linux-kernel - Re: [PATCH] tracing/boot: Replace strlcpy with strscpy

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CADmuW3UyFY8cnf=S9hVMsYrqOyYAn5hCQ258uVpaz9J-6qaw6g@mail.gmail.com>
Date:   Thu, 15 Jun 2023 14:08:46 -0400
From:   Azeem Shaikh <azeemshaikh38@...il.com>
To:     Eric Biggers <ebiggers@...nel.org>
Cc:     Kees Cook <keescook@...omium.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        linux-hardening@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-trace-kernel@...r.kernel.org
Subject: Re: [PATCH] tracing/boot: Replace strlcpy with strscpy

On Wed, Jun 14, 2023 at 1:13 PM Eric Biggers <ebiggers@...nel.org> wrote:
>
> On Wed, Jun 14, 2023 at 10:01:57AM -0400, Azeem Shaikh wrote:
> > On Tue, Jun 13, 2023 at 3:27 PM Kees Cook <keescook@...omium.org> wrote:
> > >
> > > On Tue, Jun 13, 2023 at 12:41:25AM +0000, Azeem Shaikh 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().
> > > >
> > > > Direct replacement is safe here since return value of -E2BIG
> > > > is used to check for truncation instead of sizeof(dest).
> > >
> > > This looks technically correct, but I wonder if "< 0" is a better test?
> >
> > Agreed. "< 0" might more generically represent -errno. Happy to send
> > over a v2 if you prefer that instead of sticking with this patch.
>
> Please go with "< 0", since it's easier to read and less error-prone.  (It would
> be easy to mistype -E2BIG as -EFBIG, or E2BIG, for example...)
>

Thanks, sent out a v2 with this change.