disp: msm: sde: add check before buffer copy

This change adds a check for the length of the buffer
before copying it to avoid a buffer overflow.

Change-Id: I9af9d422e0b3cf02c8d6662af3310337a9861a7a
Signed-off-by: Satya Rama Aditya Pinapala <psraditya30@codeaurora.org>

msm/sde/sde_connector.c

@@ -1698,6 +1698,7 @@ static ssize_t _sde_debugfs_conn_cmd_tx_sts_read(struct file *file,
 		return 0;
 	}
 
+	blen = min_t(size_t, MAX_CMD_PAYLOAD_SIZE, count);
 	if (copy_to_user(buf, buffer, blen)) {
 		SDE_ERROR("copy to user buffer failed\n");
 		return -EFAULT;

msm/sde_rsc.c

@@ -1102,6 +1102,7 @@ end:
 	if (blen <= 0)
 		return 0;
 
+	blen = min_t(size_t, MAX_BUFFER_SIZE, count);
 	if (copy_to_user(buf, buffer, blen))
 		return -EFAULT;
 
@@ -1195,6 +1196,7 @@ end:
 	if (blen <= 0)
 		return 0;
 
+	blen = min_t(size_t, MAX_BUFFER_SIZE, count);
 	if (copy_to_user(buf, buffer, blen))
 		return -EFAULT;