Description
In the Linux kernel, the following vulnerability has been resolved: net: fix skb length accounting after generic XDP frag adjustment Generic XDP exposes non-linear skb fragments through an xdp_buff. If an XDP program adjusts the fragment area, bpf_prog_run_generic_xdp() copies xdp_frags_size back to skb->data_len but leaves skb->len containing the old fragment contribution. After a fragment shrink, this makes skb_headlen() larger than the actual linear area. In the reproduced UDP receive path, __skb_datagram_iter() copied 1024 bytes past the actual linear tail to userspace, starting at struct skb_shared_info. The copied bytes included the affected skb's nr_frags, xdp_frags_size and a kernel pointer from skb_shinfo(skb)->frags[0]. Real packet data was displaced by the same amount and truncated at the end. Subtract the old data_len before replacing it and add the new data_len afterwards, keeping skb->len and skb->data_len synchronized. A 60000-byte UDP datagram on a veth pair with MTU 64000 was shortened by 1024 bytes from its fragment area. Before the fix, all 10 runs produced corrupted payloads. After the fix, all 10 runs matched the expected payload exactly.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
e6d5dbdd20aa6a86974af51deb9414cd2e7794cb to < 72468efcc089782fa047afddd10856b11a14ef5baffectede6d5dbdd20aa6a86974af51deb9414cd2e7794cb to < 5f30f9c302cea1f2ebf97abe574c1826544223d7affectede6d5dbdd20aa6a86974af51deb9414cd2e7794cb to < ea1ccd6d1c6370868e3b032a3fc575b9c397f2e1affectede6d5dbdd20aa6a86974af51deb9414cd2e7794cb to < 33f2b2eb33d666ecac68031e0f31424fb70528dbaffected
Linux Linux
Default version status: affected
6.9affected0 to < 6.9unaffected6.12.104 to ≤ 6.12.*unaffected6.18.45 to ≤ 6.18.*unaffected7.1.9 to ≤ 7.1.*unaffected7.2 to ≤ *unaffected