linux-kernel - Re: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom

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: <20240829180241.GJ29862@gate.crashing.org>
Date: Thu, 29 Aug 2024 13:02:41 -0500
From: Segher Boessenkool <segher@...nel.crashing.org>
To: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: Ard Biesheuvel <ardb@...nel.org>, Arnd Bergmann <arnd@...db.de>,
        "Jason A . Donenfeld" <Jason@...c4.com>,
        Eric Biggers <ebiggers@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>, Naveen N Rao <naveen@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, "Theodore Ts'o" <tytso@....edu>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Vincenzo Frascino <vincenzo.frascino@....com>,
        shuah <shuah@...nel.org>, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        Linux-Arch <linux-arch@...r.kernel.org>, linux-mm@...ck.org,
        linux-trace-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom

On Thu, Aug 29, 2024 at 07:36:38PM +0200, Christophe Leroy wrote:
> 
> 
> Le 28/08/2024 à 19:25, Segher Boessenkool a écrit :
> >
> >>Not sure about static binaries, though: do those even use the VDSO?
> >
> >With "static binary" people usually mean "a binary not using any DSOs",
> >I think the VDSO is a DSO, also in this respect?  As always, -static
> >builds are *way* less problematic (and faster and smaller :-) )
> >
> 
> AFAIK on powerpc even static binaries use the vDSO, otherwise signals 
> don't work.

How can that work?  Non-dynamic binaries do not use ld.so (that is the
definition of a dynamic binary, even).  So they cannot link (at runtime)
to any DSO (unless that is done manually?!)

Maybe there is something at a fixed offset in the vDSO, or something
like that?  Is this documented somewhere?


Segher