[PATCH 5.4 079/320] crypto: stm32/cryp - fix xts and race condition in crypto_engine requests

Greg Kroah-Hartman
2022-01-24T20:11:10Z

From: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>

[ Upstream commit d703c7a994ee34b7fa89baf21631fca0aa9f17fc ]

Don't erase key:
If key is erased before the crypto_finalize_.*_request() call, some
pending process will run with a key={ 0 }.
Moreover if the key is reset at end of request, it breaks xts chaining
mode, as for last xts block (in case input len is not a multiple of
block) a new AES request is started without calling again set_key().

Fixes: 9e054ec21ef8 ("crypto: stm32 - Support for STM32 CRYP crypto module")

Signed-off-by: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/crypto/stm32/stm32-cryp.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c
index 9b3511236ba25..92472a48c0454 100644
--- a/drivers/crypto/stm32/stm32-cryp.c
+++ b/drivers/crypto/stm32/stm32-cryp.c
@@ -669,8 +669,6 @@ static void stm32_cryp_finish_req(struct stm32_cryp *cryp, int err)
else
crypto_finalize_ablkcipher_request(cryp->engine, cryp->req,
err);
-
- memset(cryp->ctx->key, 0, cryp->ctx->keylen);
}

static int stm32_cryp_cpu_start(struct stm32_cryp *cryp)
--
2.34.1