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From:   Thara Gopinath <thara.gopinath@linaro.org>
To:     herbert@gondor.apana.org.au, davem@davemloft.net,
        bjorn.andersson@linaro.org
Cc:     ebiggers@google.com, ardb@kernel.org, sivaprak@codeaurora.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 04/11] crypto: qce: skcipher: Return unsupported if any three keys are same for DES3 algorithms
Date:   Sun,  7 Feb 2021 09:39:39 -0500
Message-Id: <20210207143946.2099859-5-thara.gopinath@linaro.org>
In-Reply-To: <20210207143946.2099859-1-thara.gopinath@linaro.org>
References: <20210207143946.2099859-1-thara.gopinath@linaro.org>
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Return unsupported if any three keys are same for DES3 algorithms
since CE does not support this and the operation causes the engine to
hang.

Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
---
 drivers/crypto/qce/skcipher.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index 12955dcd53dd..de1f37ed4ee6 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -221,12 +221,27 @@ static int qce_des3_setkey(struct crypto_skcipher *ablk, const u8 *key,
 			   unsigned int keylen)
 {
 	struct qce_cipher_ctx *ctx = crypto_skcipher_ctx(ablk);
+	u32 _key[6];
 	int err;
 
 	err = verify_skcipher_des3_key(ablk, key);
 	if (err)
 		return err;
 
+	/*
+	 * The crypto engine does not support any two keys
+	 * being the same for triple des algorithms. The
+	 * verify_skcipher_des3_key does not check for all the
+	 * below conditions. Return -ENOKEY in case any two keys
+	 * are the same. Revisit to see if a fallback cipher
+	 * is needed to handle this condition.
+	 */
+	memcpy(_key, key, DES3_EDE_KEY_SIZE);
+	if (!((_key[0] ^ _key[2]) | (_key[1] ^ _key[3])) |
+	    !((_key[2] ^ _key[4]) | (_key[3] ^ _key[5])) |
+	    !((_key[0] ^ _key[4]) | (_key[1] ^ _key[5])))
+		return -ENOKEY;
+
 	ctx->enc_keylen = keylen;
 	memcpy(ctx->enc_key, key, keylen);
 	return 0;
-- 
2.25.1