From: Prasad J Pandit <p...@fedoraproject.org> 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 <qiang...@360.cn> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- 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
