fix #47820 CVE-2016-0728

CVE-2016-0728.patch

@@ -0,0 +1,78 @@
+From 23567fd052a9abb6d67fe8e7a9ccdd9800a540f2 Mon Sep 17 00:00:00 2001
+From: Yevgeny Pats <yevgeny@perception-point.io>
+Date: Tue, 19 Jan 2016 22:09:04 +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>
+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>
+---
+ 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 a3f85d2a..e6d50172 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;
+ 	}

PKGBUILD

@@ -21,7 +21,8 @@ source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar.xz"
         'linux.preset'
         'change-default-console-loglevel.patch'
         '0001-sdhci-revert.patch'
-        'tpmdd-devel-v3-base-platform-fix-binding-for-drivers-without-probe-callback.patch')
+        'tpmdd-devel-v3-base-platform-fix-binding-for-drivers-without-probe-callback.patch'
+        'CVE-2016-0728.patch')
 
 sha256sums=('401d7c8fef594999a460d10c72c5a94e9c2e1022f16795ec51746b0d165418b2'
             'SKIP'
@@ -30,7 +31,8 @@ sha256sums=('401d7c8fef594999a460d10c72c5a94e9c2e1022f16795ec51746b0d165418b2'
             'f0d90e756f14533ee67afda280500511a62465b4f76adcc5effa95a40045179c'
             '1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99'
             '5313df7cb5b4d005422bd4cd0dae956b2dadba8f3db904275aaf99ac53894375'
-            'ab57037ecee0a425c612babdff47c831378bca0bff063a1308599989a350226d')
+            'ab57037ecee0a425c612babdff47c831378bca0bff063a1308599989a350226d'
+            '03bed5b1c6ef34a917e218a46d38cd1347c5ab5693131996113c6cad275dc4e9')
 validpgpkeys=(
               'ABAF11C65A2970B130ABE3C479BE3E4300411886' # Linus Torvalds
               '647F28654894E3BD457199BE38DBBDC86092693E' # Greg Kroah-Hartman
@@ -56,6 +58,9 @@ prepare() {
   # https://bugzilla.kernel.org/show_bug.cgi?id=110751
   patch -Np1 -i "${srcdir}/tpmdd-devel-v3-base-platform-fix-binding-for-drivers-without-probe-callback.patch"
 
+  # fixes #47820 CVE-2016-0728.patch
+  patch -Np1 -i "${srcdir}/CVE-2016-0728.patch"
+
   # set DEFAULT_CONSOLE_LOGLEVEL to 4 (same value as the 'quiet' kernel param)
   # remove this when a Kconfig knob is made available by upstream
   # (relevant patch sent upstream: https://lkml.org/lkml/2011/7/26/227)