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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0272/1039] crypto: stm32/cryp - fix xts and race condition in crypto_engine requests
Date:   Mon, 24 Jan 2022 19:34:21 +0100
Message-Id: <20220124184134.442878223@linuxfoundation.org>
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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 d13b262b36252..e2bcc4f98b0ae 100644
--- a/drivers/crypto/stm32/stm32-cryp.c
+++ b/drivers/crypto/stm32/stm32-cryp.c
@@ -674,8 +674,6 @@ static void stm32_cryp_finish_req(struct stm32_cryp *cryp, int err)
 	else
 		crypto_finalize_skcipher_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