Alma Linux: CVE-2024-26923: Important: kernel security update (Multiple Advisories)
Description
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.
Solution(s)
- alma-upgrade-bpftool
- alma-upgrade-kernel
- alma-upgrade-kernel-64k
- alma-upgrade-kernel-64k-core
- alma-upgrade-kernel-64k-debug
- alma-upgrade-kernel-64k-debug-core
- alma-upgrade-kernel-64k-debug-devel
- alma-upgrade-kernel-64k-debug-devel-matched
- alma-upgrade-kernel-64k-debug-modules
- alma-upgrade-kernel-64k-debug-modules-core
- alma-upgrade-kernel-64k-debug-modules-extra
- alma-upgrade-kernel-64k-devel
- alma-upgrade-kernel-64k-devel-matched
- alma-upgrade-kernel-64k-modules
- alma-upgrade-kernel-64k-modules-core
- alma-upgrade-kernel-64k-modules-extra
- alma-upgrade-kernel-abi-stablelists
- alma-upgrade-kernel-core
- alma-upgrade-kernel-cross-headers
- alma-upgrade-kernel-debug
- alma-upgrade-kernel-debug-core
- alma-upgrade-kernel-debug-devel
- alma-upgrade-kernel-debug-devel-matched
- alma-upgrade-kernel-debug-modules
- alma-upgrade-kernel-debug-modules-core
- alma-upgrade-kernel-debug-modules-extra
- alma-upgrade-kernel-debug-uki-virt
- alma-upgrade-kernel-devel
- alma-upgrade-kernel-devel-matched
- alma-upgrade-kernel-doc
- alma-upgrade-kernel-headers
- alma-upgrade-kernel-modules
- alma-upgrade-kernel-modules-core
- alma-upgrade-kernel-modules-extra
- alma-upgrade-kernel-rt
- alma-upgrade-kernel-rt-core
- alma-upgrade-kernel-rt-debug
- alma-upgrade-kernel-rt-debug-core
- alma-upgrade-kernel-rt-debug-devel
- alma-upgrade-kernel-rt-debug-kvm
- alma-upgrade-kernel-rt-debug-modules
- alma-upgrade-kernel-rt-debug-modules-core
- alma-upgrade-kernel-rt-debug-modules-extra
- alma-upgrade-kernel-rt-devel
- alma-upgrade-kernel-rt-kvm
- alma-upgrade-kernel-rt-modules
- alma-upgrade-kernel-rt-modules-core
- alma-upgrade-kernel-rt-modules-extra
- alma-upgrade-kernel-tools
- alma-upgrade-kernel-tools-libs
- alma-upgrade-kernel-tools-libs-devel
- alma-upgrade-kernel-uki-virt
- alma-upgrade-kernel-zfcpdump
- alma-upgrade-kernel-zfcpdump-core
- alma-upgrade-kernel-zfcpdump-devel
- alma-upgrade-kernel-zfcpdump-devel-matched
- alma-upgrade-kernel-zfcpdump-modules
- alma-upgrade-kernel-zfcpdump-modules-core
- alma-upgrade-kernel-zfcpdump-modules-extra
- alma-upgrade-libperf
- alma-upgrade-perf
- alma-upgrade-python3-perf
- alma-upgrade-rtla
- alma-upgrade-rv
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- Automated Containment
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