| 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-2021-47007: f2fs: fix panic during f2fs_resize_fs() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| f2fs: fix panic during f2fs_resize_fs() |
| |
| f2fs_resize_fs() hangs in below callstack with testcase: |
| - mkfs 16GB image & mount image |
| - dd 8GB fileA |
| - dd 8GB fileB |
| - sync |
| - rm fileA |
| - sync |
| - resize filesystem to 8GB |
| |
| kernel BUG at segment.c:2484! |
| Call Trace: |
| allocate_segment_by_default+0x92/0xf0 [f2fs] |
| f2fs_allocate_data_block+0x44b/0x7e0 [f2fs] |
| do_write_page+0x5a/0x110 [f2fs] |
| f2fs_outplace_write_data+0x55/0x100 [f2fs] |
| f2fs_do_write_data_page+0x392/0x850 [f2fs] |
| move_data_page+0x233/0x320 [f2fs] |
| do_garbage_collect+0x14d9/0x1660 [f2fs] |
| free_segment_range+0x1f7/0x310 [f2fs] |
| f2fs_resize_fs+0x118/0x330 [f2fs] |
| __f2fs_ioctl+0x487/0x3680 [f2fs] |
| __x64_sys_ioctl+0x8e/0xd0 |
| do_syscall_64+0x33/0x80 |
| entry_SYSCALL_64_after_hwframe+0x44/0xa9 |
| |
| The root cause is we forgot to check that whether we have enough space |
| in resized filesystem to store all valid blocks in before-resizing |
| filesystem, then allocator will run out-of-space during block migration |
| in free_segment_range(). |
| |
| The Linux kernel CVE team has assigned CVE-2021-47007 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.8 with commit b4b10061ef98c583bcf82a4200703fbaa98c18dc and fixed in 5.10.38 with commit 1c20a4896409f5ca1c770e1880c33d0a28a8b10f |
| Issue introduced in 5.8 with commit b4b10061ef98c583bcf82a4200703fbaa98c18dc and fixed in 5.11.22 with commit 860afd680d9cc1dabd61cda3cd246f60aa1eb705 |
| Issue introduced in 5.8 with commit b4b10061ef98c583bcf82a4200703fbaa98c18dc and fixed in 5.12.5 with commit 822054e5026c43b1dd60cf387dd999e95ee2ecc2 |
| Issue introduced in 5.8 with commit b4b10061ef98c583bcf82a4200703fbaa98c18dc and fixed in 5.13 with commit 3ab0598e6d860ef49d029943ba80f627c15c15d6 |
| |
| 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-2021-47007 |
| 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/f2fs/gc.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/1c20a4896409f5ca1c770e1880c33d0a28a8b10f |
| https://git.kernel.org/stable/c/860afd680d9cc1dabd61cda3cd246f60aa1eb705 |
| https://git.kernel.org/stable/c/822054e5026c43b1dd60cf387dd999e95ee2ecc2 |
| https://git.kernel.org/stable/c/3ab0598e6d860ef49d029943ba80f627c15c15d6 |
