• Ard Biesheuvel's avatar
    crypto: arm64/neonbs - fix out-of-bounds access on short input · 1c0cf6d1
    Ard Biesheuvel authored
    The bit-sliced implementation of AES-CTR operates on blocks of 128
    bytes, and will fall back to the plain NEON version for tail blocks or
    inputs that are shorter than 128 bytes to begin with.
    
    It will call straight into the plain NEON asm helper, which performs all
    memory accesses in granules of 16 bytes (the size of a NEON register).
    For this reason, the associated plain NEON glue code will copy inputs
    shorter than 16 bytes into a temporary buffer, given that this is a rare
    occurrence and it is not worth the effort to work around this in the asm
    code.
    
    The fallback from the bit-sliced NEON version fails to take this into
    account, potentially resulting in out-of-bounds accesses. So clone the
    same workaround, and use a temp buffer for short in/outputs.
    
    Fixes: fc074e13 ("crypto: arm64/aes-neonbs-ctr - fallback to plain NEON for final chunk")
    Cc: <stable@vger.kernel.org>
    Reported-by: syzbot+f1ceaa1a09ab891e1934@syzkaller.appspotmail.com
    Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
    Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    1c0cf6d1
aes-neonbs-glue.c 12.3 KB