Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: NFSD: Guard admin state-revocation walks with NFSD_NET_UP Writing to /proc/fs/nfsd/unlock_filesystem, or sending the NFSD_CMD_UNLOCK_FILESYSTEM or NFSD_CMD_UNLOCK_EXPORT netlink command, walks the NFSv4 client hash tables to revoke open state and cancel async COPY operations. All three handlers gate that walk on nn->nfsd_serv, but a listener added via portlist or netlink listener_set sets nn->nfsd_serv before any nfsd thread starts. nfsd_startup_net() has not yet allocated nn->conf_id_hashtbl, so the walkers dereference a NULL table. A local administrator with CAP_SYS_ADMIN can crash the kernel this way without ever starting the server. nn->nfsd_serv is set when the service is created, which precedes table allocation. NFSD_NET_UP instead brackets the window where the tables are live: set at the end of nfsd_startup_net() and cleared in nfsd_shutdown_net() after they are freed, both under nfsd_mutex. Gating the three unlock paths on NFSD_NET_UP fixes the startup-time NULL dereference while preserving the earlier post-shutdown use-after-free fix.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 1ac3629bf012592cb0320e52a1cceb319a05ad17 before 73bf459d696ecf207a9037bf9bb70c51a459469e; affected 1ac3629bf012592cb0320e52a1cceb319a05ad17 before 104a51265042b4424085741c963cb858ac29ec0b; affected 1ac3629bf012592cb0320e52a1cceb319a05ad17 before 0146467a2fce845cb6629979c3e9c58dd3d3a6a3; affected 1ac3629bf012592cb0320e52a1cceb319a05ad17 before 2f3e6638aebc0ab8afb8b4e9816ea9a1cad85378 |
| Linux / Linux | affected 6.9; unaffected 0 before 6.9; unaffected 6.12.111 through 6.12.*; unaffected 6.18.51 through 6.18.*; unaffected 7.2.5 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.