cbcvebase.
CVE-2021-46982
published 2024-02-28

CVE-2021-46982: In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: fix race condition of overwrite vs truncate pos_fsstress testcase complains…

PriorityP417medium4.7CVSS 3.1
AVLACHPRLUINSUCNINAH
EPSS
0.18%
7.6th percentile
In the Linux kernel, the following vulnerability has been resolved: f2fs: compress: fix race condition of overwrite vs truncate pos_fsstress testcase complains a panic as belew: ------------[ cut here ]------------ kernel BUG at fs/f2fs/compress.c:1082! invalid opcode: 0000 [#1] SMP PTI CPU: 4 PID: 2753477 Comm: kworker/u16:2 Tainted: G OE 5.12.0-rc1-custom #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: writeback wb_workfn (flush-252:16) RIP: 0010:prepare_compress_overwrite+0x4c0/0x760 [f2fs] Call Trace: f2fs_prepare_compress_overwrite+0x5f/0x80 [f2fs] f2fs_write_cache_pages+0x468/0x8a0 [f2fs] f2fs_write_data_pages+0x2a4/0x2f0 [f2fs] do_writepages+0x38/0xc0 __writeback_single_inode+0x44/0x2a0 writeback_sb_inodes+0x223/0x4d0 __writeback_inodes_wb+0x56/0xf0 wb_writeback+0x1dd/0x290 wb_workfn+0x309/0x500 process_one_work+0x220/0x3c0 worker_thread+0x53/0x420 kthread+0x12f/0x150 ret_from_fork+0x22/0x30 The root cause is truncate() may race with overwrite as below, so that one reference count left in page can not guarantee the page attaching in mapping tree all the time, after truncation, later find_lock_page() may return NULL pointer. - prepare_compress_overwrite - f2fs_pagecache_get_page - unlock_page - f2fs_setattr - truncate_setsize - truncate_inode_page - delete_from_page_cache - find_lock_page Fix this by avoiding referencing updated page.

Affected

14 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 5.10.38-1 (bookworm)linux 5.10.38-1 (bookworm)
linuxlinux——
linuxlinux>= 4c8ff7095bef64fc47e996a938f7d57f9e077da3 < 5639b73fd3bc6fc8ca72e3a9ac15aacaabd7ebff5639b73fd3bc6fc8ca72e3a9ac15aacaabd7ebff
linuxlinux>= 4c8ff7095bef64fc47e996a938f7d57f9e077da3 < 64acb100fe3beb5d20184d0ae3307235bd3555c464acb100fe3beb5d20184d0ae3307235bd3555c4
linuxlinux>= 4c8ff7095bef64fc47e996a938f7d57f9e077da3 < 936158b15e2648253afb824d252c910c496d34b5936158b15e2648253afb824d252c910c496d34b5
linuxlinux>= 4c8ff7095bef64fc47e996a938f7d57f9e077da3 < a949dc5f2c5cfe0c910b664650f45371254c0744a949dc5f2c5cfe0c910b664650f45371254c0744
linuxlinux_kernel——
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 0 < 5.10.38-15.10.38-1
linuxlinux_kernel>= 5.11 < 5.11.225.11.22
linuxlinux_kernel>= 5.12 < 5.12.55.12.5
linuxlinux_kernel>= 5.6 < 5.10.385.10.38

CVSS provenance

nvdv3.14.7MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
osv4.7MEDIUM
vendor_debian4.7MEDIUM
vendor_redhat4.7MEDIUM
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