| 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-2023-52481: arm64: errata: Add Cortex-A520 speculative unprivileged load workaround |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| arm64: errata: Add Cortex-A520 speculative unprivileged load workaround |
| |
| Implement the workaround for ARM Cortex-A520 erratum 2966298. On an |
| affected Cortex-A520 core, a speculatively executed unprivileged load |
| might leak data from a privileged load via a cache side channel. The |
| issue only exists for loads within a translation regime with the same |
| translation (e.g. same ASID and VMID). Therefore, the issue only affects |
| the return to EL0. |
| |
| The workaround is to execute a TLBI before returning to EL0 after all |
| loads of privileged data. A non-shareable TLBI to any address is |
| sufficient. |
| |
| The workaround isn't necessary if page table isolation (KPTI) is |
| enabled, but for simplicity it will be. Page table isolation should |
| normally be disabled for Cortex-A520 as it supports the CSV3 feature |
| and the E0PD feature (used when KASLR is enabled). |
| |
| The Linux kernel CVE team has assigned CVE-2023-52481 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 6.1.57 with commit 6e3ae2927b432a3b7c8374f14dbc1bd9ebe4372c |
| Fixed in 6.5.7 with commit 32b0a4ffcaea44a00a61e40c0d1bcc50362aee25 |
| Fixed in 6.6 with commit 471470bc7052d28ce125901877dd10e4c048e513 |
| |
| 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-2023-52481 |
| 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: |
| Documentation/arch/arm64/silicon-errata.rst |
| arch/arm64/Kconfig |
| arch/arm64/kernel/cpu_errata.c |
| arch/arm64/kernel/entry.S |
| arch/arm64/tools/cpucaps |
| |
| |
| 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/6e3ae2927b432a3b7c8374f14dbc1bd9ebe4372c |
| https://git.kernel.org/stable/c/32b0a4ffcaea44a00a61e40c0d1bcc50362aee25 |
| https://git.kernel.org/stable/c/471470bc7052d28ce125901877dd10e4c048e513 |
