Vulnerability CVE-2024-42273
Published: 2024-08-17

Description:
In the Linux kernel, the following vulnerability has been resolved:

f2fs: assign CURSEG_ALL_DATA_ATGC if blkaddr is valid

mkdir /mnt/test/comp
f2fs_io setflags compression /mnt/test/comp
dd if=/dev/zero of=/mnt/test/comp/testfile bs=16k count=1
truncate --size 13 /mnt/test/comp/testfile

In the above scenario, we can get a BUG_ON.
kernel BUG at fs/f2fs/segment.c:3589!
Call Trace:
do_write_page+0x78/0x390 [f2fs]
f2fs_outplace_write_data+0x62/0xb0 [f2fs]
f2fs_do_write_data_page+0x275/0x740 [f2fs]
f2fs_write_single_data_page+0x1dc/0x8f0 [f2fs]
f2fs_write_multi_pages+0x1e5/0xae0 [f2fs]
f2fs_write_cache_pages+0xab1/0xc60 [f2fs]
f2fs_write_data_pages+0x2d8/0x330 [f2fs]
do_writepages+0xcf/0x270
__writeback_single_inode+0x44/0x350
writeback_sb_inodes+0x242/0x530
__writeback_inodes_wb+0x54/0xf0
wb_writeback+0x192/0x310
wb_workfn+0x30d/0x400

The reason is we gave CURSEG_ALL_DATA_ATGC to COMPR_ADDR where the
page was set the gcing flag by set_cluster_dirty().

 References:
https://git.kernel.org/stable/c/5fd057160ab240dd816ae09b625395d54c297de1
https://git.kernel.org/stable/c/4239571c5db46a42f723b8fa8394039187c34439
https://git.kernel.org/stable/c/0cd106612396656d6f1ca17ef192c6759bb60791
https://git.kernel.org/stable/c/8cb1f4080dd91c6e6b01dbea013a3f42341cb6a1
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