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Groups > linux.kernel > #1316566

[PATCH 3.12 25/39] KEYS: Fix keyring ref leak in join_session_keyring()

From Jiri Slaby <jslaby@suse.cz>
Newsgroups linux.kernel
Subject [PATCH 3.12 25/39] KEYS: Fix keyring ref leak in join_session_keyring()
Date 2016-01-25 13:00 +0100
Message-ID <qUNYn-3kJ-43@gated-at.bofh.it> (permalink)
References <qUNYl-3kJ-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Yevgeny Pats <yevgeny@perception-point.io>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

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: Jiri Slaby <jslaby@suse.cz>
---
 security/keys/process_keys.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 42defae1e161..cd871dc8b7c0 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -792,6 +792,7 @@ long join_session_keyring(const char *name)
 		ret = PTR_ERR(keyring);
 		goto error2;
 	} else if (keyring == new->session_keyring) {
+		key_put(keyring);
 		ret = 0;
 		goto error2;
 	}
-- 
2.7.0

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Thread

[PATCH 3.12 01/39] efi: Disable interrupts around EFI calls, not in the epilog/prolog calls Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 02/39] tools: Add a "make all" rule Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 26/39] udp: properly support MSG_PEEK with truncated buffers Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 24/39] KEYS: Fix race between read and revoke Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 22/39] sctp: Prevent soft lockup when sctp_accept() is called during a timeout event Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 28/39] xen/gntdev: Grant maps should not be subject to NUMA balancing Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 36/39] MAINTAINERS: Add public mailing list for ARC Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 27/39] x86/signal: Fix restart_syscall number for x32 tasks Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 16/39] staging/dgnc: fix info leak in ioctl Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 37/39] ARC: Fix silly typo in MAINTAINERS file commit 30b9dbee895ff0d5cbf155bd1ef3f0f5992bca6f upstream. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 25/39] KEYS: Fix keyring ref leak in join_session_keyring() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 32/39] x86/boot: Double BOOT_HEAP_SIZE to 64KB Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 38/39] isdn_ppp: Add checks for allocation failure in isdn_ppp_open() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 12/39] block: Always check queue limits for cloned requests Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 20/39] m68k/mm: Check for mm != NULL in do_page_fault() debug code Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 18/39] m32r: fix potential NULL-pointer dereference Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 15/39] module: remove MODULE_GENERIC_TABLE Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 23/39] USB: quirks: Fix another ELAN touchscreen Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 17/39] pm: use GFP_ATOMIC when pm core call this function Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 39/39] ppp, slip: Validate VJ compression slot parameters completely Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 30/39] KVM: PPC: Book3S HV: Prohibit setting illegal transaction state in MSR Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 21/39] m68k/mac: Make SCC reset work more reliably Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 34/39] ALSA: hda - Add Intel Lewisburg device IDs Audio Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 04/39] dlm: make posix locks interruptible Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 35/39] ALSA: hda - Apply pin fixup for HP ProBook 6550b Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 14/39] qla2xxx: Fix hardware lock/unlock issue causing kernel panic. Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 29/39] x86/xen: don't reset vcpu_info on a cancelled suspend Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 10/39] drm/i915: Fix SRC_COPY width on 830/845g Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 07/39] route: Use ipv4_mtu instead of raw rt_pmtu Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 13/39] Input: aiptek - fix crash on detecting device without endpoints Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 05/39] PCI: Drop "setting latency timer" messages Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 11/39] lpfc: Fix null ndlp dereference in target_reset_handler Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 09/39] ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 06/39] ipv4: Don't increase PMTU with Datagram Too Big message. Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 03/39] ALSA: hda - Fix noise problems on Thinkpad T440s Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 08/39] SUNRPC: Fix oops when trace sunrpc_task events in nfs client Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100

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