CVE-2024-43859: f2fs: fix to truncate preallocated blocks in f2fs_file_open()
Description
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix to truncate preallocated blocks in f2fs_file_open()
chenyuwen reports a f2fs bug as below:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000011
fscrypt_set_bio_crypt_ctx+0x78/0x1e8
f2fs_grab_read_bio+0x78/0x208
f2fs_submit_page_read+0x44/0x154
f2fs_get_read_data_page+0x288/0x5f4
f2fs_get_lock_data_page+0x60/0x190
truncate_partial_data_page+0x108/0x4fc
f2fs_do_truncate_blocks+0x344/0x5f0
f2fs_truncate_blocks+0x6c/0x134
f2fs_truncate+0xd8/0x200
f2fs_iget+0x20c/0x5ac
do_garbage_collect+0x5d0/0xf6c
f2fs_gc+0x22c/0x6a4
f2fs_disable_checkpoint+0xc8/0x310
f2fs_fill_super+0x14bc/0x1764
mount_bdev+0x1b4/0x21c
f2fs_mount+0x20/0x30
legacy_get_tree+0x50/0xbc
vfs_get_tree+0x5c/0x1b0
do_new_mount+0x298/0x4cc
path_mount+0x33c/0x5fc
__arm64_sys_mount+0xcc/0x15c
invoke_syscall+0x60/0x150
el0_svc_common+0xb8/0xf8
do_el0_svc+0x28/0xa0
el0_svc+0x24/0x84
el0t_64_sync_handler+0x88/0xec
It is because inode.i_crypt_info is not initialized during below path:
- mount
- f2fs_fill_super
- f2fs_disable_checkpoint
- f2fs_gc
- f2fs_iget
- f2fs_truncate
So, let's relocate truncation of preallocated blocks to f2fs_file_open(),
after fscrypt_file_open().
Classification
CVE ID: CVE-2024-43859
Affected Products
Vendor: Linux
Product: Linux
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.05% (probability of being exploited)
EPSS Percentile: 14.39% (scored less or equal to compared to others)
EPSS Date: 2025-05-05 (when was this score calculated)
Stakeholder-Specific Vulnerability Categorization (SSVC)
SSVC Exploitation: none
SSVC Technical Impact: partial
SSVC Automatable: false
References
https://nvd.nist.gov/vuln/detail/CVE-2024-43859https://git.kernel.org/stable/c/5f04969136db674f133781626e0b692c5f2bf2f0
https://git.kernel.org/stable/c/f44a25a8bfe0c15d33244539696cd9119cf44d18
https://git.kernel.org/stable/c/3ba0ae885215b325605ff7ebf6de12ac2adf204d
https://git.kernel.org/stable/c/298b1e4182d657c3e388adcc29477904e9600ed5