From patchwork Thu Nov 25 18:02:42 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Michal_Such=C3=A1nek?= X-Patchwork-Id: 12639729 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DE990C433F5 for ; Thu, 25 Nov 2021 18:05:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355166AbhKYSIy (ORCPT ); Thu, 25 Nov 2021 13:08:54 -0500 Received: from smtp-out1.suse.de ([195.135.220.28]:45858 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239249AbhKYSGr (ORCPT ); Thu, 25 Nov 2021 13:06:47 -0500 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id DA31521958; Thu, 25 Nov 2021 18:03:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1637863413; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c5Qpcz1gFX5OMpie9ThdpX+BDLCsg65byAFOIZtk2aU=; b=h8wbFNCvjRTtSvfcBEw0Et/K3sqpnTIVUS49o9y9mKpZXaBDrra4fbBAGrlNyBrSULQdN3 /cosljaSDtvK5E11KBEo8/SrpylhCl9j896NQV/x1+nf3/dRMH8Yjpb1vWmI4Fbu8f5Zqu m2nFo3ipA/ayw9G5ptJgt6X4igQ/Ly0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1637863413; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c5Qpcz1gFX5OMpie9ThdpX+BDLCsg65byAFOIZtk2aU=; b=6WhAMlWErZSeNal6RoAurbokMncn+tOhC8kcNsoCPtfapCfBBfaNoSkXDFrNnvQouJtk42 TDnjtteNPYRcUEBQ== Received: from kitsune.suse.cz (kitsune.suse.cz [10.100.12.127]) by relay2.suse.de (Postfix) with ESMTP id 8EC53A3B8A; Thu, 25 Nov 2021 18:03:33 +0000 (UTC) From: Michal Suchanek To: keyrings@vger.kernel.org Cc: Michal Suchanek , kexec@lists.infradead.org, Philipp Rudo , Mimi Zohar , Nayna , Rob Herring , linux-s390@vger.kernel.org, Vasily Gorbik , Lakshmi Ramasubramanian , Heiko Carstens , Jessica Yu , linux-kernel@vger.kernel.org, David Howells , Christian Borntraeger , Luis Chamberlain , Paul Mackerras , Hari Bathini , Alexander Gordeev , linuxppc-dev@lists.ozlabs.org, Frank van der Linden , Thiago Jung Bauermann , Daniel Axtens , buendgen@de.ibm.com, Michael Ellerman , Benjamin Herrenschmidt , Christian Borntraeger , Herbert Xu , "David S. Miller" , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , Sven Schnelle , Baoquan He , linux-crypto@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v2 4/6] module: strip the signature marker in the verification function. Date: Thu, 25 Nov 2021 19:02:42 +0100 Message-Id: <0f9bbbc4800d5329485b6bdabbbe1ef3b2169b02.1637862358.git.msuchanek@suse.de> X-Mailer: git-send-email 2.31.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org It is stripped by each caller separately. Signed-off-by: Michal Suchanek --- arch/powerpc/kexec/elf_64.c | 9 --------- arch/s390/kernel/machine_kexec_file.c | 9 --------- kernel/module.c | 7 +------ kernel/module_signing.c | 12 ++++++++++-- 4 files changed, 11 insertions(+), 26 deletions(-) diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c index 266cb26d3ca0..63634c95265d 100644 --- a/arch/powerpc/kexec/elf_64.c +++ b/arch/powerpc/kexec/elf_64.c @@ -156,15 +156,6 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, int elf64_verify_sig(const char *kernel, unsigned long length) { size_t kernel_len = length; - const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; - - if (marker_len > kernel_len) - return -EKEYREJECTED; - - if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING, - marker_len)) - return -EKEYREJECTED; - kernel_len -= marker_len; return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, "kexec_file"); diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c index 432797249db3..c4632c1a1b59 100644 --- a/arch/s390/kernel/machine_kexec_file.c +++ b/arch/s390/kernel/machine_kexec_file.c @@ -27,20 +27,11 @@ const struct kexec_file_ops * const kexec_file_loaders[] = { int s390_verify_sig(const char *kernel, unsigned long length) { size_t kernel_len = length; - const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1; /* Skip signature verification when not secure IPLed. */ if (!ipl_secure_flag) return 0; - if (marker_len > kernel_len) - return -EKEYREJECTED; - - if (memcmp(kernel + kernel_len - marker_len, MODULE_SIG_STRING, - marker_len)) - return -EKEYREJECTED; - kernel_len -= marker_len; - return verify_appended_signature(kernel, &kernel_len, VERIFY_USE_PLATFORM_KEYRING, "kexec_file"); } diff --git a/kernel/module.c b/kernel/module.c index 8481933dfa92..d91ca0f93a40 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2882,7 +2882,6 @@ static inline void kmemleak_load_module(const struct module *mod, static int module_sig_check(struct load_info *info, int flags) { int err = -ENODATA; - const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const char *reason; const void *mod = info->hdr; @@ -2890,11 +2889,7 @@ static int module_sig_check(struct load_info *info, int flags) * Require flags == 0, as a module with version information * removed is no longer the module that was signed */ - if (flags == 0 && - info->len > markerlen && - memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { - /* We truncate the module to discard the signature */ - info->len -= markerlen; + if (flags == 0) { err = verify_appended_signature(mod, &info->len, VERIFY_USE_SECONDARY_KEYRING, "module"); if (!err) { diff --git a/kernel/module_signing.c b/kernel/module_signing.c index f492e410564d..4c28cb55275f 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -15,8 +15,7 @@ #include "module-internal.h" /** - * verify_appended_signature - Verify the signature on a module with the - * signature marker stripped. + * verify_appended_signature - Verify the signature on a module * @data: The data to be verified * @len: Size of @data. * @trusted_keys: Keyring to use for verification @@ -25,12 +24,21 @@ int verify_appended_signature(const void *data, size_t *len, struct key *trusted_keys, const char *what) { + const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; struct module_signature ms; size_t sig_len, modlen = *len; int ret; pr_devel("==>%s(,%zu)\n", __func__, modlen); + if (markerlen > modlen) + return -ENODATA; + + if (memcmp(data + modlen - markerlen, MODULE_SIG_STRING, + markerlen)) + return -ENODATA; + modlen -= markerlen; + if (modlen <= sizeof(ms)) return -EBADMSG;