Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757465AbbKSAOU (ORCPT ); Wed, 18 Nov 2015 19:14:20 -0500 Received: from mail-pa0-f42.google.com ([209.85.220.42]:33130 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756210AbbKSAOQ (ORCPT ); Wed, 18 Nov 2015 19:14:16 -0500 Subject: Re: [PATCH v3 1/4] mm: mmap: Add new /proc tunable for mmap_base ASLR. To: linux-kernel@vger.kernel.org References: <1447888808-31571-1-git-send-email-dcashman@android.com> <1447888808-31571-2-git-send-email-dcashman@android.com> Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, mingo@kernel.org, linux-arm-kernel@lists.infradead.org, corbet@lwn.net, dzickus@redhat.com, ebiederm@xmission.com, xypron.glpk@gmx.de, jpoimboe@redhat.com, kirill.shutemov@linux.intel.com, n-horiguchi@ah.jp.nec.com, aarcange@redhat.com, mgorman@suse.de, tglx@linutronix.de, rientjes@google.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, salyzyn@android.com, jeffv@google.com, nnk@google.com, catalin.marinas@arm.com, will.deacon@arm.com, hpa@zytor.com, x86@kernel.org, hecmargi@upv.es, bp@suse.de, dcashman@google.com From: Daniel Cashman Message-ID: <564D1455.4070508@android.com> Date: Wed, 18 Nov 2015 16:14:13 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1447888808-31571-2-git-send-email-dcashman@android.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3983 Lines: 117 On 11/18/2015 03:20 PM, Daniel Cashman wrote: > ============================================================== > > +mmap_rnd_bits: > + > +This value can be used to select the number of bits to use to > +determine the random offset to the base address of vma regions > +resulting from mmap allocations on architectures which support > +tuning address space randomization. This value will be bounded > +by the architecture's minimum and maximum supported values. > + > +This value can be changed after boot using the > +/proc/sys/kernel/mmap_rnd_bits tunable > + > +============================================================== > + > +mmap_rnd_compat_bits: > + > +This value can be used to select the number of bits to use to > +determine the random offset to the base address of vma regions > +resulting from mmap allocations for applications run in > +compatibility mode on architectures which support tuning address > +space randomization. This value will be bounded by the > +architecture's minimum and maximum supported values. > + > +This value can be changed after boot using the > +/proc/sys/kernel/mmap_rnd_compat_bits tunable > + > +============================================================== As Kees pointed out in my erroneously sent (missing v3 prefix) patch-set: the /proc/sys/kernel/ entries were not changed to reflect the move to /proc/sys/vm/. > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 00bad77..7d39828 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -51,6 +51,17 @@ extern int sysctl_legacy_va_layout; > #define sysctl_legacy_va_layout 0 > #endif > > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS > +extern int mmap_rnd_bits_min; > +extern int mmap_rnd_bits_max; > +extern int mmap_rnd_bits; > +#endif > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS > +extern int mmap_rnd_compat_bits_min; > +extern int mmap_rnd_compat_bits_max; > +extern int mmap_rnd_compat_bits; > +#endif > + > #include > #include > #include > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > index dc6858d..40e5de6 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -1568,6 +1568,28 @@ static struct ctl_table vm_table[] = { > .mode = 0644, > .proc_handler = proc_doulongvec_minmax, > }, > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS > + { > + .procname = "mmap_rnd_bits", > + .data = &mmap_rnd_bits, > + .maxlen = sizeof(mmap_rnd_bits), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = &mmap_rnd_bits_min, > + .extra2 = &mmap_rnd_bits_max, > + }, > +#endif > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS > + { > + .procname = "mmap_rnd_compat_bits", > + .data = &mmap_rnd_compat_bits, > + .maxlen = sizeof(mmap_rnd_compat_bits), > + .mode = 0644, > + .proc_handler = proc_dointvec_minmax, > + .extra1 = &mmap_rnd_compat_bits_min, > + .extra2 = &mmap_rnd_compat_bits_max, > + }, > +#endif > { } > }; > > diff --git a/mm/mmap.c b/mm/mmap.c > index 2ce04a6..aa49841 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -58,6 +58,18 @@ > #define arch_rebalance_pgtables(addr, len) (addr) > #endif > > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS > +int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; > +int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; > +int mmap_rnd_bits = CONFIG_ARCH_MMAP_RND_BITS; > +#endif > +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS > +int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN; > +int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX; > +int mmap_rnd_compat_bits = CONFIG_ARCH_MMAP_RND_COMPAT_BITS; > +#endif > + Again from Kees in my erroneously sent (missing v3 prefix) patch-set: the min/max should be const. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/