Description
In the Linux kernel, the following vulnerability has been resolved: NFSD: Prevent client use-after-free during admin state revocation A stateid holds only a bare pointer to its nfs4_client; a stateid reference does not pin it. The client survives only because __destroy_client() drains its stateids before free_client() runs. nfsd4_revoke_states() drops nn->client_lock across revoke_one_stid(), which dereferences the client to revoke a stateid and read clp->cl_minorversion. A teardown racing the dropped lock can free the client first. Pinning cl_rpc_users under client_lock blocks the DESTROY_CLIENTID and EXCHANGE_ID teardown, which refuses while cl_rpc_users is non-zero. force_expire_client() ignores it: once its wait for cl_rpc_users to reach zero has passed, a later pin goes unnoticed. Under client_lock, skip a client whose cl_time is already zero -- force_expire_client() clears it there before waiting -- otherwise pin cl_rpc_users before dropping the lock. The walk then either sees the expiry and skips, or pins in time for that wait to cover the revoke.
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc to < e1ba4d3c5bfdca3f013b8cbc829ae2f7975d8608affected1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc to < 549bd9868e9d77b07ea94870940d64342829c6adaffected1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc to < bf1f948691523282cc4905bc6cd325e0c0b49e6aaffected1c13bf9f2e3cd5a59ef988c6c5a49fe0f02bcdfc to < e270e5a0778e5bff852c8862ce9576ce70359393affected
Linux Linux
Default version status: affected
6.9affected0 to < 6.9unaffected6.12.111 to ≤ 6.12.*unaffected6.18.51 to ≤ 6.18.*unaffected7.2.4 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected