crypto: msm: Check destination buffer write access

Use VERIFY_WRITE to check write access to destination buffers
before writing to them.

Change-Id: If9708695e85659bb25e13762c54dd50abd9577c7
Signed-off-by: Mona Hossain <mhossain@codeaurora.org>
diff --git a/drivers/crypto/msm/qcedev.c b/drivers/crypto/msm/qcedev.c
index c726694..0b2714a 100644
--- a/drivers/crypto/msm/qcedev.c
+++ b/drivers/crypto/msm/qcedev.c
@@ -1413,12 +1413,37 @@
 			return -EFAULT;
 
 	/* Verify Destination Address's */
-	if (areq->cipher_op_req.in_place_op != 1)
-		for (i = 0; i < areq->cipher_op_req.entries; i++)
-			if (!access_ok(VERIFY_READ,
-			(void __user *)areq->cipher_op_req.vbuf.dst[i].vaddr,
-					areq->cipher_op_req.vbuf.dst[i].len))
-				return -EFAULT;
+	if (creq->in_place_op != 1) {
+		for (i = 0, total = 0; i < QCEDEV_MAX_BUFFERS; i++) {
+			if ((areq->cipher_op_req.vbuf.dst[i].vaddr != 0) &&
+						(total < creq->data_len)) {
+				if (!access_ok(VERIFY_WRITE,
+					(void __user *)creq->vbuf.dst[i].vaddr,
+						creq->vbuf.dst[i].len)) {
+					pr_err("%s:DST WR_VERIFY err %d=0x%x\n",
+						__func__, i,
+						(u32)creq->vbuf.dst[i].vaddr);
+					return -EFAULT;
+				}
+				total += creq->vbuf.dst[i].len;
+			}
+		}
+	} else  {
+		for (i = 0, total = 0; i < creq->entries; i++) {
+			if (total < creq->data_len) {
+				if (!access_ok(VERIFY_WRITE,
+					(void __user *)creq->vbuf.src[i].vaddr,
+						creq->vbuf.src[i].len)) {
+					pr_err("%s:SRC WR_VERIFY err %d=0x%x\n",
+						__func__, i,
+						(u32)creq->vbuf.src[i].vaddr);
+					return -EFAULT;
+				}
+				total += creq->vbuf.src[i].len;
+			}
+		}
+	}
+	total = 0;
 
 	if (areq->cipher_op_req.mode == QCEDEV_AES_MODE_CTR)
 		byteoffset = areq->cipher_op_req.byteoffset;