Linux v4.13.3

2017-09-20 11:12:45 -05:00 · 2017-09-20 11:12:45 -05:00 · d83c4aa672
parent 0d556acf99
commit d83c4aa672
3 changed files with 97 additions and 2 deletions
--- a/KEYS-prevent-KEYCTL_READ-on-negative-key.patch
+++ b/KEYS-prevent-KEYCTL_READ-on-negative-key.patch
@ -0,0 +1,88 @@
+From patchwork Mon Sep 18 18:37:23 2017
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 7bit
+Subject: KEYS: prevent KEYCTL_READ on negative key
+From: Eric Biggers <ebiggers3@gmail.com>
+X-Patchwork-Id: 9957387
+Message-Id: <20170918183723.114253-1-ebiggers3@gmail.com>
+To: keyrings@vger.kernel.org
+Cc: David Howells <dhowells@redhat.com>, Michael Halcrow <mhalcrow@google.com>,
+ linux-security-module@vger.kernel.org,
+ linux-kernel@vger.kernel.org, Eric Biggers <ebiggers@google.com>,
+ stable@vger.kernel.org
+Date: Mon, 18 Sep 2017 11:37:23 -0700
+
+From: Eric Biggers <ebiggers@google.com>
+
+Because keyctl_read_key() looks up the key with no permissions
+requested, it may find a negatively instantiated key.  If the key is
+also possessed, we went ahead and called ->read() on the key.  But the
+key payload will actually contain the ->reject_error rather than the
+normal payload.  Thus, the kernel oopses trying to read the
+user_key_payload from memory address (int)-ENOKEY = 0x00000000ffffff82.
+
+Fortunately the payload data is stored inline, so it shouldn't be
+possible to abuse this as an arbitrary memory read primitive...
+
+Reproducer:
+    keyctl new_session
+    keyctl request2 user desc '' @s
+    keyctl read $(keyctl show | awk '/user: desc/ {print $1}')
+
+It causes a crash like the following:
+     BUG: unable to handle kernel paging request at 00000000ffffff92
+     IP: user_read+0x33/0xa0
+     PGD 36a54067 P4D 36a54067 PUD 0
+     Oops: 0000 [#1] SMP
+     CPU: 0 PID: 211 Comm: keyctl Not tainted 4.14.0-rc1 #337
+     Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-20170228_101828-anatol 04/01/2014
+     task: ffff90aa3b74c3c0 task.stack: ffff9878c0478000
+     RIP: 0010:user_read+0x33/0xa0
+     RSP: 0018:ffff9878c047bee8 EFLAGS: 00010246
+     RAX: 0000000000000001 RBX: ffff90aa3d7da340 RCX: 0000000000000017
+     RDX: 0000000000000000 RSI: 00000000ffffff82 RDI: ffff90aa3d7da340
+     RBP: ffff9878c047bf00 R08: 00000024f95da94f R09: 0000000000000000
+     R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
+     R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
+     FS:  00007f58ece69740(0000) GS:ffff90aa3e200000(0000) knlGS:0000000000000000
+     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
+     CR2: 00000000ffffff92 CR3: 0000000036adc001 CR4: 00000000003606f0
+     Call Trace:
+      keyctl_read_key+0xac/0xe0
+      SyS_keyctl+0x99/0x120
+      entry_SYSCALL_64_fastpath+0x1f/0xbe
+     RIP: 0033:0x7f58ec787bb9
+     RSP: 002b:00007ffc8d401678 EFLAGS: 00000206 ORIG_RAX: 00000000000000fa
+     RAX: ffffffffffffffda RBX: 00007ffc8d402800 RCX: 00007f58ec787bb9
+     RDX: 0000000000000000 RSI: 00000000174a63ac RDI: 000000000000000b
+     RBP: 0000000000000004 R08: 00007ffc8d402809 R09: 0000000000000020
+     R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffc8d402800
+     R13: 00007ffc8d4016e0 R14: 0000000000000000 R15: 0000000000000000
+     Code: e5 41 55 49 89 f5 41 54 49 89 d4 53 48 89 fb e8 a4 b4 ad ff 85 c0 74 09 80 3d b9 4c 96 00 00 74 43 48 8b b3 20 01 00 00 4d 85 ed <0f> b7 5e 10 74 29 4d 85 e4 74 24 4c 39 e3 4c 89 e2 4c 89 ef 48
+     RIP: user_read+0x33/0xa0 RSP: ffff9878c047bee8
+     CR2: 00000000ffffff92
+
+Fixes: 61ea0c0ba904 ("KEYS: Skip key state checks when checking for possession")
+Cc: <stable@vger.kernel.org>	[v3.13+]
+Signed-off-by: Eric Biggers <ebiggers@google.com>
+---
+ security/keys/keyctl.c | 5 +++++
+ 1 file changed, 5 insertions(+)
+
+diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
+index ab0b337c84b4..6a82090c7fc1 100644
+--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
+@@ -766,6 +766,11 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
+ 
+ 	key = key_ref_to_ptr(key_ref);
+ 
+	if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
+		ret = -ENOKEY;
+		goto error2;
+	}
+
+ 	/* see if we can read it directly */
+ 	ret = key_permission(key_ref, KEY_NEED_READ);
+ 	if (ret == 0)
--- a/kernel.spec
+++ b/kernel.spec
@ -54,7 +54,7 @@ Summary: The Linux kernel
 %if 0%{?released_kernel}

 # Do we have a -stable update to apply?
-%define stable_update 2
+%define stable_update 3
 # Set rpm version accordingly
 %if 0%{?stable_update}
 %define stablerev %{stable_update}
@ -658,6 +658,9 @@ Patch622: qxl-fixes.patch
 Patch623: HID-rmi-Make-sure-the-HID-device-is-opened-on-resume.patch
 Patch624: input-rmi4-remove-the-need-for-artifical-IRQ.patch

+# rhbz 1493435 1493436
+Patch625: KEYS-prevent-KEYCTL_READ-on-negative-key.patch
+
 # END OF PATCH DEFINITIONS

 %endif
@ -2231,6 +2234,10 @@ fi
 #
 #
 %changelog
+* Wed Sep 20 2017 Justin M. Forbes <jforbes@fedoraproject.org> - 4.13.3-200
+- Linux v4.13.3
+- Fixes 1493435 1493436
+
 * Tue Sep 19 2017 Laura Abbott <labbott@redhat.com>
 - Disable CONFIG_VIRTIO_BLK_SCSI

--- a/2
+++ b/2
@ -1,3 +1,3 @@
 SHA512 (linux-4.13.tar.xz) = a557c2f0303ae618910b7106ff63d9978afddf470f03cb72aa748213e099a0ecd5f3119aea6cbd7b61df30ca6ef3ec57044d524b7babbaabddf8b08b8bafa7d2
 SHA512 (perf-man-4.13.tar.gz) = 9bcc2cd8e56ec583ed2d8e0b0c88e7a94035a1915e40b3177bb02d6c0f10ddd4df9b097b1f5af59efc624226b613e240ddba8ddc2156f3682f992d5455fc5c03
-SHA512 (patch-4.13.2.xz) = 2b9cc6f24c2792b619189c81d8960d6f5dd622f767d6645208c59f3f38c00db5bdfb0d1fbbfa717bea7fd86067921cf07109c9a7a1001ce7a915bfa2a6a2c03e
+SHA512 (patch-4.13.3.xz) = 7c0675386c0906178661313d2dbaf644df9b43af31c4b8c8cc840c59b952c04c5768089782d79d84fd363e26b1824e05d1516a80b8cae663225fcb9b252d848a