diff --git a/KEYS-prevent-KEYCTL_READ-on-negative-key.patch b/KEYS-prevent-KEYCTL_READ-on-negative-key.patch new file mode 100644 index 000000000..d80176e66 --- /dev/null +++ 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 +X-Patchwork-Id: 9957387 +Message-Id: <20170918183723.114253-1-ebiggers3@gmail.com> +To: keyrings@vger.kernel.org +Cc: David Howells , Michael Halcrow , + linux-security-module@vger.kernel.org, + linux-kernel@vger.kernel.org, Eric Biggers , + stable@vger.kernel.org +Date: Mon, 18 Sep 2017 11:37:23 -0700 + +From: Eric Biggers + +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: [v3.13+] +Signed-off-by: Eric Biggers +--- + 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) diff --git a/kernel.spec b/kernel.spec index f620dc38b..80878c5ad 100644 --- 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 - 4.13.3-200 +- Linux v4.13.3 +- Fixes 1493435 1493436 + * Tue Sep 19 2017 Laura Abbott - Disable CONFIG_VIRTIO_BLK_SCSI diff --git a/sources b/sources index 437172001..b01fa41b3 100644 --- a/sources +++ b/sources @@ -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