[Qemu-devel] [PATCH] sd: limit sd_cmd_type array index 'req.cmd'

[P J P <ppandit@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

While processing standard SD commands, the 'req.cmd' value could
lead to OOB read when used as an index into 'sd_cmd_type' array.
Limit 'req.cmd' value to avoid such an access.

Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/sd/sd.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index 1a9935c..b800ced 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -668,8 +668,10 @@ static sd_rsp_type_t sd_normal_command(SDState *sd,
     /* Not interpreting this as an app command */
     sd->card_status &= ~APP_CMD;
 
-    if (sd_cmd_type[req.cmd] == sd_ac || sd_cmd_type[req.cmd] == sd_adtc)
+    if (sd_cmd_type[req.cmd & 0x3F] == sd_ac
+        || sd_cmd_type[req.cmd & 0x3F] == sd_adtc) {
         rca = req.arg >> 16;
+    }
 
     DPRINTF("CMD%d 0x%08x state %d\n", req.cmd, req.arg, sd->state);
     switch (req.cmd) {
-- 
2.5.0