[PATCH AUTOSEL 5.3 167/203] s390/crypto: xts-aes-s390 fix extra run-time crypto self tests finding

Sasha Levin
2019-09-22T18:48:52Z

From: Harald Freudenberger <freude@linux.ibm.com>

[ Upstream commit 9e323d45ba94262620a073a3f9945ca927c07c71 ]

With 'extra run-time crypto self tests' enabled, the selftest
for s390-xts fails with

alg: skcipher: xts-aes-s390 encryption unexpectedly succeeded on
test vector "random: len=0 klen=64"; expected_error=-22,
cfg="random: inplace use_digest nosimd src_divs=[2.61%@+4006,
84.44%@+21, 1.55%@+13, 4.50%@+344, 4.26%@+21, 2.64%@+27]"

This special case with nbytes=0 is not handled correctly and this
fix now makes sure that -EINVAL is returned when there is en/decrypt
called with 0 bytes to en/decrypt.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/crypto/aes_s390.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/arch/s390/crypto/aes_s390.c b/arch/s390/crypto/aes_s390.c
index d00f84add5f4c..6d2dbb5089d5c 100644
--- a/arch/s390/crypto/aes_s390.c
+++ b/arch/s390/crypto/aes_s390.c
@@ -586,6 +586,9 @@ static int xts_aes_encrypt(struct blkcipher_desc *desc,
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;

+ if (!nbytes)
+ return -EINVAL;
+
if (unlikely(!xts_ctx->fc))
return xts_fallback_encrypt(desc, dst, src, nbytes);

@@ -600,6 +603,9 @@ static int xts_aes_decrypt(struct blkcipher_desc *desc,
struct s390_xts_ctx *xts_ctx = crypto_blkcipher_ctx(desc->tfm);
struct blkcipher_walk walk;

+ if (!nbytes)
+ return -EINVAL;
+
if (unlikely(!xts_ctx->fc))
return xts_fallback_decrypt(desc, dst, src, nbytes);

--
2.20.1