In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid mapping wrong physical block for swapfile
Xiaolong Guo reported a f2fs bug in bugzilla [1]
[1] https://bugzilla.kernel.org/show_bug.cgi?id=220951
Quoted:
"When using stress-ng's swap stress test on F2FS filesystem with kernel 6.6+,
the system experiences data corruption leading to either:
1 dm-verity corruption errors and device reboot
2 F2FS node corruption errors and boot hangs
The issue occurs specifically when:
1 Using F2FS filesystem (ext4 is unaffected)
2 Swapfile size is less than F2FS section size (2MB)
3 Swapfile has fragmented physical layout (multiple non-contiguous extents)
4 Kernel version is 6.6+ (6.1 is unaffected)
The root cause is in check_swap_activate() function in fs/f2fs/data.c. When the
first extent of a small swapfile (< 2MB) is not aligned to section boundaries,
the function incorrectly treats it as the last extent, failing to map
subsequent extents. This results in incorrect swap_extent creation where only
the first extent is mapped, causing subsequent swap writes to overwrite wrong
physical locations (other files' data).
Steps to Reproduce
1 Setup a device with F2FS-formatted userdata partition
2 Compile stress-ng from https://github.com/ColinIanKing/stress-ng
3 Run swap stress test: (Android devices)
adb shell "cd /data/stressng; ./stress-ng-64 --metrics-brief --timeout 60
--swap 0"
Log:
1 Ftrace shows in kernel 6.6, only first extent is mapped during second
f2fs_map_blocks call in check_swap_activate():
stress-ng-swap-8990: f2fs_map_blocks: ino=11002, file offset=0, start
blkaddr=0x43143, len=0x1
(Only 4KB mapped, not the full swapfile)
2 in kernel 6.1, both extents are correctly mapped:
stress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=0, start
blkaddr=0x13cd4, len=0x1
stress-ng-swap-5966: f2fs_map_blocks: ino=28011, file offset=1, start
blkaddr=0x60c84b, len=0xff
The problematic code is in check_swap_activate():
if ((pblock - SM_I(sbi)->main_blkaddr) % blks_per_sec ||
nr_pblocks % blks_per_sec ||
!f2fs_valid_pinned_area(sbi, pblock)) {
bool last_extent = false;
not_aligned++;
nr_pblocks = roundup(nr_pblocks, blks_per_sec);
if (cur_lblock + nr_pblocks > sis->max)
nr_pblocks -= blks_per_sec;
/* this extent is last one */
if (!nr_pblocks) {
nr_pblocks = last_lblock - cur_lblock;
last_extent = true;
}
ret = f2fs_migrate_blocks(inode, cur_lblock, nr_pblocks);
if (ret) {
if (ret == -ENOENT)
ret = -EINVAL;
goto out;
}
if (!last_extent)
goto retry;
}
When the first extent is unaligned and roundup(nr_pblocks, blks_per_sec)
exceeds sis->max, we subtract blks_per_sec resulting in nr_pblocks = 0. The
code then incorrectly assumes this is the last extent, sets nr_pblocks =
last_lblock - cur_lblock (entire swapfile), and performs migration. After
migration, it doesn't retry mapping, so subsequent extents are never processed.
"
In order to fix this issue, we need to lookup block mapping info after
we migrate all blocks in the tail of swapfile.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to avoid UAF in f2fs_write_end_io()
As syzbot reported an use-after-free issue in f2fs_write_end_io().
It is caused by below race condition:
loop device umount
- worker_thread
- loop_process_work
- do_req_filebacked
- lo_rw_aio
- lo_rw_aio_complete
- blk_mq_end_request
- blk_update_request
- f2fs_write_end_io
- dec_page_count
- folio_end_writeback
- kill_f2fs_super
- kill_block_super
- f2fs_put_super
: free(sbi)
: get_pages(, F2FS_WB_CP_DATA)
accessed sbi which is freed
In kill_f2fs_super(), we will drop all page caches of f2fs inodes before
call free(sbi), it guarantee that all folios should end its writeback, so
it should be safe to access sbi before last folio_end_writeback().
Let's relocate ckpt thread wakeup flow before folio_end_writeback() to
resolve this issue.
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix out-of-bounds access in sysfs attribute read/write
Some f2fs sysfs attributes suffer from out-of-bounds memory access and
incorrect handling of integer values whose size is not 4 bytes.
For example:
vm:~# echo 65537 > /sys/fs/f2fs/vde/carve_out
vm:~# cat /sys/fs/f2fs/vde/carve_out
65537
vm:~# echo 4294967297 > /sys/fs/f2fs/vde/atgc_age_threshold
vm:~# cat /sys/fs/f2fs/vde/atgc_age_threshold
1
carve_out maps to {struct f2fs_sb_info}->carve_out, which is a 8-bit
integer. However, the sysfs interface allows setting it to a value
larger than 255, resulting in an out-of-range update.
atgc_age_threshold maps to {struct atgc_management}->age_threshold,
which is a 64-bit integer, but its sysfs interface cannot correctly set
values larger than UINT_MAX.
The root causes are:
1. __sbi_store() treats all default values as unsigned int, which
prevents updating integers larger than 4 bytes and causes out-of-bounds
writes for integers smaller than 4 bytes.
2. f2fs_sbi_show() also assumes all default values are unsigned int,
leading to out-of-bounds reads and incorrect access to integers larger
than 4 bytes.
This patch introduces {struct f2fs_attr}->size to record the actual size
of the integer associated with each sysfs attribute. With this
information, sysfs read and write operations can correctly access and
update values according to their real data size, avoiding memory
corruption and truncation.
erase-install prior to v40.4 commit 2c31239 writes swiftDialog credential output to a hardcoded path /var/tmp/dialog.json. This allows an unauthenticated attacker to intercept admin credentials entered during reinstall/erase operations via creating a named pipe.
The server certificate was not verified when an Arc agent connected to a Guardian or CMC.
A malicious actor could perform a man-in-the-middle attack and intercept the communication between the Arc agent and the Guardian or CMC. This could result in theft of the client token and sensitive information (such as assets and alerts), impersonation of the server, or injection of spoofed data (such as false asset information or vulnerabilities) into the Guardian or CMC.
A logic error in the remove_password() function in Checkmk GmbH's Checkmk versions <2.4.0p23, <2.3.0p43, and 2.2.0 (EOL) allows a low-privileged user to cause data loss.
A Stored HTML Injection vulnerability was discovered in the Alerted Nodes Dashboard functionality due to improper validation on an input parameter.
A malicious authenticated user with the required privileges could edit a node label to inject HTML tags. If the system is configured to use the Alerted Nodes Dashboard, and alerts are reported for the affected node, then the injected HTML may render in the browser of a victim user interacting with it, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.
A Stored HTML Injection vulnerability was discovered in the CMC's Sensor Map functionality due to improper validation on connected Guardians' properties.
A malicious authenticated user with administrator privileges on a Guardian connected to a CMC can edit the Guardian's properties to inject HTML tags. If the Sensor Map functionality is enabled in the CMC, when a victim CMC user interacts with it, then the injected HTML may render in their browser, enabling phishing and possibly open redirect attacks. Full XSS exploitation and direct information disclosure are prevented by the existing input validation and Content Security Policy configuration.