Message ID | 20240217062545.1631668-2-keescook@chromium.org (mailing list archive) |
---|---|
State | New |
Headers | show
Return-Path: <owner-linux-mm@kvack.org> X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25C63C48BF6 for <linux-mm@archiver.kernel.org>; Sat, 17 Feb 2024 06:25:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1C82C6B0072; Sat, 17 Feb 2024 01:25:52 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 10AE46B0071; Sat, 17 Feb 2024 01:25:52 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D357E6B0072; Sat, 17 Feb 2024 01:25:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id B62476B006E for <linux-mm@kvack.org>; Sat, 17 Feb 2024 01:25:51 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6EC1C1C0099 for <linux-mm@kvack.org>; Sat, 17 Feb 2024 06:25:51 +0000 (UTC) X-FDA: 81800310102.16.F10892C Received: from mail-pg1-f173.google.com (mail-pg1-f173.google.com [209.85.215.173]) by imf08.hostedemail.com (Postfix) with ESMTP id 8F471160006 for <linux-mm@kvack.org>; Sat, 17 Feb 2024 06:25:48 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=bFe6mOFC; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf08.hostedemail.com: domain of keescook@chromium.org designates 209.85.215.173 as permitted sender) smtp.mailfrom=keescook@chromium.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1708151148; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=E2RXdELjA1+Y5TPLiUTm0d2mhfp+RAxxenDK5Rv9UCY=; b=GXKiU4liDgfbC7mUAdSetj/m2nAuZGExELnUMqGNdsKYxjExb1oGXxJY1P5RVymbMOiJXP 8rjYaSJ9DpYp6oE5uvZ0fjP3aaX4QiNiG8FAOns77ET/X51UPmVL2e0csRN5EA7T4xfqYf ZvF+lROkg1BEiJLjTUaWg9TJlxx102M= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=bFe6mOFC; dmarc=pass (policy=none) header.from=chromium.org; spf=pass (imf08.hostedemail.com: domain of keescook@chromium.org designates 209.85.215.173 as permitted sender) smtp.mailfrom=keescook@chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1708151148; a=rsa-sha256; cv=none; b=UV4bvsafpM3qmZ+dyfniT8+HswxOMJEoyu6xOPTzCM/zdJdbEaAtpyPaQcAsmNbUfL4dWU rjqlS311qAHQkxY6a/seaqEJQDWGjBvfTNmsKWanng0mG7HFvCnKVHDsrj5rkrDNVLZlTJ ty8Yc2ddSJUm721G6p/33i0N3RB3hMw= Received: by mail-pg1-f173.google.com with SMTP id 41be03b00d2f7-5d8ddbac4fbso2295403a12.0 for <linux-mm@kvack.org>; Fri, 16 Feb 2024 22:25:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1708151147; x=1708755947; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=E2RXdELjA1+Y5TPLiUTm0d2mhfp+RAxxenDK5Rv9UCY=; b=bFe6mOFCHWeWR49JRhtGxW0rv21CMV3vqE/s6wufO3RXIJ0+fyU8qdkgCkpNFs5cUy V1XHB7VNxFCHUkdJf/9PTpxxqBTAqHmq/wJBrxe9YHKoVGUf2CZTuLxpav8QQXQJE7TR 73yA9a+R5yQQAhGF7YZRflssBld/wL8p4M65Y= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708151147; x=1708755947; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=E2RXdELjA1+Y5TPLiUTm0d2mhfp+RAxxenDK5Rv9UCY=; b=dO3Ild8c2kyiF1lbTaawqMrXBCAylBNWVQDR4mKOWdTb+j954T0aSmu5eOXf40qaF8 cI88z8wY9aMF/KES4cbrxZDyndRB5rm1euCAnNbcitk4NF03qkRYbr1phT0cWYbJ4B0l gXIY3YeDjs/tzzijBTONGfRCzK8J51/koAIn9Rq3pgNtuenzwU82VKpm769C6j0nDEJ2 2S+6db1uDoN2Zcll0rnd/Eg0yKh5VqcLh5ROfQVslkO6DnlgYuhlUbzceyGCv4Euu2BM rvmKKYt8CM8UTWVi0QznHs30yC9C4MsgsuWsspfCHGv+LtRTtV2gtg75UDO7qla9+kUK 4N2Q== X-Forwarded-Encrypted: i=1; AJvYcCVg8XaIHspE8KqKMjh65SWSyTOZxiRs87b07PFmhG7KbGqE05THr7ySjkojZV4nQvpzVy9Ef1htZR297C3oA69yZKc= X-Gm-Message-State: AOJu0Yyvmytajwv+8PC1WAaPl4ocjaYi8QqbPJzG+ezZk5DJ3wPsTPzZ lHON0SfGeP2gG/s4aeSDAugfNPF5P9BmdS45d01CKm80z96rCyYYZT1ySUYGqQ== X-Google-Smtp-Source: AGHT+IFmbsrgSelSyVzmXuB/u0yC3Rb3JZKRSRjPThoVTEFLQ9HMIMVjPwpT7DE29BVipx3A1VGplg== X-Received: by 2002:a17:902:e80d:b0:1d9:427a:991 with SMTP id u13-20020a170902e80d00b001d9427a0991mr8385363plg.20.1708151147280; Fri, 16 Feb 2024 22:25:47 -0800 (PST) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id mm11-20020a1709030a0b00b001db6da30331sm788247plb.86.2024.02.16.22.25.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Feb 2024 22:25:46 -0800 (PST) From: Kees Cook <keescook@chromium.org> To: Jiri Kosina <jikos@kernel.org> Cc: Kees Cook <keescook@chromium.org>, y0un9n132@gmail.com, Geert Uytterhoeven <geert@linux-m68k.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>, Eric Biederman <ebiederm@xmission.com>, Christophe Leroy <christophe.leroy@csgroup.eu>, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, "H. Peter Anvin" <hpa@zytor.com>, Peter Zijlstra <peterz@infradead.org>, Qi Zheng <zhengqi.arch@bytedance.com>, Alexandre Ghiti <alexghiti@rivosinc.com>, Josh Poimboeuf <jpoimboe@kernel.org>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Rick Edgecombe <rick.p.edgecombe@intel.com>, Brian Gerst <brgerst@gmail.com>, Bjorn Helgaas <bhelgaas@google.com>, Tony Battersby <tonyb@cybernetics.com>, linux-kernel@vger.kernel.org, x86@kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH 2/2] binfmt_elf: Leave a gap between .bss and brk Date: Fri, 16 Feb 2024 22:25:44 -0800 Message-Id: <20240217062545.1631668-2-keescook@chromium.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240217062035.work.493-kees@kernel.org> References: <20240217062035.work.493-kees@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1512; i=keescook@chromium.org; h=from:subject; bh=Y9GWQSNdeMe/TiCQJCjXENrVrfi7E3amSjOSWzM2S1o=; b=owEBbQKS/ZANAwAKAYly9N/cbcAmAcsmYgBl0FFoSMLWKnRZV/Xpg3nYIyPCuv0NWoUMuFI3f ssQMNwOx8mJAjMEAAEKAB0WIQSlw/aPIp3WD3I+bhOJcvTf3G3AJgUCZdBRaAAKCRCJcvTf3G3A JvXFD/0ZGY+pv/RW0jEwUr/fOJKrMeYvRA+q8dAhwBU4yZf/9WvOK1OItaQt6erwqczIQcGDsKX RWFEhlQbXwgzOXrwCvEVU3X/MwTvOZFnZ0wTXOJZIuqX6uhvJuDZYq+kDfDixzSf+vvZ5N5gZBO TJzXBbBFV7TqO+okj4IS3xOJWZewgGjhNT8vbeQcPdzj69HDDkXXfpLkoSfygpZcWqlp9XDZiNy vXK3r7lesiRP3IhhoJj7l67XzCYktFTMcgxwx7uHCkePYddv5NSQpYuV1e3GrWYPneqbU/ta/RX cWwsnNmxh2abzRU47UKh05W/uYImIbey5l0CSZI/7QN6m152TAREIrmIXwl2k22fjZgwgd+Apv8 4oW4U/bqzoG9w1PMnHKDMQ9jsdEQB9hjMCKn8XCd+7Gv1wyNPPDXV5RFfLYuFJeaPMBdmXP7zFy E345+0/LhEK6UZl9XBsjpHxXtro8hrLNXyQJNR0dzipAEXd7VeizjMBrL4dibLwpq9Vt5GEwcbV rdHrk6W8yGkeyTm7dflKIXZxINWwAC8JEcnyTOaMiaSf+7Trt7zTSHdjJwqs75llY8Q2hwdTTG3 H4HQ8+CnaTwekWZMYV2AJy4oOxU2TWbO/56rrPwpm2xEE837qZM9Jz9EeaTLbA9t0NKKZotRk7n IeAJGDC3TTWSd+A== X-Developer-Key: i=keescook@chromium.org; a=openpgp; fpr=A5C3F68F229DD60F723E6E138972F4DFDC6DC026 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: 9eipyeizbw5y9etpaqqk71x75kkc8jy8 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 8F471160006 X-HE-Tag: 1708151148-19543 X-HE-Meta: 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 GsXIoP7x JRLEMz4n8/WC5FItHps8unPx3AseHL5nwe99MyLCT0CBTLgJ+ZKKkRU1jlapyNEA/rYDjfbaTJIHSHZajjRxRf3VPax+XvQHnVf9xS26L24y5vBcvykvKc2RrH0gclelE9g41jaXGmFRjLB8QkNpPhmGJg9ZespBmmrWIFNtqylfdoqk= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: <linux-mm.kvack.org> List-Subscribe: <mailto:majordomo@kvack.org> List-Unsubscribe: <mailto:majordomo@kvack.org> |
Series |
Adjust brk randomness
|
expand
|
On Fri, 16 Feb 2024 22:25:44 -0800, Kees Cook wrote: > Currently the brk starts its randomization immediately after .bss, > which means there is a chance that when the random offset is 0, linear > overflows from .bss can reach into the brk area. Leave at least a single > page gap between .bss and brk (when it has not already been explicitly > relocated into the mmap range). > > > [...] Patch 1/2 was already applied via x86 tip, so I'll grab this one for the execve/binfmt tree. Applied to for-next/execve. [2/2] binfmt_elf: Leave a gap between .bss and brk https://git.kernel.org/kees/c/2a5eb9995528 Take care,
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 5397b552fbeb..7862962f7a85 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1262,6 +1262,9 @@ static int load_elf_binary(struct linux_binprm *bprm) if (IS_ENABLED(CONFIG_ARCH_HAS_ELF_RANDOMIZE) && elf_ex->e_type == ET_DYN && !interpreter) { mm->brk = mm->start_brk = ELF_ET_DYN_BASE; + } else { + /* Otherwise leave a gap between .bss and brk. */ + mm->brk = mm->start_brk = mm->brk + PAGE_SIZE; } mm->brk = mm->start_brk = arch_randomize_brk(mm);
Currently the brk starts its randomization immediately after .bss, which means there is a chance that when the random offset is 0, linear overflows from .bss can reach into the brk area. Leave at least a single page gap between .bss and brk (when it has not already been explicitly relocated into the mmap range). Reported-by: y0un9n132@gmail.com Closes: https://lore.kernel.org/linux-hardening/CA+2EKTVLvc8hDZc+2Yhwmus=dzOUG5E4gV7ayCbu0MPJTZzWkw@mail.gmail.com/ Signed-off-by: Kees Cook <keescook@chromium.org> --- Cc: Jiri Kosina <jikos@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org --- fs/binfmt_elf.c | 3 +++ 1 file changed, 3 insertions(+)