From patchwork Thu Mar 9 20:52:03 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 9614173 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 B7F3C60414 for ; Thu, 9 Mar 2017 20:55:03 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AD81528334 for ; Thu, 9 Mar 2017 20:55:03 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A2286286B2; Thu, 9 Mar 2017 20:55:03 +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=-4.1 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 A0CE428334 for ; Thu, 9 Mar 2017 20:55:02 +0000 (UTC) Received: (qmail 32215 invoked by uid 550); 9 Mar 2017 20:55:01 -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 28007 invoked from network); 9 Mar 2017 20:53:26 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=XzRVwsmVTmRHXffuVXRCkgosGGizKPd3amgB/nVQ5BY=; b=dAjCrsOxCmebgTnnIqNkY184wGWMmA3JsyJote//f/FIFIstTla8ZFSjx6easPxHA+ YaaUCjoM3Xyn+UxpKuw0/oLpJ1FPeXp0qsCxVy3DSD/ydclFem/YsJlEfhSKJvln0tI1 U4/XA5yOEg3RyM5IvwQawK2P6+8AUCdGsDX+Y= 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=XzRVwsmVTmRHXffuVXRCkgosGGizKPd3amgB/nVQ5BY=; b=D9xLR8N9mSfRnkQtjDS94zyt/kfTt1RKq6+j0pag7CCF7yVe/RY0XWfrjL8pqi8Ua8 dzCSqLLMp7iSrOnmlYQd2k780pqUDDd3mZbjXJPdJWd29o9BogWWIXWx3Jl8iZ5Cdlbv 5xL5J7/hWmvAIPzLlzy46xSr6xdGW7DCUFlaRkcvfVpTmys4oEy3XhyJYcXTUPKqjxmd iY93z2NxeCssq82vCcHXBDFzzOpag+wNgnQjFWKG5/ZYgz0/ef+kllk7mQHA+3Ipq+TC mpAyFRc5FBkREsZF9mDfpBXxQvm6MMcMxhB5PlFq0OxIeZn0l/KfPW1ROlsS/NhgrLaU ji4g== X-Gm-Message-State: AMke39l418pZt8WUFJog5k5IDmKcx3OZ7R8RWP8ZMjmUgQ+H/82alvMFGXuDyGVv1upTQ1Qj X-Received: by 10.28.65.196 with SMTP id o187mr29844245wma.9.1489092795044; Thu, 09 Mar 2017 12:53:15 -0800 (PST) From: Ard Biesheuvel To: linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, keescook@chromium.org, labbott@fedoraproject.org Cc: kernel-hardening@lists.openwall.com, will.deacon@arm.com, catalin.marinas@arm.com, Ard Biesheuvel Date: Thu, 9 Mar 2017 21:52:03 +0100 Message-Id: <1489092729-16871-6-git-send-email-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1489092729-16871-1-git-send-email-ard.biesheuvel@linaro.org> References: <1489092729-16871-1-git-send-email-ard.biesheuvel@linaro.org> Subject: [kernel-hardening] [PATCH v6 05/11] arm64: mmu: apply strict permissions to .init.text and .init.data X-Virus-Scanned: ClamAV using ClamSMTP To avoid having mappings that are writable and executable at the same time, split the init region into a .init.text region that is mapped read-only, and a .init.data region that is mapped non-executable. This is possible now that the alternative patching occurs via the linear mapping, and the linear alias of the init region is always mapped writable (but never executable). Since the alternatives descriptions themselves are read-only data, move those into the .init.text region. Reviewed-by: Laura Abbott Reviewed-by: Mark Rutland Signed-off-by: Ard Biesheuvel --- arch/arm64/include/asm/sections.h | 2 ++ arch/arm64/kernel/vmlinux.lds.S | 25 +++++++++++++------- arch/arm64/mm/mmu.c | 12 ++++++---- 3 files changed, 26 insertions(+), 13 deletions(-) diff --git a/arch/arm64/include/asm/sections.h b/arch/arm64/include/asm/sections.h index 4e7e7067afdb..941267caa39c 100644 --- a/arch/arm64/include/asm/sections.h +++ b/arch/arm64/include/asm/sections.h @@ -24,6 +24,8 @@ extern char __hibernate_exit_text_start[], __hibernate_exit_text_end[]; extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; extern char __hyp_text_start[], __hyp_text_end[]; extern char __idmap_text_start[], __idmap_text_end[]; +extern char __initdata_begin[], __initdata_end[]; +extern char __inittext_begin[], __inittext_end[]; extern char __irqentry_text_start[], __irqentry_text_end[]; extern char __mmuoff_data_start[], __mmuoff_data_end[]; diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S index b8deffa9e1bf..2c93d259046c 100644 --- a/arch/arm64/kernel/vmlinux.lds.S +++ b/arch/arm64/kernel/vmlinux.lds.S @@ -143,12 +143,27 @@ SECTIONS . = ALIGN(SEGMENT_ALIGN); __init_begin = .; + __inittext_begin = .; INIT_TEXT_SECTION(8) .exit.text : { ARM_EXIT_KEEP(EXIT_TEXT) } + . = ALIGN(4); + .altinstructions : { + __alt_instructions = .; + *(.altinstructions) + __alt_instructions_end = .; + } + .altinstr_replacement : { + *(.altinstr_replacement) + } + + . = ALIGN(PAGE_SIZE); + __inittext_end = .; + __initdata_begin = .; + .init.data : { INIT_DATA INIT_SETUP(16) @@ -164,15 +179,6 @@ SECTIONS PERCPU_SECTION(L1_CACHE_BYTES) - . = ALIGN(4); - .altinstructions : { - __alt_instructions = .; - *(.altinstructions) - __alt_instructions_end = .; - } - .altinstr_replacement : { - *(.altinstr_replacement) - } .rela : ALIGN(8) { *(.rela .rela*) } @@ -181,6 +187,7 @@ SECTIONS __rela_size = SIZEOF(.rela); . = ALIGN(SEGMENT_ALIGN); + __initdata_end = .; __init_end = .; _data = .; diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 300e98e8cd63..75e21c33caff 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -459,7 +459,8 @@ early_param("rodata", parse_rodata); */ static void __init map_kernel(pgd_t *pgd) { - static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data; + static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, + vmlinux_initdata, vmlinux_data; /* * External debuggers may need to write directly to the text @@ -469,9 +470,12 @@ static void __init map_kernel(pgd_t *pgd) pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; map_kernel_segment(pgd, _text, _etext, text_prot, &vmlinux_text); - map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata); - map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC, - &vmlinux_init); + map_kernel_segment(pgd, __start_rodata, __inittext_begin, PAGE_KERNEL, + &vmlinux_rodata); + map_kernel_segment(pgd, __inittext_begin, __inittext_end, text_prot, + &vmlinux_inittext); + map_kernel_segment(pgd, __initdata_begin, __initdata_end, PAGE_KERNEL, + &vmlinux_initdata); map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data); if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {