• Horia Geanta's avatar
    crypto: ccm - Fix handling of zero plaintext when computing mac · bf2e5230
    Horia Geanta authored
    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: default avatarHoria Geanta <horia.geanta@freescale.com>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    bf2e5230
ccm.c 21.4 KB