On 2 June 2016 at 07:44, P J P <address@hidden> wrote:
From: Prasad J Pandit <address@hidden>
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 <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
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;
This is a behaviour change -- the register will now read
back as MAX_ETH_FRAME_SIZE rather than 0 if written with
an overlarge value.
Do we have any documentation on how this (simulated)
device is supposed to behave in this case?