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Eric Biggers 902ae89f84 crypto: hmac - require that the underlying hash algorithm is unkeyed 
commit af3ff8045b upstream.

Because the HMAC template didn't check that its underlying hash
algorithm is unkeyed, trying to use "hmac(hmac(sha3-512-generic))"
through AF_ALG or through KEYCTL_DH_COMPUTE resulted in the inner HMAC
being used without having been keyed, resulting in sha3_update() being
called without sha3_init(), causing a stack buffer overflow.

This is a very old bug, but it seems to have only started causing real
problems when SHA-3 support was added (requires CONFIG_CRYPTO_SHA3)
because the innermost hash's state is ->import()ed from a zeroed buffer,
and it just so happens that other hash algorithms are fine with that,
but SHA-3 is not.  However, there could be arch or hardware-dependent
hash algorithms also affected; I couldn't test everything.

Fix the bug by introducing a function crypto_shash_alg_has_setkey()
which tests whether a shash algorithm is keyed.  Then update the HMAC
template to require that its underlying hash algorithm is unkeyed.

Here is a reproducer:

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

    int main()
    {
        int algfd;
        struct sockaddr_alg addr = {
            .salg_type = "hash",
            .salg_name = "hmac(hmac(sha3-512-generic))",
        };
        char key[4096] = { 0 };

        algfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
        bind(algfd, (const struct sockaddr *)&addr, sizeof(addr));
        setsockopt(algfd, SOL_ALG, ALG_SET_KEY, key, sizeof(key));
    }

Here was the KASAN report from syzbot:

    BUG: KASAN: stack-out-of-bounds in memcpy include/linux/string.h:341  [inline]
    BUG: KASAN: stack-out-of-bounds in sha3_update+0xdf/0x2e0  crypto/sha3_generic.c:161
    Write of size 4096 at addr ffff8801cca07c40 by task syzkaller076574/3044

    CPU: 1 PID: 3044 Comm: syzkaller076574 Not tainted 4.14.0-mm1+ #25
    Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  Google 01/01/2011
    Call Trace:
      __dump_stack lib/dump_stack.c:17 [inline]
      dump_stack+0x194/0x257 lib/dump_stack.c:53
      print_address_description+0x73/0x250 mm/kasan/report.c:252
      kasan_report_error mm/kasan/report.c:351 [inline]
      kasan_report+0x25b/0x340 mm/kasan/report.c:409
      check_memory_region_inline mm/kasan/kasan.c:260 [inline]
      check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
      memcpy+0x37/0x50 mm/kasan/kasan.c:303
      memcpy include/linux/string.h:341 [inline]
      sha3_update+0xdf/0x2e0 crypto/sha3_generic.c:161
      crypto_shash_update+0xcb/0x220 crypto/shash.c:109
      shash_finup_unaligned+0x2a/0x60 crypto/shash.c:151
      crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
      hmac_finup+0x182/0x330 crypto/hmac.c:152
      crypto_shash_finup+0xc4/0x120 crypto/shash.c:165
      shash_digest_unaligned+0x9e/0xd0 crypto/shash.c:172
      crypto_shash_digest+0xc4/0x120 crypto/shash.c:186
      hmac_setkey+0x36a/0x690 crypto/hmac.c:66
      crypto_shash_setkey+0xad/0x190 crypto/shash.c:64
      shash_async_setkey+0x47/0x60 crypto/shash.c:207
      crypto_ahash_setkey+0xaf/0x180 crypto/ahash.c:200
      hash_setkey+0x40/0x90 crypto/algif_hash.c:446
      alg_setkey crypto/af_alg.c:221 [inline]
      alg_setsockopt+0x2a1/0x350 crypto/af_alg.c:254
      SYSC_setsockopt net/socket.c:1851 [inline]
      SyS_setsockopt+0x189/0x360 net/socket.c:1830
      entry_SYSCALL_64_fastpath+0x1f/0x96

Reported-by: syzbot <syzkaller@googlegroups.com>
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>
 		2017-12-20 10:10:17 +01:00
Documentation dt-bindings: usb: fix reg-property port-number range 2017-12-14 09:53:09 +01:00
arch x86/intel_rdt: Fix potential deadlock during resctrl unmount 2017-12-17 15:08:01 +01:00
block blk-mq: Avoid that request queue removal can trigger list corruption 2017-12-17 15:08:00 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto crypto: hmac - require that the underlying hash algorithm is unkeyed 2017-12-20 10:10:17 +01:00
drivers mfd: fsl-imx25: Clean up irq settings during removal 2017-12-20 10:10:16 +01:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs fcntl: don't cap l_start and l_end values for F_GETLK64 in compat syscall 2017-12-17 15:07:59 +01:00
include crypto: hmac - require that the underlying hash algorithm is unkeyed 2017-12-20 10:10:17 +01:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel audit: ensure that 'audit=1' actually enables audit for PID 1 2017-12-17 15:08:00 +01:00
lib dynamic-debug-howto: fix optional/omitted ending line number to be LARGE instead of 0 2017-12-14 09:53:08 +01:00
mm slub: fix sysfs duplicate filename creation when slub_debug=O 2017-12-14 09:53:10 +01:00
net fix kcm_clone() 2017-12-17 15:07:59 +01:00
samples License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
scripts kbuild: rpm-pkg: fix jobserver unavailable warning 2017-12-14 09:53:13 +01:00
security apparmor: fix leak of null profile name if profile allocation fails 2017-12-14 09:53:06 +01:00
sound ALSA: usb-audio: Add check return value for usb_string() 2017-12-14 09:52:55 +01:00
tools x86/mpx/selftests: Fix up weird arrays 2017-12-14 09:53:06 +01:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt KVM: arm/arm64: vgic-its: Preserve the revious read from the pending table 2017-12-17 15:07:59 +01:00
.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: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap .mailmap: Add Maciej W. Rozycki's Imagination e-mail address 2017-11-10 12:16:15 -08:00
COPYING
…
CREDITS MAINTAINERS: update TPM driver infrastructure changes 2017-11-09 17:58:40 -08:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2017-11-09 18:26:51 -08:00
Makefile Linux 4.14.7 2017-12-17 15:08:14 +01:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README 

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.