Red Hat: CVE-2024-36489: kernel: tls: fix missing memory barrier in tls_init (Multiple Advisories)

Red Hat: CVE-2024-36489: kernel: tls: fix missing memory barrier in tls_init (Multiple Advisories)

Severity

5

CVSS

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

Published

06/21/2024

Created

07/26/2024

Added

07/25/2024

Modified

12/05/2024

Description

In the Linux kernel, the following vulnerability has been resolved: tls: fix missing memory barrier in tls_init In tls_init(), a write memory barrier is missing, and store-store reordering may cause NULL dereference in tls_{setsockopt,getsockopt}. CPU0 CPU1 ---------- // In tls_init() // In tls_ctx_create() ctx = kzalloc() ctx->sk_proto = READ_ONCE(sk->sk_prot) -(1) // In update_sk_prot() WRITE_ONCE(sk->sk_prot, tls_prots) -(2) // In sock_common_setsockopt() READ_ONCE(sk->sk_prot)->setsockopt() // In tls_{setsockopt,getsockopt}() ctx->sk_proto->setsockopt()-(3) In the above scenario, when (1) and (2) are reordered, (3) can observe the NULL value of ctx->sk_proto, causing NULL dereference. To fix it, we rely on rcu_assign_pointer() which implies the release barrier semantic. By moving rcu_assign_pointer() after ctx->sk_proto is initialized, we can ensure that ctx->sk_proto are visible when changing sk->sk_prot.

Solution(s)

• redhat-upgrade-kernel
• redhat-upgrade-kernel-rt

References

• CVE-2024-36489
• RHSA-2024:4823
• RHSA-2024:4831
• RHSA-2024:5101
• RHSA-2024:5102
• RHSA-2024:5363
• RHSA-2024:6206

View more