linux.git/crypto/shash.c, branch v3.2.101

crypto: hmac - require that the underlying hash algorithm is unkeyed

2018-01-01T20:51:05+00:00

commit af3ff8045bbf3e32f1a448542e73abb4c8ceb6f1 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 
    #include 

    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 
Signed-off-by: Eric Biggers 
Signed-off-by: Herbert Xu 
Signed-off-by: Ben Hutchings

crypto: shash - Fix zero-length shash ahash digest crash

2018-01-01T20:50:56+00:00

commit b61907bb42409adf9b3120f741af7c57dd7e3db2 upstream.

The shash ahash digest adaptor function may crash if given a
zero-length input together with a null SG list.  This is because
it tries to read the SG list before looking at the length.

This patch fixes it by checking the length first.

Reported-by: Stephan Müller
Signed-off-by: Herbert Xu 
Tested-by: Stephan Müller 
Signed-off-by: Ben Hutchings

crypto: shash - Fix has_key setting

2016-02-27T14:28:44+00:00

commit 00420a65fa2beb3206090ead86942484df2275f3 upstream.

The has_key logic is wrong for shash algorithms as they always
have a setkey function.  So we should instead be testing against
shash_no_setkey.

Fixes: a5596d633278 ("crypto: hash - Add crypto_ahash_has_setkey")
Reported-by: Stephan Mueller 
Signed-off-by: Herbert Xu 
Tested-by: Stephan Mueller 
Signed-off-by: Ben Hutchings

crypto: hash - Add crypto_ahash_has_setkey

2016-02-13T10:34:12+00:00

commit a5596d6332787fd383b3b5427b41f94254430827 upstream.

This patch adds a way for ahash users to determine whether a key
is required by a crypto_ahash transform.

Signed-off-by: Herbert Xu 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

crypto: user - fix info leaks in report API

2013-03-20T15:03:37+00:00

commit 9a5467bf7b6e9e02ec9c3da4e23747c05faeaac6 upstream.

Three errors resulting in kernel memory disclosure:

1/ The structures used for the netlink based crypto algorithm report API
are located on the stack. As snprintf() does not fill the remainder of
the buffer with null bytes, those stack bytes will be disclosed to users
of the API. Switch to strncpy() to fix this.

2/ crypto_report_one() does not initialize all field of struct
crypto_user_alg. Fix this to fix the heap info leak.

3/ For the module name we should copy only as many bytes as
module_name() returns -- not as much as the destination buffer could
hold. But the current code does not and therefore copies random data
from behind the end of the module name, as the module name is always
shorter than CRYPTO_MAX_ALG_NAME.

Also switch to use strncpy() to copy the algorithm's name and
driver_name. They are strings, after all.

Signed-off-by: Mathias Krause 
Cc: Steffen Klassert 
Signed-off-by: Herbert Xu 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

crypto: algapi - Fix build problem with NET disabled

2011-11-10T22:57:06+00:00

The report functions use NLA_PUT so we need to ensure that NET
is enabled.

Reported-by: Luis Henriques 
Signed-off-by: Herbert Xu

crypto: Add userspace report for shash type algorithms

2011-10-21T12:24:04+00:00

Signed-off-by: Steffen Klassert 
Signed-off-by: Herbert Xu

crypto: hash - Fix async import on shash algorithm

2010-11-04T18:48:37+00:00

The function shash_async_import did not initialise the descriptor
correctly prior to calling the underlying shash import function.

This patch adds the required initialisation.

Reported-by: Miloslav Trmac 
Signed-off-by: Herbert Xu

crypto: shash - Remove usage of CRYPTO_MINALIGN

2010-05-19T01:50:58+00:00

The macro CRYPTO_MINALIGN is not meant to be used directly.  This
patch replaces it with crypto_tfm_ctx_alignment.

Signed-off-by: Herbert Xu

crypto: shash - Test for the algorithms import function before exporting it

2009-07-24T05:57:13+00:00

crypto_init_shash_ops_async() tests for setkey and not for import
before exporting the algorithms import function to ahash.
This patch fixes this.

Signed-off-by: Steffen Klassert 
Signed-off-by: Herbert Xu