| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2024-26958: nfs: fix UAF in direct writes |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| nfs: fix UAF in direct writes |
| |
| In production we have been hitting the following warning consistently |
| |
| ------------[ cut here ]------------ |
| refcount_t: underflow; use-after-free. |
| WARNING: CPU: 17 PID: 1800359 at lib/refcount.c:28 refcount_warn_saturate+0x9c/0xe0 |
| Workqueue: nfsiod nfs_direct_write_schedule_work [nfs] |
| RIP: 0010:refcount_warn_saturate+0x9c/0xe0 |
| PKRU: 55555554 |
| Call Trace: |
| <TASK> |
| ? __warn+0x9f/0x130 |
| ? refcount_warn_saturate+0x9c/0xe0 |
| ? report_bug+0xcc/0x150 |
| ? handle_bug+0x3d/0x70 |
| ? exc_invalid_op+0x16/0x40 |
| ? asm_exc_invalid_op+0x16/0x20 |
| ? refcount_warn_saturate+0x9c/0xe0 |
| nfs_direct_write_schedule_work+0x237/0x250 [nfs] |
| process_one_work+0x12f/0x4a0 |
| worker_thread+0x14e/0x3b0 |
| ? ZSTD_getCParams_internal+0x220/0x220 |
| kthread+0xdc/0x120 |
| ? __btf_name_valid+0xa0/0xa0 |
| ret_from_fork+0x1f/0x30 |
| |
| This is because we're completing the nfs_direct_request twice in a row. |
| |
| The source of this is when we have our commit requests to submit, we |
| process them and send them off, and then in the completion path for the |
| commit requests we have |
| |
| if (nfs_commit_end(cinfo.mds)) |
| nfs_direct_write_complete(dreq); |
| |
| However since we're submitting asynchronous requests we sometimes have |
| one that completes before we submit the next one, so we end up calling |
| complete on the nfs_direct_request twice. |
| |
| The only other place we use nfs_generic_commit_list() is in |
| __nfs_commit_inode, which wraps this call in a |
| |
| nfs_commit_begin(); |
| nfs_commit_end(); |
| |
| Which is a common pattern for this style of completion handling, one |
| that is also repeated in the direct code with get_dreq()/put_dreq() |
| calls around where we process events as well as in the completion paths. |
| |
| Fix this by using the same pattern for the commit requests. |
| |
| Before with my 200 node rocksdb stress running this warning would pop |
| every 10ish minutes. With my patch the stress test has been running for |
| several hours without popping. |
| |
| The Linux kernel CVE team has assigned CVE-2024-26958 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 5.10.215 with commit 4595d90b5d2ea5fa4d318d13f59055aa4bf3e7f5 |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 5.15.154 with commit 80d24b308b7ee7037fc90d8ac99f6f78df0a256f |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 6.1.84 with commit 3abc2d160ed8213948b147295d77d44a22c88fa3 |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 6.6.24 with commit e25447c35f8745337ea8bc0c9697fcac14df8605 |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 6.7.12 with commit 1daf52b5ffb24870fbeda20b4967526d8f9e12ab |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 6.8.3 with commit cf54f66e1dd78990ec6b32177bca7e6ea2144a95 |
| Issue introduced in 4.5 with commit af7cf057933f01dc7f33ddfb5e436ad598ed17ad and fixed in 6.9 with commit 17f46b803d4f23c66cacce81db35fef3adb8f2af |
| |
| 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-2024-26958 |
| 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/nfs/direct.c |
| fs/nfs/write.c |
| include/linux/nfs_fs.h |
| |
| |
| 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/4595d90b5d2ea5fa4d318d13f59055aa4bf3e7f5 |
| https://git.kernel.org/stable/c/80d24b308b7ee7037fc90d8ac99f6f78df0a256f |
| https://git.kernel.org/stable/c/3abc2d160ed8213948b147295d77d44a22c88fa3 |
| https://git.kernel.org/stable/c/e25447c35f8745337ea8bc0c9697fcac14df8605 |
| https://git.kernel.org/stable/c/1daf52b5ffb24870fbeda20b4967526d8f9e12ab |
| https://git.kernel.org/stable/c/cf54f66e1dd78990ec6b32177bca7e6ea2144a95 |
| https://git.kernel.org/stable/c/17f46b803d4f23c66cacce81db35fef3adb8f2af |
