From patchwork Mon Nov 22 08:48:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 1557919 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by bilbo.ozlabs.org (Postfix) with ESMTPS id 4HyLZw4p53z9sRR for ; Mon, 22 Nov 2021 19:50:48 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4HyLZw3xgvz3dbL for ; Mon, 22 Nov 2021 19:50:48 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=csgroup.eu (client-ip=93.17.235.10; helo=pegase2.c-s.fr; envelope-from=christophe.leroy@csgroup.eu; receiver=) Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4HyLY22f7Xz30JT for ; Mon, 22 Nov 2021 19:49:10 +1100 (AEDT) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4HyLXh4LfKz9sSk; Mon, 22 Nov 2021 09:48:52 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id F-Hpno9y4Il3; Mon, 22 Nov 2021 09:48:52 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4HyLXc0mQLz9sSZ; Mon, 22 Nov 2021 09:48:48 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 025038B77E; Mon, 22 Nov 2021 09:48:48 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 9UYHqUPi79zJ; Mon, 22 Nov 2021 09:48:47 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [172.25.230.108]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9C6258B765; Mon, 22 Nov 2021 09:48:47 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 1AM8meZD631732 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 22 Nov 2021 09:48:40 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 1AM8mecI631731; Mon, 22 Nov 2021 09:48:40 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , alex@ghiti.fr Subject: [PATCH 6/8] mm: Allow arch specific arch_randomize_brk() with CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT Date: Mon, 22 Nov 2021 09:48:26 +0100 Message-Id: X-Mailer: git-send-email 2.33.1 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1637570906; l=3140; s=20211009; h=from:subject:message-id; bh=AZ109l+llHd6MRuKtoBs1/7LX92fJnFaX5ppcmPYk/k=; b=c1K5qNiDUgf938Fhv0hbNI+x4nVqzA7W5nodpE2TVdar2U38+lhjeUFeWrVU1Yi1kaX+tJephyQT aDVmg4c9ANTiDlaXYDL9TLsmsG3NFa80zhie1WS5xJ91T5Jv/r9q X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Commit e7142bf5d231 ("arm64, mm: make randomization selected by generic topdown mmap layout") introduced a default version of arch_randomize_brk() provided when CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT is selected. powerpc could select CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT but needs to provide its own arch_randomize_brk(). In order to allow that, don't make CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT select CONFIG_ARCH_HAS_ELF_RANDOMIZE. Instead, ensure that selecting CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT and selecting CONFIG_ARCH_HAS_ELF_RANDOMIZE has the same effect. Then only provide the default arch_randomize_brk() when the architecture has not selected CONFIG_ARCH_HAS_ELF_RANDOMIZE. Cc: Alexandre Ghiti Signed-off-by: Christophe Leroy Reported-by: kernel test robot --- arch/Kconfig | 1 - fs/binfmt_elf.c | 3 ++- include/linux/elf-randomize.h | 3 ++- mm/util.c | 2 ++ 4 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/Kconfig b/arch/Kconfig index 26b8ed11639d..ef3ce947b7a1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -1000,7 +1000,6 @@ config HAVE_ARCH_COMPAT_MMAP_BASES config ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT bool depends on MMU - select ARCH_HAS_ELF_RANDOMIZE config HAVE_STACK_VALIDATION bool diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index f8c7f26f1fbb..28968a189a91 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1287,7 +1287,8 @@ static int load_elf_binary(struct linux_binprm *bprm) * (since it grows up, and may collide early with the stack * growing down), and into the unused ELF_ET_DYN_BASE region. */ - if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && + if ((IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) || + IS_ENABLED(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)) && elf_ex->e_type == ET_DYN && !interpreter) { mm->brk = mm->start_brk = ELF_ET_DYN_BASE; } diff --git a/include/linux/elf-randomize.h b/include/linux/elf-randomize.h index da0dbb7b6be3..1e471ca7caaf 100644 --- a/include/linux/elf-randomize.h +++ b/include/linux/elf-randomize.h @@ -4,7 +4,8 @@ struct mm_struct; -#ifndef CONFIG_ARCH_HAS_ELF_RANDOMIZE +#if !defined(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && \ + !defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT) static inline unsigned long arch_mmap_rnd(void) { return 0; } # if defined(arch_randomize_brk) && defined(CONFIG_COMPAT_BRK) # define compat_brk_randomized diff --git a/mm/util.c b/mm/util.c index e58151a61255..edb9e94cceb5 100644 --- a/mm/util.c +++ b/mm/util.c @@ -344,6 +344,7 @@ unsigned long randomize_stack_top(unsigned long stack_top) } #ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT +#ifndef CONFIG_ARCH_HAS_ELF_RANDOMIZE unsigned long arch_randomize_brk(struct mm_struct *mm) { /* Is the current task 32bit ? */ @@ -352,6 +353,7 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) return randomize_page(mm->brk, SZ_1G); } +#endif unsigned long arch_mmap_rnd(void) {