linux/security/keys
Yevgeny Pats 23567fd052 KEYS: Fix keyring ref leak in join_session_keyring()
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>
2016-01-20 10:50:48 +11:00
..
encrypted-keys KEYS: Fix handling of stored error in a negatively instantiated user key 2015-11-25 14:19:47 +11:00
Kconfig keys, trusted: select hash algorithm for TPM2 chips 2015-12-20 15:27:12 +02:00
Makefile KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches 2013-09-24 10:35:19 +01:00
big_key.c KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
compat.c switch keyctl_instantiate_key_common() to iov_iter 2015-04-11 22:27:12 -04:00
gc.c KEYS: Fix crash when attempt to garbage collect an uninstantiated keyring 2015-10-15 17:21:37 +01:00
internal.h switch keyctl_instantiate_key_common() to iov_iter 2015-04-11 22:27:12 -04:00
key.c KEYS: refcount bug fix 2016-01-07 12:56:42 -05:00
keyctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-01-17 19:13:15 -08:00
keyring.c KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
permission.c KEYS: Move the flags representing required permission to linux/key.h 2014-03-14 17:44:49 +00:00
persistent.c KEYS: Move the flags representing required permission to linux/key.h 2014-03-14 17:44:49 +00:00
proc.c KEYS: Make /proc/keys unconditional if CONFIG_KEYS=y 2015-01-22 22:34:32 +00:00
process_keys.c KEYS: Fix keyring ref leak in join_session_keyring() 2016-01-20 10:50:48 +11:00
request_key.c Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2015-11-05 15:32:38 -08:00
request_key_auth.c KEYS: Merge the type-specific data with the payload data 2015-10-21 15:18:36 +01:00
sysctl.c security: Convert use of typedef ctl_table to struct ctl_table 2014-04-15 13:39:58 +10:00
trusted.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2016-01-17 19:13:15 -08:00
trusted.h keys, trusted: move struct trusted_key_options to trusted-type.h 2015-10-19 01:01:21 +02:00
user_defined.c KEYS: Fix handling of stored error in a negatively instantiated user key 2015-11-25 14:19:47 +11:00