netdev - Re: [PATCH v7 4/8] bpftool: Ensure task comm is always NUL-terminated

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

Message-ID: <gmhyl3zdnxy6q2tn5wtasqbuhxpfbejmh7qxeuk7lnbhcdlfsc@b3b56vgdrzgm>
Date: Sun, 18 Aug 2024 10:25:30 +0200
From: Alejandro Colomar <alx@...nel.org>
To: Yafang Shao <laoar.shao@...il.com>
Cc: akpm@...ux-foundation.org, torvalds@...ux-foundation.org, 
	justinstitt@...gle.com, ebiederm@...ssion.com, alexei.starovoitov@...il.com, 
	rostedt@...dmis.org, catalin.marinas@....com, penguin-kernel@...ove.sakura.ne.jp, 
	linux-mm@...ck.org, linux-fsdevel@...r.kernel.org, 
	linux-trace-kernel@...r.kernel.org, audit@...r.kernel.org, linux-security-module@...r.kernel.org, 
	selinux@...r.kernel.org, bpf@...r.kernel.org, netdev@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, Quentin Monnet <qmo@...nel.org>
Subject: Re: [PATCH v7 4/8] bpftool: Ensure task comm is always NUL-terminated

Hi Yafang,

On Sun, Aug 18, 2024 at 10:27:01AM GMT, Yafang Shao wrote:
> On Sat, Aug 17, 2024 at 4:39 PM Alejandro Colomar <alx@...nel.org> wrote:
> >
> > Hi Yafang,
> >
> > On Sat, Aug 17, 2024 at 10:56:20AM GMT, Yafang Shao wrote:
> > > Let's explicitly ensure the destination string is NUL-terminated. This way,
> > > it won't be affected by changes to the source string.
> > >
> > > Signed-off-by: Yafang Shao <laoar.shao@...il.com>
> > > Reviewed-by: Quentin Monnet <qmo@...nel.org>
> > > ---
> > >  tools/bpf/bpftool/pids.c | 2 ++
> > >  1 file changed, 2 insertions(+)
> > >
> > > diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
> > > index 9b898571b49e..23f488cf1740 100644
> > > --- a/tools/bpf/bpftool/pids.c
> > > +++ b/tools/bpf/bpftool/pids.c
> > > @@ -54,6 +54,7 @@ static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
> > >               ref = &refs->refs[refs->ref_cnt];
> > >               ref->pid = e->pid;
> > >               memcpy(ref->comm, e->comm, sizeof(ref->comm));
> > > +             ref->comm[sizeof(ref->comm) - 1] = '\0';
> >
> > Why doesn't this use strscpy()?
> 
> bpftool is a userspace tool, so strscpy() is only applicable in kernel
> code, correct?

Ahh, makes sense.  LGTM, then.  Maybe the closest user-space function to
strscpy(9) would be strlcpy(3), but I don't know how old of a glibc you
support.  strlcpy(3) is currently in POSIX, and supported by both glibc
and musl, but that's too recent.

Have a lovely day!
Alex

> --
> Regards
> Yafang

-- 
<https://www.alejandro-colomar.es/>

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)