smb: client: avoid leaking refcount in cifs_queue_oplock_break()
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.17, 4.10, 4.15, 4.20, 5.1, and 5 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid leaking refcount in cifs_queue_oplock_break() cifs_queue_oplock_break() unconditionally takes a reference on the target file before queueing cifs_oplock_break(). Only that work item decreases the reference counter again. If another oplock break arrives while that work is still queued, queue_work() will return false and not queue this second work item. As a result, we will never reach the point to drop the file reference again and are leaking this reference. This can be triggered when interacting with a slow-responding server. As a result, later unmount operations for this file system will fail with BUG: Dentry ... still in use (1) [unmount of cifs cifs] VFS: Busy inodes after unmount of cifs (cifs) kernel BUG at fs/super.c:777! Fix this by only incrementing the reference count if the work has been queued successfully. Taking it after queue_work() is safe because all three callers hold tcon->open_file_lock across the call and _cifsFileInfo_put() decrements under that same lock, so a worker that starts the handler in the window cannot drop the reference before it has been taken.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in 735a3a610136ae10f381d0909dff38e5b5c5f056; From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in de2a6bcff2659bea40c7485115b57f0ae189fc01; From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in af0193bbf1ac8c0f67f972998b0cc629d6116cf6; From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in 2ed2c29dd9593637cfa25ac1eb23241b20202778; From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in dfe7b750c7e069873a8a57a11c816831a235618a; From b98749cac4a695f084a5ff076f4510b23e353ecd · fixed in 9f2e63f1b2d5fc5b5423424902c091123e220e7e; From 3.16.72 · fixed in 3.17; From 4.9.171 · fixed in 4.10; From 4.14.114 · fixed in 4.15; From 4.19.37 · fixed in 4.20; From 5.0.10 · fixed in 5.1
- Linux Linux
5.1
- KernelLinux
From 5.1.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7