xfs: fix out of bounds memory read error in symlink repair
In the Linux kernel, the following vulnerability has been resolved:
xfs: fix out of bounds memory read error in symlink repair
xfs/286 produced this report on my test fleet:
==================================================================
BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110
Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):
memcpy_orig+0x54/0x110
xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]
xrep_symlink_salvage+0x100/0x110 [xfs]
xrep_symlink+0x2e/0x80 [xfs]
xrep_attempt+0x61/0x1f0 [xfs]
xfs_scrub_metadata+0x34f/0x5c0 [xfs]
xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]
xfs_file_ioctl+0xe23/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128
allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):
xfs_init_local_fork+0x79/0xe0 [xfs]
xfs_iformat_local+0xa4/0x170 [xfs]
xfs_iformat_data_fork+0x148/0x180 [xfs]
xfs_inode_from_disk+0x2cd/0x480 [xfs]
xfs_iget+0x450/0xd60 [xfs]
xfs_bulkstat_one_int+0x6b/0x510 [xfs]
xfs_bulkstat_iwalk+0x1e/0x30 [xfs]
xfs_iwalk_ag_recs+0xdf/0x150 [xfs]
xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]
xfs_iwalk_ag+0x1dc/0x2f0 [xfs]
xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]
xfs_iwalk+0xa4/0xd0 [xfs]
xfs_bulkstat+0xfa/0x170 [xfs]
xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]
xfs_file_ioctl+0xbf2/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy) 3d744dd94e92690f00a04398d2bd8631dcef1954
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014
==================================================================
On further analysis, I realized that the second parameter to min() is
not correct. xfs_ifork::if_bytes is the size of the xfs_ifork::if_data
buffer. if_bytes can be smaller than the data fork size because:
(a) the forkoff code tries to keep the data area as large as possible
(b) for symbolic links, if_bytes is the ondisk file size + 1
(c) forkoff is always a multiple of 8.
Case in point: for a single-byte symlink target, forkoff will be
8 but the buffer will only be 2 bytes long.
In other words, the logic here is wrong and we walk off the end of the
incore buffer. Fix that.
CVE 정보
EPSS
EPSS는 취약점이 악용될 가능성을 예측하는 점수 모델입니다.
EPSS 점수
EPSS 모델은 0과 1(0~100%) 사이의 확률 점수를 생성합니다. 점수가 높을수록 취약점이 악용될 가능성이 높습니다.
날짜
EPSS V0
EPSS V1
EPSS V2 (> 2022-02-04)
EPSS V3 (> 2025-03-07)
EPSS V4 (> 2025-03-17)
2025-12-05
–
–
–
–
0.02%
2025-12-10
–
–
–
–
0.02%
2026-01-05
–
–
–
–
0.02%
2026-02-22
–
–
–
–
0.03%
2026-03-08
–
–
–
–
0.03%
2026-03-22
–
–
–
–
0.03%
2026-04-05
–
–
–
–
0.03%
2026-05-10
–
–
–
–
0.02%
2026-05-17
–
–
–
–
0.02%
EPSS 백분위수
백분위수는 EPSS 점수에 따라 CVE의 순위를 매기는 데 사용됩니다. 예를 들어 EPSS 점수 기준 95번째 백분위수의 CVE는 다른 CVE의 95%보다 악용될 가능성이 높습니다.