From patchwork Fri Jun 23 21:00:00 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9807281 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 ACBBC60349 for ; Fri, 23 Jun 2017 21:00:40 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9E872285A8 for ; Fri, 23 Jun 2017 21:00:40 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 91070285C9; Fri, 23 Jun 2017 21:00:40 +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=-4.1 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED,T_DKIM_INVALID 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 B7A5028578 for ; Fri, 23 Jun 2017 21:00:39 +0000 (UTC) Received: (qmail 17842 invoked by uid 550); 23 Jun 2017 21:00:26 -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: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 17782 invoked from network); 23 Jun 2017 21:00:25 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=zBIiXrk+YofUPuLgYDPuLoP7g64X/OUjZ6JPAGlVWCs=; b=KrKSNJqZPxM43KVml7gTicDCEOBGczNdscmTlxU84XFEg/yl2lCY1wiRl9W+RSe3kg hLfmsGnCt7txfeXpQAyfAnOGfv+xiLb1rH4zIRhzrVYPGDrbgZ6rFdZjH+16eRpc/LmW OVeglsapilaq5UvXw24Yp631HhFfoWAB8YhZE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=zBIiXrk+YofUPuLgYDPuLoP7g64X/OUjZ6JPAGlVWCs=; b=DEa/tBLxGWG8qaBbQ2TkGRjEqoOK87ji9anUMXl4sfbxydKw+6D8Hxa3GoMU6YH8L+ mGnrDajbZYVKWB0CNT8WEa0hgMw0ZehauGPiL8FN7YIdeSXCLi2DoeUoF2VLcYhs6pNU nyvEXUajUO8/voIi5RCf0I/ksMTzSOWdSNXvuak5h4Ws32j45phCVwwaSiaI8e75ywQi 24kIsnrqs1mnwDdNNd8Gd1SwLWjmAOsnVnNh8LlBeNfjUvxwZqIbC9tbZzsTNZ6ZPSas yywjevH7hXHjQNwMK+iCM4EuLv3Ty4t+jWid0aXgbvbL+BdVc6g7tD75Ch1tzIdlFa5U G+MQ== X-Gm-Message-State: AKS2vOz/iDPliJCLcfKyaQ9CHrGVVYYpv4xXQx9avdmPJ9eAJBOv7sIf jib8ygvtClhj+iJw X-Received: by 10.99.105.74 with SMTP id e71mr9856875pgc.51.1498251613617; Fri, 23 Jun 2017 14:00:13 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , stable@vger.kernel.org, Heiko Carstens , Martin Schwidefsky , Rik van Riel , Ard Biesheuvel , Daniel Micay , Qualys Security Advisory , Russell King , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Alexander Viro , Pratyush Anand , James Hogan , Dmitry Safonov , Grzegorz Andrejczuk , Masahiro Yamada , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, kernel-hardening@lists.openwall.com Date: Fri, 23 Jun 2017 14:00:00 -0700 Message-Id: <1498251600-132458-6-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1498251600-132458-1-git-send-email-keescook@chromium.org> References: <1498251600-132458-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH v2 5/5] s390: Move ELF_ET_DYN_BASE to 4GB / 4MB X-Virus-Scanned: ClamAV using ClamSMTP Now that explicitly executed loaders are loaded in the mmap region, we have more freedom to decide where we position PIE binaries in the address space to avoid possible collisions with mmap or stack regions. For 64-bit, align to 4GB to allow runtimes to use the entire 32-bit address space for 32-bit pointers. On 32-bit use 4MB, which is the traditional x86 minimum load location, likely to avoid historically requiring a 4MB page table entry when only a portion of the first 4MB would be used (since the NULL address is avoided). For s390 the position could be 0x10000, but that is needlessly close to the NULL address. Cc: stable@vger.kernel.org Cc: Heiko Carstens Cc: Martin Schwidefsky Signed-off-by: Kees Cook --- arch/s390/include/asm/elf.h | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h index e8f623041769..7c58d599f91b 100644 --- a/arch/s390/include/asm/elf.h +++ b/arch/s390/include/asm/elf.h @@ -161,14 +161,13 @@ extern unsigned int vdso_enabled; #define CORE_DUMP_USE_REGSET #define ELF_EXEC_PAGESIZE 4096 -/* This is the location that an ET_DYN program is loaded if exec'ed. Typical - use of this is to invoke "./ld.so someprog" to test out a new version of - the loader. We need to make sure that it is out of the way of the program - that it will "exec", and that there is sufficient room for the brk. 64-bit - tasks are aligned to 4GB. */ -#define ELF_ET_DYN_BASE (is_compat_task() ? \ - (STACK_TOP / 3 * 2) : \ - (STACK_TOP / 3 * 2) & ~((1UL << 32) - 1)) +/* + * This is the base location for PIE (ET_DYN with INTERP) loads. On + * 64-bit, this is raised to 4GB to leave the entire 32-bit address + * space open for things that want to use the area for 32-bit pointers. + */ +#define ELF_ET_DYN_BASE (is_compat_task() ? 0x000400000UL : \ + 0x100000000UL) /* This yields a mask that user programs can use to figure out what instruction set this CPU supports. */