From: "Michael Potter" <pottmi@gmail.com>
To: "Andreas Schwab" <schwab@suse.de>
Cc: "Mark Kettenis" <mark.kettenis@xs4all.nl>, gdb@sourceware.org
Subject: Re: unable to attach to setuid program that as reverted it privilege
Date: Thu, 24 Jan 2008 05:05:00 -0000 [thread overview]
Message-ID: <2379dacc0801232105r4afecc19r90a4a2f10f2d5054@mail.gmail.com> (raw)
In-Reply-To: <je8x2g8eav.fsf@sykes.suse.de>
Andreas,
works great.
Here are a few notes in case someone else has this same problem....
To turn this on, do this:
1) log in as root
2) echo 2 >/proc/sys/kernel/suid_dumpable
To turn this off, do this:
1) log in as root
2) echo 0 >/proc/sys/kernel/suid_dumpable
On some systems the target file might be in /proc/sys/fs
It will not work to just use sudo in front of echo. You must log in
as root because the redirection has the user's privilege.
I do not know what echo 1 would do.
This is documented as allowing core files to be created for setuid
programs. What I am using it for is to allow gdb run as a non-root
user to connect to setuid programs that have _permanently_ given up
their root privilege. Without suid_dumpable enabled, gdb will fail
with a EPERM error even tho the target program is no longer running as
root and can not reacquire root privilege ( a good default behavior ).
This will work fine for my needs, but I would prefer finer grained control.
that is:
1) separate attaching and core dumping.
2) don't turn on this feature for _all_ processes, just select processes.
This should only be used in a controlled environment because of the
security issues.
Because this turns on core dumping it would be prudent to also look
into /proc/sys/kernel/core_pattern to prevent name collision when core
dumps are created.
--
Michael Potter
On Jan 23, 2008 2:42 PM, Andreas Schwab <schwab@suse.de> wrote:
> "Michael Potter" <pottmi@gmail.com> writes:
>
> > I will post to a Linux kernel list in a couple of days. I posted here
> > because I felt that I was likely to find someone who had the same
> > problem in this group.
>
> /proc/sys/kernel/suid_dumpable might be what you are looking for.
>
> Andreas.
>
> --
> Andreas Schwab, SuSE Labs, schwab@suse.de
> SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
> PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
> "And now for something completely different."
>
next prev parent reply other threads:[~2008-01-24 5:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-22 20:00 Michael Potter
2008-01-22 20:09 ` Daniel Jacobowitz
2008-01-22 20:24 ` Michael Potter
2008-01-23 17:52 ` Mark Kettenis
2008-01-23 18:48 ` Michael Potter
2008-01-23 20:26 ` Michael Potter
2008-01-23 20:42 ` Andreas Schwab
2008-01-24 5:05 ` Michael Potter [this message]
2008-01-24 9:18 ` Andreas Schwab
2008-04-14 13:46 Reynolds, Brandon
2008-04-14 16:32 ` Michael Potter
2008-04-14 16:45 ` Tavis Ormandy
2008-04-15 1:02 ` Reynolds, Brandon
2008-04-15 1:24 ` Michael Potter
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=2379dacc0801232105r4afecc19r90a4a2f10f2d5054@mail.gmail.com \
--to=pottmi@gmail.com \
--cc=gdb@sourceware.org \
--cc=mark.kettenis@xs4all.nl \
--cc=schwab@suse.de \
/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;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).