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Eric Biggers 80733239c7 crypto: authenc - fix parsing key with misaligned rta_len
commit 8f9c469348 upstream.

Keys for "authenc" AEADs are formatted as an rtattr containing a 4-byte
'enckeylen', followed by an authentication key and an encryption key.
crypto_authenc_extractkeys() parses the key to find the inner keys.

However, it fails to consider the case where the rtattr's payload is
longer than 4 bytes but not 4-byte aligned, and where the key ends
before the next 4-byte aligned boundary.  In this case, 'keylen -=
RTA_ALIGN(rta->rta_len);' underflows to a value near UINT_MAX.  This
causes a buffer overread and crash during crypto_ahash_setkey().

Fix it by restricting the rtattr payload to the expected size.

Reproducer using AF_ALG:

	#include <linux/if_alg.h>
	#include <linux/rtnetlink.h>
	#include <sys/socket.h>

	int main()
	{
		int fd;
		struct sockaddr_alg addr = {
			.salg_type = "aead",
			.salg_name = "authenc(hmac(sha256),cbc(aes))",
		};
		struct {
			struct rtattr attr;
			__be32 enckeylen;
			char keys[1];
		} __attribute__((packed)) key = {
			.attr.rta_len = sizeof(key),
			.attr.rta_type = 1 /* CRYPTO_AUTHENC_KEYA_PARAM */,
		};

		fd = socket(AF_ALG, SOCK_SEQPACKET, 0);
		bind(fd, (void *)&addr, sizeof(addr));
		setsockopt(fd, SOL_ALG, ALG_SET_KEY, &key, sizeof(key));
	}

It caused:

	BUG: unable to handle kernel paging request at ffff88007ffdc000
	PGD 2e01067 P4D 2e01067 PUD 2e04067 PMD 2e05067 PTE 0
	Oops: 0000 [#1] SMP
	CPU: 0 PID: 883 Comm: authenc Not tainted 4.20.0-rc1-00108-g00c9fe37a7f27 #13
	Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014
	RIP: 0010:sha256_ni_transform+0xb3/0x330 arch/x86/crypto/sha256_ni_asm.S:155
	[...]
	Call Trace:
	 sha256_ni_finup+0x10/0x20 arch/x86/crypto/sha256_ssse3_glue.c:321
	 crypto_shash_finup+0x1a/0x30 crypto/shash.c:178
	 shash_digest_unaligned+0x45/0x60 crypto/shash.c:186
	 crypto_shash_digest+0x24/0x40 crypto/shash.c:202
	 hmac_setkey+0x135/0x1e0 crypto/hmac.c:66
	 crypto_shash_setkey+0x2b/0xb0 crypto/shash.c:66
	 shash_async_setkey+0x10/0x20 crypto/shash.c:223
	 crypto_ahash_setkey+0x2d/0xa0 crypto/ahash.c:202
	 crypto_authenc_setkey+0x68/0x100 crypto/authenc.c:96
	 crypto_aead_setkey+0x2a/0xc0 crypto/aead.c:62
	 aead_setkey+0xc/0x10 crypto/algif_aead.c:526
	 alg_setkey crypto/af_alg.c:223 [inline]
	 alg_setsockopt+0xfe/0x130 crypto/af_alg.c:256
	 __sys_setsockopt+0x6d/0xd0 net/socket.c:1902
	 __do_sys_setsockopt net/socket.c:1913 [inline]
	 __se_sys_setsockopt net/socket.c:1910 [inline]
	 __x64_sys_setsockopt+0x1f/0x30 net/socket.c:1910
	 do_syscall_64+0x4a/0x180 arch/x86/entry/common.c:290
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: e236d4a89a ("[CRYPTO] authenc: Move enckeylen into key itself")
Cc: <stable@vger.kernel.org> # v2.6.25+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2019-01-22 21:09:50 +01:00
arch arm64: Don't trap host pointer auth use to EL2 2019-01-22 21:09:47 +01:00
block block: mq-deadline: Fix write completion handling 2019-01-13 09:24:05 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: authenc - fix parsing key with misaligned rta_len 2019-01-22 21:09:50 +01:00
Documentation x86/speculation/l1tf: Drop the swap storage limit restriction when l1tf=off 2019-01-09 17:45:54 +01:00
drivers crypto: bcm - convert to use crypto_authenc_extractkeys() 2019-01-22 21:09:50 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs Btrfs: use nofs context when initializing security xattrs to avoid deadlock 2019-01-16 22:03:27 +01:00
include IN_BADCLASS: fix macro to actually work 2019-01-22 21:09:49 +01:00
init psi: fix reference to kernel commandline enable 2018-12-14 15:05:45 -08:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel fork, memcg: fix cached_stacks case 2019-01-16 22:03:23 +01:00
lib lib: fix build failure in CONFIG_DEBUG_VIRTUAL test 2019-01-13 09:24:09 +01:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm mm: page_mapped: don't assume compound page is huge or THP 2019-01-16 22:03:26 +01:00
net smc: move unhash as early as possible in smc_release() 2019-01-22 21:09:50 +01:00
samples VFIO updates for v4.20 2018-10-31 11:01:38 -07:00
scripts x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE 2019-01-16 22:03:21 +01:00
security selinux: policydb - fix byte order and alignment issues 2019-01-13 09:24:06 +01:00
sound ALSA: hda/realtek - Disable headset Mic VREF for headset mode of ALC225 2019-01-16 22:03:21 +01:00
tools selftests: Fix test errors related to lib.mk khdr target 2019-01-13 09:24:09 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm/arm64: vgic: Fix off-by-one bug in vgic_get_irq() 2019-01-09 17:46:04 +01:00
.clang-format page cache: Convert find_get_pages_contig to XArray 2018-10-21 10:46:34 -04:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap mailmap: Update email for Punit Agrawal 2018-11-05 10:02:11 +00:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: update entry for MMP platform 2018-12-03 12:39:57 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-12-21 14:21:17 -08:00
Makefile Linux 4.20.3 2019-01-16 22:03:27 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.