Date: Thu, 30 Nov 2017 10:23:44 +0000 From: David Laight <David.Laight@...LAB.COM> To: 'Andrew Morton' <akpm@...ux-foundation.org>, "Tobin C. Harding" <me@...in.cc> CC: "kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>, Linus Torvalds <torvalds@...ux-foundation.org>, "Jason A. Donenfeld" <Jason@...c4.com>, Theodore Ts'o <tytso@....edu>, Kees Cook <keescook@...omium.org>, "Paolo Bonzini" <pbonzini@...hat.com>, Tycho Andersen <tycho@...ho.ws>, "Roberts, William C" <william.c.roberts@...el.com>, Tejun Heo <tj@...nel.org>, "Jordan Glover" <Golden_Miller83@...tonmail.ch>, Greg KH <gregkh@...uxfoundation.org>, Petr Mladek <pmladek@...e.com>, Joe Perches <joe@...ches.com>, Ian Campbell <ijc@...lion.org.uk>, Sergey Senozhatsky <sergey.senozhatsky@...il.com>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <wilal.deacon@....com>, Steven Rostedt <rostedt@...dmis.org>, Chris Fries <cfries@...gle.com>, Dave Weinstein <olorin@...gle.com>, Daniel Micay <danielmicay@...il.com>, Djalal Harouni <tixxdz@...il.com>, Radim Krcmár <rkrcmar@...hat.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Network Development" <netdev@...r.kernel.org>, David Miller <davem@...emloft.net>, Stephen Rothwell <sfr@...b.auug.org.au>, Andrey Ryabinin <aryabinin@...tuozzo.com>, Alexander Potapenko <glider@...gle.com>, "Dmitry Vyukov" <dvyukov@...gle.com> Subject: RE: [PATCH V11 0/5] hash addresses printed with %p From: Andrew Morton > Sent: 29 November 2017 23:21 > > > > The added advantage of hashing %p is that security is now opt-out, if > > you _really_ want the address you have to work a little harder and use > > %px. You need a system-wide opt-out that prints the actual values. Otherwise developers will use something else to print addresses and the code will remain in the released drivers. > > The idea for creating the printk specifier %px to print the actual > > address was suggested by Kees Cook (see below for email threads by > > subject). > > Maybe I'm being thick, but... if we're rendering these addresses > unusable by hashing them, why not just print something like > "<obscured>" in their place? That loses the uniqueness thing but I > wonder how valuable that is in practice? My worry is that is you get a kernel 'oops' print with actual register values you have no easy way of tying an address or address+offset to the corresponding hash(address) printed elsewhere. David
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.