SUNRPC: Check svc pool percpu counter allocation
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.6.157, 6.12.109, 6.18.50, 7.2.4
- 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: SUNRPC: Check svc pool percpu counter allocation __svc_create() initializes three per-pool percpu_counter stats and ignores every return value. On SMP, percpu_counter_init() fails when __alloc_percpu_gfp() cannot satisfy the allocation, leaving the failed counter with fbc->counters == NULL and its embedded raw_spinlock_t, list_head, and count never initialized. __svc_create() returns the half-constructed svc_serv to nfsd, lockd, or the NFS callback service anyway. Once that service is live, the hot-path increments in svc_xprt_enqueue(), svc_handle_xprt(), and svc_pool_wake_idle_thread() reach a counter whose backing pointer is NULL. The pointer is a per-cpu offset, so the access does not fault: it resolves to offset zero of the current CPU's per-cpu area and silently corrupts whatever variable lives there. A /proc/fs/nfsd/pool_stats read walks the same NULL per-cpu storage and returns garbage, and on CONFIG_DEBUG_SPINLOCK or lockdep it splats on the never-initialized lock. Creating the broken service requires a percpu allocation failure during RPC server startup, so it is reachable only by a local administrator under memory pressure or fault injection; a remote peer cannot induce the bad state on its own. Check each percpu_counter_init() return value in __svc_create() and fail when an allocation fails, unwinding the counters already set up in the current pool and in every pool initialized before it. A discrete percpu_counter_destroy() per counter at teardown frees each per-cpu allocation exactly once.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From ccf08bed6e7a80519569456edd2ea21b7b1701c6 · fixed in 57ac7d899409b0a9b768cf417e3bb86bcca3d4c6; From ccf08bed6e7a80519569456edd2ea21b7b1701c6 · fixed in 3a2b7649de76376a69f1d3ed2a539fb15907cd4d; From ccf08bed6e7a80519569456edd2ea21b7b1701c6 · fixed in bd1ef2cfb44d72b7aa6943e87b206eb0e30fbd0c; From ccf08bed6e7a80519569456edd2ea21b7b1701c6 · fixed in b541a15046976e481618726cc23db0fb22d576db; From ccf08bed6e7a80519569456edd2ea21b7b1701c6 · fixed in 43e11e164704dde975c9edb370de1a06bec67270
- Linux Linux
6.3
- KernelLinux
From 6.3.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4