| 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-2024-35894: mptcp: prevent BPF accessing lowat from a subflow socket. |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mptcp: prevent BPF accessing lowat from a subflow socket. |
| |
| Alexei reported the following splat: |
| |
| WARNING: CPU: 32 PID: 3276 at net/mptcp/subflow.c:1430 subflow_data_ready+0x147/0x1c0 |
| Modules linked in: dummy bpf_testmod(O) [last unloaded: bpf_test_no_cfi(O)] |
| CPU: 32 PID: 3276 Comm: test_progs Tainted: GO 6.8.0-12873-g2c43c33bfd23 |
| Call Trace: |
| <TASK> |
| mptcp_set_rcvlowat+0x79/0x1d0 |
| sk_setsockopt+0x6c0/0x1540 |
| __bpf_setsockopt+0x6f/0x90 |
| bpf_sock_ops_setsockopt+0x3c/0x90 |
| bpf_prog_509ce5db2c7f9981_bpf_test_sockopt_int+0xb4/0x11b |
| bpf_prog_dce07e362d941d2b_bpf_test_socket_sockopt+0x12b/0x132 |
| bpf_prog_348c9b5faaf10092_skops_sockopt+0x954/0xe86 |
| __cgroup_bpf_run_filter_sock_ops+0xbc/0x250 |
| tcp_connect+0x879/0x1160 |
| tcp_v6_connect+0x50c/0x870 |
| mptcp_connect+0x129/0x280 |
| __inet_stream_connect+0xce/0x370 |
| inet_stream_connect+0x36/0x50 |
| bpf_trampoline_6442491565+0x49/0xef |
| inet_stream_connect+0x5/0x50 |
| __sys_connect+0x63/0x90 |
| __x64_sys_connect+0x14/0x20 |
| |
| The root cause of the issue is that bpf allows accessing mptcp-level |
| proto_ops from a tcp subflow scope. |
| |
| Fix the issue detecting the problematic call and preventing any action. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35894 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.7 with commit 5684ab1a0effbfeb706f47d85785f653005b97b1 and fixed in 6.8.5 with commit 3ffb1ab698376f09cc33101c07c1be229389fe29 |
| Issue introduced in 6.7 with commit 5684ab1a0effbfeb706f47d85785f653005b97b1 and fixed in 6.9 with commit fcf4692fa39e86a590c14a4af2de704e1d20a3b5 |
| |
| 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-2024-35894 |
| 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/mptcp/sockopt.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/ee3c845787b621cfe82c2e52c513024a9d7a78f5 |
| https://git.kernel.org/stable/c/3ffb1ab698376f09cc33101c07c1be229389fe29 |
| https://git.kernel.org/stable/c/fcf4692fa39e86a590c14a4af2de704e1d20a3b5 |
