Resource Leak The advisory has been revoked - it doesn't affect any version of package kernel-rt-trace-kvm (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS7-KERNELRTTRACEKVM-6303119
- published28 Feb 2024
- disclosed27 Feb 2024
Introduced: 27 Feb 2024
CVE-2021-46912 (opens in a new tab)Amendment
The Centos security team deemed this advisory irrelevant for Centos:7.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-trace-kvm package and not the kernel-rt-trace-kvm package as distributed by Centos.
In the Linux kernel, the following vulnerability has been resolved:
net: Make tcp_allowed_congestion_control readonly in non-init netns
Currently, tcp_allowed_congestion_control is global and writable; writing to it in any net namespace will leak into all other net namespaces.
tcp_available_congestion_control and tcp_allowed_congestion_control are the only sysctls in ipv4_net_table (the per-netns sysctl table) with a NULL data pointer; their handlers (proc_tcp_available_congestion_control and proc_allowed_congestion_control) have no other way of referencing a struct net. Thus, they operate globally.
Because ipv4_net_table does not use designated initializers, there is no easy way to fix up this one "bad" table entry. However, the data pointer updating logic shouldn't be applied to NULL pointers anyway, so we instead force these entries to be read-only.
These sysctls used to exist in ipv4_table (init-net only), but they were moved to the per-net ipv4_net_table, presumably without realizing that tcp_allowed_congestion_control was writable and thus introduced a leak.
Because the intent of that commit was only to know (i.e. read) "which congestion algorithms are available or allowed", this read-only solution should be sufficient.
The logic added in recent commit 31c4d2f160eb: ("net: Ensure net namespace isolation of sysctls") does not and cannot check for NULL data pointers, because other table entries (e.g. /proc/sys/net/netfilter/nf_log/) have .data=NULL but use other methods (.extra2) to access the struct net.