[Qemu-devel] [PATCH 28/55] hw/sd: fix out-of-bounds check for multi block reads

[Michael Roth]

From: Michael Olbrich <m.olbr...@pengutronix.de>

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-sta...@nongnu.org
Signed-off-by: Michael Olbrich <m.olbr...@pengutronix.de>
Reviewed-by: Alistair Francis <alistair.fran...@xilinx.com>
Message-id: 20170916091611.10241-1-m.olbr...@pengutronix.de
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
(cherry picked from commit 8573378e62d19e25a2434e23462ec99ef4d065ac)
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
 hw/sd/sd.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index ba47bff4db..35347a5bbc 100644
--- 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;
 
-- 
2.11.0