From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46614) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8MN0-0001JT-IO for qemu-devel@nongnu.org; Thu, 02 Jun 2016 02:44:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1b8MMw-0004f8-Fu for qemu-devel@nongnu.org; Thu, 02 Jun 2016 02:44:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49773) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1b8MMw-0004eH-9j for qemu-devel@nongnu.org; Thu, 02 Jun 2016 02:44:38 -0400 From: P J P Date: Thu, 2 Jun 2016 12:14:27 +0530 Message-Id: <1464849867-20184-1-git-send-email-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] net: mipsnet: check transmit buffer size before sending List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Jason Wang , Li Qiang , 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 | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/hw/net/mipsnet.c b/hw/net/mipsnet.c index 740cd98..8d5e5bf 100644 --- a/hw/net/mipsnet.c +++ b/hw/net/mipsnet.c @@ -158,7 +158,7 @@ static void mipsnet_ioport_write(void *opaque, hwaddr addr, trace_mipsnet_write(addr, val); switch (addr) { case MIPSNET_TX_DATA_COUNT: - s->tx_count = (val <= MAX_ETH_FRAME_SIZE) ? val : 0; + s->tx_count = (val < MAX_ETH_FRAME_SIZE) ? val : MAX_ETH_FRAME_SIZE; s->tx_written = 0; break; case MIPSNET_INT_CTL: @@ -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