crypto: caam/jr - fix ablkcipher_edesc pointer arithmetic

commit 13cc6f48c7434ce46ba6dbc90003a136a263d75a upstream.

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: 115957bb3e59 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/crypto/caam/caamalg.c b/drivers/crypto/caam/caamalg.c
index a8a2a27..43fe195 100644 (file)
--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -1511,8 +1511,8 @@ 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 */
@@ -1715,8 +1715,8 @@ 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 */