| 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-2022-49675: tick/nohz: unexport __init-annotated tick_nohz_full_setup() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| tick/nohz: unexport __init-annotated tick_nohz_full_setup() |
| |
| EXPORT_SYMBOL and __init is a bad combination because the .init.text |
| section is freed up after the initialization. Hence, modules cannot |
| use symbols annotated __init. The access to a freed symbol may end up |
| with kernel panic. |
| |
| modpost used to detect it, but it had been broken for a decade. |
| |
| Commit 28438794aba4 ("modpost: fix section mismatch check for exported |
| init/exit sections") fixed it so modpost started to warn it again, then |
| this showed up: |
| |
| MODPOST vmlinux.symvers |
| WARNING: modpost: vmlinux.o(___ksymtab_gpl+tick_nohz_full_setup+0x0): Section mismatch in reference from the variable __ksymtab_tick_nohz_full_setup to the function .init.text:tick_nohz_full_setup() |
| The symbol tick_nohz_full_setup is exported and annotated __init |
| Fix this by removing the __init annotation of tick_nohz_full_setup or drop the export. |
| |
| Drop the export because tick_nohz_full_setup() is only called from the |
| built-in code in kernel/sched/isolation.c. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49675 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit ae9e557b5be2e285f48ee945d9c8faf75d4f6a66 and fixed in 5.10.128 with commit c4ff3ffe0138234774602152fe67e3a898c615c6 |
| Issue introduced in 5.5 with commit ae9e557b5be2e285f48ee945d9c8faf75d4f6a66 and fixed in 5.15.52 with commit f4a80ec8c51d68be4b7a7830c510f75080c5e417 |
| Issue introduced in 5.5 with commit ae9e557b5be2e285f48ee945d9c8faf75d4f6a66 and fixed in 5.18.9 with commit ea32b27e2f8c58c92bff5ecba7fcf64b97707089 |
| Issue introduced in 5.5 with commit ae9e557b5be2e285f48ee945d9c8faf75d4f6a66 and fixed in 5.19 with commit 2390095113e98fc52fffe35c5206d30d9efe3f78 |
| |
| 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-2022-49675 |
| 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: |
| kernel/time/tick-sched.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/c4ff3ffe0138234774602152fe67e3a898c615c6 |
| https://git.kernel.org/stable/c/f4a80ec8c51d68be4b7a7830c510f75080c5e417 |
| https://git.kernel.org/stable/c/ea32b27e2f8c58c92bff5ecba7fcf64b97707089 |
| https://git.kernel.org/stable/c/2390095113e98fc52fffe35c5206d30d9efe3f78 |
