Messages in this thread | | | Date | Mon, 22 Dec 2008 14:23:38 +0100 | From | "stephane eranian" <> | Subject | Re: [patch] x86, ptrace: require admin privileges for ptrace BTS extension |
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Markus,
On Mon, Dec 22, 2008 at 1:02 PM, Markus Metzger <markus.t.metzger@intel.com> wrote: > Require admin privileges for ptrace BTS extension. > Can you explain the motivations for this?
I thought the BTS extension was a per-process functionality. So how come I can debug and single step my process without admin privilege and I cannot capture its own branches. Does this have to do with user vs. kernel execution of the proces (BTS captures everything if I recall)?
Thanks.
> > Reported-by: Ingo Molnar <mingo@elte.hu> > Signed-off-by: Markus Metzger <markus.t.metzger@intel.com> > --- > > Index: gits/arch/x86/kernel/ptrace.c > =================================================================== > --- gits.orig/arch/x86/kernel/ptrace.c 2008-12-22 09:09:25.000000000 +0100 > +++ gits/arch/x86/kernel/ptrace.c 2008-12-22 11:03:01.000000000 +0100 > @@ -21,6 +21,7 @@ > #include <linux/audit.h> > #include <linux/seccomp.h> > #include <linux/signal.h> > +#include <linux/capability.h> > > #include <asm/uaccess.h> > #include <asm/pgtable.h> > @@ -742,6 +743,10 @@ > struct ptrace_bts_config cfg; > int error = 0; > > + error = -EPERM; > + if (!capable(CAP_SYS_ADMIN)) > + goto errout; > + > error = -EOPNOTSUPP; > if (!bts_cfg.sizeof_bts) > goto errout; > --------------------------------------------------------------------- > Intel GmbH > Dornacher Strasse 1 > 85622 Feldkirchen/Muenchen Germany > Sitz der Gesellschaft: Feldkirchen bei Muenchen > Geschaeftsfuehrer: Douglas Lusk, Peter Gleissner, Hannes Schwaderer > Registergericht: Muenchen HRB 47456 Ust.-IdNr. > VAT Registration No.: DE129385895 > Citibank Frankfurt (BLZ 502 109 00) 600119052 > > This e-mail and any attachments may contain confidential material for > the sole use of the intended recipient(s). Any review or distribution > by others is strictly prohibited. If you are not the intended > recipient, please contact the sender and delete all copies. > >
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