NetSight
IP …
high7.8

CVE-2021-47010

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_con…

Impact

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

VendorProductAffected versions
LinuxLinux Kernel
from 4.15 before 4.19.191
from 4.20 before 5.4.119
from 5.5 before 5.10.37
from 5.11 before 5.11.21
from 5.12 before 5.12.4

Weakness classification

CWE-400

References