From:   Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>
To:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S . Miller" <davem@davemloft.net>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>
CC:     Marek Vasut <marex@denx.de>,
        Nicolas Toromanoff <nicolas.toromanoff@foss.st.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        <linux-crypto@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH v3 7/9] crypto: stm32/cryp - fix lrw chaining mode
Date:   Thu, 18 Nov 2021 16:07:54 +0100
Message-ID: <20211118150756.6593-8-nicolas.toromanoff@foss.st.com>
In-Reply-To: <20211118150756.6593-1-nicolas.toromanoff@foss.st.com>
References: <20211118150756.6593-1-nicolas.toromanoff@foss.st.com>
MIME-Version: 1.0
Content-Type: text/plain
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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>
---
 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 d61608dc416a..537443a35d81 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) {
-- 
2.17.1