| 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-2023-52659: x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| x86/mm: Ensure input to pfn_to_kaddr() is treated as a 64-bit type |
| |
| On 64-bit platforms, the pfn_to_kaddr() macro requires that the input |
| value is 64 bits in order to ensure that valid address bits don't get |
| lost when shifting that input by PAGE_SHIFT to calculate the physical |
| address to provide a virtual address for. |
| |
| One such example is in pvalidate_pages() (used by SEV-SNP guests), where |
| the GFN in the struct used for page-state change requests is a 40-bit |
| bit-field, so attempts to pass this GFN field directly into |
| pfn_to_kaddr() ends up causing guest crashes when dealing with addresses |
| above the 1TB range due to the above. |
| |
| Fix this issue with SEV-SNP guests, as well as any similar cases that |
| might cause issues in current/future code, by using an inline function, |
| instead of a macro, so that the input is implicitly cast to the |
| expected 64-bit input type prior to performing the shift operation. |
| |
| While it might be argued that the issue is on the caller side, other |
| archs/macros have taken similar approaches to deal with instances like |
| this, such as ARM explicitly casting the input to phys_addr_t: |
| |
| e48866647b48 ("ARM: 8396/1: use phys_addr_t in pfn_to_kaddr()") |
| |
| A C inline function is even better though. |
| |
| [ mingo: Refined the changelog some more & added __always_inline. ] |
| |
| The Linux kernel CVE team has assigned CVE-2023-52659 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.5 with commit 6c3211796326a9d35618b866826ca556c8f008a8 and fixed in 6.6.23 with commit 325956b0173f11e98f90462be4829a8b8b0682ce |
| Issue introduced in 6.5 with commit 6c3211796326a9d35618b866826ca556c8f008a8 and fixed in 6.7.11 with commit 7e1471888a5e6e846e9b4d306e5327db2b58e64e |
| Issue introduced in 6.5 with commit 6c3211796326a9d35618b866826ca556c8f008a8 and fixed in 6.8.2 with commit 814305b5c23cb815ada68d43019f39050472b25f |
| Issue introduced in 6.5 with commit 6c3211796326a9d35618b866826ca556c8f008a8 and fixed in 6.9 with commit 8e5647a723c49d73b9f108a8bb38e8c29d3948ea |
| |
| 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-2023-52659 |
| 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/include/asm/page.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/325956b0173f11e98f90462be4829a8b8b0682ce |
| https://git.kernel.org/stable/c/7e1471888a5e6e846e9b4d306e5327db2b58e64e |
| https://git.kernel.org/stable/c/814305b5c23cb815ada68d43019f39050472b25f |
| https://git.kernel.org/stable/c/8e5647a723c49d73b9f108a8bb38e8c29d3948ea |
