From nobody Fri Dec 19 21:57:10 2025 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 0616D1E965D; Sun, 24 Mar 2024 23:05:55 +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=1711321555; cv=none; b=lfDIBt8uIHATt/A+hn5WHpOyr0AFJhmtCfT+NLs/o2F4v1WaKCuwife3KYfjPX4TjC7ZrIG6mqlOWVMimBjDJ2UlznK0jIpGSO/zbyCizoApPfz0n9y2ymhepPitjeE2ALdNzRf+gGfZlJZZUp0mtBCgSfxBKi2GyC7kU9A8dcY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321555; c=relaxed/simple; bh=CWRgix+uDvTPQLyz3Skw1HxUUQ9clC+hsv2lUdDt+KI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gaKClxmQbCblHwy0OxlmJxoOGvCVuc4YiAlrg7MbaoaU40rLKAC8ez+RQDfJTpP/s3SeffBH4PgTUNjelciWFlCdrWZtmviX8hO3tSS2utCObrAB6Vhig91is/SHtWBf01PbXUYoNkxltOEaLhI83naRYctxHMXjWI734G6Mtb0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G2MP/LPb; 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="G2MP/LPb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36F82C43394; Sun, 24 Mar 2024 23:05:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321554; bh=CWRgix+uDvTPQLyz3Skw1HxUUQ9clC+hsv2lUdDt+KI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G2MP/LPbNx5WJSANoKGJAYdLphh1S1aXDzVZXv7kZpql9C8737IxvmPeOUzalNNTU Di8wdp1iUwA087ap9vU2gmNnCUi607CZ7B3syRzk+v2nwXj8wyG2UfIZo1eUXK9n+D 1XasxBg6XxfdTEr/io8CWQpJD8BDK0vxdhOVfnMUGw8Z/zBXo4khOTtxh8nP2s+8EH bigW6BSY6c2CWvUlHqttnlN2qJd0p3iRFOC+6LrnsFq4Lz0dtcE1twD0m3rYvaqpl/ Vm9cSrirB/Pa94Bw/xtefQ4jT5RfX4CIholry+gxPnmW+VxkIyPKPiCC/mCvvg3Hui Hnaxr/gA/ABsg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Kees Cook , Guixiong Wei , Juergen Gross , Sasha Levin Subject: [PATCH 6.6 283/638] x86, relocs: Ignore relocations in .notes section Date: Sun, 24 Mar 2024 18:55:20 -0400 Message-ID: <20240324230116.1348576-284-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324230116.1348576-1-sashal@kernel.org> References: <20240324230116.1348576-1-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: quoted-printable Content-Type: text/plain; charset="utf-8" From: Kees Cook [ Upstream commit aaa8736370db1a78f0e8434344a484f9fd20be3b ] When building with CONFIG_XEN_PV=3Dy, .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@gmai= l.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 d30949e25ebd9..e7013283640f5 100644 --- a/arch/x86/tools/relocs.c +++ b/arch/x86/tools/relocs.c @@ -653,6 +653,14 @@ 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 =3D=3D SHT_NOTE) { + continue; + } sh_symtab =3D sec_symtab->symtab; sym_strtab =3D sec_symtab->link->strtab; for (j =3D 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) { --=20 2.43.0