Re: [PATCH net v2] net: usb: catc: bound the RX packet length in catc_rx_done()

[Paolo Abeni]

On 9/15/26 01:06, Aamir Ahmed wrote:
> catc_rx_done() walks a multi-packet URB, reading a two-byte length from
> each packet header. Its bound, pkt_len > urb->actual_length, ignores the
> header offset and compares against the whole transfer rather than the
> bytes left from pkt_start, so a crafted packet header makes
> skb_copy_to_linear_data() read past the buffer.
>
> A length below ETH_HLEN is also accepted, including zero, and
> eth_type_trans() then reads a MAC header from the uninitialised tailroom
> of a shorter skb. The is_f5u011 branch takes its length straight from
> the transfer, so a zero-length URB reaches the same path.
>
> Track the bytes remaining from the current packet, and reject a header
> that does not fit, a length past what is left, and a length below an
> Ethernet header.
>
> A transfer shorter than an Ethernet header, including a zero-length one,
> previously became a runt skb passed to netif_rx() and counted as
> received; it is now counted in rx_length_errors and ends the walk.
>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Assisted-by: LLM
> Signed-off-by: Aamir Ahmed <elb12345@xxxxxxxxxxxxx>
I'm sorry, but no minor fixes for legacy drivers.

/P