| 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-2022-49562: KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| KVM: x86: Use __try_cmpxchg_user() to update guest PTE A/D bits |
| |
| Use the recently introduced __try_cmpxchg_user() to update guest PTE A/D |
| bits instead of mapping the PTE into kernel address space. The VM_PFNMAP |
| path is broken as it assumes that vm_pgoff is the base pfn of the mapped |
| VMA range, which is conceptually wrong as vm_pgoff is the offset relative |
| to the file and has nothing to do with the pfn. The horrific hack worked |
| for the original use case (backing guest memory with /dev/mem), but leads |
| to accessing "random" pfns for pretty much any other VM_PFNMAP case. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49562 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.2 with commit bd53cb35a3e9adb73a834a36586e9ad80e877767 and fixed in 5.17.13 with commit 38b888911e8dc89b89d8147cfb1d2dbe6373bf78 |
| Issue introduced in 5.2 with commit bd53cb35a3e9adb73a834a36586e9ad80e877767 and fixed in 5.18.2 with commit 8089e5e1d18402fb8152d6b6815450a36fffa9b0 |
| Issue introduced in 5.2 with commit bd53cb35a3e9adb73a834a36586e9ad80e877767 and fixed in 5.19 with commit f122dfe4476890d60b8c679128cd2259ec96a24c |
| |
| 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-2022-49562 |
| 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/x86/kvm/mmu/paging_tmpl.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/38b888911e8dc89b89d8147cfb1d2dbe6373bf78 |
| https://git.kernel.org/stable/c/8089e5e1d18402fb8152d6b6815450a36fffa9b0 |
| https://git.kernel.org/stable/c/f122dfe4476890d60b8c679128cd2259ec96a24c |
