From patchwork Fri Jun 23 20:59:59 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9807283 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 CBAE160349 for ; Fri, 23 Jun 2017 21:00:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BDA2F26530 for ; Fri, 23 Jun 2017 21:00:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B22ED28560; Fri, 23 Jun 2017 21:00:46 +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 9F9E4285C9 for ; Fri, 23 Jun 2017 21:00:45 +0000 (UTC) Received: (qmail 17881 invoked by uid 550); 23 Jun 2017 21:00:27 -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 17695 invoked from network); 23 Jun 2017 21:00:24 -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=aIw6ITh61yuV6ZHkIghtrJuYZeFoE/hWnZV1jzMnnHM=; b=S1XA33WexllScNz7dP76gv6pkCrR/RK1aLLMdc2XP+a74p4QAGGGqk1XFuUeoQGJM2 lpcBXkqW5BoTpAfLRngPjLsQGr/z94sBJRwqNiEO77YgOoOM1aLbL+bdTi51oXF9tg1n S/P8Ewc3qeN4oFTUUMgNYdgZoDg4GPx6thMgc= 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=aIw6ITh61yuV6ZHkIghtrJuYZeFoE/hWnZV1jzMnnHM=; b=BfbcnxIFizz/9rwvA45BMXvztXhpHPlFaGZqArhrCzmWfHawejbWfMIL5PQvmNN3BY GaIwool5vRclpt6vtkSFtSNyg33xZQY56skZFKm56g2lgHCm6a1y+7sVrChYqj9SF2Lg pQEFkIAwqMpd+d0g6lSZHqw1dDLyxQnPAwP86XuOp4O303WaJ5btiRCbdklEUyCbAhee b3EzkiUSLKeydfPBUhAuIbRugU/iaj3BMulr8I++BaYkyjOuB3X4tbNACoGNSQXsXpsi U6Nw6WZKIfVvKZ4hrmNMZA/kJzM1VHYafDZHfN3dVyj/gIeocS4zYld8hzz5g5UqkUy3 mWkw== X-Gm-Message-State: AKS2vOzkfI8k1cDSq8pHCfUjAwcIdUeNRaRgX2nkJ22/T7L/eb8tDBAF iyYI+GIrgfK/k9wD X-Received: by 10.98.106.66 with SMTP id f63mr10251031pfc.169.1498251612258; Fri, 23 Jun 2017 14:00:12 -0700 (PDT) From: Kees Cook To: Andrew Morton Cc: Kees Cook , stable@vger.kernel.org, Rik van Riel , Ard Biesheuvel , Daniel Micay , Qualys Security Advisory , Russell King , Catalin Marinas , Will Deacon , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Martin Schwidefsky , Heiko Carstens , 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 13:59:59 -0700 Message-Id: <1498251600-132458-5-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 4/5] powerpc: 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). Cc: stable@vger.kernel.org Signed-off-by: Kees Cook Acked-by: Michael Ellerman --- arch/powerpc/include/asm/elf.h | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/arch/powerpc/include/asm/elf.h b/arch/powerpc/include/asm/elf.h index 09bde6e34f5d..548d9a411a0d 100644 --- a/arch/powerpc/include/asm/elf.h +++ b/arch/powerpc/include/asm/elf.h @@ -23,12 +23,13 @@ #define CORE_DUMP_USE_REGSET #define ELF_EXEC_PAGESIZE PAGE_SIZE -/* 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. */ - -#define ELF_ET_DYN_BASE 0x20000000 +/* + * 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_32bit_task() ? 0x000400000UL : \ + 0x100000000UL) #define ELF_CORE_EFLAGS (is_elf2_task() ? 2 : 0)