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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 5.15 235/846] crypto: stm32/cryp - fix lrw chaining mode
Date:   Mon, 24 Jan 2022 19:35:52 +0100
Message-Id: <20220124184109.039664716@linuxfoundation.org>
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From: Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>

[ Upstream commit fa97dc2d48b476ea98199d808d3248d285987e99 ]

This fixes the lrw autotest if lrw uses the CRYP as the AES block cipher
provider (as ecb(aes)). At end of request, CRYP should not update the IV
in case of ECB chaining mode. Indeed the ECB chaining mode never uses
the IV, but the software LRW chaining mode uses the IV field as
a counter and due to the (unexpected) update done by CRYP while the AES
block process, the counter get a wrong value when the IV overflow.

Fixes: 5f49f18d27cd ("crypto: stm32/cryp - update to return iv_out")

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, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/stm32/stm32-cryp.c b/drivers/crypto/stm32/stm32-cryp.c
index 061db567908ae..9943836a5c25c 100644
--- a/drivers/crypto/stm32/stm32-cryp.c
+++ b/drivers/crypto/stm32/stm32-cryp.c
@@ -644,7 +644,7 @@ static void stm32_cryp_finish_req(struct stm32_cryp *cryp, int err)
 		/* Phase 4 : output tag */
 		err = stm32_cryp_read_auth_tag(cryp);
 
-	if (!err && (!(is_gcm(cryp) || is_ccm(cryp))))
+	if (!err && (!(is_gcm(cryp) || is_ccm(cryp) || is_ecb(cryp))))
 		stm32_cryp_get_iv(cryp);
 
 	if (cryp->sgs_copied) {
-- 
2.34.1