Re: Heap overflow vulnerabilities in network implementation of barebox

[jianqiang wang <wjq.sec@gmail.com>]

Hi Sascha,

Thanks for your work. I noticed that if the device does not use DMA,
it will probably have this problem. Yes, what you mentioned the
smc91111 driver has the same vulnerability. However, I didn't check
them carefully for each device driver.

Best


Sascha Hauer <s.hauer@pengutronix.de> 于2024年5月27日周一 09:41写道：
>
> Hi,
>
> On Thu, May 23, 2024 at 06:51:01PM +0200, jianqiang wang wrote:
> > Dear Barebox devlopers,
> >
> > I found several heap overflow vulnerabilities in Barebox.
> >
> > The Barebox implementation assumes that the network packet received is
> > less than PKTSIZE, that is 1536 bytes. For example, the /net/net.c
> > file ping_reply function assumes that the packet received is 1536
> > bytes and allocates a 1536 bytes buffer then copies the packet data
> > into the buffer.
> >
> > However, in the driver layer, it lacks a proper check of the packet length.
> > For example, in drivers/net/cs8900.c cs8900_probe function, it
> > allocates a PKTSIZE buffer and assigns it to rx_buf. In cs8900_recv
> > function, the length is read from the device register:
> >
> > len = readw(priv->regs + CS8900_RTDATA0);
> >
> > After that, the data is read from the register in a loop without a
> > boundary check.
> > The same vulnerability happens to the following drivers:
> >
> > drivers/net/ks8851_mll.c function ks8851_rx_frame, it only and the
> > packet length with RXFHBCR_CNT_MASK (4095 bytes,) which is not
> > consistent with the upper layer length check.
> >
> > drivers/net/liteeth.c function liteeth_eth_rx, It checks if the length
> > is larger than 2048 which is inconsistent with the upper layer.
> >
> > drivers/net/smc911x.c function smc911x_eth_rx. The packet length is
> > read from the register without checking.
> >
> > It would be good to add a proper and consistent boundary check for
> > these drivers otherwise it will lead to potential heap overflow
> > vulnerability.
>
> Thanks for noting this. I've just sent a series fixing the drivers you
> explicitly mentioned. Additionally I have checked a few other drivers
> and it seems at least the smc91111 driver has this issue as well. Are
> you aware of other drivers?
>
> Sascha
>
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