| From 5638cabf3e4883f38dfb246c30980cebf694fbda Mon Sep 17 00:00:00 2001 |
| From: Horia Geanta <horia.geanta@freescale.com> |
| Date: Thu, 28 Nov 2013 15:11:15 +0200 |
| Subject: crypto: ccm - Fix handling of zero plaintext when computing mac |
| |
| From: Horia Geanta <horia.geanta@freescale.com> |
| |
| commit 5638cabf3e4883f38dfb246c30980cebf694fbda upstream. |
| |
| 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 <CE,EE,ME> 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: Jussi Kivilinna <jussi.kivilinna@mbnet.fi> |
| Signed-off-by: Horia Geanta <horia.geanta@freescale.com> |
| Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| crypto/ccm.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/crypto/ccm.c |
| +++ b/crypto/ccm.c |
| @@ -271,7 +271,8 @@ static int crypto_ccm_auth(struct aead_r |
| } |
| |
| /* compute plaintext into mac */ |
| - get_data_to_compute(cipher, pctx, plain, cryptlen); |
| + if (cryptlen) |
| + get_data_to_compute(cipher, pctx, plain, cryptlen); |
| |
| out: |
| return err; |
