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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 v7 04/11] crypto: qce: skcipher: Return unsupported if any three keys are same for DES3 algorithms
Date:   Thu, 11 Feb 2021 15:01:21 -0500
Message-Id: <20210211200128.2886388-5-thara.gopinath@linaro.org>
In-Reply-To: <20210211200128.2886388-1-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>
---

v6->v7:
	- Fixed sparse warning in patch 4 as pointed out by Herbert Xu.
	  This means the checking if any two keys are same for triple
	  des algorithms has been reverted back to using conditional OR
	  instead of using bitwise OR.

 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..8aeb741ca5a3 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