| 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-2024-49979: net: gso: fix tcp fraglist segmentation after pull from frag_list |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net: gso: fix tcp fraglist segmentation after pull from frag_list |
| |
| Detect tcp gso fraglist skbs with corrupted geometry (see below) and |
| pass these to skb_segment instead of skb_segment_list, as the first |
| can segment them correctly. |
| |
| Valid SKB_GSO_FRAGLIST skbs |
| - consist of two or more segments |
| - the head_skb holds the protocol headers plus first gso_size |
| - one or more frag_list skbs hold exactly one segment |
| - all but the last must be gso_size |
| |
| Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can |
| modify these skbs, breaking these invariants. |
| |
| In extreme cases they pull all data into skb linear. For TCP, this |
| causes a NULL ptr deref in __tcpv4_gso_segment_list_csum at |
| tcp_hdr(seg->next). |
| |
| Detect invalid geometry due to pull, by checking head_skb size. |
| Don't just drop, as this may blackhole a destination. Convert to be |
| able to pass to regular skb_segment. |
| |
| Approach and description based on a patch by Willem de Bruijn. |
| |
| The Linux kernel CVE team has assigned CVE-2024-49979 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.10 with commit bee88cd5bd83d40b8aec4d6cb729378f707f6197 and fixed in 6.10.14 with commit 3fdd8c83e83fa5e82f1b5585245c51e0355c9f46 |
| Issue introduced in 6.10 with commit bee88cd5bd83d40b8aec4d6cb729378f707f6197 and fixed in 6.11.3 with commit 2d4a83a44428de45bfe9dccb0192a3711d1097e0 |
| Issue introduced in 6.10 with commit bee88cd5bd83d40b8aec4d6cb729378f707f6197 and fixed in 6.12 with commit 17bd3bd82f9f79f3feba15476c2b2c95a9b11ff8 |
| |
| 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-2024-49979 |
| 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/tcp_offload.c |
| net/ipv6/tcpv6_offload.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/3fdd8c83e83fa5e82f1b5585245c51e0355c9f46 |
| https://git.kernel.org/stable/c/2d4a83a44428de45bfe9dccb0192a3711d1097e0 |
| https://git.kernel.org/stable/c/17bd3bd82f9f79f3feba15476c2b2c95a9b11ff8 |
