ksmbd: fix use-after-free in oplock break notification
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.6.158, 6.12.111, 6.18.51, 7.1, 7.2.5
- 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: ksmbd: fix use-after-free in oplock break notification smb2_oplock_break_noti() reads opinfo->conn without any lock and dereferences it after two allocations which may sleep. When the durable handle owning the oplock is disconnected, session_fd_check() clears opinfo->conn and drops its conn reference under ci->m_lock, and the last ksmbd_conn_put() frees the connection. A break triggered by another connection that races with the teardown can then resurrect the freed connection: ksmbd_conn_get() is a plain atomic_inc, and the queued break work later dereferences the stale conn via ksmbd_conn_write(), a use-after-free reachable by any authenticated client holding a durable batch oplock. Thread the caller's inode into the notification path instead of taking a new reference on it. Every caller of oplock_break() already holds a live ksmbd_file (or an explicit ksmbd_inode_lookup_lock() reference, in the parent lease break paths) on the inode that owns the break target's oplock list, so ci cannot be freed during the call, and its lock can be taken without dereferencing opinfo->o_fp, which a concurrent close may free. Select and pin the connection under ci->m_lock, the same lock session_fd_check() and ksmbd_reopen_durable_fd() use to update opinfo->conn, so a concurrent detach either loses the race to the clear or keeps the connection alive until the notification work releases it. Transfer the reference to the work item and release it on allocation failures.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 945a86b21b40fb17183f5b27461baa6f03e2467f · fixed in 892f643b141aee3f7aa7c0fc61ddcb55c59f1996; From 1ff58dcfcab434ebb51649da33774fbb8e1f7b67 · fixed in 5de0527f782430b1109a447646e32033ad018a6a; From e735dbd489e3ea02be78dba991056fe1138be51e · fixed in c8279ae8df68cce9cd3b785e85f7a86c80a46e78; From b003086d76968298f22e7cf62239833b5a3a06b1 · fixed in 8cc98db4fc590e6c7d9db6529320982ee16c5d1d; From b003086d76968298f22e7cf62239833b5a3a06b1 · fixed in 0e753899627b5e28a9fea8bca98262a6f65a2452; From 6.6.143 · fixed in 6.6.158; From 6.12.94 · fixed in 6.12.111; From 6.18.36 · fixed in 6.18.51; From 7.0.13 · fixed in 7.1
- Linux Linux
7.1
- KernelLinux
fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.5