crypto: talitos - properly handle split ICV.

The driver assumes that the ICV is as a single piece in the last
element of the scatterlist. This assumption is wrong.

This patch ensures that the ICV is properly handled regardless of
the scatterlist layout.

Fixes: 9c4a7965 ("crypto: talitos - Freescale integrated security engine (SEC) driver")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/talitos.c

@@ -1069,7 +1069,6 @@ static void ipsec_esp_encrypt_done(struct device *dev,
 	unsigned int authsize = crypto_aead_authsize(authenc);
 	unsigned int ivsize = crypto_aead_ivsize(authenc);
 	struct talitos_edesc *edesc;
-	struct scatterlist *sg;
 	void *icvdata;
 
 	edesc = container_of(desc, struct talitos_edesc, desc);
@@ -1083,9 +1082,8 @@ static void ipsec_esp_encrypt_done(struct device *dev,
 		else
 			icvdata = &edesc->link_tbl[edesc->src_nents +
 						   edesc->dst_nents + 2];
-		sg = sg_last(areq->dst, edesc->dst_nents);
-		memcpy((char *)sg_virt(sg) + sg->length - authsize,
-		       icvdata, authsize);
+		sg_pcopy_from_buffer(areq->dst, edesc->dst_nents ? : 1, icvdata,
+				     authsize, areq->assoclen + areq->cryptlen);
 	}
 
 	dma_unmap_single(dev, edesc->iv_dma, ivsize, DMA_TO_DEVICE);
@@ -1103,7 +1101,6 @@ static void ipsec_esp_decrypt_swauth_done(struct device *dev,
 	struct crypto_aead *authenc = crypto_aead_reqtfm(req);
 	unsigned int authsize = crypto_aead_authsize(authenc);
 	struct talitos_edesc *edesc;
-	struct scatterlist *sg;
 	char *oicv, *icv;
 	struct talitos_private *priv = dev_get_drvdata(dev);
 	bool is_sec1 = has_ftr_sec1(priv);
@@ -1113,9 +1110,18 @@ static void ipsec_esp_decrypt_swauth_done(struct device *dev,
 	ipsec_esp_unmap(dev, edesc, req, false);
 
 	if (!err) {
+		char icvdata[SHA512_DIGEST_SIZE];
+		int nents = edesc->dst_nents ? : 1;
+		unsigned int len = req->assoclen + req->cryptlen;
+
 		/* auth check */
-		sg = sg_last(req->dst, edesc->dst_nents ? : 1);
-		icv = (char *)sg_virt(sg) + sg->length - authsize;
+		if (nents > 1) {
+			sg_pcopy_to_buffer(req->dst, nents, icvdata, authsize,
+					   len - authsize);
+			icv = icvdata;
+		} else {
+			icv = (char *)sg_virt(req->dst) + len - authsize;
+		}
 
 		if (edesc->dma_len) {
 			if (is_sec1)
@@ -1537,7 +1543,6 @@ static int aead_decrypt(struct aead_request *req)
 	struct talitos_ctx *ctx = crypto_aead_ctx(authenc);
 	struct talitos_private *priv = dev_get_drvdata(ctx->dev);
 	struct talitos_edesc *edesc;
-	struct scatterlist *sg;
 	void *icvdata;
 
 	/* allocate extended descriptor */
@@ -1571,9 +1576,8 @@ static int aead_decrypt(struct aead_request *req)
 	else
 		icvdata = &edesc->link_tbl[0];
 
-	sg = sg_last(req->src, edesc->src_nents ? : 1);
-
-	memcpy(icvdata, (char *)sg_virt(sg) + sg->length - authsize, authsize);
+	sg_pcopy_to_buffer(req->src, edesc->src_nents ? : 1, icvdata, authsize,
+			   req->assoclen + req->cryptlen - authsize);
 
 	return ipsec_esp(edesc, req, false, ipsec_esp_decrypt_swauth_done);
 }