| 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-2024-26740: net/sched: act_mirred: use the backlog for mirred ingress |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| net/sched: act_mirred: use the backlog for mirred ingress |
| |
| The test Davide added in commit ca22da2fbd69 ("act_mirred: use the backlog |
| for nested calls to mirred ingress") hangs our testing VMs every 10 or so |
| runs, with the familiar tcp_v4_rcv -> tcp_v4_rcv deadlock reported by |
| lockdep. |
| |
| The problem as previously described by Davide (see Link) is that |
| if we reverse flow of traffic with the redirect (egress -> ingress) |
| we may reach the same socket which generated the packet. And we may |
| still be holding its socket lock. The common solution to such deadlocks |
| is to put the packet in the Rx backlog, rather than run the Rx path |
| inline. Do that for all egress -> ingress reversals, not just once |
| we started to nest mirred calls. |
| |
| In the past there was a concern that the backlog indirection will |
| lead to loss of error reporting / less accurate stats. But the current |
| workaround does not seem to address the issue. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26740 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.10 with commit 53592b3640019f2834701093e38272fdfd367ad8 and fixed in 6.6.19 with commit 7c787888d164689da8b1b115f3ef562c1e843af4 |
| Issue introduced in 4.10 with commit 53592b3640019f2834701093e38272fdfd367ad8 and fixed in 6.7.7 with commit 60ddea1600bc476e0f5e02bce0e29a460ccbf0be |
| Issue introduced in 4.10 with commit 53592b3640019f2834701093e38272fdfd367ad8 and fixed in 6.8 with commit 52f671db18823089a02f07efc04efdb2272ddc17 |
| |
| 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-2024-26740 |
| 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/sched/act_mirred.c |
| tools/testing/selftests/net/forwarding/tc_actions.sh |
| |
| |
| 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/7c787888d164689da8b1b115f3ef562c1e843af4 |
| https://git.kernel.org/stable/c/60ddea1600bc476e0f5e02bce0e29a460ccbf0be |
| https://git.kernel.org/stable/c/52f671db18823089a02f07efc04efdb2272ddc17 |
