| From bippy-1.1.0 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-2025-21853: bpf: avoid holding freeze_mutex during mmap operation |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: avoid holding freeze_mutex during mmap operation |
| |
| We use map->freeze_mutex to prevent races between map_freeze() and |
| memory mapping BPF map contents with writable permissions. The way we |
| naively do this means we'll hold freeze_mutex for entire duration of all |
| the mm and VMA manipulations, which is completely unnecessary. This can |
| potentially also lead to deadlocks, as reported by syzbot in [0]. |
| |
| So, instead, hold freeze_mutex only during writeability checks, bump |
| (proactively) "write active" count for the map, unlock the mutex and |
| proceed with mmap logic. And only if something went wrong during mmap |
| logic, then undo that "write active" counter increment. |
| |
| [0] https://lore.kernel.org/bpf/678dcbc9.050a0220.303755.0066.GAE@google.com/ |
| |
| The Linux kernel CVE team has assigned CVE-2025-21853 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 5.10.237 with commit 2ce31c97c219b4fe797749f950274f246eb88c49 |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 5.15.181 with commit 0d90d9e154144a3a80e9fc0eb9b21b7fc990f68f |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 6.1.135 with commit 4759acbd44d24a69b7b14848012ec4201d6c5501 |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 6.6.80 with commit 29cfda62ab4d92ab94123813db49ab76c1e61b29 |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 6.12.17 with commit d95607a5f2f9bb08194c9deaf4a5f3e8ba59a9d4 |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 6.13.5 with commit 271e49f8a58edba65bc2b1250a0abaa98c4bfdbe |
| Issue introduced in 5.5 with commit fc9702273e2edb90400a34b3be76f7b08fa3344b and fixed in 6.14 with commit bc27c52eea189e8f7492d40739b7746d67b65beb |
| |
| 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-2025-21853 |
| 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: |
| kernel/bpf/syscall.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/2ce31c97c219b4fe797749f950274f246eb88c49 |
| https://git.kernel.org/stable/c/0d90d9e154144a3a80e9fc0eb9b21b7fc990f68f |
| https://git.kernel.org/stable/c/4759acbd44d24a69b7b14848012ec4201d6c5501 |
| https://git.kernel.org/stable/c/29cfda62ab4d92ab94123813db49ab76c1e61b29 |
| https://git.kernel.org/stable/c/d95607a5f2f9bb08194c9deaf4a5f3e8ba59a9d4 |
| https://git.kernel.org/stable/c/271e49f8a58edba65bc2b1250a0abaa98c4bfdbe |
| https://git.kernel.org/stable/c/bc27c52eea189e8f7492d40739b7746d67b65beb |
