| 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-2024-26704: ext4: fix double-free of blocks due to wrong extents moved_len |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ext4: fix double-free of blocks due to wrong extents moved_len |
| |
| In ext4_move_extents(), moved_len is only updated when all moves are |
| successfully executed, and only discards orig_inode and donor_inode |
| preallocations when moved_len is not zero. When the loop fails to exit |
| after successfully moving some extents, moved_len is not updated and |
| remains at 0, so it does not discard the preallocations. |
| |
| If the moved extents overlap with the preallocated extents, the |
| overlapped extents are freed twice in ext4_mb_release_inode_pa() and |
| ext4_process_freed_data() (as described in commit 94d7c16cbbbd ("ext4: |
| Fix double-free of blocks with EXT4_IOC_MOVE_EXT")), and bb_free is |
| incremented twice. Hence when trim is executed, a zero-division bug is |
| triggered in mb_update_avg_fragment_size() because bb_free is not zero |
| and bb_fragments is zero. |
| |
| Therefore, update move_len after each extent move to avoid the issue. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26704 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 4.19.307 with commit b4fbb89d722cbb16beaaea234b7230faaaf68c71 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 5.4.269 with commit afbcad9ae7d6d11608399188f03a837451b6b3a1 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 5.10.210 with commit d033a555d9a1cf53dbf3301af7199cc4a4c8f537 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 5.15.149 with commit afba9d11320dad5ce222ac8964caf64b7b4bedb1 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 6.1.79 with commit 185eab30486ba3e7bf8b9c2e049c79a06ffd2bc1 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 6.6.18 with commit 2883940b19c38d5884c8626483811acf4d7e148f |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 6.7.6 with commit 559ddacb90da1d8786dd8ec4fd76bbfa404eaef6 |
| Issue introduced in 3.18 with commit fcf6b1b729bcd23f2b49a84fb33ffbb44712ee6a and fixed in 6.8 with commit 55583e899a5357308274601364741a83e78d6ac4 |
| |
| 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-2024-26704 |
| 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/ext4/move_extent.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/b4fbb89d722cbb16beaaea234b7230faaaf68c71 |
| https://git.kernel.org/stable/c/afbcad9ae7d6d11608399188f03a837451b6b3a1 |
| https://git.kernel.org/stable/c/d033a555d9a1cf53dbf3301af7199cc4a4c8f537 |
| https://git.kernel.org/stable/c/afba9d11320dad5ce222ac8964caf64b7b4bedb1 |
| https://git.kernel.org/stable/c/185eab30486ba3e7bf8b9c2e049c79a06ffd2bc1 |
| https://git.kernel.org/stable/c/2883940b19c38d5884c8626483811acf4d7e148f |
| https://git.kernel.org/stable/c/559ddacb90da1d8786dd8ec4fd76bbfa404eaef6 |
| https://git.kernel.org/stable/c/55583e899a5357308274601364741a83e78d6ac4 |
