diff mbox series

[55/77] hw/sd/sdcard: Do not switch to ReceivingData if address is invalid

Message ID 20200903205935.27832-56-mdroth@linux.vnet.ibm.com
State New
Headers show
Series Patch Round-up for stable 5.0.1, freeze on 2020-09-10 | expand

Commit Message

Michael Roth Sept. 3, 2020, 8:59 p.m. UTC 
From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Only move the state machine to ReceivingData if there is no
pending error. This avoids later OOB access while processing
commands queued.

  "SD Specifications Part 1 Physical Layer Simplified Spec. v3.01"

  4.3.3 Data Read

  Read command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR
  occurred and no data transfer is performed.

  4.3.4 Data Write

  Write command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR
  occurred and no data transfer is performed.

WP_VIOLATION errors are not modified: the error bit is set, we
stay in receive-data state, wait for a stop command. All further
data transfer is ignored. See the check on sd->card_status at the
beginning of sd_read_data() and sd_write_data().

Fixes: CVE-2020-13253
Cc: qemu-stable@nongnu.org
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Buglink: https://bugs.launchpad.net/qemu/+bug/1880822
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20200630133912.9428-6-f4bug@amsat.org>
(cherry picked from commit 790762e5487114341cccc5bffcec4cb3c022c3cd)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/sd/sd.c | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)
diff mbox series

Patch

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index b927f7966d..837fe9053d 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1156,13 +1156,15 @@  static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
     case 17:	/* CMD17:  READ_SINGLE_BLOCK */
         switch (sd->state) {
         case sd_transfer_state:
-            sd->state = sd_sendingdata_state;
-            sd->data_start = addr;
-            sd->data_offset = 0;
 
-            if (sd->data_start + sd->blk_len > sd->size) {
+            if (addr + sd->blk_len > sd->size) {
                 sd->card_status |= ADDRESS_ERROR;
+                return sd_r1;
             }
+
+            sd->state = sd_sendingdata_state;
+            sd->data_start = addr;
+            sd->data_offset = 0;
             return sd_r1;
 
         default:
@@ -1173,13 +1175,15 @@  static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
     case 18:	/* CMD18:  READ_MULTIPLE_BLOCK */
         switch (sd->state) {
         case sd_transfer_state:
-            sd->state = sd_sendingdata_state;
-            sd->data_start = addr;
-            sd->data_offset = 0;
 
-            if (sd->data_start + sd->blk_len > sd->size) {
+            if (addr + sd->blk_len > sd->size) {
                 sd->card_status |= ADDRESS_ERROR;
+                return sd_r1;
             }
+
+            sd->state = sd_sendingdata_state;
+            sd->data_start = addr;
+            sd->data_offset = 0;
             return sd_r1;
 
         default:
@@ -1219,14 +1223,17 @@  static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
             /* Writing in SPI mode not implemented.  */
             if (sd->spi)
                 break;
+
+            if (addr + sd->blk_len > sd->size) {
+                sd->card_status |= ADDRESS_ERROR;
+                return sd_r1;
+            }
+
             sd->state = sd_receivingdata_state;
             sd->data_start = addr;
             sd->data_offset = 0;
             sd->blk_written = 0;
 
-            if (sd->data_start + sd->blk_len > sd->size) {
-                sd->card_status |= ADDRESS_ERROR;
-            }
             if (sd_wp_addr(sd, sd->data_start)) {
                 sd->card_status |= WP_VIOLATION;
             }
@@ -1246,14 +1253,17 @@  static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
             /* Writing in SPI mode not implemented.  */
             if (sd->spi)
                 break;
+
+            if (addr + sd->blk_len > sd->size) {
+                sd->card_status |= ADDRESS_ERROR;
+                return sd_r1;
+            }
+
             sd->state = sd_receivingdata_state;
             sd->data_start = addr;
             sd->data_offset = 0;
             sd->blk_written = 0;
 
-            if (sd->data_start + sd->blk_len > sd->size) {
-                sd->card_status |= ADDRESS_ERROR;
-            }
             if (sd_wp_addr(sd, sd->data_start)) {
                 sd->card_status |= WP_VIOLATION;
             }