NULL Pointer Dereference Affecting kernel-source-azure package, versions <5.14.21-150500.33.63.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-SLES155-KERNELSOURCEAZURE-7693795
  • published17 Aug 2024
  • disclosed16 Aug 2024

Introduced: 16 Aug 2024

CVE-2021-47593  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 kernel-source-azure to version 5.14.21-150500.33.63.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-source-azure package and not the kernel-source-azure package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

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 [..]

CVSS Scores

version 3.1