crypto: caam - fix memory corruption in ahash_final_ctx

When doing pointer operation for accessing the HW S/G table,
a value representing number of entries (and not number of bytes)
must be used.

Cc: <stable@vger.kernel.org> # 3.6+
Fixes: 045e36780f115 ("crypto: caam - ahash hmac support")
Signed-off-by: Horia Geant? <horia.geanta@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/crypto/caam/caamhash.c b/drivers/crypto/caam/caamhash.c
index dae1e8099969..f9c78751989e 100644
--- a/drivers/crypto/caam/caamhash.c
+++ b/drivers/crypto/caam/caamhash.c
@@ -909,13 +909,14 @@ static int ahash_final_ctx(struct ahash_request *req)
                           state->buflen_1;
         u32 *sh_desc = ctx->sh_desc_fin, *desc;
         dma_addr_t ptr = ctx->sh_desc_fin_dma;
-        int sec4_sg_bytes;
+        int sec4_sg_bytes, sec4_sg_src_index;
         int digestsize = crypto_ahash_digestsize(ahash);
         struct ahash_edesc *edesc;
         int ret = 0;
         int sh_len;
 
-        sec4_sg_bytes = (1 + (buflen ? 1 : 0)) * sizeof(struct sec4_sg_entry);
+        sec4_sg_src_index = 1 + (buflen ? 1 : 0);
+        sec4_sg_bytes = sec4_sg_src_index * sizeof(struct sec4_sg_entry);
 
         /* allocate space for base edesc and hw desc commands, link tables */
         edesc = kmalloc(sizeof(struct ahash_edesc) + DESC_JOB_IO_LEN +
@@ -942,7 +943,7 @@ static int ahash_final_ctx(struct ahash_request *req)
         state->buf_dma = try_buf_map_to_sec4_sg(jrdev, edesc->sec4_sg + 1,
                                                 buf, state->buf_dma, buflen,
                                                 last_buflen);
-        (edesc->sec4_sg + sec4_sg_bytes - 1)->len |= SEC4_SG_LEN_FIN;
+        (edesc->sec4_sg + sec4_sg_src_index - 1)->len |= SEC4_SG_LEN_FIN;
 
         edesc->sec4_sg_dma = dma_map_single(jrdev, edesc->sec4_sg,
                                             sec4_sg_bytes, DMA_TO_DEVICE);