Debian: CVE-2021-47593: linux -- security update

Debian: CVE-2021-47593: linux -- security update

Severity

5

CVSS

(AV:L/AC:L/Au:S/C:N/I:N/A:C)

Published

06/19/2024

Created

07/31/2024

Added

07/30/2024

Modified

01/30/2025

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket). But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work. This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket: BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

Solution(s)

• debian-upgrade-linux

References

• https://attackerkb.com/topics/cve-2021-47593
• CVE - 2021-47593