From 5e4b77ec2c43b3230c717e4470a7c89465fc87c5 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Mon, 30 Nov 2015 15:00:06 +0800 Subject: [PATCH] pcnet: fix rx buffer overflow(CVE-2015-7512) Backends could provide a packet whose length is greater than buffer size. Check for this and truncate the packet to avoid rx buffer overflow in this case. Cc: Prasad J Pandit Cc: qemu-stable@nongnu.org Reviewed-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/net/pcnet.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c index 00fc409ac..af691ddff 100644 --- a/hw/net/pcnet.c +++ b/hw/net/pcnet.c @@ -1087,6 +1087,12 @@ ssize_t pcnet_receive(NetClientState *nc, const uint8_t *buf, size_t size_) int pktcount = 0; if (!s->looptest) { + if (size > 4092) { +#ifdef PCNET_DEBUG_RMD + fprintf(stderr, "pcnet: truncates rx packet.\n"); +#endif + size = 4092; + } memcpy(src, buf, size); /* no need to compute the CRC */ src[size] = 0; -- 2.39.5