Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: close backchannel before destroying callback service A backchannel receive can complete a request while the NFS callback service is being torn down. xprt_complete_bc_request() removes the request from bc_pa_list, drops bc_alloc_count, marks the request in use, and then asks xprt_enqueue_bc_request() to hand it to the callback service. If teardown has already cleared xprt->bc_serv, xprt_enqueue_bc_request() currently returns without enqueueing or freeing the committed request. The xprt_get() taken on entry is leaked as well. If the producer wins the race before bc_serv is cleared, it can also enqueue onto sv_cb_list after nfs_callback_down() has stopped the callback threads, leaving the request linked to a svc_serv that is about to be freed. Close the producer side before callback threads are stopped. Add xprt_svc_shutdown_bc() to clear xprt->bc_serv under bc_pa_lock, and call it on callback shutdown and callback-start failure before stopping the service threads. Requests that lose the NULL transition in xprt_enqueue_bc_request() are released through the normal backchannel free path after balancing bc_slot_count. Finally, drain any remaining sv_cb_list requests after the callback threads have stopped and before svc_destroy() frees the service.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 441244d4273a8037b265fd254dfdaca5fa736ee2 before 6debde9e3e6ae21dcca75837b4247b13ca4ea2b8; affected 441244d4273a8037b265fd254dfdaca5fa736ee2 before 3674f780f47d2906b5a0f7199b66973067bdfeca |
| Linux / Linux | affected 6.19; unaffected 0 before 6.19; unaffected 7.2.4 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.