lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <2025050921-CVE-2025-37856-3117@gregkh> Date: Fri, 9 May 2025 08:42:34 +0200 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-cve-announce@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...nel.org> Subject: CVE-2025-37856: btrfs: harden block_group::bg_list against list_del() races From: Greg Kroah-Hartman <gregkh@...nel.org> Description =========== In the Linux kernel, the following vulnerability has been resolved: btrfs: harden block_group::bg_list against list_del() races As far as I can tell, these calls of list_del_init() on bg_list cannot run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(), as they are in transaction error paths and situations where the block group is readonly. However, if there is any chance at all of racing with mark_bg_unused(), or a different future user of bg_list, better to be safe than sorry. Otherwise we risk the following interleaving (bg_list refcount in parens) T1 (some random op) T2 (btrfs_mark_bg_unused) !list_empty(&bg->bg_list); (1) list_del_init(&bg->bg_list); (1) list_move_tail (1) btrfs_put_block_group (0) btrfs_delete_unused_bgs bg = list_first_entry list_del_init(&bg->bg_list); btrfs_put_block_group(bg); (-1) Ultimately, this results in a broken ref count that hits zero one deref early and the real final deref underflows the refcount, resulting in a WARNING. The Linux kernel CVE team has assigned CVE-2025-37856 to this issue. Affected and fixed versions =========================== Fixed in 6.12.24 with commit bf089c4d1141b27332c092b1dcca5022c415a3b6 Fixed in 6.13.12 with commit 909e60fb469d4101c6b08cf6e622efb062bb24a1 Fixed in 6.14.3 with commit 185fd73e5ac06027c4be9a129e59193f6a3ef202 Fixed in 6.15-rc1 with commit 7511e29cf1355b2c47d0effb39e463119913e2f6 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-2025-37856 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/btrfs/extent-tree.c fs/btrfs/transaction.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/bf089c4d1141b27332c092b1dcca5022c415a3b6 https://git.kernel.org/stable/c/909e60fb469d4101c6b08cf6e622efb062bb24a1 https://git.kernel.org/stable/c/185fd73e5ac06027c4be9a129e59193f6a3ef202 https://git.kernel.org/stable/c/7511e29cf1355b2c47d0effb39e463119913e2f6
Powered by blists - more mailing lists