CVE-2021-46929— Linux kernel 安全漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在安全漏洞，该漏洞源于使用call_rcu释放端点。
可能的 ATT&CK 技术 1 AI
T1059 · Command and Scripting Interpreter影响版本矩阵 14
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< 8873140f95d4977bf37e4cf0d5c5e3f6e34cdd3e |
affected |
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< af6e6e58f7ebf86b4e7201694b1e4f3a62cbc3ec |
affected | ||
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< 831de271452b87657fcf8d715ee20519b79caef5 |
affected | ||
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< 769d14abd35e0e153b5149c3e1e989a9d719e3ff |
affected | ||
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< 75799e71df1da11394740b43ae5686646179561d |
affected | ||
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab< 5ec7d18d1813a5bead0b495045606c93873aecbb |
affected | ||
4.14 |
affected | ||
< 4.14 |
unaffected | ||
| … +6 条更多 | |||
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一、 漏洞 CVE-2021-46929 基础信息
漏洞信息
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Vulnerability Title
sctp: use call_rcu to free endpoint
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
sctp: use call_rcu to free endpoint
This patch is to delay the endpoint free by calling call_rcu() to fix
another use-after-free issue in sctp_sock_dump():
BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20
Call Trace:
__lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218
lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
spin_lock_bh include/linux/spinlock.h:334 [inline]
__lock_sock+0x203/0x350 net/core/sock.c:2253
lock_sock_nested+0xfe/0x120 net/core/sock.c:2774
lock_sock include/net/sock.h:1492 [inline]
sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324
sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091
sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527
__inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049
inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065
netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244
__netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352
netlink_dump_start include/linux/netlink.h:216 [inline]
inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170
__sock_diag_cmd net/core/sock_diag.c:232 [inline]
sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263
netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274
This issue occurs when asoc is peeled off and the old sk is freed after
getting it by asoc->base.sk and before calling lock_sock(sk).
To prevent the sk free, as a holder of the sk, ep should be alive when
calling lock_sock(). This patch uses call_rcu() and moves sock_put and
ep free into sctp_endpoint_destroy_rcu(), so that it's safe to try to
hold the ep under rcu_read_lock in sctp_transport_traverse_process().
If sctp_endpoint_hold() returns true, it means this ep is still alive
and we have held it and can continue to dump it; If it returns false,
it means this ep is dead and can be freed after rcu_read_unlock, and
we should skip it.
In sctp_sock_dump(), after locking the sk, if this ep is different from
tsp->asoc->ep, it means during this dumping, this asoc was peeled off
before calling lock_sock(), and the sk should be skipped; If this ep is
the same with tsp->asoc->ep, it means no peeloff happens on this asoc,
and due to lock_sock, no peeloff will happen either until release_sock.
Note that delaying endpoint free won't delay the port release, as the
port release happens in sctp_endpoint_destroy() before calling call_rcu().
Also, freeing endpoint by call_rcu() makes it safe to access the sk by
asoc->base.sk in sctp_assocs_seq_show() and sctp_rcv().
Thanks Jones to bring this issue up.
v1->v2:
- improve the changelog.
- add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在安全漏洞，该漏洞源于使用call_rcu释放端点。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2021-46929 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2021-46929 其他参考 (6)
同批安全公告 · Linux · 2024-02-27 · 共 67 条
| CVE-2021-46911 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2021-46955 | 8.2 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46925 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46963 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46913 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46973 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46936 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46933 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46969 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46958 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46967 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46921 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46922 | 7.8 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46948 | 7.5 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46960 | 7.5 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46912 | 7.3 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46908 | 7.1 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46974 | 7.1 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46910 | 7.0 HIGH | Linux kernel 安全漏洞 |
| CVE-2021-46952 | Linux kernel 安全漏洞 |
显示前 20 条，共 67 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2021-46929
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