CVE-2016-0728 Keys: reference leak in join_session_keyring (rhbz 1296623 xxxxxxx)

KEYS-Fix-keyring-ref-leak-in-join_session_keyring.patch

@@ -0,0 +1,78 @@
+From 05fd13592b60c3e9873f56705f80ff934e98b046 Mon Sep 17 00:00:00 2001
+From: David Howells <dhowells@redhat.com>
+Date: Mon, 18 Jan 2016 10:53:31 +0000
+Subject: [PATCH] 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>
+RH-bugzilla: 1298036
+---
+ 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 43b4cddbf2b3..7877e5cd4e23 100644
+--- a/security/keys/process_keys.c
++++ b/security/keys/process_keys.c
+@@ -794,6 +794,7 @@ 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;
+ 	}
+-- 
+2.5.0
+

kernel.spec

@@ -40,7 +40,7 @@ Summary: The Linux kernel
 # For non-released -rc kernels, this will be appended after the rcX and
 # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3"
 #
-%global baserelease 302
+%global baserelease 303
 %global fedora_build %{baserelease}
 
 # base_sublevel is the kernel version we're starting with and patching
@@ -682,6 +682,9 @@ Patch632: Btrfs-fix-fitrim-discarding-device-area-reserved-for.patch
 
 Patch633: net_43.mbox
 
+#CVE-2016-0728 rhbz 1296623 xxxxxxx
+Patch634: KEYS-Fix-keyring-ref-leak-in-join_session_keyring.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -2126,6 +2129,7 @@ fi
 # 
 %changelog
 * Tue Jan 19 2016 Josh Boyer <jwboyer@fedoraproject.org>
+- CVE-2016-0728 Keys: reference leak in join_session_keyring (rhbz 1296623 xxxxxxx)
 - Add currently queued networking stable patches
 - Add a couple btrfs patches cc'd to stable upstream
 - Add SCSI patches to avoid blacklist false positives (rhbz 1299810)