| 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-2025-21712: md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime |
| |
| After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct |
| md_bitmap_stats"), following panic is reported: |
| |
| Oops: general protection fault, probably for non-canonical address |
| RIP: 0010:bitmap_get_stats+0x2b/0xa0 |
| Call Trace: |
| <TASK> |
| md_seq_show+0x2d2/0x5b0 |
| seq_read_iter+0x2b9/0x470 |
| seq_read+0x12f/0x180 |
| proc_reg_read+0x57/0xb0 |
| vfs_read+0xf6/0x380 |
| ksys_read+0x6c/0xf0 |
| do_syscall_64+0x82/0x170 |
| entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| |
| Root cause is that bitmap_get_stats() can be called at anytime if mddev |
| is still there, even if bitmap is destroyed, or not fully initialized. |
| Deferenceing bitmap in this case can crash the kernel. Meanwhile, the |
| above commit start to deferencing bitmap->storage, make the problem |
| easier to trigger. |
| |
| Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex. |
| |
| The Linux kernel CVE team has assigned CVE-2025-21712 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 2.6.13 with commit 32a7627cf3a35396a8e834faf34e38ae9f3b1309 and fixed in 6.1.130 with commit 032fa54f486eac5507976e7e31f079a767bc13a8 |
| Issue introduced in 2.6.13 with commit 32a7627cf3a35396a8e834faf34e38ae9f3b1309 and fixed in 6.6.80 with commit 52848a095b55a302af92f52ca0de5b3112059bb8 |
| Issue introduced in 2.6.13 with commit 32a7627cf3a35396a8e834faf34e38ae9f3b1309 and fixed in 6.12.13 with commit 237e19519c8ff6949f0ef57c4a0243f5b2b0fa18 |
| Issue introduced in 2.6.13 with commit 32a7627cf3a35396a8e834faf34e38ae9f3b1309 and fixed in 6.13.2 with commit 4e9316eee3885bfb311b4759513f2ccf37891c09 |
| Issue introduced in 2.6.13 with commit 32a7627cf3a35396a8e834faf34e38ae9f3b1309 and fixed in 6.14 with commit 8d28d0ddb986f56920ac97ae704cc3340a699a30 |
| |
| 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-2025-21712 |
| 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: |
| drivers/md/md-bitmap.c |
| drivers/md/md.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/032fa54f486eac5507976e7e31f079a767bc13a8 |
| https://git.kernel.org/stable/c/52848a095b55a302af92f52ca0de5b3112059bb8 |
| https://git.kernel.org/stable/c/237e19519c8ff6949f0ef57c4a0243f5b2b0fa18 |
| https://git.kernel.org/stable/c/4e9316eee3885bfb311b4759513f2ccf37891c09 |
| https://git.kernel.org/stable/c/8d28d0ddb986f56920ac97ae704cc3340a699a30 |
