linux-kernel - Re: [PATCH v5 4/9] x86-64: Remove kernel.vsyscall64 sysctl

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: <loom.20111205T192515-288@post.gmane.org>
Date:	Mon, 5 Dec 2011 18:27:09 +0000 (UTC)
From:	Matthew Maurer <maurer@...thewmaurer.org>
To:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 4/9] x86-64: Remove kernel.vsyscall64 sysctl

Andy Lutomirski <luto <at> MIT.EDU> writes:

> 
> It's unnecessary overhead in code that's supposed to be highly
> optimized.  Removing it allows us to remove one of the two syscall
> instructions in the vsyscall page.
> 
> The only sensible use for it is for UML users, and it doesn't fully
> address inconsistent vsyscall results on UML.  The real fix for UML
> is to stop using vsyscalls entirely.

UML is not the only use case for this. Anybody who wants to be able to
trace _all_ system calls (for debugging, ptrace-based sandboxing, or a
number of other purposes) needs this.

We either need this back, or need another way to make it possible to
trace these system calls.

Apologies for the late reply, I didn't notice this change until it got
into my distribution's kernel.

--Matthew Maurer

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/