hw/sd: fix out-of-bounds check for multi block reads

The current code checks if the next block exceeds the size of the card.
This generates an error while reading the last block of the card.
Do the out-of-bounds check when starting to read a new block to fix this.

This issue became visible with increased error checking in Linux 4.13.

Cc: qemu-stable@nongnu.org
Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Message-id: 20170916091611.10241-1-m.olbrich@pengutronix.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 8573378e62d19e25a2434e23462ec99ef4d065ac)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index ba47bff4db80fceb53ccda44e8fc59d7fa86fcbe..35347a5bbcde2ccfebb07b3cf1765a54e0286461 100644 (file)
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1797,8 +1797,13 @@ uint8_t sd_read_data(SDState *sd)
         break;
 
     case 18:   /* CMD18:  READ_MULTIPLE_BLOCK */
-        if (sd->data_offset == 0)
+        if (sd->data_offset == 0) {
+            if (sd->data_start + io_len > sd->size) {
+                sd->card_status |= ADDRESS_ERROR;
+                return 0x00;
+            }
             BLK_READ_BLOCK(sd->data_start, io_len);
+        }
         ret = sd->data[sd->data_offset ++];
 
         if (sd->data_offset >= io_len) {
@@ -1812,11 +1817,6 @@ uint8_t sd_read_data(SDState *sd)
                     break;
                 }
             }
-
-            if (sd->data_start + io_len > sd->size) {
-                sd->card_status |= ADDRESS_ERROR;
-                break;
-            }
         }
         break;