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 28BE21311B1; Sun, 24 Mar 2024 23:41:45 +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=1711323705; cv=none; b=qb63XLbyeN6RQ2x9PiQIJpHJSUFOqzd+lerjSJ/BParhZFkm5+cXOYhXYyGIh8S/shuq7hilv5EoyJqV9YpHXF4Tz4TZX+clk+xm3XPaAoxuZeR7VKIUhwGrxpHsbD0l7rOlt2S0DYNUIlcXZruSbrt3vqDn2luRLrZ74LJCMz8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711323705; c=relaxed/simple; bh=8lg0zeAncBldALqSh3pqQu0z65I0wQjs983ZY90vK1Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ngR/8860hoRsLZuALjxJKdp/6pJaaE+ymxouA2+mt/4qEZ++fZSq9HQTCgQTxTUyI6YaV3StnBS7JOQ8eu2W0LB1JDWcfHTdOr09VsWdzrw7m/QouNmHm8uLqYPvhRBcafXQUInKLY5ynpNgRHlxqdODfQn0QJiDP/HXGvUMo2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HodcedeH; 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="HodcedeH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F3F8C43394; Sun, 24 Mar 2024 23:41:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711323705; bh=8lg0zeAncBldALqSh3pqQu0z65I0wQjs983ZY90vK1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HodcedeHwNQyH/wa2c9kNUuMl6hE6XIRDbDnuS5FJBTuMT68egRFmyoh+a/UjX5IR iqU4B1E8J3F5a3oJQpvCIpkD3gcf3D7VdTgjVKP2y7kXn6hXMkHCnwgTxp4vqLVXFC 1r1NerGfHgB7QDqQhJ28UKzUPytoOBH2fTcLztydganR/wetxnrucg1p4ul/9XzBYN n9QNdlEKQZCbCspYLJVq1WfDbKE0FCaVHOB9hyUDDddfOLjVNhvx8AHsmyl1IFJymJ s+fYZ3VTwcMzsn2FH7XyxTtKaEQ/ruJMvLZqziEKwqtts0d7GS9Irk9ymnjMvO2PIx TKBTApW6h9V+Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , Guixiong Wei , Juergen Gross , Sasha Levin Subject: [PATCH 5.10 078/238] x86, relocs: Ignore relocations in .notes section Date: Sun, 24 Mar 2024 19:37:46 -0400 Message-ID: <20240324234027.1354210-79-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324234027.1354210-1-sashal@kernel.org> References: <20240324234027.1354210-1-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 Content-Transfer-Encoding: 8bit From: Kees Cook [ Upstream commit aaa8736370db1a78f0e8434344a484f9fd20be3b ] When building with CONFIG_XEN_PV=y, .text symbols are emitted into the .notes section so that Xen can find the "startup_xen" entry point. This information is used prior to booting the kernel, so relocations are not useful. In fact, performing relocations against the .notes section means that the KASLR base is exposed since /sys/kernel/notes is world-readable. To avoid leaking the KASLR base without breaking unprivileged tools that are expecting to read /sys/kernel/notes, skip performing relocations in the .notes section. The values readable in .notes are then identical to those found in System.map. Reported-by: Guixiong Wei Closes: https://lore.kernel.org/all/20240218073501.54555-1-guixiongwei@gmail.com/ Fixes: 5ead97c84fa7 ("xen: Core Xen implementation") Fixes: da1a679cde9b ("Add /sys/kernel/notes") Reviewed-by: Juergen Gross Signed-off-by: Kees Cook Signed-off-by: Sasha Levin --- arch/x86/tools/relocs.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c index 1c3a1962cade6..0043fd374a62f 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -596,6 +596,14 @@ static void print_absolute_relocs(void) if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) { continue; } + /* + * Do not perform relocations in .notes section; any + * values there are meant for pre-boot consumption (e.g. + * startup_xen). + */ + if (sec_applies->shdr.sh_type == SHT_NOTE) { + continue; + } sh_symtab = sec_symtab->symtab; sym_strtab = sec_symtab->link->strtab; for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { -- 2.43.0