Re: [Qemu-devel] [PATCH] net: mipsnet: check transmit buffer size before sending

[P J P]

+-- On Thu, 2 Jun 2016, Peter Maydell wrote --+
| >      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.

  IIUC, 's->tx_count' indicates expected packet data length to be processed. 
Maybe if this value was zero, packet was not to be sent; not sure.

| Do we have any documentation on how this (simulated)
| device is supposed to behave in this case?

  I tried to find a specification, but didn't come across any.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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