CVE-2021-46929: 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…

PriorityP422medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.26%

17.4th percentile

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 thi

Affected

17 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 5.15.15-1 (bookworm)	linux 5.15.15-1 (bookworm)
linux	linux	—	—
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < 8873140f95d4977bf37e4cf0d5c5e3f6e34cdd3e	8873140f95d4977bf37e4cf0d5c5e3f6e34cdd3e
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < af6e6e58f7ebf86b4e7201694b1e4f3a62cbc3ec	af6e6e58f7ebf86b4e7201694b1e4f3a62cbc3ec
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < 831de271452b87657fcf8d715ee20519b79caef5	831de271452b87657fcf8d715ee20519b79caef5
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < 769d14abd35e0e153b5149c3e1e989a9d719e3ff	769d14abd35e0e153b5149c3e1e989a9d719e3ff
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < 75799e71df1da11394740b43ae5686646179561d	75799e71df1da11394740b43ae5686646179561d
linux	linux	>= d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab < 5ec7d18d1813a5bead0b495045606c93873aecbb	5ec7d18d1813a5bead0b495045606c93873aecbb
linux	linux_kernel	>= 0 < 5.10.92-1	5.10.92-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 0 < 5.15.15-1	5.15.15-1
linux	linux_kernel	>= 4.14.0 < 4.14.261	4.14.261
linux	linux_kernel	>= 4.15.0 < 4.19.224	4.19.224
linux	linux_kernel	>= 4.20.0 < 5.4.170	5.4.170
linux	linux_kernel	>= 5.11.0 < 5.15.13	5.15.13
linux	linux_kernel	>= 5.5.0 < 5.10.90	5.10.90

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

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