5.5

CVE-2021-47007

f2fs: fix panic during f2fs_resize_fs()

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

f2fs: fix panic during f2fs_resize_fs()

f2fs_resize_fs() hangs in below callstack with testcase:
- mkfs 16GB image & mount image
- dd 8GB fileA
- dd 8GB fileB
- sync
- rm fileA
- sync
- resize filesystem to 8GB

kernel BUG at segment.c:2484!
Call Trace:
 allocate_segment_by_default+0x92/0xf0 [f2fs]
 f2fs_allocate_data_block+0x44b/0x7e0 [f2fs]
 do_write_page+0x5a/0x110 [f2fs]
 f2fs_outplace_write_data+0x55/0x100 [f2fs]
 f2fs_do_write_data_page+0x392/0x850 [f2fs]
 move_data_page+0x233/0x320 [f2fs]
 do_garbage_collect+0x14d9/0x1660 [f2fs]
 free_segment_range+0x1f7/0x310 [f2fs]
 f2fs_resize_fs+0x118/0x330 [f2fs]
 __f2fs_ioctl+0x487/0x3680 [f2fs]
 __x64_sys_ioctl+0x8e/0xd0
 do_syscall_64+0x33/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The root cause is we forgot to check that whether we have enough space
in resized filesystem to store all valid blocks in before-resizing
filesystem, then allocator will run out-of-space during block migration
in free_segment_range().
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.8 < 5.10.38
Linux ≫ Linux Kernel Version >= 5.11 < 5.11.22
Linux ≫ Linux Kernel Version >= 5.12 < 5.12.5
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.24% 0.143
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 5.5 1.8 3.6
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-754 Improper Check for Unusual or Exceptional Conditions

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

https://git.kernel.org/stable/c/1c20a4896409f5ca1c770e1880c33d0a28a8b10f
Patch
https://git.kernel.org/stable/c/3ab0598e6d860ef49d029943ba80f627c15c15d6
Patch
https://git.kernel.org/stable/c/822054e5026c43b1dd60cf387dd999e95ee2ecc2
Patch
https://git.kernel.org/stable/c/860afd680d9cc1dabd61cda3cd246f60aa1eb705
Patch