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7.8 High

CVE-2021-47010 In the Linux kernel, the following vulnerability has been resolved: net: Only allow init netns to set default tcp cong…

Description

In the Linux kernel, the following vulnerability has been resolved: net: Only allow init netns to set default tcp cong to a restricted algo tcp_set_default_congestion_control() is netns-safe in that it writes to &net->ipv4.tcp_congestion_control, but it also sets ca->flags |= TCP_CONG_NON_RESTRICTED which is not namespaced. This has the unintended side-effect of changing the global net.ipv4.tcp_allowed_congestion_control sysctl, despite the fact that it is read-only: 97684f0970f6 ("net: Make tcp_allowed_congestion_control readonly in non-init netns") Resolve this netns "leak" by only allowing the init netns to set the default algorithm to one that is restricted. This restriction could be removed if tcp_allowed_congestion_control were namespace-ified in the future. This bug was uncovered with https://github.com/JonathonReinhart/linux-netns-sysctl-verify

Affected products and versions

Product Affected versions Fixed in
Linux 5.13 earliest → < 5.13 5.13
Linux 5.12 earliest → < 5.12.4 5.12.4
Linux 5.11 earliest → < 5.11.21 5.11.21
Linux 5.10 earliest → < 5.10.37 5.10.37
Linux 5.4 earliest → < 5.4.119 5.4.119
Linux 4.19 earliest → < 4.19.191 4.19.191
Linux 4.15 No fix stated
linux_kernel 6670 6670e1524477 → latest 9884f745108f
linux_kernel 992 earliest → < 992de06308d9 992de06308d9
Show the 9 other branches
Product Affected versions Fixed in
linux_kernel 8 earliest → < 8d432592f30f 8d432592f30f
linux_kernel 6 earliest → < 6c1ea8bee75d 6c1ea8bee75d
linux_kernel 5.13 earliest → < 5.13 5.13
linux_kernel 5.12 earliest → < 5.12.4 5.12.4
linux_kernel 5.11 earliest → < 5.11.21 5.11.21
linux_kernel 5.10 earliest → < 5.10.37 5.10.37
linux_kernel 5.4 earliest → < 5.4.119 5.4.119
linux_kernel 4.19 earliest → < 4.19.191 4.19.191
linux_kernel 4.15 No fix stated

References

Timeline

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