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LIN1019-11141 : Security Advisory - linux - CVE-2021-46975

Created: Feb 27, 2024    Updated: Mar 1, 2024
Resolved Date: Feb 28, 2024
Found In Version: 10.19.45.1
Severity: Standard
Applicable for: Wind River Linux LTS 19
Component/s: Kernel

Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack: Make global sysctls readonly in non-init netns

These sysctls point to global variables:
- NF_SYSCTL_CT_MAX (&nf_conntrack_max)
- NF_SYSCTL_CT_EXPECT_MAX (&nf_ct_expect_max)
- NF_SYSCTL_CT_BUCKETS (&nf_conntrack_htable_size_user)

Because their data pointers are not updated to point to per-netns
structures, they must be marked read-only in a non-init_net ns.
Otherwise, changes in any net namespace are reflected in (leaked into)
all other net namespaces. This problem has existed since the
introduction of net namespaces.

The current logic marks them read-only only if the net namespace is
owned by an unprivileged user (other than init_user_ns).

Commit d0febd81ae77 ("netfilter: conntrack: re-visit sysctls in
unprivileged namespaces") "exposes all sysctls even if the namespace is
unpriviliged." Since we need to mark them readonly in any case, we can
forego the unprivileged user check altogether.

CREATE(Triage):(User=admin) CVE-2021-46975 (https://nvd.nist.gov/vuln/detail/CVE-2021-46975)
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