| 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-2024-58060: bpf: Reject struct_ops registration that uses module ptr and the module btf_id is missing |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Reject struct_ops registration that uses module ptr and the module btf_id is missing |
| |
| There is a UAF report in the bpf_struct_ops when CONFIG_MODULES=n. |
| In particular, the report is on tcp_congestion_ops that has |
| a "struct module *owner" member. |
| |
| For struct_ops that has a "struct module *owner" member, |
| it can be extended either by the regular kernel module or |
| by the bpf_struct_ops. bpf_try_module_get() will be used |
| to do the refcounting and different refcount is done |
| based on the owner pointer. When CONFIG_MODULES=n, |
| the btf_id of the "struct module" is missing: |
| |
| WARN: resolve_btfids: unresolved symbol module |
| |
| Thus, the bpf_try_module_get() cannot do the correct refcounting. |
| |
| Not all subsystem's struct_ops requires the "struct module *owner" member. |
| e.g. the recent sched_ext_ops. |
| |
| This patch is to disable bpf_struct_ops registration if |
| the struct_ops has the "struct module *" member and the |
| "struct module" btf_id is missing. The btf_type_is_fwd() helper |
| is moved to the btf.h header file for this test. |
| |
| This has happened since the beginning of bpf_struct_ops which has gone |
| through many changes. The Fixes tag is set to a recent commit that this |
| patch can apply cleanly. Considering CONFIG_MODULES=n is not |
| common and the age of the issue, targeting for bpf-next also. |
| |
| The Linux kernel CVE team has assigned CVE-2024-58060 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.9 with commit 1611603537a4b88cec7993f32b70c03113801a46 and fixed in 6.12.13 with commit b777b14c2a4a4e2322daf8e8ffd42d2b88831b17 |
| Issue introduced in 6.9 with commit 1611603537a4b88cec7993f32b70c03113801a46 and fixed in 6.13.2 with commit 2324fb4e92092837ee278fdd8d60c48ee1a619ce |
| Issue introduced in 6.9 with commit 1611603537a4b88cec7993f32b70c03113801a46 and fixed in 6.14 with commit 96ea081ed52bf077cad6d00153b6fba68e510767 |
| |
| 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-2024-58060 |
| 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/linux/btf.h |
| kernel/bpf/bpf_struct_ops.c |
| kernel/bpf/btf.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/b777b14c2a4a4e2322daf8e8ffd42d2b88831b17 |
| https://git.kernel.org/stable/c/2324fb4e92092837ee278fdd8d60c48ee1a619ce |
| https://git.kernel.org/stable/c/96ea081ed52bf077cad6d00153b6fba68e510767 |
