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* [PATCH v12 00/11] Appended signatures support for IMA appraisal
@ 2019-06-28  2:19 Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 01/11] MODSIGN: Export module signature definitions Thiago Jung Bauermann
                   ` (11 more replies)
  0 siblings, 12 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Hello,

This version is essentially identical to the last one.

It is only a rebase on top of today's linux-integrity/next-queued-testing,
prompted by conflicts with Prakhar Srivastava's patches to measure the
kernel command line. It also drops two patches that are already present in
that branch.

As I mentioned in an earlier email, I believe Mimi is happy with this
version but before she can accept it I still need acks from maintainers of
the module and asymmetric keys subsystems for the first three patches.

Many thanks to Mimi Zohar for her help with the development of this patch
series.

This patch which I sent earlier today needs to be applied first:

ima: Update MAX_TEMPLATE_NAME_LEN to fit largest reasonable definition

Original cover letter:

On the OpenPOWER platform, secure boot and trusted boot are being
implemented using IMA for taking measurements and verifying signatures.
Since the kernel image on Power servers is an ELF binary, kernels are
signed using the scripts/sign-file tool and thus use the same signature
format as signed kernel modules.

This patch series adds support in IMA for verifying those signatures.
It adds flexibility to OpenPOWER secure boot, because it allows it to boot
kernels with the signature appended to them as well as kernels where the
signature is stored in the IMA extended attribute.

Changes since v11:

- Patch "integrity: Introduce struct evm_xattr"
  - Dropped since it's already in linux-integrity/next-queued-testing.

- Patch "ima: Use designated initializers for struct ima_event_data"
  - Dropped since it's already in linux-integrity/next-queued-testing.

Changes since v10:

- Patch "MODSIGN: Export module signature definitions"
  - Moved config MODULE_SIG_FORMAT definition before its use. Suggested by
    Mimi Zohar.
  - Added missing kerneldoc for @name parameter. Suggested by Mimi Zohar.

- Patch "ima: Implement support for module-style appended signatures"
  - Bugfix: don't check status variable when deciding whether to verify
    modsig in ima_appraise_measurement(). Suggested by Mimi Zohar.
  - Bugfix: verify the modsig in ima_appraise_measurement() if the xattr
    contains a digest. Suggested by Mimi Zohar.

- Patch "ima: Define ima-modsig template"
  - Renamed ima_modsig_serialize() to ima_get_raw_modsig().
  - Renamed check_current_template_modsig() to check_template_modsig().
  - Fixed outdated comment in ima_eventmodsig_init(). Suggested by Mimi
    Zohar.
  - Check either the global or the per-rule template when an appraisal rule
    allows modsig. Suggested by Mimi Zohar.

- Patch "ima: Store the measurement again when appraising a modsig"
  - Bugfix: Only re-measure file containing modsig if it was measured
    before.
  - Check for modsig-related fields in the template_desc obtained in
    process_measurement() which can be a per-rule template. Suggested by Mimi
    Zohar.

- Patch "ima: Allow template= option for appraise rules as well"
  - New patch. Suggested by Mimi Zohar.

Changes since v9:

- Patch "MODSIGN: Export module signature definitions"
  - Moved mod_check_sig() to a new file so that CONFIG_IMA_APPRAISE_MODSIG
    doesn't have to depend on CONFIG_MODULES.
  - Changed scripts/Makefile to build sign-file if CONFIG_MODULE_SIG_FORMAT
    is set.
  - Removed Mimi's Reviewed-by because of the changes in this version.

- Patch "PKCS#7: Refactor verify_pkcs7_signature()"
  - Don't add function pkcs7_get_message_sig() anymore, since it's not
    needed in the current version.

- Patch "PKCS#7: Introduce pkcs7_get_digest()"
  - Changed 'len' argument from 'u8 *' to 'u32 *'.
  - Added 'hash_algo' argument to obtain the algo used for the digest.
  - Don't check whether 'buf', 'len' and 'hash_algo' output arguments are NULL,
    since the function's only caller always sets them.
  - Removed Mimi's Reviewed-by because of the changes in this version.

- Patch "integrity: Introduce asymmetric_sig_has_known_key()"
  - Dropped.

- Patch "integrity: Introduce integrity_keyring_from_id"
  - Squashed into "ima: Implement support for module-style appended signatures"
  - Changed integrity_keyring_from_id() to a static function (suggested by Mimi
    Zohar).

- Patch "ima: Introduce is_signed()"
  - Dropped.

- Patch "ima: Export func_tokens"
  - Squashed into "ima: Implement support for module-style appended signatures"

- Patch "ima: Use designated initializers for struct ima_event_data"
  - New patch.

- Patch "ima: Factor xattr_verify() out of ima_appraise_measurement()"
  - New patch.

- Patch "ima: Implement support for module-style appended signatures"
  - Renamed 'struct modsig_hdr' to 'struct modsig'.
  - Added integrity_modsig_verify() to integrity/digsig.c so that it's not
    necessary to export integrity_keyring_from_id() (Suggested by Mimi Zohar).
  - Don't add functions ima_xattr_sig_known_key() and
    modsig_has_known_key() since they're not necessary anymore.
  - Added modsig argument to ima_appraise_measurement().
  - Verify modsig in a separate function called by ima_appraise_measurement().
  - Renamed ima_read_collect_modsig() to ima_read_modsig(), with a separate
    collect function added in patch "ima: Collect modsig" (suggested by Mimi
    Zohar).
  - In ima_read_modsig(), moved code saving of raw PKCS7 data to 'struct
    modsig' to patch "ima: Collect modsig".
  - In ima_read_modsig(), moved all parts related to the modsig hash to
    patch "ima: Collect modsig".
  - In ima_read_modsig(), don't check if the buf pointer is NULL since it's
    never supposed to happen.
  - Renamed ima_free_xattr_data() to ima_free_modsig().
  - No need to check for modsig in ima_read_xattr() and
    ima_inode_set_xattr() anymore.
  - In ima_modsig_verify(), don't check if the modsig pointer is NULL since
    it's not supposed to happen.
  - Don't define IMA_MODSIG element in enum evm_ima_xattr_type.

- Patch "ima: Collect modsig"
  - New patch.

- Patch "ima: Define ima-modsig template"
  - Patch renamed from "ima: Add new "d-sig" template field"
  - Renamed 'd-sig' template field to 'd-modsig'.
  - Added 'modsig' template field.
  - Added 'ima-modsig' defined template descriptor.
  - Renamed ima_modsig_serialize_data() to ima_modsig_serialize().
  - Renamed ima_get_modsig_hash() to ima_get_modsig_digest(). Also the
    function is a lot simpler now since what it used to do is now done in
    ima_collect_modsig() and pkcs7_get_digest().
  - Added check for failed modsig collection in ima_eventdigest_modsig_init().
  - Added modsig argument to ima_store_measurement().
  - Added 'modsig' field to struct ima_event_data.
  - Removed check for modsig == NULL in ima_get_modsig_digest() and in
    ima_modsig_serialize_data() since their callers already performs that
    check.
  - Moved check_current_template_modsig() to this patch, previously was in
    "ima: Store the measurement again when appraising a modsig".

- Patch "ima: Store the measurement again when appraising a modsig"
  - Renamed ima_template_has_sig() to ima_template_has_modsig().
  - Added a change to ima_collect_measurement(), making it to call
    ima_collect_modsig() even if IMA_COLLECT is set in iint->flags.
  - Removed IMA_READ_MEASURE flag.
  - Renamed template_has_sig global variable to template_has_modsig.
  - Renamed find_sig_in_template() to find_modsig_in_template().


Thiago Jung Bauermann (11):
  MODSIGN: Export module signature definitions
  PKCS#7: Refactor verify_pkcs7_signature()
  PKCS#7: Introduce pkcs7_get_digest()
  integrity: Select CONFIG_KEYS instead of depending on it
  ima: Add modsig appraise_type option for module-style appended
    signatures
  ima: Factor xattr_verify() out of ima_appraise_measurement()
  ima: Implement support for module-style appended signatures
  ima: Collect modsig
  ima: Define ima-modsig template
  ima: Store the measurement again when appraising a modsig
  ima: Allow template= option for appraise rules as well

 Documentation/ABI/testing/ima_policy      |   6 +-
 Documentation/security/IMA-templates.rst  |   3 +
 certs/system_keyring.c                    |  61 +++++--
 crypto/asymmetric_keys/pkcs7_verify.c     |  33 ++++
 include/crypto/pkcs7.h                    |   4 +
 include/linux/module.h                    |   3 -
 include/linux/module_signature.h          |  44 +++++
 include/linux/verification.h              |  10 ++
 init/Kconfig                              |   6 +-
 kernel/Makefile                           |   1 +
 kernel/module.c                           |   1 +
 kernel/module_signature.c                 |  46 +++++
 kernel/module_signing.c                   |  56 +------
 scripts/Makefile                          |   2 +-
 security/integrity/Kconfig                |   2 +-
 security/integrity/digsig.c               |  43 ++++-
 security/integrity/ima/Kconfig            |  13 ++
 security/integrity/ima/Makefile           |   1 +
 security/integrity/ima/ima.h              |  60 ++++++-
 security/integrity/ima/ima_api.c          |  23 ++-
 security/integrity/ima/ima_appraise.c     | 194 ++++++++++++++--------
 security/integrity/ima/ima_main.c         |  24 ++-
 security/integrity/ima/ima_modsig.c       | 169 +++++++++++++++++++
 security/integrity/ima/ima_policy.c       |  68 +++++++-
 security/integrity/ima/ima_template.c     |  26 ++-
 security/integrity/ima/ima_template_lib.c |  64 ++++++-
 security/integrity/ima/ima_template_lib.h |   4 +
 security/integrity/integrity.h            |  20 +++
 28 files changed, 819 insertions(+), 168 deletions(-)
 create mode 100644 include/linux/module_signature.h
 create mode 100644 kernel/module_signature.c
 create mode 100644 security/integrity/ima/ima_modsig.c


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-07-01 14:47   ` Jessica Yu
  2019-06-28  2:19 ` [PATCH v12 02/11] PKCS#7: Refactor verify_pkcs7_signature() Thiago Jung Bauermann
                   ` (10 subsequent siblings)
  11 siblings, 1 reply; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

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 <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
---
 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 <linux/percpu.h>
 #include <asm/module.h>
 
-/* 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 <linux/export.h>
 #include <linux/extable.h>
 #include <linux/moduleloader.h>
+#include <linux/module_signature.h>
 #include <linux/trace_events.h>
 #include <linux/init.h>
 #include <linux/kallsyms.h>
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 <linux/errno.h>
+#include <linux/printk.h>
+#include <linux/module_signature.h>
+#include <asm/byteorder.h>
+
+/**
+ * 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 <linux/kernel.h>
 #include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/module_signature.h>
 #include <linux/string.h>
 #include <linux/verification.h>
 #include <crypto/public_key.h>
 #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
 

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 02/11] PKCS#7: Refactor verify_pkcs7_signature()
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 01/11] MODSIGN: Export module signature definitions Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 03/11] PKCS#7: Introduce pkcs7_get_digest() Thiago Jung Bauermann
                   ` (9 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

IMA will need to verify a PKCS#7 signature which has already been parsed.
For this reason, factor out the code which does that from
verify_pkcs7_signature() into a new function which takes a struct
pkcs7_message instead of a data buffer.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
---
 certs/system_keyring.c       | 61 ++++++++++++++++++++++++++----------
 include/linux/verification.h | 10 ++++++
 2 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index c05c29ae4d5d..4ba82e52e4b4 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -194,33 +194,27 @@ late_initcall(load_system_certificate_list);
 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
 
 /**
- * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
+ * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
  * @data: The data to be verified (NULL if expecting internal data).
  * @len: Size of @data.
- * @raw_pkcs7: The PKCS#7 message that is the signature.
- * @pkcs7_len: The size of @raw_pkcs7.
+ * @pkcs7: The PKCS#7 message that is the signature.
  * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
  *					(void *)1UL for all trusted keys).
  * @usage: The use to which the key is being put.
  * @view_content: Callback to gain access to content.
  * @ctx: Context for callback.
  */
-int verify_pkcs7_signature(const void *data, size_t len,
-			   const void *raw_pkcs7, size_t pkcs7_len,
-			   struct key *trusted_keys,
-			   enum key_being_used_for usage,
-			   int (*view_content)(void *ctx,
-					       const void *data, size_t len,
-					       size_t asn1hdrlen),
-			   void *ctx)
+int verify_pkcs7_message_sig(const void *data, size_t len,
+			     struct pkcs7_message *pkcs7,
+			     struct key *trusted_keys,
+			     enum key_being_used_for usage,
+			     int (*view_content)(void *ctx,
+						 const void *data, size_t len,
+						 size_t asn1hdrlen),
+			     void *ctx)
 {
-	struct pkcs7_message *pkcs7;
 	int ret;
 
-	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
-	if (IS_ERR(pkcs7))
-		return PTR_ERR(pkcs7);
-
 	/* The data should be detached - so we need to supply it. */
 	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
 		pr_err("PKCS#7 signature with non-detached data\n");
@@ -273,6 +267,41 @@ int verify_pkcs7_signature(const void *data, size_t len,
 	}
 
 error:
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/**
+ * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified (NULL if expecting internal data).
+ * @len: Size of @data.
+ * @raw_pkcs7: The PKCS#7 message that is the signature.
+ * @pkcs7_len: The size of @raw_pkcs7.
+ * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
+ *					(void *)1UL for all trusted keys).
+ * @usage: The use to which the key is being put.
+ * @view_content: Callback to gain access to content.
+ * @ctx: Context for callback.
+ */
+int verify_pkcs7_signature(const void *data, size_t len,
+			   const void *raw_pkcs7, size_t pkcs7_len,
+			   struct key *trusted_keys,
+			   enum key_being_used_for usage,
+			   int (*view_content)(void *ctx,
+					       const void *data, size_t len,
+					       size_t asn1hdrlen),
+			   void *ctx)
+{
+	struct pkcs7_message *pkcs7;
+	int ret;
+
+	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
+	if (IS_ERR(pkcs7))
+		return PTR_ERR(pkcs7);
+
+	ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
+				       view_content, ctx);
+
 	pkcs7_free_message(pkcs7);
 	pr_devel("<==%s() = %d\n", __func__, ret);
 	return ret;
diff --git a/include/linux/verification.h b/include/linux/verification.h
index 018fb5f13d44..5e1d41f2b336 100644
--- a/include/linux/verification.h
+++ b/include/linux/verification.h
@@ -36,6 +36,7 @@ extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR];
 #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
 
 struct key;
+struct pkcs7_message;
 
 extern int verify_pkcs7_signature(const void *data, size_t len,
 				  const void *raw_pkcs7, size_t pkcs7_len,
@@ -45,6 +46,15 @@ extern int verify_pkcs7_signature(const void *data, size_t len,
 						      const void *data, size_t len,
 						      size_t asn1hdrlen),
 				  void *ctx);
+extern int verify_pkcs7_message_sig(const void *data, size_t len,
+				    struct pkcs7_message *pkcs7,
+				    struct key *trusted_keys,
+				    enum key_being_used_for usage,
+				    int (*view_content)(void *ctx,
+							const void *data,
+							size_t len,
+							size_t asn1hdrlen),
+				    void *ctx);
 
 #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
 extern int verify_pefile_signature(const void *pebuf, unsigned pelen,


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 03/11] PKCS#7: Introduce pkcs7_get_digest()
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 01/11] MODSIGN: Export module signature definitions Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 02/11] PKCS#7: Refactor verify_pkcs7_signature() Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 04/11] integrity: Select CONFIG_KEYS instead of depending on it Thiago Jung Bauermann
                   ` (8 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

IMA will need to access the digest of the PKCS7 message (as calculated by
the kernel) before the signature is verified, so introduce
pkcs7_get_digest() for that purpose.

Also, modify pkcs7_digest() to detect when the digest was already
calculated so that it doesn't have to do redundant work. Verifying that
sinfo->sig->digest isn't NULL is sufficient because both places which
allocate sinfo->sig (pkcs7_parse_message() and pkcs7_note_signed_info())
use kzalloc() so sig->digest is always initialized to zero.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
---
 crypto/asymmetric_keys/pkcs7_verify.c | 33 +++++++++++++++++++++++++++
 include/crypto/pkcs7.h                |  4 ++++
 2 files changed, 37 insertions(+)

diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index f7b0980bf02d..3243981152b5 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -16,6 +16,7 @@
 #include <linux/err.h>
 #include <linux/asn1.h>
 #include <crypto/hash.h>
+#include <crypto/hash_info.h>
 #include <crypto/public_key.h>
 #include "pkcs7_parser.h"
 
@@ -33,6 +34,10 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
 
 	kenter(",%u,%s", sinfo->index, sinfo->sig->hash_algo);
 
+	/* The digest was calculated already. */
+	if (sig->digest)
+		return 0;
+
 	if (!sinfo->sig->hash_algo)
 		return -ENOPKG;
 
@@ -121,6 +126,34 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7,
 	return ret;
 }
 
+int pkcs7_get_digest(struct pkcs7_message *pkcs7, const u8 **buf, u32 *len,
+		     enum hash_algo *hash_algo)
+{
+	struct pkcs7_signed_info *sinfo = pkcs7->signed_infos;
+	int i, ret;
+
+	/*
+	 * This function doesn't support messages with more than one signature.
+	 */
+	if (sinfo == NULL || sinfo->next != NULL)
+		return -EBADMSG;
+
+	ret = pkcs7_digest(pkcs7, sinfo);
+	if (ret)
+		return ret;
+
+	*buf = sinfo->sig->digest;
+	*len = sinfo->sig->digest_size;
+
+	for (i = 0; i < HASH_ALGO__LAST; i++)
+		if (!strcmp(hash_algo_name[i], sinfo->sig->hash_algo)) {
+			*hash_algo = i;
+			break;
+		}
+
+	return 0;
+}
+
 /*
  * Find the key (X.509 certificate) to use to verify a PKCS#7 message.  PKCS#7
  * uses the issuer's name and the issuing certificate serial number for
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 583f199400a3..3bfe6829eaae 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -13,6 +13,7 @@
 #define _CRYPTO_PKCS7_H
 
 #include <linux/verification.h>
+#include <linux/hash_info.h>
 #include <crypto/public_key.h>
 
 struct key;
@@ -44,4 +45,7 @@ extern int pkcs7_verify(struct pkcs7_message *pkcs7,
 extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7,
 				      const void *data, size_t datalen);
 
+extern int pkcs7_get_digest(struct pkcs7_message *pkcs7, const u8 **buf,
+			    u32 *len, enum hash_algo *hash_algo);
+
 #endif /* _CRYPTO_PKCS7_H */

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 04/11] integrity: Select CONFIG_KEYS instead of depending on it
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (2 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 03/11] PKCS#7: Introduce pkcs7_get_digest() Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 05/11] ima: Add modsig appraise_type option for module-style appended signatures Thiago Jung Bauermann
                   ` (7 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

This avoids a dependency cycle in soon-to-be-introduced
CONFIG_IMA_APPRAISE_MODSIG: it will select CONFIG_MODULE_SIG_FORMAT
which in turn selects CONFIG_KEYS. Kconfig then complains that
CONFIG_INTEGRITY_SIGNATURE depends on CONFIG_KEYS.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 3ba1168b1756..93d73902c571 100644
--- a/security/integrity/Kconfig
+++ b/security/integrity/Kconfig
@@ -17,8 +17,8 @@ if INTEGRITY
 
 config INTEGRITY_SIGNATURE
 	bool "Digital signature verification using multiple keyrings"
-	depends on KEYS
 	default n
+	select KEYS
 	select SIGNATURE
 	help
 	  This option enables digital signature verification support


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 05/11] ima: Add modsig appraise_type option for module-style appended signatures
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (3 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 04/11] integrity: Select CONFIG_KEYS instead of depending on it Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 06/11] ima: Factor xattr_verify() out of ima_appraise_measurement() Thiago Jung Bauermann
                   ` (6 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Introduce the modsig keyword to the IMA policy syntax to specify that
a given hook should expect the file to have the IMA signature appended
to it. Here is how it can be used in a rule:

appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig

With this rule, IMA will accept either a signature stored in the extended
attribute or an appended signature.

For now, the rule above will behave exactly the same as if
appraise_type=imasig was specified. The actual modsig implementation
will be introduced separately.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 Documentation/ABI/testing/ima_policy |  6 +++++-
 security/integrity/ima/Kconfig       | 10 +++++++++
 security/integrity/ima/Makefile      |  1 +
 security/integrity/ima/ima.h         |  9 ++++++++
 security/integrity/ima/ima_modsig.c  | 31 ++++++++++++++++++++++++++++
 security/integrity/ima/ima_policy.c  | 12 +++++++++--
 security/integrity/integrity.h       |  1 +
 7 files changed, 67 insertions(+), 3 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index fc376a323908..29ebe9afdac4 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -37,7 +37,7 @@ Description:
 			euid:= decimal value
 			fowner:= decimal value
 		lsm:  	are LSM specific
-		option:	appraise_type:= [imasig]
+		option:	appraise_type:= [imasig] [imasig|modsig]
 			template:= name of a defined IMA template type
 			(eg, ima-ng). Only valid when action is "measure".
 			pcr:= decimal value
@@ -105,3 +105,7 @@ Description:
 
 			measure func=KEXEC_KERNEL_CHECK pcr=4
 			measure func=KEXEC_INITRAMFS_CHECK pcr=5
+
+		Example of appraise rule allowing modsig appended signatures:
+
+			appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index df65d2d41905..6fa78fbc8c30 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -232,6 +232,16 @@ config IMA_APPRAISE_BOOTPARAM
 	  This option enables the different "ima_appraise=" modes
 	  (eg. fix, log) from the boot command line.
 
+config IMA_APPRAISE_MODSIG
+	bool "Support module-style signatures for appraisal"
+	depends on IMA_APPRAISE
+	default n
+	help
+	   Adds support for signatures appended to files. The format of the
+	   appended signature is the same used for signed kernel modules.
+	   The modsig keyword can be used in the IMA policy to allow a hook
+	   to accept such signatures.
+
 config IMA_TRUSTED_KEYRING
 	bool "Require all keys on the .ima keyring be signed (deprecated)"
 	depends on IMA_APPRAISE && SYSTEM_TRUSTED_KEYRING
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index d921dc4f9eb0..31d57cdf2421 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -9,5 +9,6 @@ obj-$(CONFIG_IMA) += ima.o
 ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
 	 ima_policy.o ima_template.o ima_template_lib.o
 ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
+ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o
 ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
 obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 6aa28ab53d27..904f7dd78007 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -306,6 +306,15 @@ static inline int ima_read_xattr(struct dentry *dentry,
 
 #endif /* CONFIG_IMA_APPRAISE */
 
+#ifdef CONFIG_IMA_APPRAISE_MODSIG
+bool ima_hook_supports_modsig(enum ima_hooks func);
+#else
+static inline bool ima_hook_supports_modsig(enum ima_hooks func)
+{
+	return false;
+}
+#endif /* CONFIG_IMA_APPRAISE_MODSIG */
+
 /* LSM based policy rules require audit */
 #ifdef CONFIG_IMA_LSM_RULES
 
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
new file mode 100644
index 000000000000..87503bfe8c8b
--- /dev/null
+++ b/security/integrity/ima/ima_modsig.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IMA support for appraising module-style appended signatures.
+ *
+ * Copyright (C) 2019  IBM Corporation
+ *
+ * Author:
+ * Thiago Jung Bauermann <bauerman@linux.ibm.com>
+ */
+
+#include "ima.h"
+
+/**
+ * ima_hook_supports_modsig - can the policy allow modsig for this hook?
+ *
+ * modsig is only supported by hooks using ima_post_read_file(), because only
+ * they preload the contents of the file in a buffer. FILE_CHECK does that in
+ * some cases, but not when reached from vfs_open(). POLICY_CHECK can support
+ * it, but it's not useful in practice because it's a text file so deny.
+ */
+bool ima_hook_supports_modsig(enum ima_hooks func)
+{
+	switch (func) {
+	case KEXEC_KERNEL_CHECK:
+	case KEXEC_INITRAMFS_CHECK:
+	case MODULE_CHECK:
+		return true;
+	default:
+		return false;
+	}
+}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index a3058b03a955..ac258df2f1f4 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1132,6 +1132,10 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			ima_log_string(ab, "appraise_type", args[0].from);
 			if ((strcmp(args[0].from, "imasig")) == 0)
 				entry->flags |= IMA_DIGSIG_REQUIRED;
+			else if (ima_hook_supports_modsig(entry->func) &&
+				 strcmp(args[0].from, "imasig|modsig") == 0)
+				entry->flags |= IMA_DIGSIG_REQUIRED |
+						IMA_MODSIG_ALLOWED;
 			else
 				result = -EINVAL;
 			break;
@@ -1451,8 +1455,12 @@ int ima_policy_show(struct seq_file *m, void *v)
 	}
 	if (entry->template)
 		seq_printf(m, "template=%s ", entry->template->name);
-	if (entry->flags & IMA_DIGSIG_REQUIRED)
-		seq_puts(m, "appraise_type=imasig ");
+	if (entry->flags & IMA_DIGSIG_REQUIRED) {
+		if (entry->flags & IMA_MODSIG_ALLOWED)
+			seq_puts(m, "appraise_type=imasig|modsig ");
+		else
+			seq_puts(m, "appraise_type=imasig ");
+	}
 	if (entry->flags & IMA_PERMIT_DIRECTIO)
 		seq_puts(m, "permit_directio ");
 	rcu_read_unlock();
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 88a29f72a74f..0e7330a36a9d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -36,6 +36,7 @@
 #define IMA_NEW_FILE		0x04000000
 #define EVM_IMMUTABLE_DIGSIG	0x08000000
 #define IMA_FAIL_UNVERIFIABLE_SIGS	0x10000000
+#define IMA_MODSIG_ALLOWED	0x20000000
 
 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
 				 IMA_HASH | IMA_APPRAISE_SUBMASK)

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 06/11] ima: Factor xattr_verify() out of ima_appraise_measurement()
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (4 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 05/11] ima: Add modsig appraise_type option for module-style appended signatures Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 07/11] ima: Implement support for module-style appended signatures Thiago Jung Bauermann
                   ` (5 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Verify xattr signature in a separate function so that the logic in
ima_appraise_measurement() remains clear when it gains the ability to also
verify an appended module signature.

The code in the switch statement is unchanged except for having to
dereference the status and cause variables (since they're now pointers),
and fixing the style of a block comment to appease checkpatch.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima_appraise.c | 141 +++++++++++++++-----------
 1 file changed, 81 insertions(+), 60 deletions(-)

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 18bbe753421a..5d4772f39757 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -202,6 +202,83 @@ int ima_read_xattr(struct dentry *dentry,
 	return ret;
 }
 
+/*
+ * xattr_verify - verify xattr digest or signature
+ *
+ * Verify whether the hash or signature matches the file contents.
+ *
+ * Return 0 on success, error code otherwise.
+ */
+static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint,
+			struct evm_ima_xattr_data *xattr_value, int xattr_len,
+			enum integrity_status *status, const char **cause)
+{
+	int rc = -EINVAL, hash_start = 0;
+
+	switch (xattr_value->type) {
+	case IMA_XATTR_DIGEST_NG:
+		/* first byte contains algorithm id */
+		hash_start = 1;
+		/* fall through */
+	case IMA_XATTR_DIGEST:
+		if (iint->flags & IMA_DIGSIG_REQUIRED) {
+			*cause = "IMA-signature-required";
+			*status = INTEGRITY_FAIL;
+			break;
+		}
+		clear_bit(IMA_DIGSIG, &iint->atomic_flags);
+		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
+				iint->ima_hash->length)
+			/*
+			 * xattr length may be longer. md5 hash in previous
+			 * version occupied 20 bytes in xattr, instead of 16
+			 */
+			rc = memcmp(&xattr_value->data[hash_start],
+				    iint->ima_hash->digest,
+				    iint->ima_hash->length);
+		else
+			rc = -EINVAL;
+		if (rc) {
+			*cause = "invalid-hash";
+			*status = INTEGRITY_FAIL;
+			break;
+		}
+		*status = INTEGRITY_PASS;
+		break;
+	case EVM_IMA_XATTR_DIGSIG:
+		set_bit(IMA_DIGSIG, &iint->atomic_flags);
+		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
+					     (const char *)xattr_value,
+					     xattr_len,
+					     iint->ima_hash->digest,
+					     iint->ima_hash->length);
+		if (rc == -EOPNOTSUPP) {
+			*status = INTEGRITY_UNKNOWN;
+			break;
+		}
+		if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc &&
+		    func == KEXEC_KERNEL_CHECK)
+			rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM,
+						     (const char *)xattr_value,
+						     xattr_len,
+						     iint->ima_hash->digest,
+						     iint->ima_hash->length);
+		if (rc) {
+			*cause = "invalid-signature";
+			*status = INTEGRITY_FAIL;
+		} else {
+			*status = INTEGRITY_PASS;
+		}
+		break;
+	default:
+		*status = INTEGRITY_UNKNOWN;
+		*cause = "unknown-ima-data";
+		break;
+	}
+
+	return rc;
+}
+
 /*
  * ima_appraise_measurement - appraise file measurement
  *
@@ -221,7 +298,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 	struct dentry *dentry = file_dentry(file);
 	struct inode *inode = d_backing_inode(dentry);
 	enum integrity_status status = INTEGRITY_UNKNOWN;
-	int rc = xattr_len, hash_start = 0;
+	int rc = xattr_len;
 
 	if (!(inode->i_opflags & IOP_XATTR))
 		return INTEGRITY_UNKNOWN;
@@ -259,65 +336,9 @@ int ima_appraise_measurement(enum ima_hooks func,
 		WARN_ONCE(true, "Unexpected integrity status %d\n", status);
 	}
 
-	switch (xattr_value->type) {
-	case IMA_XATTR_DIGEST_NG:
-		/* first byte contains algorithm id */
-		hash_start = 1;
-		/* fall through */
-	case IMA_XATTR_DIGEST:
-		if (iint->flags & IMA_DIGSIG_REQUIRED) {
-			cause = "IMA-signature-required";
-			status = INTEGRITY_FAIL;
-			break;
-		}
-		clear_bit(IMA_DIGSIG, &iint->atomic_flags);
-		if (xattr_len - sizeof(xattr_value->type) - hash_start >=
-				iint->ima_hash->length)
-			/* xattr length may be longer. md5 hash in previous
-			   version occupied 20 bytes in xattr, instead of 16
-			 */
-			rc = memcmp(&xattr_value->data[hash_start],
-				    iint->ima_hash->digest,
-				    iint->ima_hash->length);
-		else
-			rc = -EINVAL;
-		if (rc) {
-			cause = "invalid-hash";
-			status = INTEGRITY_FAIL;
-			break;
-		}
-		status = INTEGRITY_PASS;
-		break;
-	case EVM_IMA_XATTR_DIGSIG:
-		set_bit(IMA_DIGSIG, &iint->atomic_flags);
-		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
-					     (const char *)xattr_value,
-					     xattr_len,
-					     iint->ima_hash->digest,
-					     iint->ima_hash->length);
-		if (rc == -EOPNOTSUPP) {
-			status = INTEGRITY_UNKNOWN;
-			break;
-		}
-		if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc &&
-		    func == KEXEC_KERNEL_CHECK)
-			rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM,
-						     (const char *)xattr_value,
-						     xattr_len,
-						     iint->ima_hash->digest,
-						     iint->ima_hash->length);
-		if (rc) {
-			cause = "invalid-signature";
-			status = INTEGRITY_FAIL;
-		} else {
-			status = INTEGRITY_PASS;
-		}
-		break;
-	default:
-		status = INTEGRITY_UNKNOWN;
-		cause = "unknown-ima-data";
-		break;
-	}
+	if (xattr_value)
+		rc = xattr_verify(func, iint, xattr_value, xattr_len, &status,
+				  &cause);
 
 out:
 	/*

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 07/11] ima: Implement support for module-style appended signatures
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (5 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 06/11] ima: Factor xattr_verify() out of ima_appraise_measurement() Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 08/11] ima: Collect modsig Thiago Jung Bauermann
                   ` (4 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Implement the appraise_type=imasig|modsig option, allowing IMA to read and
verify modsig signatures.

In case a file has both an xattr signature and an appended modsig, IMA will
only use the appended signature if the key used by the xattr signature
isn't present in the IMA or platform keyring.

Because modsig verification needs to convert from an integrity keyring id
to the keyring itself, add an integrity_keyring_from_id() function in
digsig.c so that integrity_modsig_verify() can use it.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/digsig.c           | 43 ++++++++++++----
 security/integrity/ima/Kconfig        |  3 ++
 security/integrity/ima/ima.h          | 22 ++++++++-
 security/integrity/ima/ima_appraise.c | 51 +++++++++++++++++--
 security/integrity/ima/ima_main.c     | 11 ++++-
 security/integrity/ima/ima_modsig.c   | 71 +++++++++++++++++++++++++++
 security/integrity/ima/ima_policy.c   | 12 ++---
 security/integrity/integrity.h        | 19 +++++++
 8 files changed, 209 insertions(+), 23 deletions(-)

diff --git a/security/integrity/digsig.c b/security/integrity/digsig.c
index 37869214c243..1c353b1a6ec5 100644
--- a/security/integrity/digsig.c
+++ b/security/integrity/digsig.c
@@ -43,11 +43,10 @@ static const char * const keyring_name[INTEGRITY_KEYRING_MAX] = {
 #define restrict_link_to_ima restrict_link_by_builtin_trusted
 #endif
 
-int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
-			    const char *digest, int digestlen)
+static struct key *integrity_keyring_from_id(const unsigned int id)
 {
-	if (id >= INTEGRITY_KEYRING_MAX || siglen < 2)
-		return -EINVAL;
+	if (id >= INTEGRITY_KEYRING_MAX)
+		return ERR_PTR(-EINVAL);
 
 	if (!keyring[id]) {
 		keyring[id] =
@@ -56,23 +55,49 @@ int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
 			int err = PTR_ERR(keyring[id]);
 			pr_err("no %s keyring: %d\n", keyring_name[id], err);
 			keyring[id] = NULL;
-			return err;
+			return ERR_PTR(err);
 		}
 	}
 
+	return keyring[id];
+}
+
+int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
+			    const char *digest, int digestlen)
+{
+	struct key *keyring;
+
+	if (siglen < 2)
+		return -EINVAL;
+
+	keyring = integrity_keyring_from_id(id);
+	if (IS_ERR(keyring))
+		return PTR_ERR(keyring);
+
 	switch (sig[1]) {
 	case 1:
 		/* v1 API expect signature without xattr type */
-		return digsig_verify(keyring[id], sig + 1, siglen - 1,
-				     digest, digestlen);
+		return digsig_verify(keyring, sig + 1, siglen - 1, digest,
+				     digestlen);
 	case 2:
-		return asymmetric_verify(keyring[id], sig, siglen,
-					 digest, digestlen);
+		return asymmetric_verify(keyring, sig, siglen, digest,
+					 digestlen);
 	}
 
 	return -EOPNOTSUPP;
 }
 
+int integrity_modsig_verify(const unsigned int id, const struct modsig *modsig)
+{
+	struct key *keyring;
+
+	keyring = integrity_keyring_from_id(id);
+	if (IS_ERR(keyring))
+		return PTR_ERR(keyring);
+
+	return ima_modsig_verify(keyring, modsig);
+}
+
 static int __init __integrity_init_keyring(const unsigned int id,
 					   key_perm_t perm,
 					   struct key_restriction *restriction)
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 6fa78fbc8c30..5a109707e907 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -235,6 +235,9 @@ config IMA_APPRAISE_BOOTPARAM
 config IMA_APPRAISE_MODSIG
 	bool "Support module-style signatures for appraisal"
 	depends on IMA_APPRAISE
+	depends on INTEGRITY_ASYMMETRIC_KEYS
+	select PKCS7_MESSAGE_PARSER
+	select MODULE_SIG_FORMAT
 	default n
 	help
 	   Adds support for signatures appended to files. The format of the
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 904f7dd78007..fa188de1cef6 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -200,6 +200,10 @@ enum ima_hooks {
 	__ima_hooks(__ima_hook_enumify)
 };
 
+extern const char *const func_tokens[];
+
+struct modsig;
+
 /* LIM API function definitions */
 int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 		   int mask, enum ima_hooks func, int *pcr,
@@ -253,7 +257,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 			     struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename,
 			     struct evm_ima_xattr_data *xattr_value,
-			     int xattr_len);
+			     int xattr_len, const struct modsig *modsig);
 int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
 void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
 enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
@@ -269,7 +273,8 @@ static inline int ima_appraise_measurement(enum ima_hooks func,
 					   struct file *file,
 					   const unsigned char *filename,
 					   struct evm_ima_xattr_data *xattr_value,
-					   int xattr_len)
+					   int xattr_len,
+					   const struct modsig *modsig)
 {
 	return INTEGRITY_UNKNOWN;
 }
@@ -308,11 +313,24 @@ static inline int ima_read_xattr(struct dentry *dentry,
 
 #ifdef CONFIG_IMA_APPRAISE_MODSIG
 bool ima_hook_supports_modsig(enum ima_hooks func);
+int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
+		    struct modsig **modsig);
+void ima_free_modsig(struct modsig *modsig);
 #else
 static inline bool ima_hook_supports_modsig(enum ima_hooks func)
 {
 	return false;
 }
+
+static inline int ima_read_modsig(enum ima_hooks func, const void *buf,
+				  loff_t buf_len, struct modsig **modsig)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void ima_free_modsig(struct modsig *modsig)
+{
+}
 #endif /* CONFIG_IMA_APPRAISE_MODSIG */
 
 /* LSM based policy rules require audit */
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 5d4772f39757..70252ac3321d 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -279,6 +279,33 @@ static int xattr_verify(enum ima_hooks func, struct integrity_iint_cache *iint,
 	return rc;
 }
 
+/*
+ * modsig_verify - verify modsig signature
+ *
+ * Verify whether the signature matches the file contents.
+ *
+ * Return 0 on success, error code otherwise.
+ */
+static int modsig_verify(enum ima_hooks func, const struct modsig *modsig,
+			 enum integrity_status *status, const char **cause)
+{
+	int rc;
+
+	rc = integrity_modsig_verify(INTEGRITY_KEYRING_IMA, modsig);
+	if (IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING) && rc &&
+	    func == KEXEC_KERNEL_CHECK)
+		rc = integrity_modsig_verify(INTEGRITY_KEYRING_PLATFORM,
+					     modsig);
+	if (rc) {
+		*cause = "invalid-signature";
+		*status = INTEGRITY_FAIL;
+	} else {
+		*status = INTEGRITY_PASS;
+	}
+
+	return rc;
+}
+
 /*
  * ima_appraise_measurement - appraise file measurement
  *
@@ -291,7 +318,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 			     struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename,
 			     struct evm_ima_xattr_data *xattr_value,
-			     int xattr_len)
+			     int xattr_len, const struct modsig *modsig)
 {
 	static const char op[] = "appraise_data";
 	const char *cause = "unknown";
@@ -299,11 +326,14 @@ int ima_appraise_measurement(enum ima_hooks func,
 	struct inode *inode = d_backing_inode(dentry);
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	int rc = xattr_len;
+	bool try_modsig = iint->flags & IMA_MODSIG_ALLOWED && modsig;
 
-	if (!(inode->i_opflags & IOP_XATTR))
+	/* If not appraising a modsig, we need an xattr. */
+	if (!(inode->i_opflags & IOP_XATTR) && !try_modsig)
 		return INTEGRITY_UNKNOWN;
 
-	if (rc <= 0) {
+	/* If reading the xattr failed and there's no modsig, error out. */
+	if (rc <= 0 && !try_modsig) {
 		if (rc && rc != -ENODATA)
 			goto out;
 
@@ -326,6 +356,10 @@ int ima_appraise_measurement(enum ima_hooks func,
 	case INTEGRITY_UNKNOWN:
 		break;
 	case INTEGRITY_NOXATTRS:	/* No EVM protected xattrs. */
+		/* It's fine not to have xattrs when using a modsig. */
+		if (try_modsig)
+			break;
+		/* fall through */
 	case INTEGRITY_NOLABEL:		/* No security.evm xattr. */
 		cause = "missing-HMAC";
 		goto out;
@@ -340,6 +374,15 @@ int ima_appraise_measurement(enum ima_hooks func,
 		rc = xattr_verify(func, iint, xattr_value, xattr_len, &status,
 				  &cause);
 
+	/*
+	 * If we have a modsig and either no imasig or the imasig's key isn't
+	 * known, then try verifying the modsig.
+	 */
+	if (try_modsig &&
+	    (!xattr_value || xattr_value->type == IMA_XATTR_DIGEST_NG ||
+	     rc == -ENOKEY))
+		rc = modsig_verify(func, modsig, &status, &cause);
+
 out:
 	/*
 	 * File signatures on some filesystems can not be properly verified.
@@ -356,7 +399,7 @@ int ima_appraise_measurement(enum ima_hooks func,
 				    op, cause, rc, 0);
 	} else if (status != INTEGRITY_PASS) {
 		/* Fix mode, but don't replace file signatures. */
-		if ((ima_appraise & IMA_APPRAISE_FIX) &&
+		if ((ima_appraise & IMA_APPRAISE_FIX) && !try_modsig &&
 		    (!xattr_value ||
 		     xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
 			if (!ima_fix_xattr(dentry, iint))
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 317c4b6f2c18..309058c1d50e 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -206,6 +206,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	int rc = 0, action, must_appraise = 0;
 	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 	struct evm_ima_xattr_data *xattr_value = NULL;
+	struct modsig *modsig = NULL;
 	int xattr_len = 0;
 	bool violation_check;
 	enum hash_algo hash_algo;
@@ -306,10 +307,15 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	}
 
 	if ((action & IMA_APPRAISE_SUBMASK) ||
-		    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
+	    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 		/* read 'security.ima' */
 		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
 
+		/* Read the appended modsig if allowed by the policy. */
+		if (iint->flags & IMA_MODSIG_ALLOWED)
+			ima_read_modsig(func, buf, size, &modsig);
+	}
+
 	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
 
 	rc = ima_collect_measurement(iint, file, buf, size, hash_algo);
@@ -326,7 +332,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
 		inode_lock(inode);
 		rc = ima_appraise_measurement(func, iint, file, pathname,
-					      xattr_value, xattr_len);
+					      xattr_value, xattr_len, modsig);
 		inode_unlock(inode);
 		if (!rc)
 			rc = mmap_violation_check(func, file, &pathbuf,
@@ -343,6 +349,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 		rc = -EACCES;
 	mutex_unlock(&iint->mutex);
 	kfree(xattr_value);
+	ima_free_modsig(modsig);
 out:
 	if (pathbuf)
 		__putname(pathbuf);
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index 87503bfe8c8b..f41ebe370fa0 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -8,8 +8,17 @@
  * Thiago Jung Bauermann <bauerman@linux.ibm.com>
  */
 
+#include <linux/types.h>
+#include <linux/module_signature.h>
+#include <keys/asymmetric-type.h>
+#include <crypto/pkcs7.h>
+
 #include "ima.h"
 
+struct modsig {
+	struct pkcs7_message *pkcs7_msg;
+};
+
 /**
  * ima_hook_supports_modsig - can the policy allow modsig for this hook?
  *
@@ -29,3 +38,65 @@ bool ima_hook_supports_modsig(enum ima_hooks func)
 		return false;
 	}
 }
+
+/*
+ * ima_read_modsig - Read modsig from buf.
+ *
+ * Return: 0 on success, error code otherwise.
+ */
+int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
+		    struct modsig **modsig)
+{
+	const size_t marker_len = strlen(MODULE_SIG_STRING);
+	const struct module_signature *sig;
+	struct modsig *hdr;
+	size_t sig_len;
+	const void *p;
+	int rc;
+
+	if (buf_len <= marker_len + sizeof(*sig))
+		return -ENOENT;
+
+	p = buf + buf_len - marker_len;
+	if (memcmp(p, MODULE_SIG_STRING, marker_len))
+		return -ENOENT;
+
+	buf_len -= marker_len;
+	sig = (const struct module_signature *)(p - sizeof(*sig));
+
+	rc = mod_check_sig(sig, buf_len, func_tokens[func]);
+	if (rc)
+		return rc;
+
+	sig_len = be32_to_cpu(sig->sig_len);
+	buf_len -= sig_len + sizeof(*sig);
+
+	hdr = kmalloc(sizeof(*hdr), GFP_KERNEL);
+	if (!hdr)
+		return -ENOMEM;
+
+	hdr->pkcs7_msg = pkcs7_parse_message(buf + buf_len, sig_len);
+	if (IS_ERR(hdr->pkcs7_msg)) {
+		kfree(hdr);
+		return PTR_ERR(hdr->pkcs7_msg);
+	}
+
+	*modsig = hdr;
+
+	return 0;
+}
+
+int ima_modsig_verify(struct key *keyring, const struct modsig *modsig)
+{
+	return verify_pkcs7_message_sig(NULL, 0, modsig->pkcs7_msg, keyring,
+					VERIFYING_MODULE_SIGNATURE, NULL, NULL);
+}
+
+void ima_free_modsig(struct modsig *modsig)
+{
+	if (!modsig)
+		return;
+
+	pkcs7_free_message(modsig->pkcs7_msg);
+	kfree(modsig);
+}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index ac258df2f1f4..4c5b968c4721 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1260,6 +1260,12 @@ void ima_delete_rules(void)
 	}
 }
 
+#define __ima_hook_stringify(str)	(#str),
+
+const char *const func_tokens[] = {
+	__ima_hooks(__ima_hook_stringify)
+};
+
 #ifdef	CONFIG_IMA_READ_POLICY
 enum {
 	mask_exec = 0, mask_write, mask_read, mask_append
@@ -1272,12 +1278,6 @@ static const char *const mask_tokens[] = {
 	"^MAY_APPEND"
 };
 
-#define __ima_hook_stringify(str)	(#str),
-
-static const char *const func_tokens[] = {
-	__ima_hooks(__ima_hook_stringify)
-};
-
 void *ima_policy_start(struct seq_file *m, loff_t *pos)
 {
 	loff_t l = *pos;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 0e7330a36a9d..c6e7f41db470 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -153,10 +153,13 @@ int integrity_kernel_read(struct file *file, loff_t offset,
 
 extern struct dentry *integrity_dir;
 
+struct modsig;
+
 #ifdef CONFIG_INTEGRITY_SIGNATURE
 
 int integrity_digsig_verify(const unsigned int id, const char *sig, int siglen,
 			    const char *digest, int digestlen);
+int integrity_modsig_verify(unsigned int id, const struct modsig *modsig);
 
 int __init integrity_init_keyring(const unsigned int id);
 int __init integrity_load_x509(const unsigned int id, const char *path);
@@ -171,6 +174,12 @@ static inline int integrity_digsig_verify(const unsigned int id,
 	return -EOPNOTSUPP;
 }
 
+static inline int integrity_modsig_verify(unsigned int id,
+					  const struct modsig *modsig)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline int integrity_init_keyring(const unsigned int id)
 {
 	return 0;
@@ -196,6 +205,16 @@ static inline int asymmetric_verify(struct key *keyring, const char *sig,
 }
 #endif
 
+#ifdef CONFIG_IMA_APPRAISE_MODSIG
+int ima_modsig_verify(struct key *keyring, const struct modsig *modsig);
+#else
+static inline int ima_modsig_verify(struct key *keyring,
+				    const struct modsig *modsig)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
 #ifdef CONFIG_IMA_LOAD_X509
 void __init ima_load_x509(void);
 #else

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 08/11] ima: Collect modsig
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (6 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 07/11] ima: Implement support for module-style appended signatures Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 09/11] ima: Define ima-modsig template Thiago Jung Bauermann
                   ` (3 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Obtain the modsig and calculate its corresponding hash in
ima_collect_measurement().

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 security/integrity/ima/ima.h          |  8 ++++-
 security/integrity/ima/ima_api.c      |  5 ++-
 security/integrity/ima/ima_appraise.c |  2 +-
 security/integrity/ima/ima_main.c     |  2 +-
 security/integrity/ima/ima_modsig.c   | 50 ++++++++++++++++++++++++++-
 5 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index fa188de1cef6..baf2ffd52a41 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -211,7 +211,7 @@ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
 int ima_collect_measurement(struct integrity_iint_cache *iint,
 			    struct file *file, void *buf, loff_t size,
-			    enum hash_algo algo);
+			    enum hash_algo algo, struct modsig *modsig);
 void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   const unsigned char *filename,
 			   struct evm_ima_xattr_data *xattr_value,
@@ -315,6 +315,7 @@ static inline int ima_read_xattr(struct dentry *dentry,
 bool ima_hook_supports_modsig(enum ima_hooks func);
 int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
 		    struct modsig **modsig);
+void ima_collect_modsig(struct modsig *modsig, const void *buf, loff_t size);
 void ima_free_modsig(struct modsig *modsig);
 #else
 static inline bool ima_hook_supports_modsig(enum ima_hooks func)
@@ -328,6 +329,11 @@ static inline int ima_read_modsig(enum ima_hooks func, const void *buf,
 	return -EOPNOTSUPP;
 }
 
+static inline void ima_collect_modsig(struct modsig *modsig, const void *buf,
+				      loff_t size)
+{
+}
+
 static inline void ima_free_modsig(struct modsig *modsig)
 {
 }
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index d426d4d1fe04..ac35bc3d6e35 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -209,7 +209,7 @@ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
  */
 int ima_collect_measurement(struct integrity_iint_cache *iint,
 			    struct file *file, void *buf, loff_t size,
-			    enum hash_algo algo)
+			    enum hash_algo algo, struct modsig *modsig)
 {
 	const char *audit_cause = "failed";
 	struct inode *inode = file_inode(file);
@@ -256,6 +256,9 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 	memcpy(iint->ima_hash, &hash, length);
 	iint->version = i_version;
 
+	if (modsig)
+		ima_collect_modsig(modsig, buf, size);
+
 	/* Possibly temporary failure due to type of read (eg. O_DIRECT) */
 	if (!result)
 		iint->flags |= IMA_COLLECTED;
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 70252ac3321d..aa14e3fe25d5 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -438,7 +438,7 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
 	    !(iint->flags & IMA_HASH))
 		return;
 
-	rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo);
+	rc = ima_collect_measurement(iint, file, NULL, 0, ima_hash_algo, NULL);
 	if (rc < 0)
 		return;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 309058c1d50e..cc4500f93408 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -318,7 +318,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 
 	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
 
-	rc = ima_collect_measurement(iint, file, buf, size, hash_algo);
+	rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
 	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
 		goto out_locked;
 
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index f41ebe370fa0..d438b87dba89 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -17,6 +17,19 @@
 
 struct modsig {
 	struct pkcs7_message *pkcs7_msg;
+
+	enum hash_algo hash_algo;
+
+	/* This digest will go in the 'd-modsig' field of the IMA template. */
+	const u8 *digest;
+	u32 digest_size;
+
+	/*
+	 * This is what will go to the measurement list if the template requires
+	 * storing the signature.
+	 */
+	int raw_pkcs7_len;
+	u8 raw_pkcs7[];
 };
 
 /**
@@ -71,7 +84,8 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
 	sig_len = be32_to_cpu(sig->sig_len);
 	buf_len -= sig_len + sizeof(*sig);
 
-	hdr = kmalloc(sizeof(*hdr), GFP_KERNEL);
+	/* Allocate sig_len additional bytes to hold the raw PKCS#7 data. */
+	hdr = kzalloc(sizeof(*hdr) + sig_len, GFP_KERNEL);
 	if (!hdr)
 		return -ENOMEM;
 
@@ -81,11 +95,45 @@ int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
 		return PTR_ERR(hdr->pkcs7_msg);
 	}
 
+	memcpy(hdr->raw_pkcs7, buf + buf_len, sig_len);
+	hdr->raw_pkcs7_len = sig_len;
+
+	/* We don't know the hash algorithm yet. */
+	hdr->hash_algo = HASH_ALGO__LAST;
+
 	*modsig = hdr;
 
 	return 0;
 }
 
+/**
+ * ima_collect_modsig - Calculate the file hash without the appended signature.
+ *
+ * Since the modsig is part of the file contents, the hash used in its signature
+ * isn't the same one ordinarily calculated by IMA. Therefore PKCS7 code
+ * calculates a separate one for signature verification.
+ */
+void ima_collect_modsig(struct modsig *modsig, const void *buf, loff_t size)
+{
+	int rc;
+
+	/*
+	 * Provide the file contents (minus the appended sig) so that the PKCS7
+	 * code can calculate the file hash.
+	 */
+	size -= modsig->raw_pkcs7_len + strlen(MODULE_SIG_STRING) +
+		sizeof(struct module_signature);
+	rc = pkcs7_supply_detached_data(modsig->pkcs7_msg, buf, size);
+	if (rc)
+		return;
+
+	/* Ask the PKCS7 code to calculate the file hash. */
+	rc = pkcs7_get_digest(modsig->pkcs7_msg, &modsig->digest,
+			      &modsig->digest_size, &modsig->hash_algo);
+	if (rc)
+		return;
+}
+
 int ima_modsig_verify(struct key *keyring, const struct modsig *modsig)
 {
 	return verify_pkcs7_message_sig(NULL, 0, modsig->pkcs7_msg, keyring,


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 09/11] ima: Define ima-modsig template
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (7 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 08/11] ima: Collect modsig Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 10/11] ima: Store the measurement again when appraising a modsig Thiago Jung Bauermann
                   ` (2 subsequent siblings)
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

Define new "d-modsig" template field which holds the digest that is
expected to match the one contained in the modsig, and also new "modsig"
template field which holds the appended file signature.

Add a new "ima-modsig" defined template descriptor with the new fields as
well as the ones from the "ima-sig" descriptor.

Change ima_store_measurement() to accept a struct modsig * argument so that
it can be passed along to the templates via struct ima_event_data.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 Documentation/security/IMA-templates.rst  |  3 ++
 security/integrity/ima/ima.h              | 20 ++++++-
 security/integrity/ima/ima_api.c          |  5 +-
 security/integrity/ima/ima_main.c         |  2 +-
 security/integrity/ima/ima_modsig.c       | 19 +++++++
 security/integrity/ima/ima_policy.c       | 41 +++++++++++++++
 security/integrity/ima/ima_template.c     |  7 ++-
 security/integrity/ima/ima_template_lib.c | 64 ++++++++++++++++++++++-
 security/integrity/ima/ima_template_lib.h |  4 ++
 9 files changed, 159 insertions(+), 6 deletions(-)

diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst
index 3d1cca287aa4..c5a8432972ef 100644
--- a/Documentation/security/IMA-templates.rst
+++ b/Documentation/security/IMA-templates.rst
@@ -68,8 +68,10 @@ descriptors by adding their identifier to the format string
  - 'd-ng': the digest of the event, calculated with an arbitrary hash
    algorithm (field format: [<hash algo>:]digest, where the digest
    prefix is shown only if the hash algorithm is not SHA1 or MD5);
+ - 'd-modsig': the digest of the event without the appended modsig;
  - 'n-ng': the name of the event, without size limitations;
  - 'sig': the file signature;
+ - 'modsig' the appended file signature;
  - 'buf': the buffer data that was used to generate the hash without size limitations;
 
 
@@ -79,6 +81,7 @@ Below, there is the list of defined template descriptors:
  - "ima-ng" (default): its format is ``d-ng|n-ng``;
  - "ima-sig": its format is ``d-ng|n-ng|sig``;
  - "ima-buf": its format is ``d-ng|n-ng|buf``;
+ - "ima-modsig": its format is ``d-ng|n-ng|sig|d-modsig|modsig``;
 
 
 Use
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index baf2ffd52a41..3293dd07b6c9 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -64,6 +64,7 @@ struct ima_event_data {
 	const unsigned char *filename;
 	struct evm_ima_xattr_data *xattr_value;
 	int xattr_len;
+	const struct modsig *modsig;
 	const char *violation;
 	const void *buf;
 	int buf_len;
@@ -215,7 +216,7 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   const unsigned char *filename,
 			   struct evm_ima_xattr_data *xattr_value,
-			   int xattr_len, int pcr,
+			   int xattr_len, const struct modsig *modsig, int pcr,
 			   struct ima_template_desc *template_desc);
 void ima_audit_measurement(struct integrity_iint_cache *iint,
 			   const unsigned char *filename);
@@ -316,6 +317,10 @@ bool ima_hook_supports_modsig(enum ima_hooks func);
 int ima_read_modsig(enum ima_hooks func, const void *buf, loff_t buf_len,
 		    struct modsig **modsig);
 void ima_collect_modsig(struct modsig *modsig, const void *buf, loff_t size);
+int ima_get_modsig_digest(const struct modsig *modsig, enum hash_algo *algo,
+			  const u8 **digest, u32 *digest_size);
+int ima_get_raw_modsig(const struct modsig *modsig, const void **data,
+		       u32 *data_len);
 void ima_free_modsig(struct modsig *modsig);
 #else
 static inline bool ima_hook_supports_modsig(enum ima_hooks func)
@@ -334,6 +339,19 @@ static inline void ima_collect_modsig(struct modsig *modsig, const void *buf,
 {
 }
 
+static inline int ima_get_modsig_digest(const struct modsig *modsig,
+					enum hash_algo *algo, const u8 **digest,
+					u32 *digest_size)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int ima_get_raw_modsig(const struct modsig *modsig,
+				     const void **data, u32 *data_len)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline void ima_free_modsig(struct modsig *modsig)
 {
 }
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index ac35bc3d6e35..9d1fe712a6cc 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -292,7 +292,7 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 void ima_store_measurement(struct integrity_iint_cache *iint,
 			   struct file *file, const unsigned char *filename,
 			   struct evm_ima_xattr_data *xattr_value,
-			   int xattr_len, int pcr,
+			   int xattr_len, const struct modsig *modsig, int pcr,
 			   struct ima_template_desc *template_desc)
 {
 	static const char op[] = "add_template_measure";
@@ -304,7 +304,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 					     .file = file,
 					     .filename = filename,
 					     .xattr_value = xattr_value,
-					     .xattr_len = xattr_len };
+					     .xattr_len = xattr_len,
+					     .modsig = modsig };
 	int violation = 0;
 
 	if (iint->measured_pcrs & (0x1 << pcr))
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index cc4500f93408..8b35a200e0cc 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -327,7 +327,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 
 	if (action & IMA_MEASURE)
 		ima_store_measurement(iint, file, pathname,
-				      xattr_value, xattr_len, pcr,
+				      xattr_value, xattr_len, modsig, pcr,
 				      template_desc);
 	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
 		inode_lock(inode);
diff --git a/security/integrity/ima/ima_modsig.c b/security/integrity/ima/ima_modsig.c
index d438b87dba89..b01bbfeb1d98 100644
--- a/security/integrity/ima/ima_modsig.c
+++ b/security/integrity/ima/ima_modsig.c
@@ -140,6 +140,25 @@ int ima_modsig_verify(struct key *keyring, const struct modsig *modsig)
 					VERIFYING_MODULE_SIGNATURE, NULL, NULL);
 }
 
+int ima_get_modsig_digest(const struct modsig *modsig, enum hash_algo *algo,
+			  const u8 **digest, u32 *digest_size)
+{
+	*algo = modsig->hash_algo;
+	*digest = modsig->digest;
+	*digest_size = modsig->digest_size;
+
+	return 0;
+}
+
+int ima_get_raw_modsig(const struct modsig *modsig, const void **data,
+		       u32 *data_len)
+{
+	*data = &modsig->raw_pkcs7;
+	*data_len = modsig->raw_pkcs7_len;
+
+	return 0;
+}
+
 void ima_free_modsig(struct modsig *modsig)
 {
 	if (!modsig)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 4c5b968c4721..4fc13e591f1d 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -10,6 +10,9 @@
  *	- initialize default measure policy rules
  *
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/fs.h>
@@ -847,6 +850,38 @@ static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 	ima_log_string_op(ab, key, value, NULL);
 }
 
+/*
+ * Validating the appended signature included in the measurement list requires
+ * the file hash calculated without the appended signature (i.e., the 'd-modsig'
+ * field). Therefore, notify the user if they have the 'modsig' field but not
+ * the 'd-modsig' field in the template.
+ */
+static void check_template_modsig(const struct ima_template_desc *template)
+{
+#define MSG "template with 'modsig' field also needs 'd-modsig' field\n"
+	bool has_modsig, has_dmodsig;
+	static bool checked;
+	int i;
+
+	/* We only need to notify the user once. */
+	if (checked)
+		return;
+
+	has_modsig = has_dmodsig = false;
+	for (i = 0; i < template->num_fields; i++) {
+		if (!strcmp(template->fields[i]->field_id, "modsig"))
+			has_modsig = true;
+		else if (!strcmp(template->fields[i]->field_id, "d-modsig"))
+			has_dmodsig = true;
+	}
+
+	if (has_modsig && !has_dmodsig)
+		pr_notice(MSG);
+
+	checked = true;
+#undef MSG
+}
+
 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 {
 	struct audit_buffer *ab;
@@ -1189,6 +1224,12 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 	else if (entry->action == APPRAISE)
 		temp_ima_appraise |= ima_appraise_flag(entry->func);
 
+	if (!result && entry->flags & IMA_MODSIG_ALLOWED) {
+		template_desc = entry->template ? entry->template :
+						  ima_template_desc_current();
+		check_template_modsig(template_desc);
+	}
+
 	audit_log_format(ab, "res=%d", !result);
 	audit_log_end(ab);
 	return result;
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index 7343e8e0ae2f..ac526b34973f 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -27,6 +27,7 @@ static struct ima_template_desc builtin_templates[] = {
 	{.name = "ima-ng", .fmt = "d-ng|n-ng"},
 	{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
 	{.name = "ima-buf", .fmt = "d-ng|n-ng|buf"},
+	{.name = "ima-modsig", .fmt = "d-ng|n-ng|sig|d-modsig|modsig"},
 	{.name = "", .fmt = ""},	/* placeholder for a custom format */
 };
 
@@ -46,6 +47,10 @@ static const struct ima_template_field supported_fields[] = {
 	 .field_show = ima_show_template_sig},
 	{.field_id = "buf", .field_init = ima_eventbuf_init,
 	 .field_show = ima_show_template_buf},
+	{.field_id = "d-modsig", .field_init = ima_eventdigest_modsig_init,
+	 .field_show = ima_show_template_digest_ng},
+	{.field_id = "modsig", .field_init = ima_eventmodsig_init,
+	 .field_show = ima_show_template_sig},
 };
 
 /*
@@ -53,7 +58,7 @@ static const struct ima_template_field supported_fields[] = {
  * need to be accounted for since they shouldn't be defined in the same template
  * description as 'd-ng' and 'n-ng' respectively.
  */
-#define MAX_TEMPLATE_NAME_LEN sizeof("d-ng|n-ng|sig|buf")
+#define MAX_TEMPLATE_NAME_LEN sizeof("d-ng|n-ng|sig|buf|d-modisg|modsig")
 
 static struct ima_template_desc *ima_template;
 
diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c
index baf4de45c5aa..22e71cd5ca02 100644
--- a/security/integrity/ima/ima_template_lib.c
+++ b/security/integrity/ima/ima_template_lib.c
@@ -229,7 +229,8 @@ int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp,
 	return 0;
 }
 
-static int ima_eventdigest_init_common(u8 *digest, u32 digestsize, u8 hash_algo,
+static int ima_eventdigest_init_common(const u8 *digest, u32 digestsize,
+				       u8 hash_algo,
 				       struct ima_field_data *field_data)
 {
 	/*
@@ -332,6 +333,41 @@ int ima_eventdigest_ng_init(struct ima_event_data *event_data,
 					   hash_algo, field_data);
 }
 
+/*
+ * This function writes the digest of the file which is expected to match the
+ * digest contained in the file's appended signature.
+ */
+int ima_eventdigest_modsig_init(struct ima_event_data *event_data,
+				struct ima_field_data *field_data)
+{
+	enum hash_algo hash_algo;
+	const u8 *cur_digest;
+	u32 cur_digestsize;
+
+	if (!event_data->modsig)
+		return 0;
+
+	if (event_data->violation) {
+		/* Recording a violation. */
+		hash_algo = HASH_ALGO_SHA1;
+		cur_digest = NULL;
+		cur_digestsize = 0;
+	} else {
+		int rc;
+
+		rc = ima_get_modsig_digest(event_data->modsig, &hash_algo,
+					   &cur_digest, &cur_digestsize);
+		if (rc)
+			return rc;
+		else if (hash_algo == HASH_ALGO__LAST || cur_digestsize == 0)
+			/* There was some error collecting the digest. */
+			return -EINVAL;
+	}
+
+	return ima_eventdigest_init_common(cur_digest, cur_digestsize,
+					   hash_algo, field_data);
+}
+
 static int ima_eventname_init_common(struct ima_event_data *event_data,
 				     struct ima_field_data *field_data,
 				     bool size_limit)
@@ -410,3 +446,29 @@ int ima_eventbuf_init(struct ima_event_data *event_data,
 					     event_data->buf_len, DATA_FMT_HEX,
 					     field_data);
 }
+
+/*
+ *  ima_eventmodsig_init - include the appended file signature as part of the
+ *  template data
+ */
+int ima_eventmodsig_init(struct ima_event_data *event_data,
+			 struct ima_field_data *field_data)
+{
+	const void *data;
+	u32 data_len;
+	int rc;
+
+	if (!event_data->modsig)
+		return 0;
+
+	/*
+	 * modsig is a runtime structure containing pointers. Get its raw data
+	 * instead.
+	 */
+	rc = ima_get_raw_modsig(event_data->modsig, &data, &data_len);
+	if (rc)
+		return rc;
+
+	return ima_write_template_field_data(data, data_len, DATA_FMT_HEX,
+					     field_data);
+}
diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h
index 12f1a8578b31..6544eac1c77d 100644
--- a/security/integrity/ima/ima_template_lib.h
+++ b/security/integrity/ima/ima_template_lib.h
@@ -40,10 +40,14 @@ int ima_eventname_init(struct ima_event_data *event_data,
 		       struct ima_field_data *field_data);
 int ima_eventdigest_ng_init(struct ima_event_data *event_data,
 			    struct ima_field_data *field_data);
+int ima_eventdigest_modsig_init(struct ima_event_data *event_data,
+				struct ima_field_data *field_data);
 int ima_eventname_ng_init(struct ima_event_data *event_data,
 			  struct ima_field_data *field_data);
 int ima_eventsig_init(struct ima_event_data *event_data,
 		      struct ima_field_data *field_data);
 int ima_eventbuf_init(struct ima_event_data *event_data,
 		      struct ima_field_data *field_data);
+int ima_eventmodsig_init(struct ima_event_data *event_data,
+			 struct ima_field_data *field_data);
 #endif /* __LINUX_IMA_TEMPLATE_LIB_H */

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 10/11] ima: Store the measurement again when appraising a modsig
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (8 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 09/11] ima: Define ima-modsig template Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-06-28  2:19 ` [PATCH v12 11/11] ima: Allow template= option for appraise rules as well Thiago Jung Bauermann
  2019-07-01 14:38 ` [PATCH v12 00/11] Appended signatures support for IMA appraisal Mimi Zohar
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

If the IMA template contains the "modsig" or "d-modsig" field, then the
modsig should be added to the measurement list when the file is appraised.

And that is what normally happens, but if a measurement rule caused a file
containing a modsig to be measured before a different rule causes it to be
appraised, the resulting measurement entry will not contain the modsig
because it is only fetched during appraisal. When the appraisal rule
triggers, it won't store a new measurement containing the modsig because
the file was already measured.

We need to detect that situation and store an additional measurement with
the modsig. This is done by adding an IMA_MEASURE action flag if we read a
modsig and the IMA template contains a modsig field.

Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
---
 security/integrity/ima/ima.h          |  1 +
 security/integrity/ima/ima_api.c      | 19 +++++++++++++++----
 security/integrity/ima/ima_main.c     | 15 ++++++++++++---
 security/integrity/ima/ima_template.c | 19 +++++++++++++++++++
 4 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 3293dd07b6c9..01a7a140bb4a 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -154,6 +154,7 @@ int template_desc_init_fields(const char *template_fmt,
 			      int *num_fields);
 struct ima_template_desc *ima_template_desc_current(void);
 struct ima_template_desc *lookup_template_desc(const char *name);
+bool ima_template_has_modsig(const struct ima_template_desc *ima_template);
 int ima_restore_measurement_entry(struct ima_template_entry *entry);
 int ima_restore_measurement_list(loff_t bufsize, void *buf);
 int ima_measurements_show(struct seq_file *m, void *v);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 9d1fe712a6cc..3a78373d835c 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -223,6 +223,14 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 		char digest[IMA_MAX_DIGEST_SIZE];
 	} hash;
 
+	/*
+	 * Always collect the modsig, because IMA might have already collected
+	 * the file digest without collecting the modsig in a previous
+	 * measurement rule.
+	 */
+	if (modsig)
+		ima_collect_modsig(modsig, buf, size);
+
 	if (iint->flags & IMA_COLLECTED)
 		goto out;
 
@@ -256,9 +264,6 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 	memcpy(iint->ima_hash, &hash, length);
 	iint->version = i_version;
 
-	if (modsig)
-		ima_collect_modsig(modsig, buf, size);
-
 	/* Possibly temporary failure due to type of read (eg. O_DIRECT) */
 	if (!result)
 		iint->flags |= IMA_COLLECTED;
@@ -308,7 +313,13 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 					     .modsig = modsig };
 	int violation = 0;
 
-	if (iint->measured_pcrs & (0x1 << pcr))
+	/*
+	 * We still need to store the measurement in the case of MODSIG because
+	 * we only have its contents to put in the list at the time of
+	 * appraisal, but a file measurement from earlier might already exist in
+	 * the measurement list.
+	 */
+	if (iint->measured_pcrs & (0x1 << pcr) && !modsig)
 		return;
 
 	result = ima_alloc_init_template(&event_data, &entry, template_desc);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 8b35a200e0cc..e855a4658425 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -311,9 +311,18 @@ static int process_measurement(struct file *file, const struct cred *cred,
 		/* read 'security.ima' */
 		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
 
-		/* Read the appended modsig if allowed by the policy. */
-		if (iint->flags & IMA_MODSIG_ALLOWED)
-			ima_read_modsig(func, buf, size, &modsig);
+		/*
+		 * Read the appended modsig if allowed by the policy, and allow
+		 * an additional measurement list entry, if needed, based on the
+		 * template format and whether the file was already measured.
+		 */
+		if (iint->flags & IMA_MODSIG_ALLOWED) {
+			rc = ima_read_modsig(func, buf, size, &modsig);
+
+			if (!rc && ima_template_has_modsig(template_desc) &&
+			    iint->flags & IMA_MEASURED)
+				action |= IMA_MEASURE;
+		}
 	}
 
 	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index ac526b34973f..536205735456 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -62,6 +62,25 @@ static const struct ima_template_field supported_fields[] = {
 
 static struct ima_template_desc *ima_template;
 
+/**
+ * ima_template_has_modsig - Check whether template has modsig-related fields.
+ * @ima_template: IMA template to check.
+ *
+ * Tells whether the given template has fields referencing a file's appended
+ * signature.
+ */
+bool ima_template_has_modsig(const struct ima_template_desc *ima_template)
+{
+	int i;
+
+	for (i = 0; i < ima_template->num_fields; i++)
+		if (!strcmp(ima_template->fields[i]->field_id, "modsig") ||
+		    !strcmp(ima_template->fields[i]->field_id, "d-modsig"))
+			return true;
+
+	return false;
+}
+
 static int __init ima_template_setup(char *str)
 {
 	struct ima_template_desc *template_desc;


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v12 11/11] ima: Allow template= option for appraise rules as well
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (9 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 10/11] ima: Store the measurement again when appraising a modsig Thiago Jung Bauermann
@ 2019-06-28  2:19 ` Thiago Jung Bauermann
  2019-07-01 14:38 ` [PATCH v12 00/11] Appended signatures support for IMA appraisal Mimi Zohar
  11 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-06-28  2:19 UTC (permalink / raw)
  To: linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Mimi Zohar, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI,
	Takahiro, Thiago Jung Bauermann

It's useful being able to specify a different IMA template on appraise
policy rules, so allow it.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima_policy.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 4fc13e591f1d..46ed31a0adfe 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1193,7 +1193,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			break;
 		case Opt_template:
 			ima_log_string(ab, "template", args[0].from);
-			if (entry->action != MEASURE) {
+			if (entry->action != MEASURE &&
+			    entry->action != APPRAISE) {
 				result = -EINVAL;
 				break;
 			}


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 00/11] Appended signatures support for IMA appraisal
  2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
                   ` (10 preceding siblings ...)
  2019-06-28  2:19 ` [PATCH v12 11/11] ima: Allow template= option for appraise rules as well Thiago Jung Bauermann
@ 2019-07-01 14:38 ` Mimi Zohar
  2019-07-04  6:45   ` Thiago Jung Bauermann
  11 siblings, 1 reply; 22+ messages in thread
From: Mimi Zohar @ 2019-07-01 14:38 UTC (permalink / raw)
  To: Thiago Jung Bauermann, linux-integrity
  Cc: linux-security-module, keyrings, linux-crypto, linuxppc-dev,
	linux-doc, linux-kernel, Dmitry Kasatkin, James Morris,
	Serge E. Hallyn, David Howells, David Woodhouse, Jessica Yu,
	Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI, Takahiro

On Thu, 2019-06-27 at 23:19 -0300, Thiago Jung Bauermann wrote:
> Hello,
> 
> This version is essentially identical to the last one.
> 
> It is only a rebase on top of today's linux-integrity/next-queued-testing,
> prompted by conflicts with Prakhar Srivastava's patches to measure the
> kernel command line. It also drops two patches that are already present in
> that branch.

Thanks, Thiago.  These patches are now in next-queued-testing waiting
for some additional reviews/acks.

Mimi


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-06-28  2:19 ` [PATCH v12 01/11] MODSIGN: Export module signature definitions Thiago Jung Bauermann
@ 2019-07-01 14:47   ` Jessica Yu
  2019-07-04  6:42     ` Thiago Jung Bauermann
  0 siblings, 1 reply; 22+ messages in thread
From: Jessica Yu @ 2019-07-01 14:47 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: linux-integrity, linux-security-module, keyrings, linux-crypto,
	linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI, Takahiro

+++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:
>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 <bauerman@linux.ibm.com>
>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>Cc: Jessica Yu <jeyu@kernel.org>
>---
> 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 <linux/percpu.h>
> #include <asm/module.h>
>
>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
>-#define MODULE_SIG_STRING "~Module signature appended~\n"
>-

Hi Thiago, apologies for the delay.

It looks like arch/s390/kernel/machine_kexec_file.c also relies on
MODULE_SIG_STRING being defined, so module_signature.h will need to be
included there too, otherwise we'll run into a compilation error.

Other than that, the module-related changes look good to me:

Acked-by: Jessica Yu <jeyu@kernel.org>

Thanks!

Jessica

> /* 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 <linux/export.h>
> #include <linux/extable.h>
> #include <linux/moduleloader.h>
>+#include <linux/module_signature.h>
> #include <linux/trace_events.h>
> #include <linux/init.h>
> #include <linux/kallsyms.h>
>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 <linux/errno.h>
>+#include <linux/printk.h>
>+#include <linux/module_signature.h>
>+#include <asm/byteorder.h>
>+
>+/**
>+ * 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 <linux/kernel.h>
> #include <linux/errno.h>
>+#include <linux/module.h>
>+#include <linux/module_signature.h>
> #include <linux/string.h>
> #include <linux/verification.h>
> #include <crypto/public_key.h>
> #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
>

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-01 14:47   ` Jessica Yu
@ 2019-07-04  6:42     ` Thiago Jung Bauermann
  2019-07-04 10:54       ` Philipp Rudo
  0 siblings, 1 reply; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-07-04  6:42 UTC (permalink / raw)
  To: Jessica Yu
  Cc: linux-integrity, linux-security-module, keyrings, linux-crypto,
	linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, Philipp Rudo, linux-s390


Jessica Yu <jeyu@kernel.org> writes:

> +++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:
>>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 <bauerman@linux.ibm.com>
>>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>>Cc: Jessica Yu <jeyu@kernel.org>
>>---
>> 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 <linux/percpu.h>
>> #include <asm/module.h>
>>
>>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
>>-#define MODULE_SIG_STRING "~Module signature appended~\n"
>>-
>
> Hi Thiago, apologies for the delay.

Hello Jessica, thanks for reviewing the patch!

> It looks like arch/s390/kernel/machine_kexec_file.c also relies on
> MODULE_SIG_STRING being defined, so module_signature.h will need to be
> included there too, otherwise we'll run into a compilation error.

Indeed. Thanks for spotting that. The patch below fixes it. It's
identical to the previous version except for the changes in 
arch/s390/kernel/machine_kexec_file.c and their description in the
commit message. I'm also copying some s390 people in this email.

> Other than that, the module-related changes look good to me:
>
> Acked-by: Jessica Yu <jeyu@kernel.org>

Thank you very much!

-- 
Thiago Jung Bauermann
IBM Linux Technology Center


From 0ca180c66f4cff8b1fcd51f3457cc06dac2f0e81 Mon Sep 17 00:00:00 2001
From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Date: Thu, 17 May 2018 21:46:12 -0300
Subject: [PATCH 1/1] MODSIGN: Export module signature definitions

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.

s390 duplicated the definition of struct module_signature so now they can
use the new <linux/module_signature.h> header instead.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Philipp Rudo <prudo@linux.ibm.com>
---
 arch/s390/kernel/machine_kexec_file.c | 24 +-----------
 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 +-
 9 files changed, 107 insertions(+), 76 deletions(-)
 create mode 100644 include/linux/module_signature.h
 create mode 100644 kernel/module_signature.c

diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
index fbdd3ea73667..1ac9fbc6e01e 100644
--- a/arch/s390/kernel/machine_kexec_file.c
+++ b/arch/s390/kernel/machine_kexec_file.c
@@ -10,7 +10,7 @@
 #include <linux/elf.h>
 #include <linux/errno.h>
 #include <linux/kexec.h>
-#include <linux/module.h>
+#include <linux/module_signature.h>
 #include <linux/verification.h>
 #include <asm/boot_data.h>
 #include <asm/ipl.h>
@@ -23,28 +23,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = {
 };
 
 #ifdef CONFIG_KEXEC_VERIFY_SIG
-/*
- * 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 */
-};
-
-#define PKEY_ID_PKCS7 2
-
 int s390_verify_sig(const char *kernel, unsigned long kernel_len)
 {
 	const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
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 <linux/percpu.h>
 #include <asm/module.h>
 
-/* 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 <linux/export.h>
 #include <linux/extable.h>
 #include <linux/moduleloader.h>
+#include <linux/module_signature.h>
 #include <linux/trace_events.h>
 #include <linux/init.h>
 #include <linux/kallsyms.h>
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 <linux/errno.h>
+#include <linux/printk.h>
+#include <linux/module_signature.h>
+#include <asm/byteorder.h>
+
+/**
+ * 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 <linux/kernel.h>
 #include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/module_signature.h>
 #include <linux/string.h>
 #include <linux/verification.h>
 #include <crypto/public_key.h>
 #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
 


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 00/11] Appended signatures support for IMA appraisal
  2019-07-01 14:38 ` [PATCH v12 00/11] Appended signatures support for IMA appraisal Mimi Zohar
@ 2019-07-04  6:45   ` Thiago Jung Bauermann
  0 siblings, 0 replies; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-07-04  6:45 UTC (permalink / raw)
  To: Mimi Zohar
  Cc: linux-integrity, linux-security-module, keyrings, linux-crypto,
	linuxppc-dev, linux-doc, linux-kernel, Dmitry Kasatkin,
	James Morris, Serge E. Hallyn, David Howells, David Woodhouse,
	Jessica Yu, Herbert Xu, David S. Miller, Jonathan Corbet, AKASHI\,
	Takahiro


Mimi Zohar <zohar@linux.ibm.com> writes:

> On Thu, 2019-06-27 at 23:19 -0300, Thiago Jung Bauermann wrote:
>> Hello,
>> 
>> This version is essentially identical to the last one.
>> 
>> It is only a rebase on top of today's linux-integrity/next-queued-testing,
>> prompted by conflicts with Prakhar Srivastava's patches to measure the
>> kernel command line. It also drops two patches that are already present in
>> that branch.
>
> Thanks, Thiago.  These patches are now in next-queued-testing waiting
> for some additional reviews/acks.

Thank you very much, Mimi! Now I think I'm only missing acks for the
PKCS#7 changes in patches 2 and 3, and an ack for the s390 changes in
patch 1.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-04  6:42     ` Thiago Jung Bauermann
@ 2019-07-04 10:54       ` Philipp Rudo
  2019-07-04 18:57         ` Thiago Jung Bauermann
  0 siblings, 1 reply; 22+ messages in thread
From: Philipp Rudo @ 2019-07-04 10:54 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, linux-s390

Hi Thiago,


On Thu, 04 Jul 2019 03:42:57 -0300
Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:

> Jessica Yu <jeyu@kernel.org> writes:
> 
> > +++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:  
> >>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 <bauerman@linux.ibm.com>
> >>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> >>Cc: Jessica Yu <jeyu@kernel.org>
> >>---
> >> 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 <linux/percpu.h>
> >> #include <asm/module.h>
> >>
> >>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
> >>-#define MODULE_SIG_STRING "~Module signature appended~\n"
> >>-  
> >
> > Hi Thiago, apologies for the delay.  
> 
> Hello Jessica, thanks for reviewing the patch!
> 
> > It looks like arch/s390/kernel/machine_kexec_file.c also relies on
> > MODULE_SIG_STRING being defined, so module_signature.h will need to be
> > included there too, otherwise we'll run into a compilation error.  
> 
> Indeed. Thanks for spotting that. The patch below fixes it. It's
> identical to the previous version except for the changes in 
> arch/s390/kernel/machine_kexec_file.c and their description in the
> commit message. I'm also copying some s390 people in this email.

to me the s390 part looks good but for one minor nit.

In arch/s390/Kconfig KEXEC_VERIFY_SIG currently depends on
SYSTEM_DATA_VERIFICATION. I'd prefer when you update this to the new
MODULE_SIG_FORMAT. It shouldn't make any difference right now, as we don't
use mod_check_sig in our code path. But it could cause problems in the future,
when more code might be shared.

Thanks
Philipp

> > Other than that, the module-related changes look good to me:
> >
> > Acked-by: Jessica Yu <jeyu@kernel.org>  
> 
> Thank you very much!
> 


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-04 10:54       ` Philipp Rudo
@ 2019-07-04 18:57         ` Thiago Jung Bauermann
  2019-07-05 13:00           ` Philipp Rudo
  0 siblings, 1 reply; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-07-04 18:57 UTC (permalink / raw)
  To: Philipp Rudo
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, linux-s390


Hello Philipp,

Philipp Rudo <prudo@linux.ibm.com> writes:

> Hi Thiago,
>
>
> On Thu, 04 Jul 2019 03:42:57 -0300
> Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>
>> Jessica Yu <jeyu@kernel.org> writes:
>> 
>> > +++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:  
>> >>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 <bauerman@linux.ibm.com>
>> >>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>> >>Cc: Jessica Yu <jeyu@kernel.org>
>> >>---
>> >> 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 <linux/percpu.h>
>> >> #include <asm/module.h>
>> >>
>> >>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
>> >>-#define MODULE_SIG_STRING "~Module signature appended~\n"
>> >>-  
>> >
>> > Hi Thiago, apologies for the delay.  
>> 
>> Hello Jessica, thanks for reviewing the patch!
>> 
>> > It looks like arch/s390/kernel/machine_kexec_file.c also relies on
>> > MODULE_SIG_STRING being defined, so module_signature.h will need to be
>> > included there too, otherwise we'll run into a compilation error.  
>> 
>> Indeed. Thanks for spotting that. The patch below fixes it. It's
>> identical to the previous version except for the changes in 
>> arch/s390/kernel/machine_kexec_file.c and their description in the
>> commit message. I'm also copying some s390 people in this email.
>
> to me the s390 part looks good but for one minor nit.

Thanks for the prompt review!

> In arch/s390/Kconfig KEXEC_VERIFY_SIG currently depends on
> SYSTEM_DATA_VERIFICATION. I'd prefer when you update this to the new
> MODULE_SIG_FORMAT. It shouldn't make any difference right now, as we don't
> use mod_check_sig in our code path. But it could cause problems in the future,
> when more code might be shared.

Makes sense. Here is the updated patch with the Kconfig change.

-- 
Thiago Jung Bauermann
IBM Linux Technology Center


From d0e870a6eccc7126c0416ad7369888052c15eb18 Mon Sep 17 00:00:00 2001
From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Date: Thu, 17 May 2018 21:46:12 -0300
Subject: [PATCH 1/1] MODSIGN: Export module signature definitions

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.

s390 duplicated the definition of struct module_signature so now they can
use the new <linux/module_signature.h> header instead.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Philipp Rudo <prudo@linux.ibm.com>
---
 arch/s390/Kconfig                     |  2 +-
 arch/s390/kernel/machine_kexec_file.c | 24 +-----------
 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 +-
 10 files changed, 108 insertions(+), 77 deletions(-)
 create mode 100644 include/linux/module_signature.h
 create mode 100644 kernel/module_signature.c

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 109243fdb6ec..446b7ffa1294 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -557,7 +557,7 @@ config ARCH_HAS_KEXEC_PURGATORY
 
 config KEXEC_VERIFY_SIG
 	bool "Verify kernel signature during kexec_file_load() syscall"
-	depends on KEXEC_FILE && SYSTEM_DATA_VERIFICATION
+	depends on KEXEC_FILE && MODULE_SIG_FORMAT
 	help
 	  This option makes kernel signature verification mandatory for
 	  the kexec_file_load() syscall.
diff --git a/arch/s390/kernel/machine_kexec_file.c b/arch/s390/kernel/machine_kexec_file.c
index fbdd3ea73667..1ac9fbc6e01e 100644
--- a/arch/s390/kernel/machine_kexec_file.c
+++ b/arch/s390/kernel/machine_kexec_file.c
@@ -10,7 +10,7 @@
 #include <linux/elf.h>
 #include <linux/errno.h>
 #include <linux/kexec.h>
-#include <linux/module.h>
+#include <linux/module_signature.h>
 #include <linux/verification.h>
 #include <asm/boot_data.h>
 #include <asm/ipl.h>
@@ -23,28 +23,6 @@ const struct kexec_file_ops * const kexec_file_loaders[] = {
 };
 
 #ifdef CONFIG_KEXEC_VERIFY_SIG
-/*
- * 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 */
-};
-
-#define PKEY_ID_PKCS7 2
-
 int s390_verify_sig(const char *kernel, unsigned long kernel_len)
 {
 	const unsigned long marker_len = sizeof(MODULE_SIG_STRING) - 1;
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 <linux/percpu.h>
 #include <asm/module.h>
 
-/* 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 <linux/export.h>
 #include <linux/extable.h>
 #include <linux/moduleloader.h>
+#include <linux/module_signature.h>
 #include <linux/trace_events.h>
 #include <linux/init.h>
 #include <linux/kallsyms.h>
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 <linux/errno.h>
+#include <linux/printk.h>
+#include <linux/module_signature.h>
+#include <asm/byteorder.h>
+
+/**
+ * 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 <linux/kernel.h>
 #include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/module_signature.h>
 #include <linux/string.h>
 #include <linux/verification.h>
 #include <crypto/public_key.h>
 #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
 

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-04 18:57         ` Thiago Jung Bauermann
@ 2019-07-05 13:00           ` Philipp Rudo
  2019-07-23 22:39             ` Thiago Jung Bauermann
  0 siblings, 1 reply; 22+ messages in thread
From: Philipp Rudo @ 2019-07-05 13:00 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, linux-s390

Hi Thiago,

On Thu, 04 Jul 2019 15:57:34 -0300
Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:

> Hello Philipp,
> 
> Philipp Rudo <prudo@linux.ibm.com> writes:
> 
> > Hi Thiago,
> >
> >
> > On Thu, 04 Jul 2019 03:42:57 -0300
> > Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
> >  
> >> Jessica Yu <jeyu@kernel.org> writes:
> >>   
> >> > +++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:    
> >> >>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 <bauerman@linux.ibm.com>
> >> >>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
> >> >>Cc: Jessica Yu <jeyu@kernel.org>
> >> >>---
> >> >> 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 <linux/percpu.h>
> >> >> #include <asm/module.h>
> >> >>
> >> >>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
> >> >>-#define MODULE_SIG_STRING "~Module signature appended~\n"
> >> >>-    
> >> >
> >> > Hi Thiago, apologies for the delay.    
> >> 
> >> Hello Jessica, thanks for reviewing the patch!
> >>   
> >> > It looks like arch/s390/kernel/machine_kexec_file.c also relies on
> >> > MODULE_SIG_STRING being defined, so module_signature.h will need to be
> >> > included there too, otherwise we'll run into a compilation error.    
> >> 
> >> Indeed. Thanks for spotting that. The patch below fixes it. It's
> >> identical to the previous version except for the changes in 
> >> arch/s390/kernel/machine_kexec_file.c and their description in the
> >> commit message. I'm also copying some s390 people in this email.  
> >
> > to me the s390 part looks good but for one minor nit.  
> 
> Thanks for the prompt review!
> 
> > In arch/s390/Kconfig KEXEC_VERIFY_SIG currently depends on
> > SYSTEM_DATA_VERIFICATION. I'd prefer when you update this to the new
> > MODULE_SIG_FORMAT. It shouldn't make any difference right now, as we don't
> > use mod_check_sig in our code path. But it could cause problems in the future,
> > when more code might be shared.  
> 
> Makes sense. Here is the updated patch with the Kconfig change.
> 

The patch looks good now.

Thanks a lot
PHilipp


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-05 13:00           ` Philipp Rudo
@ 2019-07-23 22:39             ` Thiago Jung Bauermann
  2019-08-05 13:11               ` Philipp Rudo
  0 siblings, 1 reply; 22+ messages in thread
From: Thiago Jung Bauermann @ 2019-07-23 22:39 UTC (permalink / raw)
  To: Philipp Rudo
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, linux-s390


Hello Philipp,


Philipp Rudo <prudo@linux.ibm.com> writes:

> Hi Thiago,
>
> On Thu, 04 Jul 2019 15:57:34 -0300
> Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>
>> Hello Philipp,
>> 
>> Philipp Rudo <prudo@linux.ibm.com> writes:
>> 
>> > Hi Thiago,
>> >
>> >
>> > On Thu, 04 Jul 2019 03:42:57 -0300
>> > Thiago Jung Bauermann <bauerman@linux.ibm.com> wrote:
>> >  
>> >> Jessica Yu <jeyu@kernel.org> writes:
>> >>   
>> >> > +++ Thiago Jung Bauermann [27/06/19 23:19 -0300]:    
>> >> >>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 <bauerman@linux.ibm.com>
>> >> >>Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
>> >> >>Cc: Jessica Yu <jeyu@kernel.org>
>> >> >>---
>> >> >> 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 <linux/percpu.h>
>> >> >> #include <asm/module.h>
>> >> >>
>> >> >>-/* In stripped ARM and x86-64 modules, ~ is surprisingly rare. */
>> >> >>-#define MODULE_SIG_STRING "~Module signature appended~\n"
>> >> >>-    
>> >> >
>> >> > Hi Thiago, apologies for the delay.    
>> >> 
>> >> Hello Jessica, thanks for reviewing the patch!
>> >>   
>> >> > It looks like arch/s390/kernel/machine_kexec_file.c also relies on
>> >> > MODULE_SIG_STRING being defined, so module_signature.h will need to be
>> >> > included there too, otherwise we'll run into a compilation error.    
>> >> 
>> >> Indeed. Thanks for spotting that. The patch below fixes it. It's
>> >> identical to the previous version except for the changes in 
>> >> arch/s390/kernel/machine_kexec_file.c and their description in the
>> >> commit message. I'm also copying some s390 people in this email.  
>> >
>> > to me the s390 part looks good but for one minor nit.  
>> 
>> Thanks for the prompt review!
>> 
>> > In arch/s390/Kconfig KEXEC_VERIFY_SIG currently depends on
>> > SYSTEM_DATA_VERIFICATION. I'd prefer when you update this to the new
>> > MODULE_SIG_FORMAT. It shouldn't make any difference right now, as we don't
>> > use mod_check_sig in our code path. But it could cause problems in the future,
>> > when more code might be shared.  
>> 
>> Makes sense. Here is the updated patch with the Kconfig change.
>> 
>
> The patch looks good now.

Thanks! Can I add your Reviewed-by?

-- 
Thiago Jung Bauermann
IBM Linux Technology Center


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-07-23 22:39             ` Thiago Jung Bauermann
@ 2019-08-05 13:11               ` Philipp Rudo
  2019-08-05 14:25                 ` Mimi Zohar
  0 siblings, 1 reply; 22+ messages in thread
From: Philipp Rudo @ 2019-08-05 13:11 UTC (permalink / raw)
  To: Thiago Jung Bauermann
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel, Mimi Zohar,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI\,
	Takahiro, Heiko Carstens, linux-s390

Hi Thiago,

> > The patch looks good now.  
> 
> Thanks! Can I add your Reviewed-by?

sorry, for the late answer, but I was on vacation the last two weeks. I hope
it's not too late now.

Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v12 01/11] MODSIGN: Export module signature definitions
  2019-08-05 13:11               ` Philipp Rudo
@ 2019-08-05 14:25                 ` Mimi Zohar
  0 siblings, 0 replies; 22+ messages in thread
From: Mimi Zohar @ 2019-08-05 14:25 UTC (permalink / raw)
  To: Philipp Rudo, Thiago Jung Bauermann
  Cc: Jessica Yu, linux-integrity, linux-security-module, keyrings,
	linux-crypto, linuxppc-dev, linux-doc, linux-kernel,
	Dmitry Kasatkin, James Morris, Serge E. Hallyn, David Howells,
	David Woodhouse, Herbert Xu, David S. Miller, Jonathan Corbet,
	AKASHI, Takahiro, Heiko Carstens, linux-s390

On Mon, 2019-08-05 at 15:11 +0200, Philipp Rudo wrote:
> Hi Thiago,
> 
> > > The patch looks good now.  
> > 
> > Thanks! Can I add your Reviewed-by?
> 
> sorry, for the late answer, but I was on vacation the last two weeks. I hope
> it's not too late now.
> 
> Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>

Thanks!  This patch set is still in the #next-queued-testing
branch.  I'm still hoping for a few more tags, before pushing it out
to the #next-integrity branch later today.

Mimi


^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, back to index

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-28  2:19 [PATCH v12 00/11] Appended signatures support for IMA appraisal Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 01/11] MODSIGN: Export module signature definitions Thiago Jung Bauermann
2019-07-01 14:47   ` Jessica Yu
2019-07-04  6:42     ` Thiago Jung Bauermann
2019-07-04 10:54       ` Philipp Rudo
2019-07-04 18:57         ` Thiago Jung Bauermann
2019-07-05 13:00           ` Philipp Rudo
2019-07-23 22:39             ` Thiago Jung Bauermann
2019-08-05 13:11               ` Philipp Rudo
2019-08-05 14:25                 ` Mimi Zohar
2019-06-28  2:19 ` [PATCH v12 02/11] PKCS#7: Refactor verify_pkcs7_signature() Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 03/11] PKCS#7: Introduce pkcs7_get_digest() Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 04/11] integrity: Select CONFIG_KEYS instead of depending on it Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 05/11] ima: Add modsig appraise_type option for module-style appended signatures Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 06/11] ima: Factor xattr_verify() out of ima_appraise_measurement() Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 07/11] ima: Implement support for module-style appended signatures Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 08/11] ima: Collect modsig Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 09/11] ima: Define ima-modsig template Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 10/11] ima: Store the measurement again when appraising a modsig Thiago Jung Bauermann
2019-06-28  2:19 ` [PATCH v12 11/11] ima: Allow template= option for appraise rules as well Thiago Jung Bauermann
2019-07-01 14:38 ` [PATCH v12 00/11] Appended signatures support for IMA appraisal Mimi Zohar
2019-07-04  6:45   ` Thiago Jung Bauermann

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