From bc4b0e1c80d9f9e2acf44ef99b7771f96be90791 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 20 Dec 2018 12:31:01 +0000
Subject: [PATCH 6/8] scsi-generic: avoid out-of-bounds access to VPD page list
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RH-Author: Paolo Bonzini <pbonzini@redhat.com>
Message-id: <20181220123103.29579-7-pbonzini@redhat.com>
Patchwork-id: 83715
O-Subject: [PATCH 6/8] scsi-generic: avoid out-of-bounds access to VPD page list
Bugzilla: 1639957
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

A device can report an excessive number of VPD pages when asked for a
list; this can cause an out-of-bounds access to buf in
scsi_generic_set_vpd_bl_emulation.  It should not happen, but
it is technically not incorrect so handle it: do not check any byte
past the allocation length that was sent to the INQUIRY command.

Reported-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(cherry picked from commit 57dbb58d800f62b9e56d946660dba4e8dbd20204)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/scsi/scsi-generic.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 98c6a34..6d6db69 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -539,7 +539,7 @@ static void scsi_generic_set_vpd_bl_emulation(SCSIDevice *s)
     }
 
     page_len = buf[3];
-    for (i = 4; i < page_len + 4; i++) {
+    for (i = 4; i < MIN(sizeof(buf), page_len + 4); i++) {
         if (buf[i] == 0xb0) {
             s->needs_vpd_bl_emulation = false;
             return;
-- 
1.8.3.1