| 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-2024-26773: ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ext4: avoid allocating blocks from corrupted group in ext4_mb_try_best_found() |
| |
| Determine if the group block bitmap is corrupted before using ac_b_ex in |
| ext4_mb_try_best_found() to avoid allocating blocks from a group with a |
| corrupted block bitmap in the following concurrency and making the |
| situation worse. |
| |
| ext4_mb_regular_allocator |
| ext4_lock_group(sb, group) |
| ext4_mb_good_group |
| // check if the group bbitmap is corrupted |
| ext4_mb_complex_scan_group |
| // Scan group gets ac_b_ex but doesn't use it |
| ext4_unlock_group(sb, group) |
| ext4_mark_group_bitmap_corrupted(group) |
| // The block bitmap was corrupted during |
| // the group unlock gap. |
| ext4_mb_try_best_found |
| ext4_lock_group(ac->ac_sb, group) |
| ext4_mb_use_best_found |
| mb_mark_used |
| // Allocating blocks in block bitmap corrupted group |
| |
| The Linux kernel CVE team has assigned CVE-2024-26773 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 4.19.308 with commit 21f8cfe79f776287459343e9cfa6055af61328ea |
| Fixed in 5.4.270 with commit 260fc96283c0f594de18a1b045faf6d8fb42874d |
| Fixed in 5.10.211 with commit 927794a02169778c9c2e7b25c768ab3ea8c1dc03 |
| Fixed in 5.15.150 with commit 4c21fa60a6f4606f6214a38f50612b17b2f738f5 |
| Fixed in 6.1.80 with commit f97e75fa4e12b0aa0224e83fcbda8853ac2adf36 |
| Fixed in 6.6.19 with commit 0184747b552d6b5a14db3b7fcc3b792ce64dedd1 |
| Fixed in 6.7.7 with commit a2576ae9a35c078e488f2c573e9e6821d651fbbe |
| Fixed in 6.8 with commit 4530b3660d396a646aad91a787b6ab37cf604b53 |
| |
| 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-2024-26773 |
| 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/mballoc.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/21f8cfe79f776287459343e9cfa6055af61328ea |
| https://git.kernel.org/stable/c/260fc96283c0f594de18a1b045faf6d8fb42874d |
| https://git.kernel.org/stable/c/927794a02169778c9c2e7b25c768ab3ea8c1dc03 |
| https://git.kernel.org/stable/c/4c21fa60a6f4606f6214a38f50612b17b2f738f5 |
| https://git.kernel.org/stable/c/f97e75fa4e12b0aa0224e83fcbda8853ac2adf36 |
| https://git.kernel.org/stable/c/0184747b552d6b5a14db3b7fcc3b792ce64dedd1 |
| https://git.kernel.org/stable/c/a2576ae9a35c078e488f2c573e9e6821d651fbbe |
| https://git.kernel.org/stable/c/4530b3660d396a646aad91a787b6ab37cf604b53 |
