netdev - Re: [PATCH] SUNRPC: Replace strlcpy with strscpy

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Date: Tue, 13 Jun 2023 18:55:03 -0400
From: Azeem Shaikh <azeemshaikh38@...il.com>
To: Chuck Lever III <chuck.lever@...cle.com>
Cc: Kees Cook <keescook@...omium.org>, Jeff Layton <jlayton@...nel.org>, 
	"linux-hardening@...r.kernel.org" <linux-hardening@...r.kernel.org>, Neil Brown <neilb@...e.de>, 
	Olga Kornievskaia <kolga@...app.com>, Dai Ngo <dai.ngo@...cle.com>, Tom Talpey <tom@...pey.com>, 
	Linux NFS Mailing List <linux-nfs@...r.kernel.org>, open list <linux-kernel@...r.kernel.org>, 
	Trond Myklebust <trond.myklebust@...merspace.com>, Anna Schumaker <anna@...nel.org>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH] SUNRPC: Replace strlcpy with strscpy

On Tue, Jun 13, 2023 at 3:43 PM Chuck Lever III <chuck.lever@...cle.com> wrote:
>
> > On Jun 13, 2023, at 3:42 PM, Kees Cook <keescook@...omium.org> wrote:
> >
> > On Tue, Jun 13, 2023 at 02:18:06PM +0000, Chuck Lever III wrote:
> >>
> >>
> >>> On Jun 12, 2023, at 8:40 PM, Azeem Shaikh <azeemshaikh38@...il.com> wrote:
> >>>
> >>> strlcpy() reads the entire source buffer first.
> >>> This read may exceed the destination size limit.
> >>> This is both inefficient and can lead to linear read
> >>> overflows if a source string is not NUL-terminated [1].
> >>> In an effort to remove strlcpy() completely [2], replace
> >>> strlcpy() here with strscpy().
> >>
> >> Using sprintf() seems cleaner to me: it would get rid of
> >> the undocumented naked integer. Would that work for you?
> >
> > This is changing the "get" routine for reporting module parameters out
> > of /sys. I think the right choice here is sysfs_emit(), as it performs
> > the size tracking correctly. (Even the "default" sprintf() call should
> > be replaced too, IMO.)
>
> Agreed, that's even better.
>

Thanks folks. Will send over a v2 which replaces strlcpy with sysfs_emit.