[PATCH 5.0 035/123] crypto: x86/crct10dif-pcl - fix use via crypto_shash_digest()

From: Greg Kroah-Hartman
Date: Mon May 20 2019 - 08:47:40 EST

From: Eric Biggers <ebiggers@xxxxxxxxxx>

commit dec3d0b1071a0f3194e66a83d26ecf4aa8c5910e upstream.

The ->digest() method of crct10dif-pclmul reads the current CRC value
from the shash_desc context. But this value is uninitialized, causing
crypto_shash_digest() to compute the wrong result. Fix it.

Probably this wasn't noticed before because lib/crc-t10dif.c only uses
crypto_shash_update(), not crypto_shash_digest(). Likewise,
crypto_shash_digest() is not yet tested by the crypto self-tests because
those only test the ahash API which only uses shash init/update/final.

Fixes: 0b95a7f85718 ("crypto: crct10dif - Glue code to cast accelerated CRCT10DIF assembly as a crypto transform")
Cc: <stable@xxxxxxxxxxxxxxx> # v3.11+
Cc: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/x86/crypto/crct10dif-pclmul_glue.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)

--- a/arch/x86/crypto/crct10dif-pclmul_glue.c
+++ b/arch/x86/crypto/crct10dif-pclmul_glue.c
@@ -76,15 +76,14 @@ static int chksum_final(struct shash_des
return 0;

-static int __chksum_finup(__u16 *crcp, const u8 *data, unsigned int len,
- u8 *out)
+static int __chksum_finup(__u16 crc, const u8 *data, unsigned int len, u8 *out)
if (irq_fpu_usable()) {
- *(__u16 *)out = crc_t10dif_pcl(*crcp, data, len);
+ *(__u16 *)out = crc_t10dif_pcl(crc, data, len);
} else
- *(__u16 *)out = crc_t10dif_generic(*crcp, data, len);
+ *(__u16 *)out = crc_t10dif_generic(crc, data, len);
return 0;

@@ -93,15 +92,13 @@ static int chksum_finup(struct shash_des
struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);

- return __chksum_finup(&ctx->crc, data, len, out);
+ return __chksum_finup(ctx->crc, data, len, out);

static int chksum_digest(struct shash_desc *desc, const u8 *data,
unsigned int length, u8 *out)
- struct chksum_desc_ctx *ctx = shash_desc_ctx(desc);
- return __chksum_finup(&ctx->crc, data, length, out);
+ return __chksum_finup(0, data, length, out);

static struct shash_alg alg = {