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.
Metrics
Affected Vendors & Products
References
History
Fri, 22 Nov 2024 12:00:00 +0000
Type | Values Removed | Values Added |
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References |
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Tue, 05 Nov 2024 10:45:00 +0000
Type | Values Removed | Values Added |
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References |
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Wed, 30 Oct 2024 15:30:00 +0000
Type | Values Removed | Values Added |
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CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
Wed, 02 Oct 2024 15:00:00 +0000
Type | Values Removed | Values Added |
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First Time appeared |
Redhat rhel Aus
Redhat rhel E4s Redhat rhel Tus |
|
CPEs | cpe:/o:redhat:rhel_aus:8.6 cpe:/o:redhat:rhel_e4s:8.6 cpe:/o:redhat:rhel_tus:8.6 |
|
Vendors & Products |
Redhat rhel Aus
Redhat rhel E4s Redhat rhel Tus |
Tue, 24 Sep 2024 11:15:00 +0000
Type | Values Removed | Values Added |
---|---|---|
CPEs | cpe:/o:redhat:enterprise_linux:8 cpe:/o:redhat:rhel_eus:8.8 |
Tue, 24 Sep 2024 06:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
First Time appeared |
Redhat enterprise Linux
|
|
CPEs | cpe:/a:redhat:enterprise_linux:8::nfv | |
Vendors & Products |
Redhat enterprise Linux
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-04-24T21:49:22.001Z
Updated: 2024-12-19T08:50:13.384Z
Reserved: 2024-02-19T14:20:24.194Z
Link: CVE-2024-26923
Vulnrichment
Updated: 2024-08-02T00:21:05.612Z
NVD
Status : Awaiting Analysis
Published: 2024-04-25T06:15:57.160
Modified: 2024-11-21T09:03:23.543
Link: CVE-2024-26923
Redhat