Re: [PATCH iproute2 1/2] ss: validate sscanf() return value in packet_show_line()

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 31 Aug 2026 10:41:15 +0000
Prabhakar Pujeri <prabhakar.pujeri@dell.com> wrote:

> The /proc/net/packet fallback parser never checks the return value of
> sscanf().  On a malformed or truncated line some of the output
> variables (type, prot, iface, state, rq, uid, ino) stay
> uninitialized and garbage values are used both for type based
> filtering and for the printed socket state.
> 
> Require all eight fields to be converted before using the values and
> return -1 on failure, which makes generic_record_read() stop
> processing, the same way tcp_show_line() bails out on a malformed
> /proc/net/tcp line.
> 
> Fixes: aba5acdfdb34 ("(Logical change 1.3)")
> Signed-off-by: Prabhakar Pujeri <prabhakar.pujeri@dell.com>
> ---

Good to check but if kernel gives garbage, kernel is seriously buggy.

I am thinking it would be best to just remove /proc fallback stuff.
It only exists to handle really old systems before netlink diag info
was supported; or embedded hardware kernel configs without netlink diag info.