[Qemu-devel] [PATCH] scsi: initialise info object with appropriate size

[P J P]

  Hello,

A stack overflow issue was reported by Mr Qinghao Tang, CC'd here. It occurs 
while processing the SCSI controller's CTRL_GET_INFO command, as the memset(2) 
call uses driver supplied 'cmd->iov_size' to initialise the '&info' object.

Please see below a proposed patch to fix this issue. Does it look okay?

===
> From 5823b4a214ede884f4ba597fdd629862620e0f92 Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <address@hidden>
Date: Mon, 21 Dec 2015 14:48:18 +0530
Subject: [PATCH] scsi: initialise info object with appropriate size

While processing controller 'CTRL_GET_INFO' command, the routine
'megasas_ctrl_get_info' overflows the '&info' object size. Use its
appropriate size to null initialise it.

Reported-by: Qinghao Tang <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
 hw/scsi/megasas.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/scsi/megasas.c b/hw/scsi/megasas.c
index d7dc667..576f56c 100644
--- a/hw/scsi/megasas.c
+++ b/hw/scsi/megasas.c
@@ -718,7 +718,7 @@ static int megasas_ctrl_get_info(MegasasState *s, 
MegasasCmd *cmd)
     BusChild *kid;
     int num_pd_disks = 0;

-    memset(&info, 0x0, cmd->iov_size);
+    memset(&info, 0x0, dcmd_size);
     if (cmd->iov_size < dcmd_size) {
         trace_megasas_dcmd_invalid_xfer_len(cmd->index, cmd->iov_size,
                                             dcmd_size);
--
2.4.3
===


Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
47AF CE69 3A90 54AA 9045 1053 DD13 3D32 FE5B 041F