| 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-2022-49464: erofs: fix buffer copy overflow of ztailpacking feature |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| erofs: fix buffer copy overflow of ztailpacking feature |
| |
| I got some KASAN report as below: |
| |
| [ 46.959738] ================================================================== |
| [ 46.960430] BUG: KASAN: use-after-free in z_erofs_shifted_transform+0x2bd/0x370 |
| [ 46.960430] Read of size 4074 at addr ffff8880300c2f8e by task fssum/188 |
| ... |
| [ 46.960430] Call Trace: |
| [ 46.960430] <TASK> |
| [ 46.960430] dump_stack_lvl+0x41/0x5e |
| [ 46.960430] print_report.cold+0xb2/0x6b7 |
| [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 |
| [ 46.960430] kasan_report+0x8a/0x140 |
| [ 46.960430] ? z_erofs_shifted_transform+0x2bd/0x370 |
| [ 46.960430] kasan_check_range+0x14d/0x1d0 |
| [ 46.960430] memcpy+0x20/0x60 |
| [ 46.960430] z_erofs_shifted_transform+0x2bd/0x370 |
| [ 46.960430] z_erofs_decompress_pcluster+0xaae/0x1080 |
| |
| The root cause is that the tail pcluster won't be a complete filesystem |
| block anymore. So if ztailpacking is used, the second part of an |
| uncompressed tail pcluster may not be ``rq->pageofs_out``. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49464 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.17 with commit ab749badf9f41f32509cd103391b81ea7e684b76 and fixed in 5.17.14 with commit 4d53a625f29074e7b8236c2c0e0922edb7608df9 |
| Issue introduced in 5.17 with commit ab749badf9f41f32509cd103391b81ea7e684b76 and fixed in 5.18.3 with commit 6b59e1907f58cf877c563dcf013159eb9f994b64 |
| Issue introduced in 5.17 with commit ab749badf9f41f32509cd103391b81ea7e684b76 and fixed in 5.19 with commit dcbe6803fffd387f72b48c2373b5f5ed12a5804b |
| |
| 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-2022-49464 |
| 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: |
| fs/erofs/decompressor.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/4d53a625f29074e7b8236c2c0e0922edb7608df9 |
| https://git.kernel.org/stable/c/6b59e1907f58cf877c563dcf013159eb9f994b64 |
| https://git.kernel.org/stable/c/dcbe6803fffd387f72b48c2373b5f5ed12a5804b |
