一、漏洞信息
漏洞编号：CVE-2024-26923
漏洞归属组件：kernel
漏洞归属的版本：4.19.140,4.19.194,4.19.90,5.10.0,6.1.0,6.1.14,6.1.19,6.1.5,6.1.6,6.1.8,6.4.0,6.6.0
CVSS V2.0分值：
BaseScore：0.0 Low
Vector：CVSS：2.0/
漏洞简述：
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 gettingenqueued during the garbage collection. If such embryo has a peer thatcarries SCM_RIGHTS, two consecutive passes of scan_children() may see adifferent set of children. Leading to an incorrectly elevated inflightcount, and then a dangling pointer within the gc_inflight_list.sockets are AF_UNIX/SOCK_STREAMS is an unconnected socketL is a listening in-flight socket bound to addr, not in fdtableV s fd will be passed via sendmsg(), gets inflight count bumpedconnect(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. Thismakes GC wait until the end of any ongoing connect() to that socket. Afterflipping the lock, a possibly SCM-laden embryo is already enqueued. And ifthere is another embryo coming, it can not possibly carry SCM_RIGHTS. Atthis point, unix_inflight() can not happen because unix_gc_lock is alreadytaken. Inflight graph remains unaffected.
漏洞公开时间：2024-04-25 14:15:57
漏洞创建时间：2024-04-25 07:28:43
漏洞详情参考链接：
https://nvd.nist.gov/vuln/detail/CVE-2024-26923

漏洞分析指导链接：
https://gitee.com/openeuler/cve-manager/blob/master/cve-vulner-manager/doc/md/manual.md
漏洞数据来源:
openBrain开源漏洞感知系统
漏洞补丁信息：

二、漏洞分析结构反馈
影响性分析说明：
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 gettingenqueued during the garbage collection. If such embryo has a peer thatcarries SCM_RIGHTS, two consecutive passes of scan_children() may see adifferent set of children. Leading to an incorrectly elevated inflightcount, and then a dangling pointer within the gc_inflight_list.sockets are AF_UNIX/SOCK_STREAMS is an unconnected socketL is a listening in-flight socket bound to addr, not in fdtableV s fd will be passed via sendmsg(), gets inflight count bumpedconnect(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=1close(V)// V count=1 inflight=1// GC candidate condition metfor 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. Thismakes GC wait until the end of any ongoing connect() to that socket. Afterflipping the lock, a possibly SCM-laden embryo is already enqueued. And ifthere is another embryo coming, it can not possibly carry SCM_RIGHTS. Atthis point, unix_inflight() can not happen because unix_gc_lock is alreadytaken. Inflight graph remains unaffected.
openEuler评分：
7.0
Vector：CVSS：2.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
受影响版本排查(受影响/不受影响)：
1.openEuler-20.03-LTS-SP1(4.19.90):受影响
2.openEuler-20.03-LTS-SP4:受影响
3.openEuler-22.03-LTS(5.10.0):受影响
4.openEuler-22.03-LTS-SP1(5.10.0):受影响
5.openEuler-22.03-LTS-SP2(5.10.0):受影响
6.openEuler-22.03-LTS-SP3:受影响
7.openEuler-22.03-LTS-SP4:不受影响
8.master(6.1.0):不受影响
9.openEuler-22.03-LTS-Next(5.10.0):不受影响
10.openEuler-24.03-LTS(6.6.0):不受影响
11.openEuler-24.03-LTS-Next(6.6.0):不受影响

修复是否涉及abi变化(是/否)：
1.openEuler-20.03-LTS-SP1(4.19.90):否
2.openEuler-20.03-LTS-SP4:否
3.openEuler-22.03-LTS(5.10.0):否
4.openEuler-22.03-LTS-SP1(5.10.0):否
5.openEuler-22.03-LTS-SP2(5.10.0):否
6.openEuler-22.03-LTS-SP3:否
7.master(6.1.0):否
8.openEuler-22.03-LTS-Next(5.10.0):否
9.openEuler-24.03-LTS(6.6.0):否
10.openEuler-24.03-LTS-Next(6.6.0):否
11.openEuler-22.03-LTS-SP4:否

三、漏洞修复
安全公告链接：https://www.openeuler.org/zh/security/safety-bulletin/detail/?id=openEuler-SA-2024-1681