| 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-2022-49172: parisc: Fix non-access data TLB cache flush faults |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| parisc: Fix non-access data TLB cache flush faults |
| |
| When a page is not present, we get non-access data TLB faults from |
| the fdc and fic instructions in flush_user_dcache_range_asm and |
| flush_user_icache_range_asm. When these occur, the cache line is |
| not invalidated and potentially we get memory corruption. The |
| problem was hidden by the nullification of the flush instructions. |
| |
| These faults also affect performance. With pa8800/pa8900 processors, |
| there will be 32 faults per 4 KB page since the cache line is 128 |
| bytes. There will be more faults with earlier processors. |
| |
| The problem is fixed by using flush_cache_pages(). It does the flush |
| using a tmp alias mapping. |
| |
| The flush_cache_pages() call in flush_cache_range() flushed too |
| large a range. |
| |
| V2: Remove unnecessary preempt_disable() and preempt_enable() calls. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49172 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.16.19 with commit b3d6adb3a49d82e4e557c5fc16f50c9ff731da5d |
| Fixed in 5.17.2 with commit ddca4b82027e2a66333dd40fab21a4beff435c7e |
| Fixed in 5.18 with commit f839e5f1cef36ce268950c387129b1bfefdaebc9 |
| |
| 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-2022-49172 |
| 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/parisc/kernel/cache.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/b3d6adb3a49d82e4e557c5fc16f50c9ff731da5d |
| https://git.kernel.org/stable/c/ddca4b82027e2a66333dd40fab21a4beff435c7e |
| https://git.kernel.org/stable/c/f839e5f1cef36ce268950c387129b1bfefdaebc9 |
