crypto: crypto4xx - perform aead icv check in the driver

The ccm-aes-ppc4xx now fails one of testmgr's expected
failure test cases as such:

|decryption failed on test 10 for ccm-aes-ppc4xx:
|ret was 0, |expected -EBADMSG

It doesn't look like the hardware sets the authentication failure
flag. The original vendor source from which this was ported does
not have any special code or notes about why this would happen or
if there are any WAs.

Hence, this patch converts the aead_done callback handler to
perform the icv check in the driver. And this fixes the false
negative and the ccm-aes-ppc4xx passes the selftests once again.

|name         : ccm(aes)
|driver       : ccm-aes-ppc4xx
|module       : crypto4xx
|priority     : 300
|refcnt       : 1
|selftest     : passed
|internal     : no
|type         : aead
|async        : yes
|blocksize    : 1
|ivsize       : 16
|maxauthsize  : 16
|geniv        : <none>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/amcc/crypto4xx_alg.c

@@ -256,10 +256,6 @@ static inline bool crypto4xx_aead_need_fallback(struct aead_request *req,
 	if (is_ccm && !(req->iv[0] == 1 || req->iv[0] == 3))
 		return true;
 
-	/* CCM - fix CBC MAC mismatch in special case */
-	if (is_ccm && decrypt && !req->assoclen)
-		return true;
-
 	return false;
 }
 
@@ -330,7 +326,7 @@ int crypto4xx_setkey_aes_ccm(struct crypto_aead *cipher, const u8 *key,
 	sa = (struct dynamic_sa_ctl *) ctx->sa_in;
 	sa->sa_contents.w = SA_AES_CCM_CONTENTS | (keylen << 2);
 
-	set_dynamic_sa_command_0(sa, SA_NOT_SAVE_HASH, SA_NOT_SAVE_IV,
+	set_dynamic_sa_command_0(sa, SA_SAVE_HASH, SA_NOT_SAVE_IV,
 				 SA_LOAD_HASH_FROM_SA, SA_LOAD_IV_FROM_STATE,
 				 SA_NO_HEADER_PROC, SA_HASH_ALG_CBC_MAC,
 				 SA_CIPHER_ALG_AES,

drivers/crypto/amcc/crypto4xx_core.c

@@ -577,15 +577,14 @@ static void crypto4xx_aead_done(struct crypto4xx_device *dev,
 				struct pd_uinfo *pd_uinfo,
 				struct ce_pd *pd)
 {
-	struct aead_request *aead_req;
-	struct crypto4xx_ctx *ctx;
+	struct aead_request *aead_req = container_of(pd_uinfo->async_req,
+		struct aead_request, base);
 	struct scatterlist *dst = pd_uinfo->dest_va;
+	size_t cp_len = crypto_aead_authsize(
+		crypto_aead_reqtfm(aead_req));
+	u32 icv[cp_len];
 	int err = 0;
 
-	aead_req = container_of(pd_uinfo->async_req, struct aead_request,
-				base);
-	ctx  = crypto_tfm_ctx(aead_req->base.tfm);
-
 	if (pd_uinfo->using_sd) {
 		crypto4xx_copy_pkt_to_dst(dev, pd, pd_uinfo,
 					  pd->pd_ctl_len.bf.pkt_len,
@@ -597,24 +596,26 @@ static void crypto4xx_aead_done(struct crypto4xx_device *dev,
 
 	if (pd_uinfo->sa_va->sa_command_0.bf.dir == DIR_OUTBOUND) {
 		/* append icv at the end */
-		size_t cp_len = crypto_aead_authsize(
-			crypto_aead_reqtfm(aead_req));
-		u32 icv[cp_len];
-
 		crypto4xx_memcpy_from_le32(icv, pd_uinfo->sr_va->save_digest,
 					   cp_len);
 
 		scatterwalk_map_and_copy(icv, dst, aead_req->cryptlen,
 					 cp_len, 1);
+	} else {
+		/* check icv at the end */
+		scatterwalk_map_and_copy(icv, aead_req->src,
+			aead_req->assoclen + aead_req->cryptlen -
+			cp_len, cp_len, 0);
+
+		crypto4xx_memcpy_from_le32(icv, icv, cp_len);
+
+		if (crypto_memneq(icv, pd_uinfo->sr_va->save_digest, cp_len))
+			err = -EBADMSG;
 	}
 
 	crypto4xx_ret_sg_desc(dev, pd_uinfo);
 
 	if (pd->pd_ctl.bf.status & 0xff) {
-		if (pd->pd_ctl.bf.status & 0x1) {
-			/* authentication error */
-			err = -EBADMSG;
-		} else {
 		if (!__ratelimit(&dev->aead_ratelimit)) {
 			if (pd->pd_ctl.bf.status & 2)
 				pr_err("pad fail error\n");
@@ -629,7 +630,6 @@ static void crypto4xx_aead_done(struct crypto4xx_device *dev,
 		}
 		err = -EINVAL;
 	}
-	}
 
 	if (pd_uinfo->state & PD_ENTRY_BUSY)
 		aead_request_complete(aead_req, -EINPROGRESS);