• Ard Biesheuvel's avatar
    crypto: skcipher - fix crash in virtual walk · 18e615ad
    Ard Biesheuvel authored
    The new skcipher walk API may crash in the following way. (Interestingly,
    the tcrypt boot time tests seem unaffected, while an explicit test using
    the module triggers it)
      Unable to handle kernel NULL pointer dereference at virtual address 00000000
      [<ffff000008431d84>] __memcpy+0x84/0x180
      [<ffff0000083ec0d0>] skcipher_walk_done+0x328/0x340
      [<ffff0000080c5c04>] ctr_encrypt+0x84/0x100
      [<ffff000008406d60>] simd_skcipher_encrypt+0x88/0x98
      [<ffff0000083fa05c>] crypto_rfc3686_crypt+0x8c/0x98
      [<ffff0000009b0900>] test_skcipher_speed+0x518/0x820 [tcrypt]
      [<ffff0000009b31c0>] do_test+0x1408/0x3b70 [tcrypt]
      [<ffff0000009bd050>] tcrypt_mod_init+0x50/0x1000 [tcrypt]
      [<ffff0000080838f4>] do_one_initcall+0x44/0x138
      [<ffff0000081aee60>] do_init_module+0x68/0x1e0
      [<ffff0000081524d0>] load_module+0x1fd0/0x2458
      [<ffff000008152c38>] SyS_finit_module+0xe0/0xf0
      [<ffff0000080836f0>] el0_svc_naked+0x24/0x28
    This is due to the fact that skcipher_done_slow() may be entered with
    walk->buffer unset. Since skcipher_walk_done() already deals with the
    case where walk->buffer == walk->page, it appears to be the intention
    that walk->buffer point to walk->page after skcipher_next_slow(), so
    ensure that is the case.
    Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
skcipher.c 24.6 KB