From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48711) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQQpq-0007ph-Ri for qemu-devel@nongnu.org; Mon, 01 Feb 2016 21:36:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aQQpn-00007Y-Ku for qemu-devel@nongnu.org; Mon, 01 Feb 2016 21:36:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37594) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aQQpn-00006w-Fh for qemu-devel@nongnu.org; Mon, 01 Feb 2016 21:36:51 -0500 From: Jason Wang Date: Tue, 2 Feb 2016 10:36:08 +0800 Message-Id: <1454380581-7881-5-git-send-email-jasowang@redhat.com> In-Reply-To: <1454380581-7881-1-git-send-email-jasowang@redhat.com> References: <1454380581-7881-1-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 04/17] cadence_gem: fix buffer overflow List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: peter.maydell@linaro.org, qemu-devel@nongnu.org Cc: Jason Wang , "Michael S. Tsirkin" From: "Michael S. Tsirkin" gem_transmit copies a packet from guest into an tx_packet[2048] array on stack, with size limited by descriptor length set by guest. If guest is malicious and specifies a descriptor length that is too large, and should packet size exceed array size, this results in a buffer overflow. Reported-by: =E5=88=98=E4=BB=A4 Signed-off-by: Michael S. Tsirkin Signed-off-by: Jason Wang --- hw/net/cadence_gem.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c index e513d9d..0346f3e 100644 --- a/hw/net/cadence_gem.c +++ b/hw/net/cadence_gem.c @@ -867,6 +867,14 @@ static void gem_transmit(CadenceGEMState *s) break; } =20 + if (tx_desc_get_length(desc) > sizeof(tx_packet) - (p - tx_packe= t)) { + DB_PRINT("TX descriptor @ 0x%x too large: size 0x%x space 0x= %x\n", + (unsigned)packet_desc_addr, + (unsigned)tx_desc_get_length(desc), + sizeof(tx_packet) - (p - tx_packet)); + break; + } + /* Gather this fragment of the packet from "dma memory" to our c= ontig. * buffer. */ --=20 2.5.0