[PATCH v10 0/9] powerpc: Enabling IMA arch specific secure boot policies

[PATCH v10 0/9] powerpc: Enabling IMA arch specific secure boot policies

[Mimi Zohar]

This patchset extends the previous version[1] by adding support for
checking against a blacklist of binary hashes.

The IMA subsystem supports custom, built-in, arch-specific policies to
define the files to be measured and appraised. These policies are honored
based on priority, where arch-specific policy is the highest and custom
is the lowest.

PowerNV system uses a Linux-based bootloader to kexec the OS. The
bootloader kernel relies on IMA for signature verification of the OS
kernel before doing the kexec. This patchset adds support for powerpc
arch-specific IMA policies that are conditionally defined based on a
system's secure boot and trusted boot states. The OS secure boot and
trusted boot states are determined via device-tree properties.

The verification needs to be performed only for binaries that are not
blacklisted. The kernel currently only checks against the blacklist of
keys. However, doing so results in blacklisting all the binaries that
are signed by the same key. In order to prevent just one particular
binary from being loaded, it must be checked against a blacklist of
binary hashes. This patchset also adds support to IMA for checking
against a hash blacklist for files. signed by appended signature.

[1] http://patchwork.ozlabs.org/cover/1149262/ 

Changelog:

v10: (Mimi posting patch set on Nayna's behalf)
- Minor patch description changes
- Include comment in process_buffer_measurement()
- Additional patch: Enforcing kernel module appended signatures should
be reflected in "/sys/module/module/parameters/sig_enforce".
- Trimmed Cc list.

v9:
* Includes feedbacks from Michael
  * fix the missing of_node_put()
* Includes Mimi's feedbacks
  * fix the policy show() function to display check_blacklist
  * fix the other comment related and patch description
  * add the example of blacklist in the Patch 7/8
Note: Patch 7/8 is giving errors when checkpatch.pl is run because
of the format of showing measurement record as part of the example. I am
not very sure if that can be fixed as we need to represent the
measurements as is.

v8:
* Updates the Patch Description as per Michael's and Mimi's feedback
* Includes feedbacks from Michael for the device tree and policies
  * removes the arch-policy hack by defining three arrays.
  * fixes related to device-tree calls 
  * other code specific feedbacks
* Includes feedbacks from Mimi on the blacklist
  * generic blacklist function is modified than previous version
  * other coding fixes

v7:
* Removes patch related to dt-bindings as per input from Rob Herring. 
* fixes Patch 1/8 to use new device-tree updates as per Oliver
  feedback to device-tree documentation in skiboot mailing list.
(https://lists.ozlabs.org/pipermail/skiboot/2019-September/015329.html)
* Includes feedbacks from Mimi, Thiago
  * moves function get_powerpc_fw_sb_node() from Patch 1 to Patch 3 
  * fixes Patch 2/8 to use CONFIG_MODULE_SIG_FORCE.
  * updates Patch description in Patch 5/8
  * adds a new patch to add wrapper is_binary_blacklisted()
  * removes the patch that deprecated permit_directio

v6:
* includes feedbacks from Michael Ellerman on the patchset v5
  * removed email ids from comments
  * add the doc for the device-tree
  * renames the secboot.c to secure_boot.c and secboot.h to secure_boot.h
  * other code specific fixes
* split the patches to differentiate between secureboot and trustedboot
state of the system
* adds the patches to support the blacklisting of the binary hash.

v5:
* secureboot state is now read via device tree entry rather than OPAL
secure variables
* ima arch policies are updated to use policy based template for
measurement rules

v4:
* Fixed the build issue as reported by Satheesh Rajendran.

v3:
* OPAL APIs in Patch 1 are updated to provide generic interface based on
key/keylen. This patchset updates kernel OPAL APIs to be compatible with
generic interface.
* Patch 2 is cleaned up to use new OPAL APIs.
* Since OPAL can support different types of backend which can vary in the
variable interpretation, the Patch 2 is updated to add a check for the
backend version
* OPAL API now expects consumer to first check the supported backend version
before calling other secvar OPAL APIs. This check is now added in patch 2.
* IMA policies in Patch 3 is updated to specify appended signature and
per policy template.
* The patches now are free of any EFIisms.

v2:

* Removed Patch 1: powerpc/include: Override unneeded early ioremap
functions
* Updated Subject line and patch description of the Patch 1 of this series
* Removed dependency of OPAL_SECVAR on EFI, CPU_BIG_ENDIAN and UCS2_STRING
* Changed OPAL APIs from static to non-static. Added opal-secvar.h for the
same
* Removed EFI hooks from opal_secvar.c
* Removed opal_secvar_get_next(), opal_secvar_enqueue() and
opal_query_variable_info() function
* get_powerpc_sb_mode() in secboot.c now directly calls OPAL Runtime API
rather than via EFI hooks.
* Fixed log messages in get_powerpc_sb_mode() function.
* Added dependency for PPC_SECURE_BOOT on configs PPC64 and OPAL_SECVAR
* Replaced obj-$(CONFIG_IMA) with obj-$(CONFIG_PPC_SECURE_BOOT) in
arch/powerpc/kernel/Makefile

Mimi Zohar (1):
  powerpc/ima: indicate kernel modules appended signatures are enforced

Nayna Jain (8):
  powerpc: detect the secure boot mode of the system
  powerpc/ima: add support to initialize ima policy rules
  powerpc: detect the trusted boot state of the system
  powerpc/ima: define trusted boot policy
  ima: make process_buffer_measurement() generic
  certs: add wrapper function to check blacklisted binary hash
  ima: check against blacklisted hashes for files with modsig
  powerpc/ima: update ima arch policy to check for blacklist

 Documentation/ABI/testing/ima_policy   |  4 ++
 arch/powerpc/Kconfig                   | 11 +++++
 arch/powerpc/include/asm/secure_boot.h | 29 +++++++++++++
 arch/powerpc/kernel/Makefile           |  2 +
 arch/powerpc/kernel/ima_arch.c         | 78 ++++++++++++++++++++++++++++++++++
 arch/powerpc/kernel/secure_boot.c      | 58 +++++++++++++++++++++++++
 certs/blacklist.c                      |  9 ++++
 include/keys/system_keyring.h          |  6 +++
 include/linux/ima.h                    |  3 +-
 security/integrity/ima/ima.h           | 11 +++++
 security/integrity/ima/ima_appraise.c  | 33 ++++++++++++++
 security/integrity/ima/ima_main.c      | 70 ++++++++++++++++++++----------
 security/integrity/ima/ima_policy.c    | 12 +++++-
 security/integrity/integrity.h         |  1 +
 14 files changed, 302 insertions(+), 25 deletions(-)
 create mode 100644 arch/powerpc/include/asm/secure_boot.h
 create mode 100644 arch/powerpc/kernel/ima_arch.c
 create mode 100644 arch/powerpc/kernel/secure_boot.c

-- 
2.7.5

[PATCH v10 1/9] powerpc: detect the secure boot mode of the system

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

This patch defines a function to detect the secure boot state of a
PowerNV system.

The PPC_SECURE_BOOT config represents the base enablement of secure boot
for powerpc.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 arch/powerpc/Kconfig                   | 10 ++++++++++
 arch/powerpc/include/asm/secure_boot.h | 23 +++++++++++++++++++++++
 arch/powerpc/kernel/Makefile           |  2 ++
 arch/powerpc/kernel/secure_boot.c      | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 67 insertions(+)
 create mode 100644 arch/powerpc/include/asm/secure_boot.h
 create mode 100644 arch/powerpc/kernel/secure_boot.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3e56c9c2f16e..56ea0019b616 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -934,6 +934,16 @@ config PPC_MEM_KEYS
 
 	  If unsure, say y.
 
+config PPC_SECURE_BOOT
+	prompt "Enable secure boot support"
+	bool
+	depends on PPC_POWERNV
+	help
+	  Systems with firmware secure boot enabled need to define security
+	  policies to extend secure boot to the OS. This config allows a user
+	  to enable OS secure boot on systems that have firmware support for
+	  it. If in doubt say N.
+
 endmenu
 
 config ISA_DMA_API
diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
new file mode 100644
index 000000000000..07d0fe0ca81f
--- /dev/null
+++ b/arch/powerpc/include/asm/secure_boot.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Secure boot definitions
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#ifndef _ASM_POWER_SECURE_BOOT_H
+#define _ASM_POWER_SECURE_BOOT_H
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+bool is_ppc_secureboot_enabled(void);
+
+#else
+
+static inline bool is_ppc_secureboot_enabled(void)
+{
+	return false;
+}
+
+#endif
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index a7ca8fe62368..e2a54fa240ac 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,6 +161,8 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
 obj-y				+= ucall.o
 endif
 
+obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o
+
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
 KCOV_INSTRUMENT_prom_init.o := n
diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
new file mode 100644
index 000000000000..63dc82c50862
--- /dev/null
+++ b/arch/powerpc/kernel/secure_boot.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#include <linux/types.h>
+#include <linux/of.h>
+#include <asm/secure_boot.h>
+
+bool is_ppc_secureboot_enabled(void)
+{
+	struct device_node *node;
+	bool enabled = false;
+
+	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-v1");
+	if (!of_device_is_available(node)) {
+		pr_err("Cannot find secure variable node in device tree; failing to secure state\n");
+		goto out;
+	}
+
+	/*
+	 * secureboot is enabled if os-secure-enforcing property exists,
+	 * else disabled.
+	 */
+	enabled = of_property_read_bool(node, "os-secure-enforcing");
+
+out:
+	of_node_put(node);
+
+	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
+	return enabled;
+}
-- 
2.7.5

[PATCH v10 2/9] powerpc/ima: add support to initialize ima policy rules

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

PowerNV systems use a Linux-based bootloader, which rely on the IMA
subsystem to enforce different secure boot modes.  Since the verification
policy may differ based on the secure boot mode of the system, the
policies must be defined at runtime.

This patch implements arch-specific support to define IMA policy
rules based on the runtime secure boot mode of the system.

This patch provides arch-specific IMA policies if PPC_SECURE_BOOT
config is enabled.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 arch/powerpc/Kconfig           |  1 +
 arch/powerpc/kernel/Makefile   |  2 +-
 arch/powerpc/kernel/ima_arch.c | 43 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/ima.h            |  3 ++-
 4 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/kernel/ima_arch.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 56ea0019b616..c795039bdc73 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -938,6 +938,7 @@ config PPC_SECURE_BOOT
 	prompt "Enable secure boot support"
 	bool
 	depends on PPC_POWERNV
+	depends on IMA_ARCH_POLICY
 	help
 	  Systems with firmware secure boot enabled need to define security
 	  policies to extend secure boot to the OS. This config allows a user
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index e2a54fa240ac..e8eb2955b7d5 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,7 +161,7 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
 obj-y				+= ucall.o
 endif
 
-obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o
+obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o ima_arch.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
new file mode 100644
index 000000000000..d88913dc0da7
--- /dev/null
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -0,0 +1,43 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+
+#include <linux/ima.h>
+#include <asm/secure_boot.h>
+
+bool arch_ima_get_secureboot(void)
+{
+	return is_ppc_secureboot_enabled();
+}
+
+/*
+ * The "secure_rules" are enabled only on "secureboot" enabled systems.
+ * These rules verify the file signatures against known good values.
+ * The "appraise_type=imasig|modsig" option allows the known good signature
+ * to be stored as an xattr or as an appended signature.
+ *
+ * To avoid duplicate signature verification as much as possible, the IMA
+ * policy rule for module appraisal is added only if CONFIG_MODULE_SIG_FORCE
+ * is not enabled.
+ */
+static const char *const secure_rules[] = {
+	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig",
+#ifndef CONFIG_MODULE_SIG_FORCE
+	"appraise func=MODULE_CHECK appraise_type=imasig|modsig",
+#endif
+	NULL
+};
+
+/*
+ * Returns the relevant IMA arch-specific policies based on the system secure
+ * boot state.
+ */
+const char *const *arch_get_ima_policy(void)
+{
+	if (is_ppc_secureboot_enabled())
+		return secure_rules;
+
+	return NULL;
+}
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 1c37f17f7203..6d904754d858 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -29,7 +29,8 @@ extern void ima_kexec_cmdline(const void *buf, int size);
 extern void ima_add_kexec_buffer(struct kimage *image);
 #endif
 
-#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390)
+#if (defined(CONFIG_X86) && defined(CONFIG_EFI)) || defined(CONFIG_S390) \
+	|| defined(CONFIG_PPC_SECURE_BOOT)
 extern bool arch_ima_get_secureboot(void);
 extern const char * const *arch_get_ima_policy(void);
 #else
-- 
2.7.5

[PATCH v10 3/9] powerpc: detect the trusted boot state of the system

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

While secure boot permits only properly verified signed kernels to be
booted, trusted boot calculates the file hash of the kernel image and
stores the measurement prior to boot, that can be subsequently compared
against good known values via attestation services.

This patch reads the trusted boot state of a PowerNV system. The state
is used to conditionally enable additional measurement rules in the IMA
arch-specific policies.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 arch/powerpc/include/asm/secure_boot.h |  6 ++++++
 arch/powerpc/kernel/secure_boot.c      | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
index 07d0fe0ca81f..a2ff556916c6 100644
--- a/arch/powerpc/include/asm/secure_boot.h
+++ b/arch/powerpc/include/asm/secure_boot.h
@@ -11,6 +11,7 @@
 #ifdef CONFIG_PPC_SECURE_BOOT
 
 bool is_ppc_secureboot_enabled(void);
+bool is_ppc_trustedboot_enabled(void);
 
 #else
 
@@ -19,5 +20,10 @@ static inline bool is_ppc_secureboot_enabled(void)
 	return false;
 }
 
+static inline bool is_ppc_trustedboot_enabled(void)
+{
+	return false;
+}
+
 #endif
 #endif
diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
index 63dc82c50862..a6a5f17ede03 100644
--- a/arch/powerpc/kernel/secure_boot.c
+++ b/arch/powerpc/kernel/secure_boot.c
@@ -7,6 +7,17 @@
 #include <linux/of.h>
 #include <asm/secure_boot.h>
 
+static struct device_node *get_ppc_fw_sb_node(void)
+{
+	static const struct of_device_id ids[] = {
+		{ .compatible = "ibm,secureboot-v1", },
+		{ .compatible = "ibm,secureboot-v2", },
+		{},
+	};
+
+	return of_find_matching_node(NULL, ids);
+}
+
 bool is_ppc_secureboot_enabled(void)
 {
 	struct device_node *node;
@@ -30,3 +41,18 @@ bool is_ppc_secureboot_enabled(void)
 	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
 	return enabled;
 }
+
+bool is_ppc_trustedboot_enabled(void)
+{
+	struct device_node *node;
+	bool enabled = false;
+
+	node = get_ppc_fw_sb_node();
+	enabled = of_property_read_bool(node, "trusted-enabled");
+
+	of_node_put(node);
+
+	pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled");
+
+	return enabled;
+}
-- 
2.7.5

[PATCH v10 4/9] powerpc/ima: define trusted boot policy

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

This patch defines an arch-specific trusted boot only policy and a
combined secure and trusted boot policy.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 arch/powerpc/kernel/ima_arch.c | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
index d88913dc0da7..0ef5956c9753 100644
--- a/arch/powerpc/kernel/ima_arch.c
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -31,13 +31,44 @@ static const char *const secure_rules[] = {
 };
 
 /*
+ * The "trusted_rules" are enabled only on "trustedboot" enabled systems.
+ * These rules add the kexec kernel image and kernel modules file hashes to
+ * the IMA measurement list.
+ */
+static const char *const trusted_rules[] = {
+	"measure func=KEXEC_KERNEL_CHECK",
+	"measure func=MODULE_CHECK",
+	NULL
+};
+
+/*
+ * The "secure_and_trusted_rules" contains rules for both the secure boot and
+ * trusted boot. The "template=ima-modsig" option includes the appended
+ * signature, when available, in the IMA measurement list.
+ */
+static const char *const secure_and_trusted_rules[] = {
+	"measure func=KEXEC_KERNEL_CHECK template=ima-modsig",
+	"measure func=MODULE_CHECK template=ima-modsig",
+	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig",
+#ifndef CONFIG_MODULE_SIG_FORCE
+	"appraise func=MODULE_CHECK appraise_type=imasig|modsig",
+#endif
+	NULL
+};
+
+/*
  * Returns the relevant IMA arch-specific policies based on the system secure
  * boot state.
  */
 const char *const *arch_get_ima_policy(void)
 {
 	if (is_ppc_secureboot_enabled())
-		return secure_rules;
+		if (is_ppc_trustedboot_enabled())
+			return secure_and_trusted_rules;
+		else
+			return secure_rules;
+	else if (is_ppc_trustedboot_enabled())
+		return trusted_rules;
 
 	return NULL;
 }
-- 
2.7.5

[PATCH v10 5/9] ima: make process_buffer_measurement() generic

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

process_buffer_measurement() is limited to measuring the kexec boot
command line. This patch makes process_buffer_measurement() more
generic, allowing it to measure other types of buffer data (e.g.
blacklisted binary hashes or key hashes).

process_buffer_measurement() may be called directly from an IMA
hook or as an auxiliary measurement record. In both cases the buffer
measurement is based on policy. This patch modifies the function to
conditionally retrieve the policy defined PCR and template for the IMA
hook case.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
[zohar@linux.ibm.com: added comment in process_buffer_measurement()]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/ima/ima.h      |  3 ++
 security/integrity/ima/ima_main.c | 58 +++++++++++++++++++++++++++------------
 2 files changed, 43 insertions(+), 18 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 3689081aaf38..a65772ffa427 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -217,6 +217,9 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   struct evm_ima_xattr_data *xattr_value,
 			   int xattr_len, const struct modsig *modsig, int pcr,
 			   struct ima_template_desc *template_desc);
+void process_buffer_measurement(const void *buf, int size,
+				const char *eventname, enum ima_hooks func,
+				int pcr);
 void ima_audit_measurement(struct integrity_iint_cache *iint,
 			   const unsigned char *filename);
 int ima_alloc_init_template(struct ima_event_data *event_data,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 60027c643ecd..a26e3ad4e886 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -626,14 +626,14 @@ int ima_load_data(enum kernel_load_data_id id)
  * @buf: pointer to the buffer that needs to be added to the log.
  * @size: size of buffer(in bytes).
  * @eventname: event name to be used for the buffer entry.
- * @cred: a pointer to a credentials structure for user validation.
- * @secid: the secid of the task to be validated.
+ * @func: IMA hook
+ * @pcr: pcr to extend the measurement
  *
  * Based on policy, the buffer is measured into the ima log.
  */
-static void process_buffer_measurement(const void *buf, int size,
-				       const char *eventname,
-				       const struct cred *cred, u32 secid)
+void process_buffer_measurement(const void *buf, int size,
+				const char *eventname, enum ima_hooks func,
+				int pcr)
 {
 	int ret = 0;
 	struct ima_template_entry *entry = NULL;
@@ -642,19 +642,45 @@ static void process_buffer_measurement(const void *buf, int size,
 					    .filename = eventname,
 					    .buf = buf,
 					    .buf_len = size};
-	struct ima_template_desc *template_desc = NULL;
+	struct ima_template_desc *template = NULL;
 	struct {
 		struct ima_digest_data hdr;
 		char digest[IMA_MAX_DIGEST_SIZE];
 	} hash = {};
 	int violation = 0;
-	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 	int action = 0;
+	u32 secid;
 
-	action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
-				&template_desc);
-	if (!(action & IMA_MEASURE))
-		return;
+	/*
+	 * Both LSM hooks and auxilary based buffer measurements are
+	 * based on policy.  To avoid code duplication, differentiate
+	 * between the LSM hooks and auxilary buffer measurements,
+	 * retrieving the policy rule information only for the LSM hook
+	 * buffer measurements.
+	 */
+	if (func) {
+		security_task_getsecid(current, &secid);
+		action = ima_get_action(NULL, current_cred(), secid, 0, func,
+					&pcr, &template);
+		if (!(action & IMA_MEASURE))
+			return;
+	}
+
+	if (!pcr)
+		pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+
+	if (!template) {
+		template = lookup_template_desc("ima-buf");
+		ret = template_desc_init_fields(template->fmt,
+						&(template->fields),
+						&(template->num_fields));
+		if (ret < 0) {
+			pr_err("template %s init failed, result: %d\n",
+			       (strlen(template->name) ?
+				template->name : template->fmt), ret);
+			return;
+		}
+	}
 
 	iint.ima_hash = &hash.hdr;
 	iint.ima_hash->algo = ima_hash_algo;
@@ -664,7 +690,7 @@ static void process_buffer_measurement(const void *buf, int size,
 	if (ret < 0)
 		goto out;
 
-	ret = ima_alloc_init_template(&event_data, &entry, template_desc);
+	ret = ima_alloc_init_template(&event_data, &entry, template);
 	if (ret < 0)
 		goto out;
 
@@ -686,13 +712,9 @@ static void process_buffer_measurement(const void *buf, int size,
  */
 void ima_kexec_cmdline(const void *buf, int size)
 {
-	u32 secid;
-
-	if (buf && size != 0) {
-		security_task_getsecid(current, &secid);
+	if (buf && size != 0)
 		process_buffer_measurement(buf, size, "kexec-cmdline",
-					   current_cred(), secid);
-	}
+					   KEXEC_CMDLINE, 0);
 }
 
 static int __init init_ima(void)
-- 
2.7.5

[PATCH v10 6/9] certs: add wrapper function to check blacklisted binary hash

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

The -EKEYREJECTED error returned by existing is_hash_blacklisted() is
misleading when called for checking against blacklisted hash of a
binary.

This patch adds a wrapper function is_binary_blacklisted() to return
-EPERM error if binary is blacklisted.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 certs/blacklist.c             | 9 +++++++++
 include/keys/system_keyring.h | 6 ++++++
 2 files changed, 15 insertions(+)

diff --git a/certs/blacklist.c b/certs/blacklist.c
index ec00bf337eb6..6514f9ebc943 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -135,6 +135,15 @@ int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type)
 }
 EXPORT_SYMBOL_GPL(is_hash_blacklisted);
 
+int is_binary_blacklisted(const u8 *hash, size_t hash_len)
+{
+	if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED)
+		return -EPERM;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(is_binary_blacklisted);
+
 /*
  * Initialise the blacklist
  */
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index c1a96fdf598b..fb8b07daa9d1 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -35,12 +35,18 @@ extern int restrict_link_by_builtin_and_secondary_trusted(
 extern int mark_hash_blacklisted(const char *hash);
 extern int is_hash_blacklisted(const u8 *hash, size_t hash_len,
 			       const char *type);
+extern int is_binary_blacklisted(const u8 *hash, size_t hash_len);
 #else
 static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len,
 				      const char *type)
 {
 	return 0;
 }
+
+static inline int is_binary_blacklisted(const u8 *hash, size_t hash_len)
+{
+	return 0;
+}
 #endif
 
 #ifdef CONFIG_IMA_BLACKLIST_KEYRING
-- 
2.7.5

[PATCH v10 7/9] ima: check against blacklisted hashes for files with modsig

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

Asymmetric private keys are used to sign multiple files.  The kernel
currently supports checking against blacklisted keys.  However, if the
public key is blacklisted, any file signed by the blacklisted key will
automatically fail signature verification.  Blacklisting the public
key is not fine enough granularity, as we might want to only blacklist
a particular file.

This patch adds support for checking against the blacklisted hash of
the file, without the appended signature, based on the IMA policy.  It
defines a new policy option "appraise_flag=check_blacklist".

In addition to the blacklisted binary hashes stored in the firmware "dbx"
variable, the Linux kernel may be configured to load blacklisted binary
hashes onto the .blacklist keyring as well.  The following example shows
how to blacklist a specific kernel module hash.

$ sha256sum kernel/kheaders.ko
77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
kernel/kheaders.ko

$ grep BLACKLIST .config
CONFIG_SYSTEM_BLACKLIST_KEYRING=y
CONFIG_SYSTEM_BLACKLIST_HASH_LIST="blacklist-hash-list"

$ cat certs/blacklist-hash-list
"bin:77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3"

Update the IMA custom measurement and appraisal policy rules
(/etc/ima-policy):

measure func=MODULE_CHECK template=ima-modsig
appraise func=MODULE_CHECK appraise_flag=check_blacklist
appraise_type=imasig|modsig

After building, installing, and rebooting the kernel:

 545660333 ---lswrv      0     0   \_ blacklist:
bin:77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3

measure func=MODULE_CHECK template=ima-modsig
appraise func=MODULE_CHECK appraise_flag=check_blacklist
appraise_type=imasig|modsig

modprobe: ERROR: could not insert 'kheaders': Permission denied

10 0c9834db5a0182c1fb0cdc5d3adcf11a11fd83dd ima-sig
sha256:3bc6ed4f0b4d6e31bc1dbc9ef844605abc7afdc6d81a57d77a1ec9407997c40
2 /usr/lib/modules/5.4.0-rc3+/kernel/kernel/kheaders.ko

10 82aad2bcc3fa8ed94762356b5c14838f3bcfa6a0 ima-modsig
sha256:3bc6ed4f0b4d6e31bc1dbc9ef844605abc7afdc6d81a57d77a1ec9407997c40
2 /usr/lib/modules/5.4.0rc3+/kernel/kernel/kheaders.ko  sha256:77fa889b3
5a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
3082029a06092a864886f70d010702a082028b30820287020101310d300b0609608648
016503040201300b06092a864886f70d01070131820264....

10 25b72217cc1152b44b134ce2cd68f12dfb71acb3 ima-buf
sha256:8b58427fedcf8f4b20bc8dc007f2e232bf7285d7b93a66476321f9c2a3aa132
b blacklisted-hash
77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: David Howells <dhowells@redhat.com>
[zohar@linux.ibm.com: updated patch description]
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 Documentation/ABI/testing/ima_policy  |  4 ++++
 security/integrity/ima/ima.h          |  8 ++++++++
 security/integrity/ima/ima_appraise.c | 33 +++++++++++++++++++++++++++++++++
 security/integrity/ima/ima_main.c     | 12 ++++++++----
 security/integrity/ima/ima_policy.c   | 12 ++++++++++--
 security/integrity/integrity.h        |  1 +
 6 files changed, 64 insertions(+), 6 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 29ebe9afdac4..29aaedf33246 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -25,6 +25,7 @@ Description:
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]
 				 [obj_user=] [obj_role=] [obj_type=]]
 			option:	[[appraise_type=]] [template=] [permit_directio]
+				[appraise_flag=]
 		base: 	func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
 				[FIRMWARE_CHECK]
 				[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
@@ -38,6 +39,9 @@ Description:
 			fowner:= decimal value
 		lsm:  	are LSM specific
 		option:	appraise_type:= [imasig] [imasig|modsig]
+			appraise_flag:= [check_blacklist]
+			Currently, blacklist check is only for files signed with appended
+			signature.
 			template:= name of a defined IMA template type
 			(eg, ima-ng). Only valid when action is "measure".
 			pcr:= decimal value
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index a65772ffa427..df4ca482fb53 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -256,6 +256,8 @@ int ima_policy_show(struct seq_file *m, void *v);
 #define IMA_APPRAISE_KEXEC	0x40
 
 #ifdef CONFIG_IMA_APPRAISE
+int ima_check_blacklist(struct integrity_iint_cache *iint,
+			const struct modsig *modsig, int pcr);
 int ima_appraise_measurement(enum ima_hooks func,
 			     struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename,
@@ -271,6 +273,12 @@ int ima_read_xattr(struct dentry *dentry,
 		   struct evm_ima_xattr_data **xattr_value);
 
 #else
+static inline int ima_check_blacklist(struct integrity_iint_cache *iint,
+				      const struct modsig *modsig, int pcr)
+{
+	return 0;
+}
+
 static inline int ima_appraise_measurement(enum ima_hooks func,
 					   struct integrity_iint_cache *iint,
 					   struct file *file,
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 136ae4e0ee92..300c8d2943c5 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -12,6 +12,7 @@
 #include <linux/magic.h>
 #include <linux/ima.h>
 #include <linux/evm.h>
+#include <keys/system_keyring.h>
 
 #include "ima.h"
 
@@ -304,6 +305,38 @@ static int modsig_verify(enum ima_hooks func, const struct modsig *modsig,
 }
 
 /*
+ * ima_check_blacklist - determine if the binary is blacklisted.
+ *
+ * Add the hash of the blacklisted binary to the measurement list, based
+ * on policy.
+ *
+ * Returns -EPERM if the hash is blacklisted.
+ */
+int ima_check_blacklist(struct integrity_iint_cache *iint,
+			const struct modsig *modsig, int pcr)
+{
+	enum hash_algo hash_algo;
+	const u8 *digest = NULL;
+	u32 digestsize = 0;
+	int rc = 0;
+
+	if (!(iint->flags & IMA_CHECK_BLACKLIST))
+		return 0;
+
+	if (iint->flags & IMA_MODSIG_ALLOWED && modsig) {
+		ima_get_modsig_digest(modsig, &hash_algo, &digest, &digestsize);
+
+		rc = is_binary_blacklisted(digest, digestsize);
+		if ((rc == -EPERM) && (iint->flags & IMA_MEASURE))
+			process_buffer_measurement(digest, digestsize,
+						   "blacklisted-hash", NONE,
+						   pcr);
+	}
+
+	return rc;
+}
+
+/*
  * ima_appraise_measurement - appraise file measurement
  *
  * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index a26e3ad4e886..d7e987baf127 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -335,10 +335,14 @@ static int process_measurement(struct file *file, const struct cred *cred,
 				      xattr_value, xattr_len, modsig, pcr,
 				      template_desc);
 	if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
-		inode_lock(inode);
-		rc = ima_appraise_measurement(func, iint, file, pathname,
-					      xattr_value, xattr_len, modsig);
-		inode_unlock(inode);
+		rc = ima_check_blacklist(iint, modsig, pcr);
+		if (rc != -EPERM) {
+			inode_lock(inode);
+			rc = ima_appraise_measurement(func, iint, file,
+						      pathname, xattr_value,
+						      xattr_len, modsig);
+			inode_unlock(inode);
+		}
 		if (!rc)
 			rc = mmap_violation_check(func, file, &pathbuf,
 						  &pathname, filename);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5380aca2b351..f19a895ad7cd 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -765,8 +765,8 @@ enum {
 	Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
 	Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
 	Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
-	Opt_appraise_type, Opt_permit_directio,
-	Opt_pcr, Opt_template, Opt_err
+	Opt_appraise_type, Opt_appraise_flag,
+	Opt_permit_directio, Opt_pcr, Opt_template, Opt_err
 };
 
 static const match_table_t policy_tokens = {
@@ -798,6 +798,7 @@ static const match_table_t policy_tokens = {
 	{Opt_euid_lt, "euid<%s"},
 	{Opt_fowner_lt, "fowner<%s"},
 	{Opt_appraise_type, "appraise_type=%s"},
+	{Opt_appraise_flag, "appraise_flag=%s"},
 	{Opt_permit_directio, "permit_directio"},
 	{Opt_pcr, "pcr=%s"},
 	{Opt_template, "template=%s"},
@@ -1172,6 +1173,11 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 			else
 				result = -EINVAL;
 			break;
+		case Opt_appraise_flag:
+			ima_log_string(ab, "appraise_flag", args[0].from);
+			if (strstr(args[0].from, "blacklist"))
+				entry->flags |= IMA_CHECK_BLACKLIST;
+			break;
 		case Opt_permit_directio:
 			entry->flags |= IMA_PERMIT_DIRECTIO;
 			break;
@@ -1500,6 +1506,8 @@ int ima_policy_show(struct seq_file *m, void *v)
 		else
 			seq_puts(m, "appraise_type=imasig ");
 	}
+	if (entry->flags & IMA_CHECK_BLACKLIST)
+		seq_puts(m, "appraise_flag=check_blacklist ");
 	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 d9323d31a3a8..73fc286834d7 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -32,6 +32,7 @@
 #define EVM_IMMUTABLE_DIGSIG	0x08000000
 #define IMA_FAIL_UNVERIFIABLE_SIGS	0x10000000
 #define IMA_MODSIG_ALLOWED	0x20000000
+#define IMA_CHECK_BLACKLIST	0x40000000
 
 #define IMA_DO_MASK		(IMA_MEASURE | IMA_APPRAISE | IMA_AUDIT | \
 				 IMA_HASH | IMA_APPRAISE_SUBMASK)
-- 
2.7.5

[PATCH v10 8/9] powerpc/ima: update ima arch policy to check for blacklist

[Mimi Zohar]

From: Nayna Jain <nayna@linux.ibm.com>

This patch updates the arch-specific policies for PowerNV system to make
sure that the binary hash is not blacklisted.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
---
 arch/powerpc/kernel/ima_arch.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
index 0ef5956c9753..b9de0fb45bb9 100644
--- a/arch/powerpc/kernel/ima_arch.c
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -23,9 +23,9 @@ bool arch_ima_get_secureboot(void)
  * is not enabled.
  */
 static const char *const secure_rules[] = {
-	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig",
+	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
 #ifndef CONFIG_MODULE_SIG_FORCE
-	"appraise func=MODULE_CHECK appraise_type=imasig|modsig",
+	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
 #endif
 	NULL
 };
@@ -49,9 +49,9 @@ static const char *const trusted_rules[] = {
 static const char *const secure_and_trusted_rules[] = {
 	"measure func=KEXEC_KERNEL_CHECK template=ima-modsig",
 	"measure func=MODULE_CHECK template=ima-modsig",
-	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig",
+	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
 #ifndef CONFIG_MODULE_SIG_FORCE
-	"appraise func=MODULE_CHECK appraise_type=imasig|modsig",
+	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
 #endif
 	NULL
 };
-- 
2.7.5

[RFC PATCH v10 9/9] powerpc/ima: indicate kernel modules appended signatures are enforced

[Mimi Zohar]

The arch specific kernel module policy rule requires kernel modules to
be signed, either as an IMA signature, stored as an xattr, or as an
appended signature.  As a result, kernel modules appended signatures
could be enforced without "sig_enforce" being set or reflected in
/sys/module/module/parameters/sig_enforce.  This patch sets
"sig_enforce".

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Jessica Yu <jeyu@kernel.org>
---
 arch/powerpc/kernel/ima_arch.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
index b9de0fb45bb9..e34116255ced 100644
--- a/arch/powerpc/kernel/ima_arch.c
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -62,13 +62,17 @@ static const char *const secure_and_trusted_rules[] = {
  */
 const char *const *arch_get_ima_policy(void)
 {
-	if (is_ppc_secureboot_enabled())
+	if (is_ppc_secureboot_enabled()) {
+		if (IS_ENABLED(CONFIG_MODULE_SIG))
+			set_module_sig_enforced();
+
 		if (is_ppc_trustedboot_enabled())
 			return secure_and_trusted_rules;
 		else
 			return secure_rules;
-	else if (is_ppc_trustedboot_enabled())
+	} else if (is_ppc_trustedboot_enabled()) {
 		return trusted_rules;
+	}
 
 	return NULL;
 }
-- 
2.7.5

Re: [PATCH v10 5/9] ima: make process_buffer_measurement() generic

[Lakshmi Ramasubramanian]

On 10/30/19 8:31 PM, Mimi Zohar wrote:

>   void ima_kexec_cmdline(const void *buf, int size)
>   {
> -	u32 secid;
> -
> -	if (buf && size != 0) {
> -		security_task_getsecid(current, &secid);
> +	if (buf && size != 0)

Open brace { is missing in the above if statement.

>   		process_buffer_measurement(buf, size, "kexec-cmdline",
> -					   current_cred(), secid);
> -	}
> +					   KEXEC_CMDLINE, 0);
>   }

  -lakshmi

Re: [PATCH v10 5/9] ima: make process_buffer_measurement() generic

[Lakshmi Ramasubramanian]

On 10/31/19 10:02 AM, Lakshmi Ramasubramanian wrote:

> On 10/30/19 8:31 PM, Mimi Zohar wrote:
> 
>>   void ima_kexec_cmdline(const void *buf, int size)
>>   {
>> -    u32 secid;
>> -
>> -    if (buf && size != 0) {
>> -        security_task_getsecid(current, &secid);
>> +    if (buf && size != 0)
> 
> Open brace { is missing in the above if statement.

My mistake -
I now see that the braces {} have been removed in the if statement since 
there is only line body  the call to process_buffer_measurement()

  -lakshmi

> 
>>           process_buffer_measurement(buf, size, "kexec-cmdline",
>> -                       current_cred(), secid);
>> -    }
>> +                       KEXEC_CMDLINE, 0);
>>   }
> 
>   -lakshmi

Re: [PATCH v10 1/9] powerpc: detect the secure boot mode of the system

[Eric Richter]

On 10/30/19 10:31 PM, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> This patch defines a function to detect the secure boot state of a
> PowerNV system.
> 
> The PPC_SECURE_BOOT config represents the base enablement of secure boot
> for powerpc.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> ---
>  arch/powerpc/Kconfig                   | 10 ++++++++++
>  arch/powerpc/include/asm/secure_boot.h | 23 +++++++++++++++++++++++
>  arch/powerpc/kernel/Makefile           |  2 ++
>  arch/powerpc/kernel/secure_boot.c      | 32 ++++++++++++++++++++++++++++++++
>  4 files changed, 67 insertions(+)
>  create mode 100644 arch/powerpc/include/asm/secure_boot.h
>  create mode 100644 arch/powerpc/kernel/secure_boot.c
> 
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 3e56c9c2f16e..56ea0019b616 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -934,6 +934,16 @@ config PPC_MEM_KEYS
>  
>  	  If unsure, say y.
>  
> +config PPC_SECURE_BOOT
> +	prompt "Enable secure boot support"
> +	bool
> +	depends on PPC_POWERNV
> +	help
> +	  Systems with firmware secure boot enabled need to define security
> +	  policies to extend secure boot to the OS. This config allows a user
> +	  to enable OS secure boot on systems that have firmware support for
> +	  it. If in doubt say N.
> +
>  endmenu
>  
>  config ISA_DMA_API
> diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
> new file mode 100644
> index 000000000000..07d0fe0ca81f
> --- /dev/null
> +++ b/arch/powerpc/include/asm/secure_boot.h
> @@ -0,0 +1,23 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Secure boot definitions
> + *
> + * Copyright (C) 2019 IBM Corporation
> + * Author: Nayna Jain
> + */
> +#ifndef _ASM_POWER_SECURE_BOOT_H
> +#define _ASM_POWER_SECURE_BOOT_H
> +
> +#ifdef CONFIG_PPC_SECURE_BOOT
> +
> +bool is_ppc_secureboot_enabled(void);
> +
> +#else
> +
> +static inline bool is_ppc_secureboot_enabled(void)
> +{
> +	return false;
> +}
> +
> +#endif
> +#endif
> diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
> index a7ca8fe62368..e2a54fa240ac 100644
> --- a/arch/powerpc/kernel/Makefile
> +++ b/arch/powerpc/kernel/Makefile
> @@ -161,6 +161,8 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
>  obj-y				+= ucall.o
>  endif
>  
> +obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o
> +
>  # Disable GCOV, KCOV & sanitizers in odd or sensitive code
>  GCOV_PROFILE_prom_init.o := n
>  KCOV_INSTRUMENT_prom_init.o := n
> diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
> new file mode 100644
> index 000000000000..63dc82c50862
> --- /dev/null
> +++ b/arch/powerpc/kernel/secure_boot.c
> @@ -0,0 +1,32 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019 IBM Corporation
> + * Author: Nayna Jain
> + */
> +#include <linux/types.h>
> +#include <linux/of.h>
> +#include <asm/secure_boot.h>
> +
> +bool is_ppc_secureboot_enabled(void)
> +{
> +	struct device_node *node;
> +	bool enabled = false;
> +
> +	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-v1");

Per skiboot changes, should instead look for "ibm,secureboot".

Updated set can be found here:
https://patchwork.ozlabs.org/project/skiboot/list/?series=140626

> +	if (!of_device_is_available(node)) {
> +		pr_err("Cannot find secure variable node in device tree; failing to secure state\n");

The default value for "enabled" is false, so it's actually failing insecure. Although, the print is
probably unnecessary.

> +		goto out;
> +	}
> +
> +	/*
> +	 * secureboot is enabled if os-secure-enforcing property exists,
> +	 * else disabled.
> +	 */
> +	enabled = of_property_read_bool(node, "os-secure-enforcing");

Property has been renamed to "os-secureboot-enforcing".

> +> +out:
> +	of_node_put(node);
> +
> +	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
> +	return enabled;
> +}
> 

[PATCH v10a 1/9] powerpc: detect the secure boot mode of the system

[Eric Richter]

From: Nayna Jain <nayna@linux.ibm.com>

This patch defines a function to detect the secure boot state of a
PowerNV system.

The PPC_SECURE_BOOT config represents the base enablement of secure boot
for powerpc.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
v10a:
- moved get_ppc_fw_sb_node to this patch
- updated based on skiboot device tree changes
  - os-secure-enforcing was renamed os-secureboot-enforcing
  - os-secureboot-enforcing was moved to ibm,secureboot
- removed now unnecessary node availibility check

 arch/powerpc/Kconfig                   | 10 ++++++++
 arch/powerpc/include/asm/secure_boot.h | 23 +++++++++++++++++
 arch/powerpc/kernel/Makefile           |  2 ++
 arch/powerpc/kernel/secure_boot.c      | 34 ++++++++++++++++++++++++++
 4 files changed, 69 insertions(+)
 create mode 100644 arch/powerpc/include/asm/secure_boot.h
 create mode 100644 arch/powerpc/kernel/secure_boot.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3e56c9c2f16e..56ea0019b616 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -934,6 +934,16 @@ config PPC_MEM_KEYS
 
 	  If unsure, say y.
 
+config PPC_SECURE_BOOT
+	prompt "Enable secure boot support"
+	bool
+	depends on PPC_POWERNV
+	help
+	  Systems with firmware secure boot enabled need to define security
+	  policies to extend secure boot to the OS. This config allows a user
+	  to enable OS secure boot on systems that have firmware support for
+	  it. If in doubt say N.
+
 endmenu
 
 config ISA_DMA_API
diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
new file mode 100644
index 000000000000..07d0fe0ca81f
--- /dev/null
+++ b/arch/powerpc/include/asm/secure_boot.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Secure boot definitions
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#ifndef _ASM_POWER_SECURE_BOOT_H
+#define _ASM_POWER_SECURE_BOOT_H
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+bool is_ppc_secureboot_enabled(void);
+
+#else
+
+static inline bool is_ppc_secureboot_enabled(void)
+{
+	return false;
+}
+
+#endif
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index a7ca8fe62368..e2a54fa240ac 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,6 +161,8 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
 obj-y				+= ucall.o
 endif
 
+obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o
+
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
 KCOV_INSTRUMENT_prom_init.o := n
diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
new file mode 100644
index 000000000000..3f55be33f5c8
--- /dev/null
+++ b/arch/powerpc/kernel/secure_boot.c
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+#include <linux/types.h>
+#include <linux/of.h>
+#include <asm/secure_boot.h>
+
+static struct device_node *get_ppc_fw_sb_node(void)
+{
+	static const struct of_device_id ids[] = {
+		{ .compatible = "ibm,secureboot-v1", },
+		{ .compatible = "ibm,secureboot-v2", },
+		{},
+	};
+
+	return of_find_matching_node(NULL, ids);
+}
+
+bool is_ppc_secureboot_enabled(void)
+{
+	struct device_node *node;
+	bool enabled = false;
+
+	node = get_ppc_fw_sb_node();
+	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
+
+	of_node_put(node);
+
+	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
+
+	return enabled;
+}
-- 
2.20.1

[PATCH v10a 3/9] powerpc: detect the trusted boot state of the system

[Eric Richter]

From: Nayna Jain <nayna@linux.ibm.com>

While secure boot permits only properly verified signed kernels to be
booted, trusted boot calculates the file hash of the kernel image and
stores the measurement prior to boot, that can be subsequently compared
against good known values via attestation services.

This patch reads the trusted boot state of a PowerNV system. The state
is used to conditionally enable additional measurement rules in the IMA
arch-specific policies.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
v10a:
- moved get_ppc_fw_sb_node to patch 1 in the series

 arch/powerpc/include/asm/secure_boot.h |  6 ++++++
 arch/powerpc/kernel/secure_boot.c      | 15 +++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/arch/powerpc/include/asm/secure_boot.h b/arch/powerpc/include/asm/secure_boot.h
index 07d0fe0ca81f..a2ff556916c6 100644
--- a/arch/powerpc/include/asm/secure_boot.h
+++ b/arch/powerpc/include/asm/secure_boot.h
@@ -11,6 +11,7 @@
 #ifdef CONFIG_PPC_SECURE_BOOT
 
 bool is_ppc_secureboot_enabled(void);
+bool is_ppc_trustedboot_enabled(void);
 
 #else
 
@@ -19,5 +20,10 @@ static inline bool is_ppc_secureboot_enabled(void)
 	return false;
 }
 
+static inline bool is_ppc_trustedboot_enabled(void)
+{
+	return false;
+}
+
 #endif
 #endif
diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
index 3f55be33f5c8..95d2ff086e55 100644
--- a/arch/powerpc/kernel/secure_boot.c
+++ b/arch/powerpc/kernel/secure_boot.c
@@ -32,3 +32,18 @@ bool is_ppc_secureboot_enabled(void)
 
 	return enabled;
 }
+
+bool is_ppc_trustedboot_enabled(void)
+{
+	struct device_node *node;
+	bool enabled = false;
+
+	node = get_ppc_fw_sb_node();
+	enabled = of_property_read_bool(node, "trusted-enabled");
+
+	of_node_put(node);
+
+	pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled");
+
+	return enabled;
+}
-- 
2.20.1

Re: [PATCH v10 2/9] powerpc/ima: add support to initialize ima policy rules

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:27 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> PowerNV systems use a Linux-based bootloader, which rely on the IMA
> subsystem to enforce different secure boot modes.  Since the verification
> policy may differ based on the secure boot mode of the system, the
> policies must be defined at runtime.
> 
> This patch implements arch-specific support to define IMA policy
> rules based on the runtime secure boot mode of the system.
> 
> This patch provides arch-specific IMA policies if PPC_SECURE_BOOT
> config is enabled.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/4238fad366a660cbc6499ca1ea4be42bd4d1ac5b

cheers

Re: [PATCH v10 4/9] powerpc/ima: define trusted boot policy

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:29 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> This patch defines an arch-specific trusted boot only policy and a
> combined secure and trusted boot policy.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/1917855f4e0658c313e280671ad87774dbfb7b24

cheers

Re: [PATCH v10 5/9] ima: make process_buffer_measurement() generic

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:30 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> process_buffer_measurement() is limited to measuring the kexec boot
> command line. This patch makes process_buffer_measurement() more
> generic, allowing it to measure other types of buffer data (e.g.
> blacklisted binary hashes or key hashes).
> 
> process_buffer_measurement() may be called directly from an IMA
> hook or as an auxiliary measurement record. In both cases the buffer
> measurement is based on policy. This patch modifies the function to
> conditionally retrieve the policy defined PCR and template for the IMA
> hook case.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> [zohar@linux.ibm.com: added comment in process_buffer_measurement()]
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/e14555e3d0e9edfad0a6840c0152f71aba97e793

cheers

Re: [PATCH v10 6/9] certs: add wrapper function to check blacklisted binary hash

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:31 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> The -EKEYREJECTED error returned by existing is_hash_blacklisted() is
> misleading when called for checking against blacklisted hash of a
> binary.
> 
> This patch adds a wrapper function is_binary_blacklisted() to return
> -EPERM error if binary is blacklisted.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Cc: David Howells <dhowells@redhat.com>
> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/2434f7d2d488c3301ae81f1031e1c66c6f076fb7

cheers

Re: [PATCH v10 7/9] ima: check against blacklisted hashes for files with modsig

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:32 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> Asymmetric private keys are used to sign multiple files.  The kernel
> currently supports checking against blacklisted keys.  However, if the
> public key is blacklisted, any file signed by the blacklisted key will
> automatically fail signature verification.  Blacklisting the public
> key is not fine enough granularity, as we might want to only blacklist
> a particular file.
> 
> This patch adds support for checking against the blacklisted hash of
> the file, without the appended signature, based on the IMA policy.  It
> defines a new policy option "appraise_flag=check_blacklist".
> 
> In addition to the blacklisted binary hashes stored in the firmware "dbx"
> variable, the Linux kernel may be configured to load blacklisted binary
> hashes onto the .blacklist keyring as well.  The following example shows
> how to blacklist a specific kernel module hash.
> 
> $ sha256sum kernel/kheaders.ko
> 77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
> kernel/kheaders.ko
> 
> $ grep BLACKLIST .config
> CONFIG_SYSTEM_BLACKLIST_KEYRING=y
> CONFIG_SYSTEM_BLACKLIST_HASH_LIST="blacklist-hash-list"
> 
> $ cat certs/blacklist-hash-list
> "bin:77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3"
> 
> Update the IMA custom measurement and appraisal policy rules
> (/etc/ima-policy):
> 
> measure func=MODULE_CHECK template=ima-modsig
> appraise func=MODULE_CHECK appraise_flag=check_blacklist
> appraise_type=imasig|modsig
> 
> After building, installing, and rebooting the kernel:
> 
>  545660333 ---lswrv      0     0   \_ blacklist:
> bin:77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
> 
> measure func=MODULE_CHECK template=ima-modsig
> appraise func=MODULE_CHECK appraise_flag=check_blacklist
> appraise_type=imasig|modsig
> 
> modprobe: ERROR: could not insert 'kheaders': Permission denied
> 
> 10 0c9834db5a0182c1fb0cdc5d3adcf11a11fd83dd ima-sig
> sha256:3bc6ed4f0b4d6e31bc1dbc9ef844605abc7afdc6d81a57d77a1ec9407997c40
> 2 /usr/lib/modules/5.4.0-rc3+/kernel/kernel/kheaders.ko
> 
> 10 82aad2bcc3fa8ed94762356b5c14838f3bcfa6a0 ima-modsig
> sha256:3bc6ed4f0b4d6e31bc1dbc9ef844605abc7afdc6d81a57d77a1ec9407997c40
> 2 /usr/lib/modules/5.4.0rc3+/kernel/kernel/kheaders.ko  sha256:77fa889b3
> 5a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
> 3082029a06092a864886f70d010702a082028b30820287020101310d300b0609608648
> 016503040201300b06092a864886f70d01070131820264....
> 
> 10 25b72217cc1152b44b134ce2cd68f12dfb71acb3 ima-buf
> sha256:8b58427fedcf8f4b20bc8dc007f2e232bf7285d7b93a66476321f9c2a3aa132
> b blacklisted-hash
> 77fa889b35a05338ec52e51591c1b89d4c8d1c99a21251d7c22b1a8642a6bad3
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Cc: Jessica Yu <jeyu@kernel.org>
> Cc: David Howells <dhowells@redhat.com>
> [zohar@linux.ibm.com: updated patch description]
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/273df864cf7466fb170b8dcc1abd672cd08ad8d3

cheers

Re: [PATCH v10 8/9] powerpc/ima: update ima arch policy to check for blacklist

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:33 UTC, Mimi Zohar wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> This patch updates the arch-specific policies for PowerNV system to make
> sure that the binary hash is not blacklisted.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Cc: Jessica Yu <jeyu@kernel.org>
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/dc87f18615db9dc74a75cfb4a57ed33b07a3903a

cheers

Re: [RFC PATCH v10 9/9] powerpc/ima: indicate kernel modules appended signatures are enforced

[Michael Ellerman]

On Thu, 2019-10-31 at 03:31:34 UTC, Mimi Zohar wrote:
> The arch specific kernel module policy rule requires kernel modules to
> be signed, either as an IMA signature, stored as an xattr, or as an
> appended signature.  As a result, kernel modules appended signatures
> could be enforced without "sig_enforce" being set or reflected in
> /sys/module/module/parameters/sig_enforce.  This patch sets
> "sig_enforce".
> 
> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
> Cc: Jessica Yu <jeyu@kernel.org>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/d72ea4915c7e6fa5e7b9022a34df66e375bfe46c

cheers

Re: [PATCH v10a 1/9] powerpc: detect the secure boot mode of the system

[Michael Ellerman]

On Tue, 2019-11-05 at 23:00:22 UTC, Eric Richter wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> This patch defines a function to detect the secure boot state of a
> PowerNV system.
> 
> The PPC_SECURE_BOOT config represents the base enablement of secure boot
> for powerpc.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Signed-off-by: Eric Richter <erichte@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/1a8916ee3ac29054322cdac687d36e1b5894d272

cheers

Re: [PATCH v10a 3/9] powerpc: detect the trusted boot state of the system

[Michael Ellerman]

On Tue, 2019-11-05 at 23:02:07 UTC, Eric Richter wrote:
> From: Nayna Jain <nayna@linux.ibm.com>
> 
> While secure boot permits only properly verified signed kernels to be
> booted, trusted boot calculates the file hash of the kernel image and
> stores the measurement prior to boot, that can be subsequently compared
> against good known values via attestation services.
> 
> This patch reads the trusted boot state of a PowerNV system. The state
> is used to conditionally enable additional measurement rules in the IMA
> arch-specific policies.
> 
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Signed-off-by: Eric Richter <erichte@linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/2702809a4a1ab414d75c00936cda70ea77c8234e

cheers

Re: [PATCH v10 0/9] powerpc: Enabling IMA arch specific secure boot policies

[Lakshmi Ramasubramanian]

Hi Mimi,

On 10/30/2019 8:31 PM, Mimi Zohar wrote:

> This patchset extends the previous version[1] by adding support for
> checking against a blacklist of binary hashes.
> 
> The IMA subsystem supports custom, built-in, arch-specific policies to
> define the files to be measured and appraised. These policies are honored
> based on priority, where arch-specific policy is the highest and custom
> is the lowest.

Has this change been signed off and merged for the next update of the 
kernel (v5.5)?

thanks,
  -lakshmi

Re: [PATCH v10 0/9] powerpc: Enabling IMA arch specific secure boot policies

[Mimi Zohar]

On Mon, 2019-12-09 at 12:27 -0800, Lakshmi Ramasubramanian wrote:
> Hi Mimi,
> 
> On 10/30/2019 8:31 PM, Mimi Zohar wrote:
> 
> > This patchset extends the previous version[1] by adding support for
> > checking against a blacklist of binary hashes.
> > 
> > The IMA subsystem supports custom, built-in, arch-specific policies to
> > define the files to be measured and appraised. These policies are honored
> > based on priority, where arch-specific policy is the highest and custom
> > is the lowest.
> 
> Has this change been signed off and merged for the next update of the 
> kernel (v5.5)?

Yes, refer to the linuxppc mailing list archives.

Mimi

[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/