netdev - Re: [PATCH iproute2] tc: u32: check return value from snprintf

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Message-ID: <20240212085358.22be1db6@hermes.local>
Date: Mon, 12 Feb 2024 08:53:58 -0800
From: Stephen Hemminger <stephen@...workplumber.org>
To: Hangbin Liu <liuhangbin@...il.com>
Cc: netdev@...r.kernel.org, jhs@...atatu.com
Subject: Re: [PATCH iproute2] tc: u32: check return value from snprintf

On Mon, 12 Feb 2024 15:24:49 +0800
Hangbin Liu <liuhangbin@...il.com> wrote:

> On Sat, Feb 10, 2024 at 05:04:23PM -0800, Stephen Hemminger wrote:
> > Add assertion to check for case of snprintf failing (bad format?)
> > or buffer getting full.
> > 
> > Signed-off-by: Stephen Hemminger <stephen@...workplumber.org>  
> 
> Hi Stephen,
> 
> Is there a bug report or something else that we only do the assertion
> for tc/f_u32.c?
> 
> Thanks
> Hangbin

No bug, it is not possible to trigger with current code.
Return of < 0 only happens with improper format string,
and the overrun would only happen if buffer was not big enough
The bsize is SPRINT_BUF() which is 64 bytes.

It is more a way to avoid some code checker complaining in future.