| 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-2024-35996: cpu: Re-enable CPU mitigations by default for !X86 architectures |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cpu: Re-enable CPU mitigations by default for !X86 architectures |
| |
| Rename x86's to CPU_MITIGATIONS, define it in generic code, and force it |
| on for all architectures exception x86. A recent commit to turn |
| mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta |
| missed that "cpu_mitigations" is completely generic, whereas |
| SPECULATION_MITIGATIONS is x86-specific. |
| |
| Rename x86's SPECULATIVE_MITIGATIONS instead of keeping both and have it |
| select CPU_MITIGATIONS, as having two configs for the same thing is |
| unnecessary and confusing. This will also allow x86 to use the knob to |
| manage mitigations that aren't strictly related to speculative |
| execution. |
| |
| Use another Kconfig to communicate to common code that CPU_MITIGATIONS |
| is already defined instead of having x86's menu depend on the common |
| CPU_MITIGATIONS. This allows keeping a single point of contact for all |
| of x86's mitigations, and it's not clear that other architectures *want* |
| to allow disabling mitigations at compile-time. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35996 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.15.156 with commit 70688450dddaf91e12fd4fc625da3297025932c9 and fixed in 5.15.158 with commit 36b32816fbab267611f073223f1b0b816ec5920f |
| Issue introduced in 6.1.87 with commit 9c09773917fbb77dff85b433e1e89123fc5fb530 and fixed in 6.1.90 with commit 38f17d1fbb5bfb56ca1419e2d06376d57a9396f9 |
| Issue introduced in 6.6.28 with commit 2978ee7c973ce81b6e51100ba1e5ae001af624b9 and fixed in 6.6.30 with commit 8292f4f8dd1b005d0688d726261004f816ef730a |
| Issue introduced in 6.8.7 with commit c4a9babdd5d5a41a74269a2e1aa1647b1b4c45bb and fixed in 6.8.9 with commit fd8547ebc187037cc69441a15c1441aeaab80f49 |
| |
| 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-2024-35996 |
| 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: |
| arch/Kconfig |
| arch/x86/Kconfig |
| kernel/cpu.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/af6d6a923b40bf6471e44067ac61cc5814b48e7f |
| https://git.kernel.org/stable/c/36b32816fbab267611f073223f1b0b816ec5920f |
| https://git.kernel.org/stable/c/38f17d1fbb5bfb56ca1419e2d06376d57a9396f9 |
| https://git.kernel.org/stable/c/8292f4f8dd1b005d0688d726261004f816ef730a |
| https://git.kernel.org/stable/c/fd8547ebc187037cc69441a15c1441aeaab80f49 |
| https://git.kernel.org/stable/c/fe42754b94a42d08cf9501790afc25c4f6a5f631 |
