| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-49340: ip_gre: test csum_start instead of transport header |
| |
| Description |
| =========== |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49340 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.19.207 with commit 774430026bd9a472d08c5d3c33351a782315771a and fixed in 4.19.247 with commit 7596bd7920985f7fc8579a92e48bc53ce4475b21 |
| Issue introduced in 5.4.148 with commit 3d32ce5472bb2ca720bef84089b85f76a705fd1a and fixed in 5.4.198 with commit 3d08bc3a5d9b2106f5c8bcf1adb73147824aa006 |
| Issue introduced in 5.10.68 with commit 87b34cd6485192777f632f92d592f2a71d8801a6 and fixed in 5.10.122 with commit fbeb8dfa8b87ef259eef0c89e39b53962a3cf604 |
| Issue introduced in 5.15 with commit 8a0ed250f911da31a2aef52101bc707846a800ff and fixed in 5.15.47 with commit e6b6f98fc7605c06c0a3baa70f62c534d7b4ce58 |
| Issue introduced in 5.15 with commit 8a0ed250f911da31a2aef52101bc707846a800ff and fixed in 5.17.15 with commit 0c92d813c7c9ca2212ecd879232e7d87362fce98 |
| Issue introduced in 5.15 with commit 8a0ed250f911da31a2aef52101bc707846a800ff and fixed in 5.18.4 with commit 0ffa268724656633af5f37a38c212326d98ebe8c |
| Issue introduced in 5.15 with commit 8a0ed250f911da31a2aef52101bc707846a800ff and fixed in 5.19 with commit 8d21e9963bec1aad2280cdd034c8993033ef2948 |
| Issue introduced in 5.14.7 with commit 4bf5d5224ffca069df4501ba5fcc6ded9c002ead |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2022-49340 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/ipv4/ip_gre.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| 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 |
