In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reje

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

net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes

Reject invalid net.ipv4.tcp_reordering values before they reach TCP
socket state. The sysctl is stored as an int but copied into the
u32 tp->reordering field for new sockets, so negative writes wrap
to large values.

With tcp_mtu_probing=2, the wrapped value can overflow the
tcp_mtu_probe() size calculation and drive the MTU probing path into
an out-of-bounds read. Route tcp_reordering writes through
proc_dointvec_minmax() and require it to be at least 1. Also require
tcp_max_reordering to be at least 1 so the configured maximum cannot
become negative either.

When registering the table for a non-init network namespace, relocate
extra2 pointers that refer into init_net.ipv4 so the
tcp_reordering upper bound follows that namespace's
tcp_max_reordering.

Harden tcp_mtu_probe() itself by computing size_needed as u64.
This keeps the send queue and window checks from being bypassed through
signed integer overflow.