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From b00154f43c01657e4299c486f451ad50891d80f1 Mon Sep 17 00:00:00 2001
From: Fam Zheng <famz@redhat.com>
Date: Fri, 29 Jun 2018 06:11:52 +0200
Subject: [PATCH 178/268] iscsi: Don't blindly use designator length in
 response for memcpy

RH-Author: Fam Zheng <famz@redhat.com>
Message-id: <20180629061153.12687-13-famz@redhat.com>
Patchwork-id: 81162
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH v2 12/13] iscsi: Don't blindly use designator length in response for memcpy
Bugzilla: 1482537
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>

Per SCSI definition the designator_length we receive from INQUIRY is 8,
12 or at most 16, but we should be careful because the remote iscsi
target may misbehave, otherwise we could have a buffer overflow.

Reported-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/iscsi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index fbcd5bb..751884d 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2226,7 +2226,7 @@ static void iscsi_populate_target_desc(unsigned char *desc, IscsiLun *lun)
     desc[5] = (dd->designator_type & 0xF)
         | ((dd->association & 3) << 4);
     desc[7] = dd->designator_length;
-    memcpy(desc + 8, dd->designator, dd->designator_length);
+    memcpy(desc + 8, dd->designator, MIN(dd->designator_length, 20));
 
     desc[28] = 0;
     desc[29] = (lun->block_size >> 16) & 0xFF;
-- 
1.8.3.1