crypto: caam/jr - fix ablkcipher_edesc pointer arithmetic

horiag · herbertx · commit 13cc6f48c743 · 2018-09-21T13:04:46.000+08:00
In some cases the zero-length hw_desc array at the end of ablkcipher_edesc struct requires for 4B of tail padding. Due to tail padding and the way pointers to S/G table and IV are computed: edesc->sec4_sg = (void *)edesc + sizeof(struct ablkcipher_edesc) + desc_bytes; iv = (u8 *)edesc->hw_desc + desc_bytes + sec4_sg_bytes; first 4 bytes of IV are overwritten by S/G table. Update computation of pointer to S/G table to rely on offset of hw_desc member and not on sizeof() operator. Cc: <stable@vger.kernel.org> # 4.13+ Fixes: 115957b ("crypto: caam - fix IV DMA mapping and updating") Signed-off-by: Horia Geantă <horia.geanta@nxp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
@@ -1553,8 +1553,8 @@ static struct ablkcipher_edesc *ablkcipher_edesc_alloc(struct ablkcipher_request
 	edesc->src_nents = src_nents;
 	edesc->dst_nents = dst_nents;
 	edesc->sec4_sg_bytes = sec4_sg_bytes;
-	edesc->sec4_sg = (void *)edesc + sizeof(struct ablkcipher_edesc) +
-			 desc_bytes;
+	edesc->sec4_sg = (struct sec4_sg_entry *)((u8 *)edesc->hw_desc +
+						  desc_bytes);
 	edesc->iv_dir = DMA_TO_DEVICE;
 
 	/* Make sure IV is located in a DMAable area */
@@ -1757,8 +1757,8 @@ static struct ablkcipher_edesc *ablkcipher_giv_edesc_alloc(
 	edesc->src_nents = src_nents;
 	edesc->dst_nents = dst_nents;
 	edesc->sec4_sg_bytes = sec4_sg_bytes;
-	edesc->sec4_sg = (void *)edesc + sizeof(struct ablkcipher_edesc) +
-			 desc_bytes;
+	edesc->sec4_sg = (struct sec4_sg_entry *)((u8 *)edesc->hw_desc +
+						  desc_bytes);
 	edesc->iv_dir = DMA_FROM_DEVICE;
 
 	/* Make sure IV is located in a DMAable area */
