From patchwork Thu Jul 28 20:47:25 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Cooper X-Patchwork-Id: 9251705 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B75D96075F for ; Thu, 28 Jul 2016 21:26:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A70AA27E71 for ; Thu, 28 Jul 2016 21:26:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9AFA627F0B; Thu, 28 Jul 2016 21:26:03 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id DA5E027E71 for ; Thu, 28 Jul 2016 21:26:01 +0000 (UTC) Received: (qmail 1453 invoked by uid 550); 28 Jul 2016 21:25:53 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 32765 invoked from network); 28 Jul 2016 21:25:52 -0000 X-MHO-User: fe4d85bb-5509-11e6-8929-8ded99d5e9d7 X-Report-Abuse-To: https://support.duocircle.com/support/solutions/articles/5000540958-duocircle-standard-smtp-abuse-information X-Originating-IP: 74.99.77.15 X-Mail-Handler: DuoCircle Outbound SMTP From: Jason Cooper To: william.c.roberts@intel.com, Yann Droneaud , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Cc: linux@arm.linux.org.uk, akpm@linux-foundation.org, keescook@chromium.org, tytso@mit.edu, arnd@arndb.de, gregkh@linuxfoundation.org, catalin.marinas@arm.com, will.deacon@arm.com, ralf@linux-mips.org, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, davem@davemloft.net, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, viro@zeniv.linux.org.uk, nnk@google.com, jeffv@google.com, dcashman@android.com, Jason Cooper Date: Thu, 28 Jul 2016 20:47:25 +0000 Message-Id: <20160728204730.27453-3-jason@lakedaemon.net> X-Mailer: git-send-email 2.9.2 In-Reply-To: <20160728204730.27453-1-jason@lakedaemon.net> References: <20160728204730.27453-1-jason@lakedaemon.net> Subject: [kernel-hardening] [PATCH 2/7] x86: Use simpler API for random address requests X-Virus-Scanned: ClamAV using ClamSMTP Currently, all callers to randomize_range() set the length to 0 and calculate end by adding a constant to the start address. We can simplify the API to remove a bunch of needless checks and variables. Use the new randomize_addr(start, range) call to set the requested address. Signed-off-by: Jason Cooper --- arch/x86/kernel/process.c | 3 +-- arch/x86/kernel/sys_x86_64.c | 5 +---- 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 96becbbb52e0..a083a2c0744e 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -507,8 +507,7 @@ unsigned long arch_align_stack(unsigned long sp) unsigned long arch_randomize_brk(struct mm_struct *mm) { - unsigned long range_end = mm->brk + 0x02000000; - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; + return randomize_addr(mm->brk, 0x02000000); } /* diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c index 10e0272d789a..f9cad22808fc 100644 --- a/arch/x86/kernel/sys_x86_64.c +++ b/arch/x86/kernel/sys_x86_64.c @@ -101,7 +101,6 @@ static void find_start_end(unsigned long flags, unsigned long *begin, unsigned long *end) { if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) { - unsigned long new_begin; /* This is usually used needed to map code in small model, so it needs to be in the first 31bit. Limit it to that. This means we need to move the @@ -112,9 +111,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin, *begin = 0x40000000; *end = 0x80000000; if (current->flags & PF_RANDOMIZE) { - new_begin = randomize_range(*begin, *begin + 0x02000000, 0); - if (new_begin) - *begin = new_begin; + *begin = randomize_addr(*begin, 0x02000000); } } else { *begin = current->mm->mmap_legacy_base;