| 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-2024-26710: powerpc/kasan: Limit KASAN thread size increase to 32KB |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| powerpc/kasan: Limit KASAN thread size increase to 32KB |
| |
| KASAN is seen to increase stack usage, to the point that it was reported |
| to lead to stack overflow on some 32-bit machines (see link). |
| |
| To avoid overflows the stack size was doubled for KASAN builds in |
| commit 3e8635fb2e07 ("powerpc/kasan: Force thread size increase with |
| KASAN"). |
| |
| However with a 32KB stack size to begin with, the doubling leads to a |
| 64KB stack, which causes build errors: |
| arch/powerpc/kernel/switch.S:249: Error: operand out of range (0x000000000000fe50 is not between 0xffffffffffff8000 and 0x0000000000007fff) |
| |
| Although the asm could be reworked, in practice a 32KB stack seems |
| sufficient even for KASAN builds - the additional usage seems to be in |
| the 2-3KB range for a 64-bit KASAN build. |
| |
| So only increase the stack for KASAN if the stack size is < 32KB. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26710 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit 18f14afe281648e31ed35c9ad2fcb724c4838ad9 and fixed in 6.1.79 with commit 4297217bcf1f0948a19c2bacc6b68d92e7778ad9 |
| Issue introduced in 6.6.14 with commit b38014874530d3776de75679315e8c1fe04aa89b and fixed in 6.6.18 with commit 4cc31fa07445879a13750cb061bb8c2654975fcb |
| Issue introduced in 6.7.2 with commit 58f396513cb1fa4ef91838c78698d458100cc27c and fixed in 6.7.6 with commit b29b16bd836a838b7690f80e37f8376414c74cbe |
| |
| 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-2024-26710 |
| 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/powerpc/include/asm/thread_info.h |
| |
| |
| 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/4297217bcf1f0948a19c2bacc6b68d92e7778ad9 |
| https://git.kernel.org/stable/c/4cc31fa07445879a13750cb061bb8c2654975fcb |
| https://git.kernel.org/stable/c/b29b16bd836a838b7690f80e37f8376414c74cbe |
| https://git.kernel.org/stable/c/f1acb109505d983779bbb7e20a1ee6244d2b5736 |
