Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Ido Schimmel
authored
The kernel does not currently validate that both the minimum and maximum
ports of a port range are specified. This can lead user space to think
that a filter matching on a port range was successfully added, when in
fact it was not. For example, with a patched (buggy) iproute2 that only
sends the minimum port, the following commands do not return an error:
# tc filter add dev swp1 ingress pref 1 proto ip flower ip_proto udp src_port 100-200 action pass
# tc filter add dev swp1 ingress pref 1 proto ip flower ip_proto udp dst_port 100-200 action pass
# tc filter show dev swp1 ingress
filter protocol ip pref 1 flower chain 0
filter protocol ip pref 1 flower chain 0 handle 0x1
eth_type ipv4
ip_proto udp
not_in_hw
action order 1: gact action pass
random type none pass val 0
index 1 ref 1 bind 1
filter protocol ip pref 1 flower chain 0 handle 0x2
eth_type ipv4
ip_proto udp
not_in_hw
action order 1: gact action pass
random type none pass val 0
index 2 ref 1 bind 1
Fix by returning an error unless both ports are specified:
# tc filter add dev swp1 ingress pref 1 proto ip flower ip_proto udp src_port 100-200 action pass
Error: Both min and max source ports must be specified.
We have an error talking to the kernel
# tc filter add dev swp1 ingress pref 1 proto ip flower ip_proto udp dst_port 100-200 action pass
Error: Both min and max destination ports must be specified.
We have an error talking to the kernel
Fixes: 5c72299f ("net: sched: cls_flower: Classify packets using port ranges")
Signed-off-by: 
Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>