| 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-2022-49001: riscv: fix race when vmap stack overflow |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| riscv: fix race when vmap stack overflow |
| |
| Currently, when detecting vmap stack overflow, riscv firstly switches |
| to the so called shadow stack, then use this shadow stack to call the |
| get_overflow_stack() to get the overflow stack. However, there's |
| a race here if two or more harts use the same shadow stack at the same |
| time. |
| |
| To solve this race, we introduce spin_shadow_stack atomic var, which |
| will be swap between its own address and 0 in atomic way, when the |
| var is set, it means the shadow_stack is being used; when the var |
| is cleared, it means the shadow_stack isn't being used. |
| |
| [Palmer: Add AQ to the swap, and also some comments.] |
| |
| The Linux kernel CVE team has assigned CVE-2022-49001 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.14 with commit 31da94c25aea835ceac00575a9fd206c5a833fed and fixed in 5.15.82 with commit ac00301adb19df54f2eae1efc4bad7447c0156ce |
| Issue introduced in 5.14 with commit 31da94c25aea835ceac00575a9fd206c5a833fed and fixed in 6.0.12 with commit 879fabc5a95401d9bce357e4b1d24ae4a360a81f |
| Issue introduced in 5.14 with commit 31da94c25aea835ceac00575a9fd206c5a833fed and fixed in 6.1 with commit 7e1864332fbc1b993659eab7974da9fe8bf8c128 |
| |
| 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-2022-49001 |
| 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/riscv/include/asm/asm.h |
| arch/riscv/kernel/entry.S |
| arch/riscv/kernel/traps.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/ac00301adb19df54f2eae1efc4bad7447c0156ce |
| https://git.kernel.org/stable/c/879fabc5a95401d9bce357e4b1d24ae4a360a81f |
| https://git.kernel.org/stable/c/7e1864332fbc1b993659eab7974da9fe8bf8c128 |
