Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ip_gre: test csum_start instead of transport header GRE with TUNNEL_CSUM will apply local checksum offload on CHECKSUM_PARTIAL packets. ipgre_xmit must validate csum_start after an optional skb_pull, else lco_csum may trigger an overflow. The original check was if (csum && skb_checksum_start(skb) < skb->data) return -EINVAL; This had false positives when skb_checksum_start is undefined: when ip_summed is not CHECKSUM_PARTIAL. A discussed refinement was straightforward if (csum && skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_start(skb) < skb->data) return -EINVAL; But was eventually revised more thoroughly: - restrict the check to the only branch where needed, in an uncommon GRE path that uses header_ops and calls skb_pull. - test skb_transport_header, which is set along with csum_start in skb_partial_csum_set in the normal header_ops datapath. Turns out skbs can arrive in this branch without the transport header set, e.g., through BPF redirection. Revise the check back to check csum_start directly, and only if CHECKSUM_PARTIAL. Do leave the check in the updated location. Check field regardless of whether TUNNEL_CSUM is configured.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 774430026bd9a472d08c5d3c33351a782315771a before 7596bd7920985f7fc8579a92e48bc53ce4475b21; affected 3d32ce5472bb2ca720bef84089b85f76a705fd1a before 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006; affected 87b34cd6485192777f632f92d592f2a71d8801a6 before fbeb8dfa8b87ef259eef0c89e39b53962a3cf604; affected 8a0ed250f911da31a2aef52101bc707846a800ff before e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58; affected 8a0ed250f911da31a2aef52101bc707846a800ff before 0c92d813c7c9ca2212ecd879232e7d87362fce98; affected 8a0ed250f911da31a2aef52101bc707846a800ff before 0ffa268724656633af5f37a38c212326d98ebe8c; affected 8a0ed250f911da31a2aef52101bc707846a800ff before 8d21e9963bec1aad2280cdd034c8993033ef2948; affected 4bf5d5224ffca069df4501ba5fcc6ded9c002ead; affected 4.19.207 before 4.19.247; affected 5.4.148 before 5.4.198; affected 5.10.68 before 5.10.122; affected 5.14.7 before 5.15 |
| Linux / Linux | affected 5.15; unaffected 0 before 5.15; unaffected 4.19.247 through 4.19.*; unaffected 5.4.198 through 5.4.*; unaffected 5.10.122 through 5.10.*; unaffected 5.15.47 through 5.15.*; unaffected 5.17.15 through 5.17.*; unaffected 5.18.4 through 5.18.*; unaffected 5.19 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/7596bd7920985f7fc8579a92e48bc53ce4475b21
- https://git.kernel.org/stable/c/3d08bc3a5d9b2106f5c8bcf1adb73147824aa006
- https://git.kernel.org/stable/c/fbeb8dfa8b87ef259eef0c89e39b53962a3cf604
- https://git.kernel.org/stable/c/e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58
- https://git.kernel.org/stable/c/0c92d813c7c9ca2212ecd879232e7d87362fce98
- https://git.kernel.org/stable/c/0ffa268724656633af5f37a38c212326d98ebe8c
- https://git.kernel.org/stable/c/8d21e9963bec1aad2280cdd034c8993033ef2948