| 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-2024-56638: netfilter: nft_inner: incorrect percpu area handling under softirq |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfilter: nft_inner: incorrect percpu area handling under softirq |
| |
| Softirq can interrupt ongoing packet from process context that is |
| walking over the percpu area that contains inner header offsets. |
| |
| Disable bh and perform three checks before restoring the percpu inner |
| header offsets to validate that the percpu area is valid for this |
| skbuff: |
| |
| 1) If the NFT_PKTINFO_INNER_FULL flag is set on, then this skbuff |
| has already been parsed before for inner header fetching to |
| register. |
| |
| 2) Validate that the percpu area refers to this skbuff using the |
| skbuff pointer as a cookie. If there is a cookie mismatch, then |
| this skbuff needs to be parsed again. |
| |
| 3) Finally, validate if the percpu area refers to this tunnel type. |
| |
| Only after these three checks the percpu area is restored to a on-stack |
| copy and bh is enabled again. |
| |
| After inner header fetching, the on-stack copy is stored back to the |
| percpu area. |
| |
| The Linux kernel CVE team has assigned CVE-2024-56638 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.2 with commit 3a07327d10a09379315c844c63f27941f5081e0a and fixed in 6.6.66 with commit 53c7314208c865086d78b4e88da53bc33da0b603 |
| Issue introduced in 6.2 with commit 3a07327d10a09379315c844c63f27941f5081e0a and fixed in 6.12.5 with commit da5cc778e7bf78fe525bc90ec2043f41415c31d9 |
| Issue introduced in 6.2 with commit 3a07327d10a09379315c844c63f27941f5081e0a and fixed in 6.13 with commit 7b1d83da254be3bf054965c8f3b1ad976f460ae5 |
| |
| 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-2024-56638 |
| 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: |
| include/net/netfilter/nf_tables_core.h |
| net/netfilter/nft_inner.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/53c7314208c865086d78b4e88da53bc33da0b603 |
| https://git.kernel.org/stable/c/da5cc778e7bf78fe525bc90ec2043f41415c31d9 |
| https://git.kernel.org/stable/c/7b1d83da254be3bf054965c8f3b1ad976f460ae5 |
