From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Pedro Alves <pedro@palves.net>, Kees Cook <keescook@chromium.org>,
Borislav Petkov <bp@alien8.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] x86/ptrace: Remove questionable TS_COMPAT usage in ptrace
Date: Mon, 20 Jun 2016 18:14:10 +0200 [thread overview]
Message-ID: <20160620161409.GA29851@redhat.com> (raw)
In-Reply-To: <CALCETrUTJkGHWZ=3yKa-myVhKrNuoJhtingKv4B+YbUu5ZX=2g@mail.gmail.com>
On 06/20, Andy Lutomirski wrote:
>
> On Mon, Jun 20, 2016 at 8:24 AM, Oleg Nesterov <oleg@redhat.com> wrote:
> >
> > How about the simple change below for now? IIRC 32-bit task can't use
> > "syscall" so if syscall_get_nr() >= 0 then even the wrong TS_COMPAT is
> > not that bad, even if it "leaks" to user-mode.
>
> Hmm. That should fix the minor security issue, but it will even
> further break cross-arch tracing: now a 32-bit tracer tracing a 64-bit
> task that does int $0x80 will malfunction even more than it would
> have.
This is broken in any case. I mean, a 32-bit debugger can't really
debug a 64-bit task.
I don't think this change makes the things really worse.
> Also, it relies on bizarre arch details IMO.
Heh, it looks as if your patch do not ;)
> I think I prefer my version, coming momentarily.
I disagree... I don't really understand why do we need the additional
complications for the minimal fix which doesn't look very nice anyway.
But I won't argue, and your patch looks correct to me.
Oleg.
next prev parent reply other threads:[~2016-06-20 17:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-18 10:21 Andy Lutomirski
2016-06-18 13:55 ` Pedro Alves
2016-06-18 14:41 ` Pedro Alves
2016-06-18 17:02 ` Andy Lutomirski
2016-06-19 22:09 ` Andy Lutomirski
2016-06-20 10:27 ` Pedro Alves
2016-06-20 15:24 ` Oleg Nesterov
2016-06-20 16:30 ` Andy Lutomirski
2016-06-20 16:14 ` Oleg Nesterov [this message]
2016-06-20 17:25 ` Andy Lutomirski
2016-06-20 10:07 ` Pedro Alves
2016-06-20 11:12 ` Jan Kratochvil
2016-06-18 17:48 ` Kees Cook
2016-06-19 21:19 ` Oleg Nesterov
2016-06-19 22:23 ` Andy Lutomirski
2016-06-20 6:12 ` Andy Lutomirski
2016-06-20 15:31 ` Oleg Nesterov
2016-06-20 17:53 ` the usage of __SYSCALL_MASK in entry_SYSCALL_64/do_syscall_64 is not consistent Oleg Nesterov
2016-06-21 19:01 ` Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20160620161409.GA29851@redhat.com \
--to=oleg@redhat.com \
--cc=bp@alien8.de \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@amacapital.net \
--cc=pedro@palves.net \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome