From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EBECD1A71FD; Thu, 1 Aug 2024 00:35:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722472511; cv=none; b=oxut7J+cdJ5WM5uFNUS3wSpeJf4CKuHVqeUu+RlTNKltIWYRkJIELZJeXAQYczEbonoI8iHciDSM/r5ngSdcjljai9q+9PprtsHf0KGu7/qVHusRRERBuHRaDr2TaI6kGbtpoNkodCDGQmnCdy+VDYBlh9wGcZIkk8R68OGCGds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722472511; c=relaxed/simple; bh=cmjFbj4dkpWcVlZABFJ28iwCCS6WyrWAhdu12n0Iwms=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=St9u40/4MIVSncHcLLymL7EkzLf434QFFbVyoUeuTnjNtTVqop9qPS+Au7J593XhrRa+8rky4/PRGwshFzIqU5QppcI4g/qiY7XiOT7LtEfMOasqT5e0ncGjSqLpQ9e9FYLHbICR+IHiFFC8YbNSE4Co7NNGil83KBZBlM+rZK8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IryUmZ+m; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IryUmZ+m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60413C116B1; Thu, 1 Aug 2024 00:35:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722472510; bh=cmjFbj4dkpWcVlZABFJ28iwCCS6WyrWAhdu12n0Iwms=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IryUmZ+mXF4GfyQdAHopS4/cmmA+xngA6VRRg1SncpJsF4RmFhXXRSDGRoorqw4za hA0/IfoJk/XxY2olUVGCV5msq6vk+3GWfXNhgqXliqRzF6viIfKlZgKZLwDOatUOK1 CH+67oBvFyksjumqvQu6BF+4uu8Lvofiwui5pUMRL6I0BDTHUlNctW+AuroRFsXijf PnOn8EkXIenlS1OnkJ5N+QDQazWOaXqS9oqt6WM0Tt9DzXXknaGYH6QnLbdyO/U81Y 31ruFNPBrRImfzVwt59jh1ZNtfaWcTvcXEPSUYZ7BiGDXcML6K59FFj6iyusVWBdAU JFeTt9TgQMoJA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Alexey Dobriyan , Kees Cook , Sasha Levin , viro@zeniv.linux.org.uk, brauner@kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH AUTOSEL 5.15 34/47] ELF: fix kernel.randomize_va_space double read Date: Wed, 31 Jul 2024 20:31:24 -0400 Message-ID: <20240801003256.3937416-34-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240801003256.3937416-1-sashal@kernel.org> References: <20240801003256.3937416-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.164 Content-Transfer-Encoding: 8bit From: Alexey Dobriyan [ Upstream commit 2a97388a807b6ab5538aa8f8537b2463c6988bd2 ] ELF loader uses "randomize_va_space" twice. It is sysctl and can change at any moment, so 2 loads could see 2 different values in theory with unpredictable consequences. Issue exactly one load for consistent value across one exec. Signed-off-by: Alexey Dobriyan Link: https://lore.kernel.org/r/3329905c-7eb8-400a-8f0a-d87cff979b5b@p183 Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- fs/binfmt_elf.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 30379c33ad20c..4a11784b9f896 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1008,7 +1008,8 @@ static int load_elf_binary(struct linux_binprm *bprm) if (elf_read_implies_exec(*elf_ex, executable_stack)) current->personality |= READ_IMPLIES_EXEC; - if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space) + const int snapshot_randomize_va_space = READ_ONCE(randomize_va_space); + if (!(current->personality & ADDR_NO_RANDOMIZE) && snapshot_randomize_va_space) current->flags |= PF_RANDOMIZE; setup_new_exec(bprm); @@ -1278,7 +1279,7 @@ static int load_elf_binary(struct linux_binprm *bprm) mm->end_data = end_data; mm->start_stack = bprm->p; - if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) { + if ((current->flags & PF_RANDOMIZE) && (snapshot_randomize_va_space > 1)) { /* * For architectures with ELF randomization, when executing * a loader directly (i.e. no interpreter listed in ELF -- 2.43.0