From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10A7DC48BE9 for ; Mon, 24 Jun 2019 19:52:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF72B20645 for ; Mon, 24 Jun 2019 19:52:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728330AbfFXTw3 (ORCPT ); Mon, 24 Jun 2019 15:52:29 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42748 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727101AbfFXTw2 (ORCPT ); Mon, 24 Jun 2019 15:52:28 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5OJlXge010945 for ; Mon, 24 Jun 2019 15:52:27 -0400 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tb1stgv2d-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 24 Jun 2019 15:52:26 -0400 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 24 Jun 2019 20:52:24 +0100 Received: from b03cxnp07028.gho.boulder.ibm.com (9.17.130.15) by e34.co.us.ibm.com (192.168.1.134) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 24 Jun 2019 20:52:18 +0100 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5OJqHtw38404584 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 24 Jun 2019 19:52:17 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 501DFC6055; Mon, 24 Jun 2019 19:52:17 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF23AC605B; Mon, 24 Jun 2019 19:52:12 +0000 (GMT) Received: from morokweng.localdomain (unknown [9.85.209.86]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTPS; Mon, 24 Jun 2019 19:52:11 +0000 (GMT) References: <20190611062817.18412-1-bauerman@linux.ibm.com> <20190611062817.18412-2-bauerman@linux.ibm.com> User-agent: mu4e 1.2.0; emacs 26.2 From: Thiago Jung Bauermann To: Jessica Yu Cc: linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Herbert Xu , "David S. Miller" , Jonathan Corbet , "AKASHI\, Takahiro" , linux-integrity@vger.kernel.org Subject: Re: [PATCH v11 01/13] MODSIGN: Export module signature definitions In-reply-to: <20190611062817.18412-2-bauerman@linux.ibm.com> Date: Mon, 24 Jun 2019 16:52:09 -0300 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 x-cbid: 19062419-0016-0000-0000-000009C64D7D X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011322; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01222738; UDB=6.00643410; IPR=6.01003899; MB=3.00027449; MTD=3.00000008; XFM=3.00000015; UTC=2019-06-24 19:52:22 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19062419-0017-0000-0000-000043C4ABE1 Message-Id: <87imsukbh2.fsf@morokweng.localdomain> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-24_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906240158 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Hello Jessica, AFAIK Mimi is happy with this patch set, but I still need acks from maintainers of other subsystems that my changes touch before she can accept it. Is this patch OK from your PoV? -- Thiago Jung Bauermann IBM Linux Technology Center Thiago Jung Bauermann writes: > IMA will use the module_signature format for append signatures, so export > the relevant definitions and factor out the code which verifies that the > appended signature trailer is valid. > > Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it > and be able to use mod_check_sig() without having to depend on either > CONFIG_MODULE_SIG or CONFIG_MODULES. > > Signed-off-by: Thiago Jung Bauermann > Reviewed-by: Mimi Zohar > Cc: Jessica Yu > --- > include/linux/module.h | 3 -- > include/linux/module_signature.h | 44 +++++++++++++++++++++++++ > init/Kconfig | 6 +++- > kernel/Makefile | 1 + > kernel/module.c | 1 + > kernel/module_signature.c | 46 ++++++++++++++++++++++++++ > kernel/module_signing.c | 56 +++++--------------------------- > scripts/Makefile | 2 +- > 8 files changed, 106 insertions(+), 53 deletions(-) > > diff --git a/include/linux/module.h b/include/linux/module.h > index 188998d3dca9..aa56f531cf1e 100644 > --- a/include/linux/module.h > +++ b/include/linux/module.h > @@ -25,9 +25,6 @@ > #include > #include > > -/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */ > -#define MODULE_SIG_STRING "~Module signature appended~\n" > - > /* Not Yet Implemented */ > #define MODULE_SUPPORTED_DEVICE(name) > > diff --git a/include/linux/module_signature.h b/include/linux/module_signature.h > new file mode 100644 > index 000000000000..523617fc5b6a > --- /dev/null > +++ b/include/linux/module_signature.h > @@ -0,0 +1,44 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > +/* > + * Module signature handling. > + * > + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. > + * Written by David Howells (dhowells@redhat.com) > + */ > + > +#ifndef _LINUX_MODULE_SIGNATURE_H > +#define _LINUX_MODULE_SIGNATURE_H > + > +/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */ > +#define MODULE_SIG_STRING "~Module signature appended~\n" > + > +enum pkey_id_type { > + PKEY_ID_PGP, /* OpenPGP generated key ID */ > + PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ > + PKEY_ID_PKCS7, /* Signature in PKCS#7 message */ > +}; > + > +/* > + * Module signature information block. > + * > + * The constituents of the signature section are, in order: > + * > + * - Signer's name > + * - Key identifier > + * - Signature data > + * - Information block > + */ > +struct module_signature { > + u8 algo; /* Public-key crypto algorithm [0] */ > + u8 hash; /* Digest algorithm [0] */ > + u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ > + u8 signer_len; /* Length of signer's name [0] */ > + u8 key_id_len; /* Length of key identifier [0] */ > + u8 __pad[3]; > + __be32 sig_len; /* Length of signature data */ > +}; > + > +int mod_check_sig(const struct module_signature *ms, size_t file_len, > + const char *name); > + > +#endif /* _LINUX_MODULE_SIGNATURE_H */ > diff --git a/init/Kconfig b/init/Kconfig > index 8b9ffe236e4f..c2286a3c74c5 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1852,6 +1852,10 @@ config BASE_SMALL > default 0 if BASE_FULL > default 1 if !BASE_FULL > > +config MODULE_SIG_FORMAT > + def_bool n > + select SYSTEM_DATA_VERIFICATION > + > menuconfig MODULES > bool "Enable loadable module support" > option modules > @@ -1929,7 +1933,7 @@ config MODULE_SRCVERSION_ALL > config MODULE_SIG > bool "Module signature verification" > depends on MODULES > - select SYSTEM_DATA_VERIFICATION > + select MODULE_SIG_FORMAT > help > Check modules for valid signatures upon load: the signature > is simply appended to the module. For more information see > diff --git a/kernel/Makefile b/kernel/Makefile > index 33824f0385b3..f29ae2997a43 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -58,6 +58,7 @@ endif > obj-$(CONFIG_UID16) += uid16.o > obj-$(CONFIG_MODULES) += module.o > obj-$(CONFIG_MODULE_SIG) += module_signing.o > +obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o > obj-$(CONFIG_KALLSYMS) += kallsyms.o > obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o > obj-$(CONFIG_CRASH_CORE) += crash_core.o > diff --git a/kernel/module.c b/kernel/module.c > index 6e6712b3aaf5..2712f4d217f5 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -19,6 +19,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/kernel/module_signature.c b/kernel/module_signature.c > new file mode 100644 > index 000000000000..4224a1086b7d > --- /dev/null > +++ b/kernel/module_signature.c > @@ -0,0 +1,46 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Module signature checker > + * > + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. > + * Written by David Howells (dhowells@redhat.com) > + */ > + > +#include > +#include > +#include > +#include > + > +/** > + * mod_check_sig - check that the given signature is sane > + * > + * @ms: Signature to check. > + * @file_len: Size of the file to which @ms is appended. > + * @name: What is being checked. Used for error messages. > + */ > +int mod_check_sig(const struct module_signature *ms, size_t file_len, > + const char *name) > +{ > + if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms)) > + return -EBADMSG; > + > + if (ms->id_type != PKEY_ID_PKCS7) { > + pr_err("%s: Module is not signed with expected PKCS#7 message\n", > + name); > + return -ENOPKG; > + } > + > + if (ms->algo != 0 || > + ms->hash != 0 || > + ms->signer_len != 0 || > + ms->key_id_len != 0 || > + ms->__pad[0] != 0 || > + ms->__pad[1] != 0 || > + ms->__pad[2] != 0) { > + pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n", > + name); > + return -EBADMSG; > + } > + > + return 0; > +} > diff --git a/kernel/module_signing.c b/kernel/module_signing.c > index 6b9a926fd86b..cdd04a6b8074 100644 > --- a/kernel/module_signing.c > +++ b/kernel/module_signing.c > @@ -11,37 +11,13 @@ > > #include > #include > +#include > +#include > #include > #include > #include > #include "module-internal.h" > > -enum pkey_id_type { > - PKEY_ID_PGP, /* OpenPGP generated key ID */ > - PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ > - PKEY_ID_PKCS7, /* Signature in PKCS#7 message */ > -}; > - > -/* > - * Module signature information block. > - * > - * The constituents of the signature section are, in order: > - * > - * - Signer's name > - * - Key identifier > - * - Signature data > - * - Information block > - */ > -struct module_signature { > - u8 algo; /* Public-key crypto algorithm [0] */ > - u8 hash; /* Digest algorithm [0] */ > - u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */ > - u8 signer_len; /* Length of signer's name [0] */ > - u8 key_id_len; /* Length of key identifier [0] */ > - u8 __pad[3]; > - __be32 sig_len; /* Length of signature data */ > -}; > - > /* > * Verify the signature on a module. > */ > @@ -49,6 +25,7 @@ int mod_verify_sig(const void *mod, struct load_info *info) > { > struct module_signature ms; > size_t sig_len, modlen = info->len; > + int ret; > > pr_devel("==>%s(,%zu)\n", __func__, modlen); > > @@ -56,32 +33,15 @@ int mod_verify_sig(const void *mod, struct load_info *info) > return -EBADMSG; > > memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms)); > - modlen -= sizeof(ms); > + > + ret = mod_check_sig(&ms, modlen, info->name); > + if (ret) > + return ret; > > sig_len = be32_to_cpu(ms.sig_len); > - if (sig_len >= modlen) > - return -EBADMSG; > - modlen -= sig_len; > + modlen -= sig_len + sizeof(ms); > info->len = modlen; > > - if (ms.id_type != PKEY_ID_PKCS7) { > - pr_err("%s: Module is not signed with expected PKCS#7 message\n", > - info->name); > - return -ENOPKG; > - } > - > - if (ms.algo != 0 || > - ms.hash != 0 || > - ms.signer_len != 0 || > - ms.key_id_len != 0 || > - ms.__pad[0] != 0 || > - ms.__pad[1] != 0 || > - ms.__pad[2] != 0) { > - pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n", > - info->name); > - return -EBADMSG; > - } > - > return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len, > VERIFY_USE_SECONDARY_KEYRING, > VERIFYING_MODULE_SIGNATURE, > diff --git a/scripts/Makefile b/scripts/Makefile > index 9d442ee050bd..52098b080ab7 100644 > --- a/scripts/Makefile > +++ b/scripts/Makefile > @@ -17,7 +17,7 @@ hostprogs-$(CONFIG_VT) += conmakehash > hostprogs-$(BUILD_C_RECORDMCOUNT) += recordmcount > hostprogs-$(CONFIG_BUILDTIME_EXTABLE_SORT) += sortextable > hostprogs-$(CONFIG_ASN1) += asn1_compiler > -hostprogs-$(CONFIG_MODULE_SIG) += sign-file > +hostprogs-$(CONFIG_MODULE_SIG_FORMAT) += sign-file > hostprogs-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += extract-cert > hostprogs-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE) += insert-sys-cert >