| 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-2025-37739: f2fs: fix to avoid out-of-bounds access in f2fs_truncate_inode_blocks() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| f2fs: fix to avoid out-of-bounds access in f2fs_truncate_inode_blocks() |
| |
| syzbot reports an UBSAN issue as below: |
| |
| ------------[ cut here ]------------ |
| UBSAN: array-index-out-of-bounds in fs/f2fs/node.h:381:10 |
| index 18446744073709550692 is out of range for type '__le32[5]' (aka 'unsigned int[5]') |
| CPU: 0 UID: 0 PID: 5318 Comm: syz.0.0 Not tainted 6.14.0-rc3-syzkaller-00060-g6537cfb395f3 #0 |
| Call Trace: |
| <TASK> |
| __dump_stack lib/dump_stack.c:94 [inline] |
| dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 |
| ubsan_epilogue lib/ubsan.c:231 [inline] |
| __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429 |
| get_nid fs/f2fs/node.h:381 [inline] |
| f2fs_truncate_inode_blocks+0xa5e/0xf60 fs/f2fs/node.c:1181 |
| f2fs_do_truncate_blocks+0x782/0x1030 fs/f2fs/file.c:808 |
| f2fs_truncate_blocks+0x10d/0x300 fs/f2fs/file.c:836 |
| f2fs_truncate+0x417/0x720 fs/f2fs/file.c:886 |
| f2fs_file_write_iter+0x1bdb/0x2550 fs/f2fs/file.c:5093 |
| aio_write+0x56b/0x7c0 fs/aio.c:1633 |
| io_submit_one+0x8a7/0x18a0 fs/aio.c:2052 |
| __do_sys_io_submit fs/aio.c:2111 [inline] |
| __se_sys_io_submit+0x171/0x2e0 fs/aio.c:2081 |
| do_syscall_x64 arch/x86/entry/common.c:52 [inline] |
| do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 |
| entry_SYSCALL_64_after_hwframe+0x77/0x7f |
| RIP: 0033:0x7f238798cde9 |
| |
| index 18446744073709550692 (decimal, unsigned long long) |
| = 0xfffffffffffffc64 (hexadecimal, unsigned long long) |
| = -924 (decimal, long long) |
| |
| In f2fs_truncate_inode_blocks(), UBSAN detects that get_nid() tries to |
| access .i_nid[-924], it means both offset[0] and level should zero. |
| |
| The possible case should be in f2fs_do_truncate_blocks(), we try to |
| truncate inode size to zero, however, dn.ofs_in_node is zero and |
| dn.node_page is not an inode page, so it fails to truncate inode page, |
| and then pass zeroed free_from to f2fs_truncate_inode_blocks(), result |
| in this issue. |
| |
| if (dn.ofs_in_node || IS_INODE(dn.node_page)) { |
| f2fs_truncate_data_blocks_range(&dn, count); |
| free_from += count; |
| } |
| |
| I guess the reason why dn.node_page is not an inode page could be: there |
| are multiple nat entries share the same node block address, once the node |
| block address was reused, f2fs_get_node_page() may load a non-inode block. |
| |
| Let's add a sanity check for such condition to avoid out-of-bounds access |
| issue. |
| |
| The Linux kernel CVE team has assigned CVE-2025-37739 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.10.237 with commit a67e1bf03c609a751d1740a1789af25e599966fa |
| Fixed in 5.15.181 with commit 67e16ccba74dd8de0a7b10062f1e02d77432f573 |
| Fixed in 6.1.135 with commit 98dbf2af63de0b551082c9bc48333910e009b09f |
| Fixed in 6.6.88 with commit 8b5e5aac44fee122947a269f9034c048e4c295de |
| Fixed in 6.12.24 with commit ecc461331604b07cdbdb7360dbdf78471653264c |
| Fixed in 6.13.12 with commit d7242fd7946d4cba0411effb6b5048ca55125747 |
| Fixed in 6.14.3 with commit 6ba8b41d0aa4b82f90f0c416cb53fcef9696525d |
| Fixed in 6.15 with commit e6494977bd4a83862118a05f57a8df40256951c0 |
| |
| 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-2025-37739 |
| 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/f2fs/node.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/a67e1bf03c609a751d1740a1789af25e599966fa |
| https://git.kernel.org/stable/c/67e16ccba74dd8de0a7b10062f1e02d77432f573 |
| https://git.kernel.org/stable/c/98dbf2af63de0b551082c9bc48333910e009b09f |
| https://git.kernel.org/stable/c/8b5e5aac44fee122947a269f9034c048e4c295de |
| https://git.kernel.org/stable/c/ecc461331604b07cdbdb7360dbdf78471653264c |
| https://git.kernel.org/stable/c/d7242fd7946d4cba0411effb6b5048ca55125747 |
| https://git.kernel.org/stable/c/6ba8b41d0aa4b82f90f0c416cb53fcef9696525d |
| https://git.kernel.org/stable/c/e6494977bd4a83862118a05f57a8df40256951c0 |
