linux-toradex.git/crypto/ccm.c, branch v4.9.97

crypto: ccm - preserve the IV buffer

2017-11-15T14:53:18+00:00

commit 441f99c90497e15aa3ad1dbabd56187e29614348 upstream.

The IV buffer used during CCM operations is used twice, during both the
hashing step and the ciphering step.

When using a hardware accelerator that updates the contents of the IV
buffer at the end of ciphering operations, the value will be modified.
In the decryption case, the subsequent setup of the hashing algorithm
will interpret the updated IV instead of the original value, which can
lead to out-of-bounds writes.

Reuse the idata buffer, only used in the hashing step, to preserve the
IV's value during the ciphering step in the decryption case.

Signed-off-by: Romain Izard 
Reviewed-by: Tudor Ambarus 
Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: ccm - Use skcipher

2016-07-18T09:35:40+00:00

This patch converts ccm to use the new skcipher interface as opposed
to ablkcipher.

Signed-off-by: Herbert Xu

crypto: aead - Remove CRYPTO_ALG_AEAD_NEW flag

2015-08-17T08:53:53+00:00

This patch removes the CRYPTO_ALG_AEAD_NEW flag now that everyone
has been converted.

Signed-off-by: Herbert Xu

crypto: ccm - Convert to new AEAD interface

2015-07-17T13:20:09+00:00

This patch converts generic ccm and its associated transforms to
the new AEAD interface.

Signed-off-by: Herbert Xu

crypto: ccm - Use crypto_aead_set_reqsize helper

2015-05-13T02:31:39+00:00

This patch uses the crypto_aead_set_reqsize helper to avoid directly
touching the internals of aead.

Signed-off-by: Herbert Xu

crypto: include crypto- module prefix in template

2014-11-26T12:06:30+00:00

This adds the module loading prefix "crypto-" to the template lookup
as well.

For example, attempting to load 'vfat(blowfish)' via AF_ALG now correctly
includes the "crypto-" prefix at every level, correctly rejecting "vfat":

	net-pf-38
	algif-hash
	crypto-vfat(blowfish)
	crypto-vfat(blowfish)-all
	crypto-vfat

Reported-by: Mathias Krause 
Signed-off-by: Kees Cook 
Acked-by: Mathias Krause 
Signed-off-by: Herbert Xu

crypto: prefix module autoloading with "crypto-"

2014-11-24T14:43:57+00:00

This prefixes all crypto module loading with "crypto-" so we never run
the risk of exposing module auto-loading to userspace via a crypto API,
as demonstrated by Mathias Krause:

https://lkml.org/lkml/2013/3/4/70

Signed-off-by: Kees Cook 
Signed-off-by: Herbert Xu

crypto: ccm - Fix handling of zero plaintext when computing mac

2013-11-28T14:25:17+00:00

There are cases when cryptlen can be zero in crypto_ccm_auth():
-encryptiom: input scatterlist length is zero (no plaintext)
-decryption: input scatterlist contains only the mac
plus the condition of having different source and destination buffers
(or else scatterlist length = max(plaintext_len, ciphertext_len)).

These are not handled correctly, leading to crashes like:

root@p4080ds:~/crypto# insmod tcrypt.ko mode=45
------------[ cut here ]------------
kernel BUG at crypto/scatterwalk.c:37!
Oops: Exception in kernel mode, sig: 5 [#1]
SMP NR_CPUS=8 P4080 DS
Modules linked in: tcrypt(+) crc32c xts xcbc vmac pcbc ecb gcm ghash_generic gf128mul ccm ctr seqiv
CPU: 3 PID: 1082 Comm: cryptomgr_test Not tainted 3.11.0 #14
task: ee12c5b0 ti: eecd0000 task.ti: eecd0000
NIP: c0204d98 LR: f9225848 CTR: c0204d80
REGS: eecd1b70 TRAP: 0700   Not tainted  (3.11.0)
MSR: 00029002   CR: 22044022  XER: 20000000

GPR00: f9225c94 eecd1c20 ee12c5b0 eecd1c28 ee879400 ee879400 00000000 ee607464
GPR08: 00000001 00000001 00000000 006b0000 c0204d80 00000000 00000002 c0698e20
GPR16: ee987000 ee895000 fffffff4 ee879500 00000100 eecd1d58 00000001 00000000
GPR24: ee879400 00000020 00000000 00000000 ee5b2800 ee607430 00000004 ee607460
NIP [c0204d98] scatterwalk_start+0x18/0x30
LR [f9225848] get_data_to_compute+0x28/0x2f0 [ccm]
Call Trace:
[eecd1c20] [f9225974] get_data_to_compute+0x154/0x2f0 [ccm] (unreliable)
[eecd1c70] [f9225c94] crypto_ccm_auth+0x184/0x1d0 [ccm]
[eecd1cb0] [f9225d40] crypto_ccm_encrypt+0x60/0x2d0 [ccm]
[eecd1cf0] [c020d77c] __test_aead+0x3ec/0xe20
[eecd1e20] [c020f35c] test_aead+0x6c/0xe0
[eecd1e40] [c020f420] alg_test_aead+0x50/0xd0
[eecd1e60] [c020e5e4] alg_test+0x114/0x2e0
[eecd1ee0] [c020bd1c] cryptomgr_test+0x4c/0x60
[eecd1ef0] [c0047058] kthread+0xa8/0xb0
[eecd1f40] [c000eb0c] ret_from_kernel_thread+0x5c/0x64
Instruction dump:
0f080000 81290024 552807fe 0f080000 5529003a 4bffffb4 90830000 39400000
39000001 8124000c 2f890000 7d28579e <0f090000> 81240008 91230004 4e800020
---[ end trace 6d652dfcd1be37bd ]---

Cc: 
Cc: Jussi Kivilinna 
Signed-off-by: Horia Geanta 
Signed-off-by: Herbert Xu

crypto: crypto_memneq - add equality testing of memory regions w/o timing leaks

2013-10-07T06:17:06+00:00

When comparing MAC hashes, AEAD authentication tags, or other hash
values in the context of authentication or integrity checking, it
is important not to leak timing information to a potential attacker,
i.e. when communication happens over a network.

Bytewise memory comparisons (such as memcmp) are usually optimized so
that they return a nonzero value as soon as a mismatch is found. E.g,
on x86_64/i5 for 512 bytes this can be ~50 cyc for a full mismatch
and up to ~850 cyc for a full match (cold). This early-return behavior
can leak timing information as a side channel, allowing an attacker to
iteratively guess the correct result.

This patch adds a new method crypto_memneq ("memory not equal to each
other") to the crypto API that compares memory areas of the same length
in roughly "constant time" (cache misses could change the timing, but
since they don't reveal information about the content of the strings
being compared, they are effectively benign). Iow, best and worst case
behaviour take the same amount of time to complete (in contrast to
memcmp).

Note that crypto_memneq (unlike memcmp) can only be used to test for
equality or inequality, NOT for lexicographical order. This, however,
is not an issue for its use-cases within the crypto API.

We tried to locate all of the places in the crypto API where memcmp was
being used for authentication or integrity checking, and convert them
over to crypto_memneq.

crypto_memneq is declared noinline, placed in its own source file,
and compiled with optimizations that might increase code size disabled
("Os") because a smart compiler (or LTO) might notice that the return
value is always compared against zero/nonzero, and might then
reintroduce the same early-return optimization that we are trying to
avoid.

Using #pragma or __attribute__ optimization annotations of the code
for disabling optimization was avoided as it seems to be considered
broken or unmaintained for long time in GCC [1]. Therefore, we work
around that by specifying the compile flag for memneq.o directly in
the Makefile. We found that this seems to be most appropriate.

As we use ("Os"), this patch also provides a loop-free "fast-path" for
frequently used 16 byte digests. Similarly to kernel library string
functions, leave an option for future even further optimized architecture
specific assembler implementations.

This was a joint work of James Yonan and Daniel Borkmann. Also thanks
for feedback from Florian Weimer on this and earlier proposals [2].

  [1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html
  [2] https://lkml.org/lkml/2013/2/10/131

Signed-off-by: James Yonan 
Signed-off-by: Daniel Borkmann 
Cc: Florian Weimer 
Signed-off-by: Herbert Xu

crypto: use ERR_CAST

2013-02-04T13:16:53+00:00

Replace PTR_ERR followed by ERR_PTR by ERR_CAST, to be more concise.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// 
@@
expression err,x;
@@
-       err = PTR_ERR(x);
        if (IS_ERR(x))
-                return ERR_PTR(err);
+                return ERR_CAST(x);
// 

Signed-off-by: Julia Lawall 
Signed-off-by: Herbert Xu