391d067 PUD 3894a067 PMD 0
  Oops: 0002 [#1] SMP
  CPU 1
  Pid: 4354, comm: keyctl Not tainted 3.1.0-fsdevel+ #1140                  /DG965RY
  RIP: 0010:[]  [] __call_rcu+0x11/0x13e
  RSP: 0018:ffff88003d591df8  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000000006e
  RDX: ffffffff8161d0c0 RSI: 0000000000000000 RDI: 0000000000000000
  RBP: ffff88003d591e18 R08: 0000000000000000 R09: ffffffff8152fa6c
  R10: 0000000000000000 R11: 0000000000000300 R12: ffff88003b8f9538
  R13: ffffffff8161d0c0 R14: ffff88003b8f9d50 R15: ffff88003c69f908
  FS:  00007f97eb18c720(0000) GS:ffff88003bd00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000008 CR3: 000000003d47a000 CR4: 00000000000006e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process keyctl (pid: 4354, threadinfo ffff88003d590000, task ffff88003c78a040)
  Stack:
   ffff88003e0ffde0 ffff88003b8f9538 0000000000000001 ffff88003b8f9d50
   ffff88003d591e28 ffffffff810860f0 ffff88003d591e68 ffffffff8117bfea
   ffff88003d591e68 ffffffff00000000 ffff88003e0ffde1 ffff88003e0ffde0
  Call Trace:
   [] call_rcu_sched+0x10/0x12
   [] user_update+0x8d/0xa2
   [] key_create_or_update+0x236/0x270
   [] sys_add_key+0x123/0x17e
   [] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells 
Acked-by: Jeff Layton 
Acked-by: Neil Horman 
Acked-by: Steve Dickson 
Acked-by: James Morris 
Signed-off-by: Linus Torvalds 
[PG: pre-3.0 kernels dont have kfree_rcu, so tweak accordingly]
Signed-off-by: Paul Gortmaker

fcaps: clear the same personality flags as suid when fcaps are used

2012-08-17T19:35:05+00:00

commit d52fc5dde171f030170a6cb78034d166b13c9445 upstream.

If a process increases permissions using fcaps all of the dangerous
personality flags which are cleared for suid apps should also be cleared.
Thus programs given priviledge with fcaps will continue to have address space
randomization enabled even if the parent tried to disable it to make it
easier to attack.

Signed-off-by: Eric Paris 
Reviewed-by: Serge Hallyn 
Signed-off-by: James Morris 
Signed-off-by: Paul Gortmaker

security: fix compile error in commoncap.c

2012-08-17T19:35:04+00:00

commit 51b79bee627d526199b2f6a6bef8ee0c0739b6d1 upstream.

Add missing "personality.h"
security/commoncap.c: In function 'cap_bprm_set_creds':
security/commoncap.c:510: error: 'PER_CLEAR_ON_SETID' undeclared (first use in this function)
security/commoncap.c:510: error: (Each undeclared identifier is reported only once
security/commoncap.c:510: error: for each function it appears in.)

Signed-off-by: Jonghwan Choi 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris 
Signed-off-by: Paul Gortmaker

CRED: Fix BUG() upon security_cred_alloc_blank() failure

2011-06-26T16:46:42+00:00

commit 2edeaa34a6e3f2c43b667f6c4f7b27944b811695 upstream.

In cred_alloc_blank() since 2.6.32, abort_creds(new) is called with
new->security == NULL and new->magic == 0 when security_cred_alloc_blank()
returns an error.  As a result, BUG() will be triggered if SELinux is enabled
or CONFIG_DEBUG_CREDENTIALS=y.

If CONFIG_DEBUG_CREDENTIALS=y, BUG() is called from __invalid_creds() because
cred->magic == 0.  Failing that, BUG() is called from selinux_cred_free()
because selinux_cred_free() is not expecting cred->security == NULL.  This does
not affect smack_cred_free(), tomoyo_cred_free() or apparmor_cred_free().

Fix these bugs by

(1) Set new->magic before calling security_cred_alloc_blank().

(2) Handle null cred->security in creds_are_invalid() and selinux_cred_free().

Signed-off-by: Tetsuo Handa 
Signed-off-by: David Howells 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker

SELinux: do not compute transition labels on mountpoint labeled filesystems

2011-06-26T16:46:34+00:00

commit 415103f9932d45f7927f4b17e3a9a13834cdb9a1 upstream.

selinux_inode_init_security computes transitions sids even for filesystems
that use mount point labeling.  It shouldn't do that.  It should just use
the mount point label always and no matter what.

This causes 2 problems.  1) it makes file creation slower than it needs to be
since we calculate the transition sid and 2) it allows files to be created
with a different label than the mount point!

# id -Z
staff_u:sysadm_r:sysadm_t:s0-s0:c0.c1023
# sesearch --type --class file --source sysadm_t --target tmp_t
Found 1 semantic te rules:
   type_transition sysadm_t tmp_t : file user_tmp_t;

# mount -o loop,context="system_u:object_r:tmp_t:s0"  /tmp/fs /mnt/tmp

# ls -lZ /mnt/tmp
drwx------. root root system_u:object_r:tmp_t:s0       lost+found
# touch /mnt/tmp/file1
# ls -lZ /mnt/tmp
-rw-r--r--. root root staff_u:object_r:user_tmp_t:s0   file1
drwx------. root root system_u:object_r:tmp_t:s0       lost+found

Whoops, we have a mount point labeled filesystem tmp_t with a user_tmp_t
labeled file!

Signed-off-by: Eric Paris 
Reviewed-by: Reviewed-by: James Morris 
Signed-off-by: Paul Gortmaker

SELinux: define permissions for DCB netlink messages

2011-06-26T16:46:34+00:00

commit 350e4f31e0eaf56dfc3b328d24a11bdf42a41fb8 upstream.

Commit 2f90b865 added two new netlink message types to the netlink route
socket.  SELinux has hooks to define if netlink messages are allowed to
be sent or received, but it did not know about these two new message
types.  By default we allow such actions so noone likely noticed.  This
patch adds the proper definitions and thus proper permissions
enforcement.

Signed-off-by: Eric Paris 
Signed-off-by: Paul Gortmaker

ima: fix add LSM rule bug

2011-04-17T20:16:14+00:00

commit 867c20265459d30a01b021a9c1e81fb4c5832aa9 upstream.

If security_filter_rule_init() doesn't return a rule, then not everything
is as fine as the return code implies.

This bug only occurs when the LSM (eg. SELinux) is disabled at runtime.

Adding an empty LSM rule causes ima_match_rules() to always succeed,
ignoring any remaining rules.

 default IMA TCB policy:
  # PROC_SUPER_MAGIC
  dont_measure fsmagic=0x9fa0
  # SYSFS_MAGIC
  dont_measure fsmagic=0x62656572
  # DEBUGFS_MAGIC
  dont_measure fsmagic=0x64626720
  # TMPFS_MAGIC
  dont_measure fsmagic=0x01021994
  # SECURITYFS_MAGIC
  dont_measure fsmagic=0x73636673

  < LSM specific rule >
  dont_measure obj_type=var_log_t

  measure func=BPRM_CHECK
  measure func=FILE_MMAP mask=MAY_EXEC
  measure func=FILE_CHECK mask=MAY_READ uid=0

Thus without the patch, with the boot parameters 'tcb selinux=0', adding
the above 'dont_measure obj_type=var_log_t' rule to the default IMA TCB
measurement policy, would result in nothing being measured.  The patch
prevents the default TCB policy from being replaced.

Signed-off-by: Mimi Zohar 
Cc: James Morris 
Acked-by: Serge Hallyn 
Cc: David Safford 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker

KEYS: Fix bug in keyctl_session_to_parent() if parent has no session keyring

2011-01-06T23:08:02+00:00

commit 3d96406c7da1ed5811ea52a3b0905f4f0e295376 upstream.

Fix a bug in keyctl_session_to_parent() whereby it tries to check the ownership
of the parent process's session keyring whether or not the parent has a session
keyring [CVE-2010-2960].

This results in the following oops:

  BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
  IP: [] keyctl_session_to_parent+0x251/0x443
  ...
  Call Trace:
   [] ? keyctl_session_to_parent+0x67/0x443
   [] ? __do_fault+0x24b/0x3d0
   [] sys_keyctl+0xb4/0xb8
   [] system_call_fastpath+0x16/0x1b

if the parent process has no session keyring.

If the system is using pam_keyinit then it mostly protected against this as all
processes derived from a login will have inherited the session keyring created
by pam_keyinit during the log in procedure.

To test this, pam_keyinit calls need to be commented out in /etc/pam.d/.

Reported-by: Tavis Ormandy 
Signed-off-by: David Howells 
Acked-by: Tavis Ormandy 
Cc: dann frazier 
Signed-off-by: Linus Torvalds 
Signed-off-by: Paul Gortmaker