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CVE-2021-47189 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix memory ordering between normal and ordered work functions Ordered work functions aren't guaranteed to be handled by the same thread which executed the normal work functions. The only way execution between normal/ordered functions is synchronized is via the WORK_DONE_BIT, unfortunately the used bitops don't guarantee any ordering whatsoever. This manifested as seemingly inexplicable crashes on ARM64, where async_chunk::inode is seen as non-null in async_cow_submit which causes submit_compressed_extents to be called and crash occurs because async_chunk::inode suddenly became NULL. The call trace was similar to: pc : submit_compressed_extents+0x38/0x3d0 lr : async_cow_submit+0x50/0xd0 sp : ffff800015d4bc20 <registers omitted for brevity> Call trace: submit_compressed_extents+0x38/0x3d0 async_cow_submit+0x50/0xd0 run_ordered_work+0xc8/0x280 btrfs_work_helper+0x98/0x250 process_one_work+0x1f0/0x4ac worker_thread+0x188/0x504 kthread+0x110/0x114 ret_from_fork+0x10/0x18 Fix this by adding respective barrier calls which ensure that all accesses preceding setting of WORK_DONE_BIT are strictly ordered before setting the flag. At the same time add a read barrier after reading of WORK_DONE_BIT in run_ordered_work which ensures all subsequent loads would be strictly ordered after reading the bit. This in turn ensures are all accesses before WORK_DONE_BIT are going to be strictly ordered before any access that can occur in ordered_func.


Severity



CVSS 4.0 Severity and Metrics:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

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Hyperlink Resource
https://git.kernel.org/stable/c/45da9c1767ac31857df572f0a909fbe88fd5a7e9
https://git.kernel.org/stable/c/47e6f9f69153247109042010f3a77579e9dc61ff
https://git.kernel.org/stable/c/637d652d351fd4f263ef302dc52f3971d314e500
https://git.kernel.org/stable/c/670f6b3867c8f0f11e5097f353b164cecfec6179
https://git.kernel.org/stable/c/6adbc07ebcaf8bead08b21687d49e0fc94400987
https://git.kernel.org/stable/c/804a9d239ae9cbe88e861a7cd62319cc6ec7b136
https://git.kernel.org/stable/c/bd660a20fea3ec60a49709ef5360f145ec0fe779
https://git.kernel.org/stable/c/ed058d735a70f4b063323f1a7bb33cda0f987513

Weakness Enumeration

CWE-ID CWE Name Source

Change History

3 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2021-47189
NVD Published Date:
04/10/2024
NVD Last Modified:
04/10/2024
Source:
kernel.org