smb: client: fix use-after-free of iface in cifs_try_adding_channels()
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.6.160, 6.12.112, 6.18.54, 7.2.8
- 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: fix use-after-free of iface in cifs_try_adding_channels() cifs_try_adding_channels() iterates ses->iface_list with list_for_each_entry_safe_from(), which captures the next entry (niface) under iface_lock. The loop body then drops iface_lock for the whole duration of cifs_ses_add_channel(). A concurrent interface refresh (SMB3_request_interfaces() -> parse_server_interfaces()) marks all ifaces inactive and removes and frees any that are not re-advertised via list_del() + kref_put(), where release_iface() is a bare kfree(). Since niface typically has no channel holding a reference, the list reference is its last and it can be freed inside the unlocked window. On continue, the iterator advance step then dereferences niface->iface_head.next, and the loop body reads iface->rdma_capable/is_active, both on freed memory. Fix this by never keeping an unreferenced list pointer across the unlocked window. Each channel attempt now re-scans the list from the head under iface_lock, takes a kref on the selected candidate, and passes only that referenced candidate to cifs_ses_add_channel(). weight_fulfilled still tracks selection progress, so restarting the scan preserves the original weighted distribution and the weight_fulfilled-before-kref_put ordering on the failure path. Add a per-pass attempts cap so a flapping interface refresh cannot keep the inner loop spinning within a single tries increment.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From aa45dadd34e44fcd6a9df4b395bee5b5633b4cec · fixed in ee0d8f83d68f6e6509f092c997ccab3c8c801538; From aa45dadd34e44fcd6a9df4b395bee5b5633b4cec · fixed in c941f1ebfd26f683de81091473f3596a218abff0; From aa45dadd34e44fcd6a9df4b395bee5b5633b4cec · fixed in e99040e5e9c60441e6b4725e1a7b88c3106ae903; From aa45dadd34e44fcd6a9df4b395bee5b5633b4cec · fixed in ec36b38e65596950e6c29bed7dfc90b98707c19c; From aa45dadd34e44fcd6a9df4b395bee5b5633b4cec · fixed in d034e836eefd7ce75e588f7031cffbeec594f5ac
- Linux Linux
5.19
- KernelLinux
From 5.19.0 · fixed in 6.6.160; From 6.7.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.54; From 6.19.0 · fixed in 7.2.8