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]
Date:	Mon, 30 Apr 2007 10:33:31 +0100
From:	Russell King <rmk+lkml@....linux.org.uk>
To:	Christoph Hellwig <hch@....de>
Cc:	Christoph Hellwig <hch@...radead.org>,
	Roland McGrath <roland@...hat.com>,
	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: utrace comments

On Mon, Apr 30, 2007 at 11:22:00AM +0200, Christoph Hellwig wrote:
> On Mon, Apr 30, 2007 at 10:18:09AM +0100, Russell King wrote:
> > Roland's idea of single-stepping is that it *must* be supported by
> > hardware for utrace to use it.  There are a number of architectures
> > which can only do single-stepping by modifying the text of the
> > program being single stepped.  ARM is one such example.
> > 
> > As such, even when utrace is complete, some architectures will never
> > support in-kernel single step with utrace.  I believe Roland's idea
> > is to have single step supported on these via some vapourware userspace
> > library.
> 
> Does the current arm ptrace code support single stepping in kernelspace?
> If yes we absolutely need to continue to support it.

single stepping of user space code via standard ptrace calls, yes.

> > I'd also like to see utrace become *optional*
> > for architectures to support, rather than as it currently stands as
> > a *mandatory* requirement when merged.
> 
> No way we'd keep both the old ptrace mess and utrace in the same tree.

Given the stated arguments from yourself and Roland, that only leaves
one solution to that.

I have no real problem with a decision being made to drop kernel-based
single stepping _provided_ we have some replacement strategy in place
and readily available.  At the moment I've not seen such a strategy.

I'm not sure if Roland's expecting architecture maintainers to
create such a strategy themselves - which would probably turn out to
being far worse since you could end up with different implementations
for each architecture.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:
-
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/

Powered by blists - more mailing lists