Skip to content

L
linux
Switch branch/tag
  1. 21 Jan, 2016 15 commits
  3. 20 Jan, 2016 24 commits
  5. 19 Jan, 2016 1 commit
    • Yevgeny Pats's avatar
      KEYS: Fix keyring ref leak in join_session_keyring() · 23567fd0
      Yevgeny Pats authored 
      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: default avatarYevgeny Pats <yevgeny@perception-point.io>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Acked-by: default avatarDon Zickus <dzickus@redhat.com>
Acked-by: default avatarPrarit Bhargava <prarit@redhat.com>
Acked-by: default avatarJarod Wilson <jarod@redhat.com>
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
      23567fd0
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7