From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Fri, 15 Jan 2016 07:00:40 +0000 (+0530)
Subject: net: cadence_gem: check packet size in gem_recieve
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=a37e0e9de748f58b793a83e5d680f474c640f87e;p=qemu-upstream-4.4-testing.git

net: cadence_gem: check packet size in gem_recieve

While receiving packets in 'gem_receive' routine, if Frame Check
Sequence(FCS) is enabled, it copies the packet into a local
buffer without checking its size. Add check to validate packet
length against the buffer size to avoid buffer overflow.

Reported-by: Ling Liu <liuling-it@360.cn>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---

diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index 4a355bbbe..770965cd0 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -640,6 +640,10 @@ static ssize_t gem_receive(NetClientState *nc, const uint8_t *buf, size_t size)
         unsigned crc_val;
         int      crc_offset;
 
+        if (size > sizeof(rxbuf) - sizeof(crc_val)) {
+            size = sizeof(rxbuf) - sizeof(crc_val);
+        }
+        bytes_to_copy = size;
         /* The application wants the FCS field, which QEMU does not provide.
          * We must try and caclculate one.
          */