From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50145) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bAarQ-00020S-F0 for qemu-devel@nongnu.org; Wed, 08 Jun 2016 06:37:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bAarL-0004r0-77 for qemu-devel@nongnu.org; Wed, 08 Jun 2016 06:37:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45661) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bAarL-0004qt-0l for qemu-devel@nongnu.org; Wed, 08 Jun 2016 06:37:15 -0400 From: P J P Date: Wed, 8 Jun 2016 16:07:04 +0530 Message-Id: <1465382224-6791-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH v2] net: mipsnet: check transmit buffer size before sending List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: Qemu Developers , Peter Maydell , Leon Alrae , Li Qiang , Aurelien Jarno , Prasad J Pandit From: Prasad J Pandit When processing MIPSnet I/O port write operation, it uses a transmit buffer tx_buffer[MAX_ETH_FRAME_SIZE=1514]. Two indices 's->tx_written' and 's->tx_count' are used to control data written to this buffer. If the two were to be equal before writing, it'd lead to an OOB write access beyond tx_buffer. Add check to avoid it. Reported-by: Li Qiang Signed-off-by: Prasad J Pandit --- hw/net/mipsnet.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) Update as per: -> https://lists.gnu.org/archive/html/qemu-devel/2016-06/msg02089.html diff --git a/hw/net/mipsnet.c b/hw/net/mipsnet.c index 740cd98..450e42d 100644 --- a/hw/net/mipsnet.c +++ b/hw/net/mipsnet.c @@ -180,10 +180,12 @@ static void mipsnet_ioport_write(void *opaque, hwaddr addr, break; case MIPSNET_TX_DATA_BUFFER: s->tx_buffer[s->tx_written++] = val; - if (s->tx_written == s->tx_count) { + if ((s->tx_written >= MAX_ETH_FRAME_SIZE) + || (s->tx_written == s->tx_count)) { /* Send buffer. */ - trace_mipsnet_send(s->tx_count); - qemu_send_packet(qemu_get_queue(s->nic), s->tx_buffer, s->tx_count); + trace_mipsnet_send(s->tx_written); + qemu_send_packet(qemu_get_queue(s->nic), + s->tx_buffer, s->tx_written); s->tx_count = s->tx_written = 0; s->intctl |= MIPSNET_INTCTL_TXDONE; s->busy = 1; -- 2.5.5