From 7da8c6f20d4838285af004884666c18f16fb331e Mon Sep 17 00:00:00 2001
From: Xiao Wang <jasowang@redhat.com>
Date: Fri, 11 Jan 2019 07:58:58 +0000
Subject: [PATCH 03/11] pcnet: fix possible buffer overflow
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RH-Author: Xiao Wang <jasowang@redhat.com>
Message-id: <20190111075904.2030-4-jasowang@redhat.com>
Patchwork-id: 83977
O-Subject: [RHEL8 qemu-kvm PATCH 3/9] pcnet: fix possible buffer overflow
Bugzilla: 1636784
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Jens Freimann <jfreimann@redhat.com>
RH-Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
RH-Acked-by: Michael S. Tsirkin <mst@redhat.com>

In pcnet_receive(), we try to assign size_ to size which converts from
size_t to integer. This will cause troubles when size_ is greater
INT_MAX, this will lead a negative value in size and it can then pass
the check of size < MIN_BUF_SIZE which may lead out of bound access
for both buf and buf1.

Fixing by converting the type of size to size_t.

CC: qemu-stable@nongnu.org
Reported-by: Daniel Shapira <daniel@twistlock.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
(cherry picked from commit b1d80d12c5f7ff081bb80ab4f4241d4248691192)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/net/pcnet.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c
index 0c44554..d9ba04b 100644
--- a/hw/net/pcnet.c
+++ b/hw/net/pcnet.c
@@ -988,14 +988,14 @@ ssize_t pcnet_receive(NetClientState *nc, const uint8_t *buf, size_t size_)
     uint8_t buf1[60];
     int remaining;
     int crc_err = 0;
-    int size = size_;
+    size_t size = size_;
 
     if (CSR_DRX(s) || CSR_STOP(s) || CSR_SPND(s) || !size ||
         (CSR_LOOP(s) && !s->looptest)) {
         return -1;
     }
 #ifdef PCNET_DEBUG
-    printf("pcnet_receive size=%d\n", size);
+    printf("pcnet_receive size=%zu\n", size);
 #endif
 
     /* if too small buffer, then expand it */
-- 
1.8.3.1