From: Jim Meyering <meyering@redhat.com>
Date: Thu, 10 May 2012 06:19:48 +0000 (+0000)
Subject: cadence_gem: avoid stack-writing buffer-overrun
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=5fbe02e8bb7c62ee55b8edc5fd688c369164c49c;p=qemu.git

cadence_gem: avoid stack-writing buffer-overrun

Use sizeof(rxbuf)-size (not sizeof(rxbuf-size)) as the number
of bytes to clear.  The latter would always clear 4 or 8
bytes, possibly writing beyond the end of that stack buffer.
Alternatively, depending on the value of the "size" parameter,
it could fail to initialize the end of "rxbuf".
Spotted by coverity.

Signed-off-by: Jim Meyering <meyering@redhat.com>
Reviewed-by: Peter A.G. Crosthwaite <peter.crosthwaite@petalogix.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---

diff --git a/hw/cadence_gem.c b/hw/cadence_gem.c
index e2140aea2b..dbde3920d0 100644
--- a/hw/cadence_gem.c
+++ b/hw/cadence_gem.c
@@ -664,7 +664,7 @@ static ssize_t gem_receive(VLANClientState *nc, const uint8_t *buf, size_t size)
          */
 
         memcpy(rxbuf, buf, size);
-        memset(rxbuf + size, 0, sizeof(rxbuf - size));
+        memset(rxbuf + size, 0, sizeof(rxbuf) - size);
         rxbuf_ptr = rxbuf;
         crc_val = cpu_to_le32(crc32(0, rxbuf, MAX(size, 60)));
         if (size < 60) {