From:   Christian Lamparter <chunkeey@gmail.com>
To:     linux-crypto@vger.kernel.org
Cc:     Kees Cook <keescook@chromium.org>,
        Eric Biggers <ebiggers@google.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        stable@vger.kernel.org
Subject: [PATCH 1/4] crypto4xx: fix ctr-aes missing output IV
Date:   Mon, 22 Apr 2019 13:25:58 +0200
Message-Id: <4c860f87b9339da1d1f700ba6a56a7a5e2eb14da.1555932334.git.chunkeey@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-crypto-owner@vger.kernel.org
Precedence: bulk

Commit 8efd972ef96a ("crypto: testmgr - support checking skcipher output IV")
caused the crypto4xx driver to produce the following error:

| ctr-aes-ppc4xx encryption test failed (wrong output IV)
| on test vector 0, cfg="in-place"

This patch fixes this by reworking the crypto4xx_setkey_aes()
function to:

 - not save the iv for ECB (as per 18.2.38 CRYP0_SA_CMD_0:
   "This bit mut be cleared for DES ECB mode or AES ECB mode,
   when no IV is used.")

 - instruct the hardware to save the generated IV for all
   other modes of operations that have IV and then supply
   it back to the callee in pretty much the same way as we
   do it for cbc-aes already.

 - make it clear that the DIR_(IN|OUT)BOUND is the important
   bit that tells the hardware to encrypt or decrypt the data.
   (this is cosmetic - but it hopefully prevents me from
    getting confused again).

 - don't load any bogus hash when we don't use any hash
   operation to begin with.

Cc: stable@vger.kernel.org
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
---
 drivers/crypto/amcc/crypto4xx_alg.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/amcc/crypto4xx_alg.c b/drivers/crypto/amcc/crypto4xx_alg.c
index 4092c2aad8e2..3458c5a085d9 100644
--- a/drivers/crypto/amcc/crypto4xx_alg.c
+++ b/drivers/crypto/amcc/crypto4xx_alg.c
@@ -141,9 +141,10 @@ static int crypto4xx_setkey_aes(struct crypto_skcipher *cipher,
 	/* Setup SA */
 	sa = ctx->sa_in;
 
-	set_dynamic_sa_command_0(sa, SA_NOT_SAVE_HASH, (cm == CRYPTO_MODE_CBC ?
-				 SA_SAVE_IV : SA_NOT_SAVE_IV),
-				 SA_LOAD_HASH_FROM_SA, SA_LOAD_IV_FROM_STATE,
+	set_dynamic_sa_command_0(sa, SA_NOT_SAVE_HASH, (cm == CRYPTO_MODE_ECB ?
+				 SA_NOT_SAVE_IV : SA_SAVE_IV),
+				 SA_NOT_LOAD_HASH, (cm == CRYPTO_MODE_ECB ?
+				 SA_LOAD_IV_FROM_SA : SA_LOAD_IV_FROM_STATE),
 				 SA_NO_HEADER_PROC, SA_HASH_ALG_NULL,
 				 SA_CIPHER_ALG_AES, SA_PAD_TYPE_ZERO,
 				 SA_OP_GROUP_BASIC, SA_OPCODE_DECRYPT,
@@ -162,6 +163,11 @@ static int crypto4xx_setkey_aes(struct crypto_skcipher *cipher,
 	memcpy(ctx->sa_out, ctx->sa_in, ctx->sa_len * 4);
 	sa = ctx->sa_out;
 	sa->sa_command_0.bf.dir = DIR_OUTBOUND;
+	/*
+	 * SA_OPCODE_ENCRYPT is the same value as SA_OPCODE_DECRYPT.
+	 * it's the DIR_(IN|OUT)BOUND that matters
+	 */
+	sa->sa_command_0.bf.opcode = SA_OPCODE_ENCRYPT;
 
 	return 0;
 }
-- 
2.20.1