CVSS 4.7 · Medium EPSS 0,21%
Kerentanan Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') pada linux kernel, debian linux. Skor CVSS 3.1 4.7 (Medium) menurut NVD.
In the Linux kernel, the following vulnerability has been resolved: af_unix: Fix garbage collector racing against connect() Garbage collector does not take into account the risk of embryo getting enqueued during the garbage collection. If such embryo has a peer that carries SCM_RIGHTS, two consecutive passes of scan_children() may see a different set of children. Leading to an incorrectly elevated inflight count, and then a dangling pointer within the gc_inflight_list. sockets are AF_UNIX/SOCK_STREAM S is an unconnected socket L is a listening in-flight socket bound to addr, not in fdtable V's fd will be passed via sendmsg(), gets inflight count bumped connect(S, addr) sendmsg(S, [V]); close(V) __unix_gc() ---------------- ------------------------- ----------- NS = unix_create1() skb1 = sock_wmalloc(NS) L = unix_find_other(addr) unix_state_lock(L) unix_peer(S) = NS // V count=1 inflight=0 NS = unix_peer(S) skb2 = sock_alloc() skb_queue_tail(NS, skb2[V]) // V became in-flight // V count=2 inflight=1 close(V) // V count=1 inflight=1 // GC candidate condition met for u in gc_inflight_list: if (total_refs == inflight_refs) add u to gc_candidates // gc_candidates={L, V} for u in gc_candidates: scan_children(u, dec_inflight) // embryo (skb1) was not // reachable from L yet, so V's // inflight remains unchanged __skb_queue_tail(L, skb1) unix_state_unlock(L) for u in gc_candidates: if (u.inflight) scan_children(u, inc_inflight_move_tail) // V count=1 inflight=2 (!) If there is a GC-candidate listening socket, lock/unlock its state. This makes GC wait until the end of any ongoing connect() to that socket. After flipping the lock, a possibly SCM-laden embryo is already enqueued. And if there is another embryo coming, it can not possibly carry SCM_RIGHTS. At this point, unix_inflight() can not happen because unix_gc_lock is already taken. Inflight graph remains unaffected.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
· uraikan di kalkulator | Vendor | Produk | Versi terdampak |
|---|---|---|
| linux | linux kernel | Versi 2.6.23 hingga sebelum 4.19.314 |
| linux | linux kernel | Versi 4.20 hingga sebelum 5.4.275 |
| linux | linux kernel | Versi 5.5 hingga sebelum 5.10.216 |
| linux | linux kernel | Versi 5.11 hingga sebelum 5.15.156 |
| linux | linux kernel | Versi 5.16 hingga sebelum 6.1.87 |
| linux | linux kernel | Versi 6.2 hingga sebelum 6.6.28 |
| linux | linux kernel | Versi 6.7 hingga sebelum 6.8.7 |
| linux | linux kernel | Versi 6.9 rc1 |
| linux | linux kernel | Versi 6.9 rc2 |
| linux | linux kernel | Versi 6.9 rc3 |
| debian | debian linux | Versi 10.0 |