From: Thomas Gleixner <tglx@linutronix.de>
To: Ren Qiaowei <qiaowei.ren@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-mips@linux-mips.org
Subject: Re: [PATCH v9 09/12] x86, mpx: decode MPX instruction to get bound violation information
Date: Fri, 31 Oct 2014 10:09:13 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.11.1410311007230.5308@nanos> (raw)
In-Reply-To: <5452EFF7.4090204@intel.com>
On Fri, 31 Oct 2014, Ren Qiaowei wrote:
> On 10/31/2014 06:38 AM, Dave Hansen wrote:
> > > @@ -316,6 +317,11 @@ dotraplinkage void do_bounds(struct pt_regs *regs,
> > > long error_code)
> > > break;
> > >
> > > case 1: /* Bound violation. */
> > > + do_mpx_bounds(regs, &info, xsave_buf);
> > > + do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs,
> > > + error_code, &info);
> > > + break;
> > > +
> > > case 0: /* No exception caused by Intel MPX operations. */
> > > do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code,
> > > NULL);
> > > break;
> > >
> >
> > So, siginfo is stack-allocarted here. do_mpx_bounds() can error out if
> > it sees an invalid bndregno. We still send the signal with the &info
> > whether or not we filled the 'info' in do_mpx_bounds().
> >
> > Can't this leak some kernel stack out in the 'info'?
> >
>
> This should check the return value of do_mpx_bounds and should be fixed.
And how's that answering Dave's question about leaking stack information?
Thanks,
tglx
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next prev parent reply other threads:[~2014-10-31 9:09 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-12 4:41 [PATCH v9 00/12] Intel MPX support Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 01/12] x86, mpx: introduce VM_MPX to indicate that a VMA is MPX specific Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 02/12] x86, mpx: rename cfg_reg_u and status_reg Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 03/12] x86, mpx: add MPX specific mmap interface Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 04/12] x86, mpx: add MPX to disaabled features Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 05/12] x86, mpx: on-demand kernel allocation of bounds tables Qiaowei Ren
2014-10-24 12:08 ` Thomas Gleixner
2014-10-27 3:20 ` Ren Qiaowei
2014-10-28 17:43 ` Dave Hansen
2014-10-28 17:57 ` Thomas Gleixner
2014-10-12 4:41 ` [PATCH v9 06/12] mpx: extend siginfo structure to include bound violation information Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 07/12] mips: sync struct siginfo with general version Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 08/12] ia64: " Qiaowei Ren
2014-10-12 4:41 ` [PATCH v9 09/12] x86, mpx: decode MPX instruction to get bound violation information Qiaowei Ren
2014-10-24 12:36 ` Thomas Gleixner
2014-10-27 1:43 ` Ren, Qiaowei
2014-10-27 20:36 ` Thomas Gleixner
2014-10-28 5:58 ` Ren Qiaowei
2014-10-31 20:16 ` Dave Hansen
2014-10-31 20:33 ` Thomas Gleixner
2014-10-30 22:38 ` Dave Hansen
2014-10-31 2:12 ` Ren Qiaowei
2014-10-31 9:09 ` Thomas Gleixner [this message]
2014-10-12 4:41 ` [PATCH v9 10/12] x86, mpx: add prctl commands PR_MPX_ENABLE_MANAGEMENT, PR_MPX_DISABLE_MANAGEMENT Qiaowei Ren
2014-10-24 12:49 ` Thomas Gleixner
2014-10-24 15:10 ` Thomas Gleixner
2014-10-27 2:17 ` Ren, Qiaowei
2014-10-27 20:38 ` Thomas Gleixner
2014-10-28 5:57 ` Ren Qiaowei
2014-10-12 4:41 ` [PATCH v9 11/12] x86, mpx: cleanup unused bound tables Qiaowei Ren
2014-10-24 14:40 ` Thomas Gleixner
2014-10-27 3:13 ` Ren Qiaowei
2014-10-27 20:49 ` Thomas Gleixner
2014-10-28 5:56 ` Ren Qiaowei
2014-10-28 10:42 ` Thomas Gleixner
2014-11-03 20:53 ` Dave Hansen
2014-11-03 21:29 ` Thomas Gleixner
2014-11-04 16:00 ` Dave Hansen
2014-11-04 17:02 ` Thomas Gleixner
2014-11-06 21:50 ` Dave Hansen
2014-11-11 18:27 ` Thomas Gleixner
2014-11-11 20:44 ` Dave Hansen
2014-11-11 21:36 ` Thomas Gleixner
2014-10-12 4:41 ` [PATCH v9 12/12] x86, mpx: add documentation on Intel MPX Qiaowei Ren
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