commit b61907bb42409adf9b3120f741af7c57dd7e3db2
author Herbert Xu <herbert@gondor.apana.org.au> Mon Oct 09 23:30:02 2017 +0800
committer Herbert Xu <herbert@gondor.apana.org.au> Wed Oct 11 00:34:07 2017 +0800
tree 5e2e631bddf0f13336e2c52ac93cbce361bfcbd7
parent 0cabf2af6f5ac3c88cb106c4e06087a5a39b8e1e

crypto: shash - Fix zero-length shash ahash digest crash

The shash ahash digest adaptor function may crash if given a
zero-length input together with a null SG list.  This is because
it tries to read the SG list before looking at the length.

This patch fixes it by checking the length first.

Cc: <stable@vger.kernel.org>
Reported-by: Stephan Müller<smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tested-by: Stephan Müller <smueller@chronox.de>