| 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-2022-49699: filemap: Handle sibling entries in filemap_get_read_batch() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| filemap: Handle sibling entries in filemap_get_read_batch() |
| |
| If a read races with an invalidation followed by another read, it is |
| possible for a folio to be replaced with a higher-order folio. If that |
| happens, we'll see a sibling entry for the new folio in the next iteration |
| of the loop. This manifests as a NULL pointer dereference while holding |
| the RCU read lock. |
| |
| Handle this by simply returning. The next call will find the new folio |
| and handle it correctly. The other ways of handling this rare race are |
| more complex and it's just not worth it. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49699 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.12 with commit cbd59c48ae2bcadc4a7599c29cf32fd3f9b78251 and fixed in 5.18.8 with commit a66f131d30e53000f08301776bf85c912ef47aad |
| Issue introduced in 5.12 with commit cbd59c48ae2bcadc4a7599c29cf32fd3f9b78251 and fixed in 5.19 with commit cb995f4eeba9d268fd4b56c2423ad6c1d1ea1b82 |
| |
| 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-2022-49699 |
| 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: |
| mm/filemap.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/a66f131d30e53000f08301776bf85c912ef47aad |
| https://git.kernel.org/stable/c/cb995f4eeba9d268fd4b56c2423ad6c1d1ea1b82 |
