lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 30 Nov 2015 16:01:18 -0800 From: Andrew Morton <akpm@...ux-foundation.org> To: Daniel Cashman <dcashman@...roid.com>, linux-kernel@...r.kernel.org, linux@....linux.org.uk, keescook@...omium.org, mingo@...nel.org, linux-arm-kernel@...ts.infradead.org, corbet@....net, dzickus@...hat.com, ebiederm@...ssion.com, xypron.glpk@....de, jpoimboe@...hat.com, kirill.shutemov@...ux.intel.com, n-horiguchi@...jp.nec.com, aarcange@...hat.com, mgorman@...e.de, tglx@...utronix.de, rientjes@...gle.com, linux-mm@...ck.org, linux-doc@...r.kernel.org, salyzyn@...roid.com, jeffv@...gle.com, nnk@...gle.com, catalin.marinas@....com, will.deacon@....com, hpa@...or.com, x86@...nel.org, hecmargi@....es, bp@...e.de, dcashman@...gle.com Subject: Re: [PATCH v4 1/4] mm: mmap: Add new /proc tunable for mmap_base ASLR. On Mon, 30 Nov 2015 15:54:12 -0800 Andrew Morton <akpm@...ux-foundation.org> wrote: > On Thu, 26 Nov 2015 14:59:42 -0800 Daniel Cashman <dcashman@...roid.com> wrote: > > > ASLR only uses as few as 8 bits to generate the random offset for the > > mmap base address on 32 bit architectures. This value was chosen to > > prevent a poorly chosen value from dividing the address space in such > > a way as to prevent large allocations. This may not be an issue on all > > platforms. Allow the specification of a minimum number of bits so that > > platforms desiring greater ASLR protection may determine where to place > > the trade-off. > > > > --- 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 = 0600, > > + .proc_handler = proc_dointvec_minmax, > > + .extra1 = (void *) &mmap_rnd_bits_min, > > + .extra2 = (void *) &mmap_rnd_bits_max, > > hm, why the typecasts? They're unneeded and are omitted everywhere(?) > else in kernel/sysctl.c. > Oh. Casting away constness. What's the thinking here? They can change at any time so they aren't const so we shouldn't declare them to be const? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists