Description

In the Linux kernel, the following vulnerability has been resolved:

igc: avoid returning frame twice in XDP_REDIRECT

When a frame can not be transmitted in XDP_REDIRECT
(e.g. due to a full queue), it is necessary to free
it by calling xdp_return_frame_rx_napi.

However, this is the responsibility of the caller of
the ndo_xdp_xmit (see for example bq_xmit_all in
kernel/bpf/devmap.c) and thus calling it inside
igc_xdp_xmit (which is the ndo_xdp_xmit of the igc
driver) as well will lead to memory corruption.

In fact, bq_xmit_all expects that it can return all
frames after the last successfully transmitted one.
Therefore, break for the first not transmitted frame,
but do not call xdp_return_frame_rx_napi in igc_xdp_xmit.
This is equally implemented in other Intel drivers
such as the igb.

There are two alternatives to this that were rejected:
1. Return num_frames as all the frames would have been
transmitted and release them inside igc_xdp_xmit.
While it might work technically, it is not what
the return value is meant to represent (i.e. the
number of SUCCESSFULLY transmitted packets).
2. Rework kernel/bpf/devmap.c and all drivers to
support non-consecutively dropped packets.
Besides being complex, it likely has a negative
performance impact without a significant gain
since it is anyway unlikely that the next frame
can be transmitted if the previous one was dropped.

The memory corruption can be reproduced with
the following script which leads to a...

Classification

CVE ID: CVE-2024-26853

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 17.83% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/63a3c1f3c9ecc654d851e7906d05334cd0c236e2
https://git.kernel.org/stable/c/8df393af9e7e8dfd62e9c41dbaa4d2ff53bf794a
https://git.kernel.org/stable/c/1b3b8231386a572bac8cd5b6fd7e944b84f9bb1f
https://git.kernel.org/stable/c/ef27f655b438bed4c83680e4f01e1cde2739854b

Timeline