android_kernel_samsung_msm8976/security
Yevgeny Pats 84de97ff50 KEYS: Fix keyring ref leak in join_session_keyring()
commit 23567fd052a9abb6d67fe8e7a9ccdd9800a540f2 upstream.

This fixes CVE-2016-0728.

If a thread is asked to join as a session keyring the keyring that's already
set as its session, we leak a keyring reference.

This can be tested with the following program:

	#include <stddef.h>
	#include <stdio.h>
	#include <sys/types.h>
	#include <keyutils.h>

	int main(int argc, const char *argv[])
	{
		int i = 0;
		key_serial_t serial;

		serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
				"leaked-keyring");
		if (serial < 0) {
			perror("keyctl");
			return -1;
		}

		if (keyctl(KEYCTL_SETPERM, serial,
			   KEY_POS_ALL | KEY_USR_ALL) < 0) {
			perror("keyctl");
			return -1;
		}

		for (i = 0; i < 100; i++) {
			serial = keyctl(KEYCTL_JOIN_SESSION_KEYRING,
					"leaked-keyring");
			if (serial < 0) {
				perror("keyctl");
				return -1;
			}
		}

		return 0;
	}

If, after the program has run, there something like the following line in
/proc/keys:

3f3d898f I--Q---   100 perm 3f3f0000     0     0 keyring   leaked-keyring: empty

with a usage count of 100 * the number of times the program has been run,
then the kernel is malfunctioning.  If leaked-keyring has zero usages or
has been garbage collected, then the problem is fixed.

Reported-by: Yevgeny Pats <yevgeny@perception-point.io>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>
Acked-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-22 19:47:57 -08:00
..
apparmor
integrity evm: check xattr value length and type in evm_inode_setxattr() 2014-11-14 08:47:54 -08:00
keys KEYS: Fix keyring ref leak in join_session_keyring() 2016-01-22 19:47:57 -08:00
selinux move d_rcu from overlapping d_child to overlapping d_alias 2015-04-29 10:34:00 +02:00
smack
tomoyo Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-05-01 17:51:54 -07:00
yama
capability.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-04-30 16:27:51 -07:00
commoncap.c CAPABILITIES: remove undefined caps from all processes 2014-09-17 09:03:57 -07:00
device_cgroup.c devcg: remove parent_cgroup. 2013-04-18 11:34:35 -07:00
inode.c
Kconfig
lsm_audit.c
Makefile
min_addr.c
security.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2013-04-30 16:27:51 -07:00