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* [RFC][PATCH v1 0/9] ima: appraisal extension
@ 2012-01-30 22:13 Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 1/9] vfs: extend vfs_removexattr locking Mimi Zohar
                   ` (8 more replies)
  0 siblings, 9 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:13 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford, Dmitry Kasatkin

This is the initial posting of the IMA-appraisal patch set, separate
from EVM.

IMA currently maintains an integrity measurement list used to assert the
integrity of the running system to a third party.  The IMA-appraisal
extension adds local integrity validation and enforcement of the
measurement against a "good" value stored as an extended attribute
'security.ima'.  The initial methods for validating 'security.ima' are
hashed based, which provides file data integrity, and digital signature
based, which in addition to providing file data integrity, provides
authenticity.

New hooks:
ima_inode_setxattr(), ima_inode_removexattr(), ima_inode_post_setattr()

IMA-appraisal extends the measurement policy ABI with two new keywords:
appraise/dont_appraise and extends the ima_tcb policy to appraise all
files owned by root.  Like the ima_tcb measurement policy, the ima_tcb
appraisal policy does not appraise pseudo filesystem files (eg. debugfs,
tmpfs, securityfs, selinuxfs or ramfs.)

Additional rules can be added to the default IMA measurement/appraisal
policy, which take advantage of the SELinux labels, for a more fine
grained policy.

Locking changes:

The ima-appraisal extension maintains the file integrity measurement as
an extended attribute 'security.ima'.  ima_file_free(), called on __fput(),
updates 'security.ima' to reflect any changes made to the file.  In fix
mode, process_measurement() writes 'security.ima' to reflect the current
file hash.  Writing extended attributes and other file metadata (eg. chmod),
requires taking the i_mutex.  Both ima_file_free() and process_measurement()
took the iint->mutex and then the i_mutex, while chmod() took the locks in
reverse order.  To resolve the potential lock inversion deadlock, the
redundant iint->mutex was eliminated.

Prereqs:
   vfs: fix IMA lockdep circular locking dependency
   vfs: Correctly set the dir i_mutex lockdep class
   vfs: iversion truncate bug fix

Mimi

Dmitry Kasatkin (2):
  ima: allocating iint improvements
  ima: digital signature verification support

Mimi Zohar (7):
  vfs: extend vfs_removexattr locking
  vfs: move ima_file_free before releasing the file
  ima: integrity appraisal extension
  ima: add appraise action keywords and default rules
  ima: add inode_post_setattr call
  ima: add ima_inode_setxattr/removexattr function and calls
  ima: add support for different security.ima data types

 Documentation/ABI/testing/ima_policy  |   25 +++-
 Documentation/kernel-parameters.txt   |    4 +
 fs/attr.c                             |    2 +
 fs/file_table.c                       |    2 +-
 fs/xattr.c                            |    6 +-
 include/linux/ima.h                   |   27 ++++
 include/linux/integrity.h             |    7 +-
 include/linux/xattr.h                 |    3 +
 security/integrity/evm/evm_main.c     |    3 +
 security/integrity/iint.c             |   64 ++++-----
 security/integrity/ima/Kconfig        |   15 ++
 security/integrity/ima/Makefile       |    2 +
 security/integrity/ima/ima.h          |   39 +++++-
 security/integrity/ima/ima_api.c      |   55 +++++--
 security/integrity/ima/ima_appraise.c |  261 +++++++++++++++++++++++++++++++++
 security/integrity/ima/ima_crypto.c   |    9 +-
 security/integrity/ima/ima_main.c     |   89 +++++++----
 security/integrity/ima/ima_policy.c   |   88 ++++++++++--
 security/integrity/integrity.h        |   11 +-
 security/security.c                   |    6 +
 20 files changed, 605 insertions(+), 113 deletions(-)
 create mode 100644 security/integrity/ima/ima_appraise.c

-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 1/9] vfs: extend vfs_removexattr locking
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
@ 2012-01-30 22:13 ` Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 2/9] vfs: move ima_file_free before releasing the file Mimi Zohar
                   ` (7 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:13 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar, Dmitry Kasatkin

This patch takes the i_mutex lock before security_inode_removexattr(),
instead of after, in preparation of calling ima_inode_removexattr().

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
---
 fs/xattr.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 82f4337..6112c92 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -294,11 +294,13 @@ vfs_removexattr(struct dentry *dentry, const char *name)
 	if (error)
 		return error;
 
+	mutex_lock(&inode->i_mutex);
 	error = security_inode_removexattr(dentry, name);
-	if (error)
+	if (error) {
+		mutex_unlock(&inode->i_mutex);
 		return error;
+	}
 
-	mutex_lock(&inode->i_mutex);
 	error = inode->i_op->removexattr(dentry, name);
 	mutex_unlock(&inode->i_mutex);
 
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 2/9] vfs: move ima_file_free before releasing the file
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 1/9] vfs: extend vfs_removexattr locking Mimi Zohar
@ 2012-01-30 22:13 ` Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 3/9] ima: integrity appraisal extension Mimi Zohar
                   ` (6 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:13 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar

ima_file_free(), called on __fput(), currently flags files that have
changed, so that the file is re-measured.  For appraising a files's
integrity, flagging the file is not enough.  The file's hash must be
re-calculated and stored in the 'security.ima' xattr to reflect any
changes.

This patch moves the ima_file_free() call to before releasing the file
in preparation of ima-appraisal measuring the file and updating the
'security.ima' xattr.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
 fs/file_table.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index 20002e3..554161a 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -243,10 +243,10 @@ static void __fput(struct file *file)
 		if (file->f_op && file->f_op->fasync)
 			file->f_op->fasync(-1, file, 0);
 	}
+	ima_file_free(file);
 	if (file->f_op && file->f_op->release)
 		file->f_op->release(inode, file);
 	security_file_free(file);
-	ima_file_free(file);
 	if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL &&
 		     !(file->f_mode & FMODE_PATH))) {
 		cdev_put(inode->i_cdev);
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 3/9] ima: integrity appraisal extension
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 1/9] vfs: extend vfs_removexattr locking Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 2/9] vfs: move ima_file_free before releasing the file Mimi Zohar
@ 2012-01-30 22:13 ` Mimi Zohar
  2012-01-30 22:13 ` [RFC][PATCH v1 4/9] ima: add appraise action keywords and default rules Mimi Zohar
                   ` (5 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:13 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar

This patch adds local measurement integrity appraisal to IMA.  New is the
creation and maintainance of an extended attribute 'security.ima' containing
the file hash measurement.  Protection of the xattr is provided by EVM, if
enabled and configured.

Based on policy, IMA calls evm_verifyxattr() to verify the security.ima
xattr integrity and, assuming success, compares the xattr hash value with
the collected file measurement.

Changlog v1:
- removed unused iint mutex (Dmitry Kasatkin)
- setattr hook must not reset appraised (Dmitry Kasatkin)
- evm_verifyxattr() now differentiates between no 'security.evm' xattr
  (INTEGRITY_NOLABEL) and no EVM 'protected' xattrs included in the
  'security.evm' (INTEGRITY_NOXATTRS).
- replace hash_status with ima_status (Dmitry Kasatkin)
- re-initialize slab element ima_status on free (Dmitry Kasatkin)
- include 'security.ima' in EVM if CONFIG_IMA_APPRAISE, not CONFIG_IMA
- merged half "ima: ima_must_appraise_or_measure API change" (Dmitry Kasatkin)
- removed unnecessary error variable in process_measurement() (Dmitry Kasatkin)
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured
  (moved ima_inode_post_setattr() to ima_appraise.c)
- make sure ima_collect_measurement() can read file

Changelog:
- add 'iint' to evm_verifyxattr() call (Dimitry Kasatkin)
- fix the race condition between chmod, which takes the i_mutex and then
  iint->mutex, and ima_file_free() and process_measurement(), which take
  the locks in the reverse order, by eliminating iint->mutex. (Dmitry Kasatkin)
- cleanup of ima_appraise_measurement() (Dmitry Kasatkin)
- changes as a result of the iint not allocated for all regular files, but
  only for those measured/appraised.
- don't try to appraise new/empty files
- expanded ima_appraisal description in ima/Kconfig
- IMA appraise definitions required even if IMA_APPRAISE not enabled
- add return value to ima_must_appraise() stub
- unconditionally set status = INTEGRITY_PASS *after* testing status,
  not before.  (Found by Joe Perches)

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
 Documentation/kernel-parameters.txt   |    4 +
 include/linux/xattr.h                 |    3 +
 security/integrity/evm/evm_main.c     |    3 +
 security/integrity/iint.c             |    3 +-
 security/integrity/ima/Kconfig        |   15 +++
 security/integrity/ima/Makefile       |    2 +
 security/integrity/ima/ima.h          |   39 +++++++-
 security/integrity/ima/ima_api.c      |   49 +++++++---
 security/integrity/ima/ima_appraise.c |  167 +++++++++++++++++++++++++++++++++
 security/integrity/ima/ima_crypto.c   |    9 ++-
 security/integrity/ima/ima_main.c     |   78 +++++++++++-----
 security/integrity/ima/ima_policy.c   |   32 +++++--
 security/integrity/integrity.h        |    8 +-
 13 files changed, 359 insertions(+), 53 deletions(-)
 create mode 100644 security/integrity/ima/ima_appraise.c

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 033d4e6..b4dc3fc 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1004,6 +1004,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 	ihash_entries=	[KNL]
 			Set number of hash buckets for inode cache.
 
+	ima_appraise=	[IMA] appraise integrity measurements
+			Format: { "off" | "enforce" | "log" | "fix" }
+			default: "enforce"
+
 	ima_audit=	[IMA]
 			Format: { "0" | "1" }
 			0 -- integrity auditing messages. (Default)
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index e5d1220..77a3e68 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -33,6 +33,9 @@
 #define XATTR_EVM_SUFFIX "evm"
 #define XATTR_NAME_EVM XATTR_SECURITY_PREFIX XATTR_EVM_SUFFIX
 
+#define XATTR_IMA_SUFFIX "ima"
+#define XATTR_NAME_IMA XATTR_SECURITY_PREFIX XATTR_IMA_SUFFIX
+
 #define XATTR_SELINUX_SUFFIX "selinux"
 #define XATTR_NAME_SELINUX XATTR_SECURITY_PREFIX XATTR_SELINUX_SUFFIX
 
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 8901501..eb54845 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -34,6 +34,9 @@ char *evm_config_xattrnames[] = {
 #ifdef CONFIG_SECURITY_SMACK
 	XATTR_NAME_SMACK,
 #endif
+#ifdef CONFIG_IMA_APPRAISE
+	XATTR_NAME_IMA,
+#endif
 	XATTR_NAME_CAPS,
 	NULL
 };
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index 399641c..e600986 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -74,6 +74,7 @@ static void iint_free(struct integrity_iint_cache *iint)
 {
 	iint->version = 0;
 	iint->flags = 0UL;
+	iint->ima_status = INTEGRITY_UNKNOWN;
 	iint->evm_status = INTEGRITY_UNKNOWN;
 	kmem_cache_free(iint_cache, iint);
 }
@@ -157,7 +158,7 @@ static void init_once(void *foo)
 	memset(iint, 0, sizeof *iint);
 	iint->version = 0;
 	iint->flags = 0UL;
-	mutex_init(&iint->mutex);
+	iint->ima_status = INTEGRITY_UNKNOWN;
 	iint->evm_status = INTEGRITY_UNKNOWN;
 }
 
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index 063298a..b2d0fe4 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -54,3 +54,18 @@ config IMA_LSM_RULES
 	default y
 	help
 	  Disabling this option will disregard LSM based policy rules.
+
+config IMA_APPRAISE
+	bool "Appraise integrity measurements"
+	depends on IMA
+	default n
+	help
+	  This option enables local measurement integrity appraisal.
+	  It requires the system to be labeled with a security extended
+	  attribute containing the file hash measurement.  To protect
+	  the security extended attributes from offline attack, enable
+	  and configure EVM.
+
+	  For more information on integrity appraisal refer to:
+	  <http://linux-ima.sourceforge.net>
+	  If unsure, say N.
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index 5690c02..bd31516 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -7,3 +7,5 @@ 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_audit.o
+
+ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 3ccf7ac..f2721a7 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -40,6 +40,7 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
 extern int ima_initialized;
 extern int ima_used_chip;
 extern char *ima_hash;
+extern int ima_appraise;
 
 /* IMA inode template definition */
 struct ima_template_data {
@@ -98,6 +99,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
 }
 
 /* LIM API function definitions */
+int ima_must_appraise_or_measure(struct inode *inode, int mask, int function);
 int ima_must_measure(struct inode *inode, int mask, int function);
 int ima_collect_measurement(struct integrity_iint_cache *iint,
 			    struct file *file);
@@ -114,14 +116,47 @@ struct integrity_iint_cache *integrity_iint_insert(struct inode *inode);
 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
 
 /* IMA policy related functions */
-enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK };
+enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK, POST_SETATTR };
 
-int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask);
+int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
+		     int flags);
 void ima_init_policy(void);
 void ima_update_policy(void);
 ssize_t ima_parse_add_rule(char *);
 void ima_delete_rules(void);
 
+/* Appraise integrity measurements */
+#define IMA_APPRAISE_ENABLED	0x01
+#define IMA_APPRAISE_ENFORCE	0x02
+#define IMA_APPRAISE_LOG	0x04
+#define IMA_APPRAISE_FIX	0x08
+
+#ifdef CONFIG_IMA_APPRAISE
+int ima_appraise_measurement(struct integrity_iint_cache *iint,
+			     struct file *file, const unsigned char *filename);
+int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask);
+void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
+
+#else
+static inline int ima_appraise_measurement(struct integrity_iint_cache *iint,
+					   struct file *file,
+					   const unsigned char *filename)
+{
+	return INTEGRITY_UNKNOWN;
+}
+
+static inline int ima_must_appraise(struct inode *inode,
+				    enum ima_hooks func, int mask)
+{
+	return 0;
+}
+
+static inline void ima_update_xattr(struct integrity_iint_cache *iint,
+				    struct file *file)
+{
+}
+#endif
+
 /* LSM based policy rules require audit */
 #ifdef CONFIG_IMA_LSM_RULES
 
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 88a2788..d73b13e 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -9,13 +9,17 @@
  * License.
  *
  * File: ima_api.c
- *	Implements must_measure, collect_measurement, store_measurement,
- *	and store_template.
+ *	Implements must_appraise_or_measure, collect_measurement,
+ *	appraise_measurement, store_measurement and store_template.
  */
 #include <linux/module.h>
 #include <linux/slab.h>
-
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/evm.h>
 #include "ima.h"
+
 static const char *IMA_TEMPLATE_NAME = "ima";
 
 /*
@@ -93,7 +97,7 @@ err_out:
 }
 
 /**
- * ima_must_measure - measure decision based on policy.
+ * ima_must_appraise_or_measure - appraise & measure decision based on policy.
  * @inode: pointer to inode to measure
  * @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXECUTE)
  * @function: calling function (FILE_CHECK, BPRM_CHECK, FILE_MMAP)
@@ -105,15 +109,22 @@ err_out:
  * 	mask: contains the permission mask
  *	fsmagic: hex value
  *
- * Return 0 to measure. For matching a DONT_MEASURE policy, no policy,
- * or other error, return an error code.
-*/
-int ima_must_measure(struct inode *inode, int mask, int function)
+ * Returns IMA_MEASURE, IMA_APPRAISE mask.
+ *
+ */
+int ima_must_appraise_or_measure(struct inode *inode, int mask, int function)
 {
-	int must_measure;
+	int flags = IMA_MEASURE | IMA_APPRAISE;
+
+	if (!ima_appraise || !inode->i_op->getxattr)
+		flags &= ~IMA_APPRAISE;
+
+	return ima_match_policy(inode, function, mask, flags);
+}
 
-	must_measure = ima_match_policy(inode, function, mask);
-	return must_measure ? 0 : -EACCES;
+int ima_must_measure(struct inode *inode, int mask, int function)
+{
+	return ima_match_policy(inode, function, mask, IMA_MEASURE);
 }
 
 /*
@@ -129,16 +140,23 @@ int ima_must_measure(struct inode *inode, int mask, int function)
 int ima_collect_measurement(struct integrity_iint_cache *iint,
 			    struct file *file)
 {
-	int result = -EEXIST;
+	struct inode *inode = file->f_dentry->d_inode;
+	const char *filename = file->f_dentry->d_name.name;
+	int result = 0;
 
-	if (!(iint->flags & IMA_MEASURED)) {
+	if (!(iint->flags & IMA_COLLECTED)) {
 		u64 i_version = file->f_dentry->d_inode->i_version;
 
 		memset(iint->digest, 0, IMA_DIGEST_SIZE);
 		result = ima_calc_hash(file, iint->digest);
-		if (!result)
+		if (!result) {
 			iint->version = i_version;
+			iint->flags |= IMA_COLLECTED;
+		}
 	}
+	if (result)
+		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode,
+				    filename, "collect_data", "failed", 0, 0);
 	return result;
 }
 
@@ -167,6 +185,9 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 	struct ima_template_entry *entry;
 	int violation = 0;
 
+	if (iint->flags & IMA_MEASURED)
+		return;
+
 	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry) {
 		integrity_audit_msg(AUDIT_INTEGRITY_PCR, inode, filename,
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
new file mode 100644
index 0000000..fbbbfcb
--- /dev/null
+++ b/security/integrity/ima/ima_appraise.c
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2011 IBM Corporation
+ *
+ * Author:
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ */
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/xattr.h>
+#include <linux/magic.h>
+#include <linux/ima.h>
+#include <linux/evm.h>
+
+#include "ima.h"
+
+static int __init default_appraise_setup(char *str)
+{
+	if (strncmp(str, "off", 3) == 0)
+		ima_appraise = 0;
+	else if (strncmp(str, "log", 3) == 0)
+		ima_appraise = IMA_APPRAISE_ENABLED | IMA_APPRAISE_LOG;
+	else if (strncmp(str, "fix", 3) == 0)
+		ima_appraise = IMA_APPRAISE_ENABLED | IMA_APPRAISE_FIX;
+	return 1;
+}
+
+__setup("ima_appraise=", default_appraise_setup);
+
+/*
+ * ima_must_appraise - set appraise flag
+ *
+ * Return 1 to appraise
+ */
+int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask)
+{
+	return 0;
+}
+
+static void ima_fix_xattr(struct dentry *dentry,
+			  struct integrity_iint_cache *iint)
+{
+	iint->digest[0] = IMA_XATTR_DIGEST;
+	__vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
+			      iint->digest, IMA_DIGEST_SIZE + 1, 0);
+}
+
+/*
+ * ima_appraise_measurement - appraise file measurement
+ *
+ * Call evm_verifyxattr() to verify the integrity of 'security.ima'.
+ * Assuming success, compare the xattr hash with the collected measurement.
+ *
+ * Return 0 on success, error code otherwise
+ */
+int ima_appraise_measurement(struct integrity_iint_cache *iint,
+			     struct file *file, const unsigned char *filename)
+{
+	struct dentry *dentry = file->f_dentry;
+	struct inode *inode = dentry->d_inode;
+	u8 xattr_value[IMA_DIGEST_SIZE];
+	enum integrity_status status = INTEGRITY_UNKNOWN;
+	const char *op = "appraise_data";
+	char *cause = "unknown";
+	int rc;
+
+	if (!ima_appraise || !inode->i_op->getxattr)
+		return 0;
+	if (iint->flags & IMA_APPRAISED)
+		return iint->ima_status;
+
+	rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, xattr_value,
+				   IMA_DIGEST_SIZE);
+	if (rc <= 0) {
+		if (rc && rc != -ENODATA)
+			goto out;
+
+		cause = "missing-hash";
+		status =
+		    (inode->i_size == 0) ? INTEGRITY_PASS : INTEGRITY_NOLABEL;
+		goto out;
+	}
+
+	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
+	if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
+		if ((status == INTEGRITY_NOLABEL)
+		    || (status == INTEGRITY_NOXATTRS))
+			cause = "missing-HMAC";
+		else if (status == INTEGRITY_FAIL)
+			cause = "invalid-HMAC";
+		goto out;
+	}
+
+	rc = memcmp(xattr_value, iint->digest, IMA_DIGEST_SIZE);
+	if (rc) {
+		status = INTEGRITY_FAIL;
+		cause = "invalid-hash";
+		print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE,
+				     xattr_value, IMA_DIGEST_SIZE);
+		print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE,
+				     iint->digest, IMA_DIGEST_SIZE);
+		goto out;
+	}
+	status = INTEGRITY_PASS;
+	iint->flags |= IMA_APPRAISED;
+out:
+	if (status != INTEGRITY_PASS) {
+		if (ima_appraise & IMA_APPRAISE_FIX) {
+			ima_fix_xattr(dentry, iint);
+			status = INTEGRITY_PASS;
+		}
+		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
+				    op, cause, 1, 0);
+	}
+	iint->ima_status = status;
+	return status;
+}
+
+/*
+ * ima_update_xattr - update 'security.ima' hash value
+ */
+void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
+{
+	struct dentry *dentry = file->f_dentry;
+	int rc = 0;
+
+	rc = ima_collect_measurement(iint, file);
+	if (rc < 0)
+		return;
+	ima_fix_xattr(dentry, iint);
+}
+
+/**
+ * ima_inode_post_setattr - reflect file metadata changes
+ * @dentry: pointer to the affected dentry
+ *
+ * Changes to a dentry's metadata might result in needing to appraise.
+ *
+ * This function is called from notify_change(), which expects the caller
+ * to lock the inode's i_mutex.
+ */
+void ima_inode_post_setattr(struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct integrity_iint_cache *iint;
+	int must_appraise, rc;
+
+	if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode)
+	    || !inode->i_op->removexattr)
+		return;
+
+	must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
+	iint = integrity_iint_find(inode);
+	if (iint) {
+		if (must_appraise)
+			iint->flags |= IMA_APPRAISE;
+		else
+			iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED);
+	}
+	if (!must_appraise)
+		rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
+	return;
+}
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 9b3ade7..dcf6b02 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -48,7 +48,7 @@ int ima_calc_hash(struct file *file, char *digest)
 	struct scatterlist sg[1];
 	loff_t i_size, offset = 0;
 	char *rbuf;
-	int rc;
+	int rc, read = 0;
 
 	rc = init_desc(&desc);
 	if (rc != 0)
@@ -65,6 +65,11 @@ int ima_calc_hash(struct file *file, char *digest)
 
 		rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
 		if (rbuf_len < 0) {
+			if (!(file->f_mode & FMODE_READ)) {
+				file->f_mode |= FMODE_READ;
+				read = 1;
+				continue;
+			}
 			rc = rbuf_len;
 			break;
 		}
@@ -80,6 +85,8 @@ int ima_calc_hash(struct file *file, char *digest)
 	kfree(rbuf);
 	if (!rc)
 		rc = crypto_hash_final(&desc, digest);
+	if (read)
+		file->f_mode &= ~FMODE_READ;
 out:
 	crypto_free_hash(desc.tfm);
 	return rc;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 5b222eb..f5d7f28 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -22,12 +22,19 @@
 #include <linux/mount.h>
 #include <linux/mman.h>
 #include <linux/slab.h>
+#include <linux/xattr.h>
 #include <linux/ima.h>
 
 #include "ima.h"
 
 int ima_initialized;
 
+#ifdef CONFIG_IMA_APPRAISE
+int ima_appraise = IMA_APPRAISE_ENABLED | IMA_APPRAISE_ENFORCE;
+#else
+int ima_appraise;
+#endif
+
 char *ima_hash = "sha1";
 static int __init hash_setup(char *str)
 {
@@ -52,7 +59,7 @@ static void ima_rdwr_violation_check(struct file *file)
 	struct dentry *dentry = file->f_path.dentry;
 	struct inode *inode = dentry->d_inode;
 	fmode_t mode = file->f_mode;
-	int rc;
+	int must_measure;
 	bool send_tomtou = false, send_writers = false;
 
 	if (!S_ISREG(inode->i_mode) || !ima_initialized)
@@ -66,8 +73,8 @@ static void ima_rdwr_violation_check(struct file *file)
 		goto out;
 	}
 
-	rc = ima_must_measure(inode, MAY_READ, FILE_CHECK);
-	if (rc < 0)
+	must_measure = ima_must_measure(inode, MAY_READ, FILE_CHECK);
+	if (!must_measure)
 		goto out;
 
 	if (atomic_read(&inode->i_writecount) > 0)
@@ -84,17 +91,21 @@ out:
 }
 
 static void ima_check_last_writer(struct integrity_iint_cache *iint,
-				  struct inode *inode,
-				  struct file *file)
+				  struct inode *inode, struct file *file)
 {
 	fmode_t mode = file->f_mode;
 
-	mutex_lock(&iint->mutex);
-	if (mode & FMODE_WRITE &&
-	    atomic_read(&inode->i_writecount) == 1 &&
-	    iint->version != inode->i_version)
-		iint->flags &= ~IMA_MEASURED;
-	mutex_unlock(&iint->mutex);
+	if (!(mode & FMODE_WRITE))
+		return;
+
+	mutex_lock(&inode->i_mutex);
+	if (atomic_read(&inode->i_writecount) == 1 &&
+	    iint->version != inode->i_version) {
+		iint->flags &= ~(IMA_COLLECTED | IMA_APPRAISED | IMA_MEASURED);
+		if (iint->flags & IMA_APPRAISE)
+			ima_update_xattr(iint, file);
+	}
+	mutex_unlock(&inode->i_mutex);
 }
 
 /**
@@ -123,14 +134,17 @@ static int process_measurement(struct file *file, const unsigned char *filename,
 {
 	struct inode *inode = file->f_dentry->d_inode;
 	struct integrity_iint_cache *iint;
-	int rc = 0;
+	int rc = -ENOMEM, action, must_appraise;
 
 	if (!ima_initialized || !S_ISREG(inode->i_mode))
 		return 0;
 
-	rc = ima_must_measure(inode, mask, function);
-	if (rc != 0)
-		return rc;
+	/* Determine if in appraise/measurement policy,
+	 * returns IMA_MEASURE, IMA_APPRAISE bitmask.  */
+	action = ima_must_appraise_or_measure(inode, mask, function);
+	if (!action)
+		return 0;
+
 retry:
 	iint = integrity_iint_find(inode);
 	if (!iint) {
@@ -140,18 +154,32 @@ retry:
 		return rc;
 	}
 
-	mutex_lock(&iint->mutex);
+	must_appraise = action & IMA_APPRAISE;
 
-	rc = iint->flags & IMA_MEASURED ? 1 : 0;
-	if (rc != 0)
+	mutex_lock(&inode->i_mutex);
+
+	/* Determine if already appraised/measured based on bitmask
+	 * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED) */
+	iint->flags |= action;
+	action &= ~((iint->flags & (IMA_MEASURED | IMA_APPRAISED)) >> 1);
+
+	/* Nothing to do, just return existing appraised status */
+	if (!action) {
+		if (iint->flags & IMA_APPRAISED)
+			rc = iint->ima_status;
 		goto out;
+	}
 
 	rc = ima_collect_measurement(iint, file);
-	if (!rc)
+	if (rc != 0)
+		goto out;
+	if (action & IMA_MEASURE)
 		ima_store_measurement(iint, file, filename);
+	if (action & IMA_APPRAISE)
+		rc = ima_appraise_measurement(iint, file, filename);
 out:
-	mutex_unlock(&iint->mutex);
-	return rc;
+	mutex_unlock(&inode->i_mutex);
+	return (rc && must_appraise) ? -EACCES : 0;
 }
 
 /**
@@ -167,14 +195,14 @@ out:
  */
 int ima_file_mmap(struct file *file, unsigned long prot)
 {
-	int rc;
+	int rc = 0;
 
 	if (!file)
 		return 0;
 	if (prot & PROT_EXEC)
 		rc = process_measurement(file, file->f_dentry->d_name.name,
 					 MAY_EXEC, FILE_MMAP);
-	return 0;
+	return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;
 }
 EXPORT_SYMBOL_GPL(ima_file_mmap);
 
@@ -197,7 +225,7 @@ int ima_bprm_check(struct linux_binprm *bprm)
 
 	rc = process_measurement(bprm->file, bprm->filename,
 				 MAY_EXEC, BPRM_CHECK);
-	return 0;
+	return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;
 }
 
 /**
@@ -218,7 +246,7 @@ int ima_file_check(struct file *file, int mask)
 	rc = process_measurement(file, file->f_dentry->d_name.name,
 				 mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
 				 FILE_CHECK);
-	return 0;
+	return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;
 }
 EXPORT_SYMBOL_GPL(ima_file_check);
 
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 0fb643a..37367a4 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -25,7 +25,13 @@
 #define IMA_FSMAGIC	0x0004
 #define IMA_UID		0x0008
 
-enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };
+#define UNKNOWN			0
+#define MEASURE			1	/* same as IMA_MEASURE */
+#define DONT_MEASURE		2
+#define MEASURE_MASK		3
+#define APPRAISE		4	/* same as IMA_APPRAISE */
+#define DONT_APPRAISE		8
+#define APPRAISE_MASK		12
 
 #define MAX_LSM_RULES 6
 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
@@ -34,7 +40,7 @@ enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
 
 struct ima_measure_rule_entry {
 	struct list_head list;
-	enum ima_action action;
+	int action;
 	unsigned int flags;
 	enum ima_hooks func;
 	int mask;
@@ -161,18 +167,28 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
  * as elements in the list are never deleted, nor does the list
  * change.)
  */
-int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
+int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
+		     int flags)
 {
 	struct ima_measure_rule_entry *entry;
+	int action = 0, actmask = flags | (flags << 1);
 
 	list_for_each_entry(entry, ima_measure, list) {
-		bool rc;
 
-		rc = ima_match_rules(entry, inode, func, mask);
-		if (rc)
-			return entry->action;
+		if (!(entry->action & actmask))
+			continue;
+
+		if (!ima_match_rules(entry, inode, func, mask))
+			continue;
+
+		action |= (entry->action & (IMA_APPRAISE | IMA_MEASURE));
+		actmask &= (entry->action & APPRAISE_MASK) ?
+		    ~APPRAISE_MASK : ~MEASURE_MASK;
+		if (!actmask)
+			break;
 	}
-	return 0;
+
+	return action;
 }
 
 /**
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 7a25ece..295702d 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -16,7 +16,11 @@
 #include <crypto/sha.h>
 
 /* iint cache flags */
-#define IMA_MEASURED		0x01
+#define IMA_MEASURE		1
+#define IMA_MEASURED		2
+#define IMA_APPRAISE		4
+#define IMA_APPRAISED		8
+#define IMA_COLLECTED		16
 
 enum evm_ima_xattr_type {
 	IMA_XATTR_DIGEST = 0x01,
@@ -36,7 +40,7 @@ struct integrity_iint_cache {
 	u64 version;		/* track inode changes */
 	unsigned char flags;
 	u8 digest[SHA1_DIGEST_SIZE];
-	struct mutex mutex;	/* protects: version, flags, digest */
+	enum integrity_status ima_status;
 	enum integrity_status evm_status;
 };
 
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 4/9] ima: add appraise action keywords and default rules
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (2 preceding siblings ...)
  2012-01-30 22:13 ` [RFC][PATCH v1 3/9] ima: integrity appraisal extension Mimi Zohar
@ 2012-01-30 22:13 ` Mimi Zohar
  2012-01-30 22:14 ` [RFC][PATCH v1 5/9] ima: allocating iint improvements Mimi Zohar
                   ` (4 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:13 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar

Unlike the IMA measurement policy, the appraise policy can not be dependent
on runtime process information, such as the task uid, as the 'security.ima'
xattr is written on file close and must be updated each time the file changes,
regardless of the current task uid.

This patch extends the policy language with 'fowner'.  The appraise default
policy appraises all files owned by root.

Changelog v1:
- don't appraise RAMFS (Dmitry Kasatkin)
- merged rest of "ima: ima_must_appraise_or_measure API change" commit
  (Dmtiry Kasatkin)

  ima_must_appraise_or_measure() called ima_match_policy twice, which
  searched the policy for a matching rule.  Once for a matching measurement
  rule and subsequently for an appraisal rule. Searching the policy twice
  is unnecessary overhead, which could be noticeable with a large policy.

  The new version of ima_must_appraise_or_measure() does everything in a
  single iteration using a new version of ima_match_policy().  It returns
  IMA_MEASURE, IMA_APPRAISE mask.

  With the use of action mask only one efficient matching function
  is enough.  Removed other specific versions of matching functions.

Changelog:
- change 'owner' to 'fowner' to conform to the new LSM conditions posted by
  Roberto Sassu.
- fix calls to ima_log_string()

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
 Documentation/ABI/testing/ima_policy  |   25 ++++++++++++--
 security/integrity/ima/ima_appraise.c |    5 ++-
 security/integrity/ima/ima_policy.c   |   56 +++++++++++++++++++++++++++++++--
 3 files changed, 78 insertions(+), 8 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 6cd6dae..dcff822 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -12,11 +12,14 @@ Description:
 		then closing the file.  The new policy takes effect after
 		the file ima/policy is closed.
 
+		IMA appraisal, if configured, uses these file measurements
+		for local measurement appraisal.
+
 		rule format: action [condition ...]
 
-		action: measure | dont_measure
+		action: measure | dont_measure | appraise | dont_appraise
 		condition:= base | lsm
-			base:	[[func=] [mask=] [fsmagic=] [uid=]]
+			base:	[[func=] [mask=] [fsmagic=] [uid=] [fowner]]
 			lsm:	[[subj_user=] [subj_role=] [subj_type=]
 				 [obj_user=] [obj_role=] [obj_type=]]
 
@@ -24,36 +27,50 @@ Description:
 			mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
 			fsmagic:= hex value
 			uid:= decimal value
+			fowner:=decimal value
 		lsm:  	are LSM specific
 
 		default policy:
 			# PROC_SUPER_MAGIC
 			dont_measure fsmagic=0x9fa0
+			dont_appraise fsmagic=0x9fa0
 			# SYSFS_MAGIC
 			dont_measure fsmagic=0x62656572
+			dont_appraise fsmagic=0x62656572
 			# DEBUGFS_MAGIC
 			dont_measure fsmagic=0x64626720
+			dont_appraise fsmagic=0x64626720
 			# TMPFS_MAGIC
 			dont_measure fsmagic=0x01021994
+			dont_appraise fsmagic=0x01021994
+			# RAMFS_MAGIC
+			dont_measure fsmagic=0x858458f6
+			dont_appraise fsmagic=0x858458f6
 			# SECURITYFS_MAGIC
 			dont_measure fsmagic=0x73636673
+			dont_appraise fsmagic=0x73636673
 
 			measure func=BPRM_CHECK
 			measure func=FILE_MMAP mask=MAY_EXEC
 			measure func=FILE_CHECK mask=MAY_READ uid=0
+			appraise fowner=0
 
 		The default policy measures all executables in bprm_check,
 		all files mmapped executable in file_mmap, and all files
-		open for read by root in do_filp_open.
+		open for read by root in do_filp_open.  The default appraisal
+		policy appraises all files owned by root.
 
 		Examples of LSM specific definitions:
 
 		SELinux:
 			# SELINUX_MAGIC
-			dont_measure fsmagic=0xF97CFF8C
+			dont_measure fsmagic=0xf97cff8c
+			dont_appraise fsmagic=0xf97cff8c
 
 			dont_measure obj_type=var_log_t
+			dont_appraise obj_type=var_log_t
 			dont_measure obj_type=auditd_log_t
+			dont_appraise obj_type=auditd_log_t
 			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
 			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
 
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index fbbbfcb..392ceb2 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -38,7 +38,10 @@ __setup("ima_appraise=", default_appraise_setup);
  */
 int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask)
 {
-	return 0;
+	if (!ima_appraise || !inode->i_op->getxattr)
+		return 0;
+
+	return ima_match_policy(inode, func, mask, IMA_APPRAISE);
 }
 
 static void ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 37367a4..9e71014 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -24,6 +24,7 @@
 #define IMA_MASK 	0x0002
 #define IMA_FSMAGIC	0x0004
 #define IMA_UID		0x0008
+#define IMA_FOWNER	0x0010
 
 #define UNKNOWN			0
 #define MEASURE			1	/* same as IMA_MEASURE */
@@ -46,6 +47,7 @@ struct ima_measure_rule_entry {
 	int mask;
 	unsigned long fsmagic;
 	uid_t uid;
+	uid_t fowner;
 	struct {
 		void *rule;	/* LSM file metadata specific */
 		int type;	/* audit type */
@@ -54,7 +56,7 @@ struct ima_measure_rule_entry {
 
 /*
  * Without LSM specific knowledge, the default policy can only be
- * written in terms of .action, .func, .mask, .fsmagic, and .uid
+ * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  */
 
 /*
@@ -77,6 +79,14 @@ static struct ima_measure_rule_entry default_rules[] = {
 	 .flags = IMA_FUNC | IMA_MASK},
 	{.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = 0,
 	 .flags = IMA_FUNC | IMA_MASK | IMA_UID},
+	{.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC},
+	{.action = APPRAISE,.fowner = 0,.flags = IMA_FOWNER},
 };
 
 static LIST_HEAD(measure_default_rules);
@@ -118,6 +128,8 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
 		return false;
 	if ((rule->flags & IMA_UID) && rule->uid != cred->uid)
 		return false;
+	if ((rule->flags & IMA_FOWNER) && rule->fowner != inode->i_uid)
+		return false;
 	for (i = 0; i < MAX_LSM_RULES; i++) {
 		int rc = 0;
 		u32 osid, sid;
@@ -238,14 +250,17 @@ void ima_update_policy(void)
 enum {
 	Opt_err = -1,
 	Opt_measure = 1, Opt_dont_measure,
+	Opt_appraise, Opt_dont_appraise,
 	Opt_obj_user, Opt_obj_role, Opt_obj_type,
 	Opt_subj_user, Opt_subj_role, Opt_subj_type,
-	Opt_func, Opt_mask, Opt_fsmagic, Opt_uid
+	Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner
 };
 
 static match_table_t policy_tokens = {
 	{Opt_measure, "measure"},
 	{Opt_dont_measure, "dont_measure"},
+	{Opt_appraise, "appraise"},
+	{Opt_dont_appraise, "dont_appraise"},
 	{Opt_obj_user, "obj_user=%s"},
 	{Opt_obj_role, "obj_role=%s"},
 	{Opt_obj_type, "obj_type=%s"},
@@ -256,6 +271,7 @@ static match_table_t policy_tokens = {
 	{Opt_mask, "mask=%s"},
 	{Opt_fsmagic, "fsmagic=%s"},
 	{Opt_uid, "uid=%s"},
+	{Opt_fowner, "fowner=%s"},
 	{Opt_err, NULL}
 };
 
@@ -292,6 +308,7 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
 	ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 
 	entry->uid = -1;
+	entry->fowner = -1;
 	entry->action = UNKNOWN;
 	while ((p = strsep(&rule, " \t")) != NULL) {
 		substring_t args[MAX_OPT_ARGS];
@@ -320,11 +337,27 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
 
 			entry->action = DONT_MEASURE;
 			break;
+		case Opt_appraise:
+			ima_log_string(ab, "action", "appraise");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = APPRAISE;
+			break;
+		case Opt_dont_appraise:
+			ima_log_string(ab, "action", "dont_appraise");
+
+			if (entry->action != UNKNOWN)
+				result = -EINVAL;
+
+			entry->action = DONT_APPRAISE;
+			break;
 		case Opt_func:
 			ima_log_string(ab, "func", args[0].from);
 
 			if (entry->func)
-				result  = -EINVAL;
+				result = -EINVAL;
 
 			if (strcmp(args[0].from, "FILE_CHECK") == 0)
 				entry->func = FILE_CHECK;
@@ -389,6 +422,23 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
 					entry->flags |= IMA_UID;
 			}
 			break;
+		case Opt_fowner:
+			ima_log_string(ab, "fowner", args[0].from);
+
+			if (entry->fowner != -1) {
+				result = -EINVAL;
+				break;
+			}
+
+			result = strict_strtoul(args[0].from, 10, &lnum);
+			if (!result) {
+				entry->fowner = (uid_t) lnum;
+				if (entry->fowner != lnum)
+					result = -EINVAL;
+				else
+					entry->flags |= IMA_FOWNER;
+			}
+			break;
 		case Opt_obj_user:
 			ima_log_string(ab, "obj_user", args[0].from);
 			result = ima_lsm_rule_init(entry, args[0].from,
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 5/9] ima: allocating iint improvements
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (3 preceding siblings ...)
  2012-01-30 22:13 ` [RFC][PATCH v1 4/9] ima: add appraise action keywords and default rules Mimi Zohar
@ 2012-01-30 22:14 ` Mimi Zohar
  2012-02-01 16:58   ` Eric Paris
  2012-01-30 22:14 ` [RFC][PATCH v1 6/9] ima: add inode_post_setattr call Mimi Zohar
                   ` (3 subsequent siblings)
  8 siblings, 1 reply; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:14 UTC (permalink / raw)
  To: linux-security-module
  Cc: Dmitry Kasatkin, linux-kernel, linux-fsdevel, David Safford, Mimi Zohar

From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

With IMA-appraisal's removal of the iint mutex and taking the i_mutex
instead, allocating the iint becomes a lot simplier, as we don't need
to be concerned with two processes racing to allocate the iint. This
patch cleans up and improves performance for allocating the iint.

- removed redundant double i_mutex locking
- combined iint allocation with tree search
- replaced spinlock with rwlock/read_lock

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
 include/linux/integrity.h         |    7 ++--
 security/integrity/iint.c         |   61 ++++++++++++++++---------------------
 security/integrity/ima/ima_main.c |   13 ++-----
 3 files changed, 34 insertions(+), 47 deletions(-)

diff --git a/include/linux/integrity.h b/include/linux/integrity.h
index a0c4125..66c5fe9 100644
--- a/include/linux/integrity.h
+++ b/include/linux/integrity.h
@@ -22,13 +22,14 @@ enum integrity_status {
 
 /* List of EVM protected security xattrs */
 #ifdef CONFIG_INTEGRITY
-extern int integrity_inode_alloc(struct inode *inode);
+extern struct integrity_iint_cache *integrity_inode_get(struct inode *inode);
 extern void integrity_inode_free(struct inode *inode);
 
 #else
-static inline int integrity_inode_alloc(struct inode *inode)
+static inline struct integrity_iint_cache *
+				integrity_inode_get(struct inode *inode)
 {
-	return 0;
+	return NULL;
 }
 
 static inline void integrity_inode_free(struct inode *inode)
diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index e600986..d82a5a1 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -22,7 +22,7 @@
 #include "integrity.h"
 
 static struct rb_root integrity_iint_tree = RB_ROOT;
-static DEFINE_SPINLOCK(integrity_iint_lock);
+static DEFINE_RWLOCK(integrity_iint_lock);
 static struct kmem_cache *iint_cache __read_mostly;
 
 int iint_initialized;
@@ -35,8 +35,6 @@ static struct integrity_iint_cache *__integrity_iint_find(struct inode *inode)
 	struct integrity_iint_cache *iint;
 	struct rb_node *n = integrity_iint_tree.rb_node;
 
-	assert_spin_locked(&integrity_iint_lock);
-
 	while (n) {
 		iint = rb_entry(n, struct integrity_iint_cache, rb_node);
 
@@ -63,9 +61,9 @@ struct integrity_iint_cache *integrity_iint_find(struct inode *inode)
 	if (!IS_IMA(inode))
 		return NULL;
 
-	spin_lock(&integrity_iint_lock);
+	read_lock(&integrity_iint_lock);
 	iint = __integrity_iint_find(inode);
-	spin_unlock(&integrity_iint_lock);
+	read_unlock(&integrity_iint_lock);
 
 	return iint;
 }
@@ -80,54 +78,47 @@ static void iint_free(struct integrity_iint_cache *iint)
 }
 
 /**
- * integrity_inode_alloc - allocate an iint associated with an inode
+ * integrity_inode_get - find or allocate an iint associated with an inode
  * @inode: pointer to the inode
+ * @return: allocated iint
+ *
+ * Caller must lock i_mutex
  */
-int integrity_inode_alloc(struct inode *inode)
+struct integrity_iint_cache *integrity_inode_get(struct inode *inode)
 {
 	struct rb_node **p;
-	struct rb_node *new_node, *parent = NULL;
-	struct integrity_iint_cache *new_iint, *test_iint;
-	int rc;
+	struct rb_node *node, *parent = NULL;
+	struct integrity_iint_cache *iint, *test_iint;
 
-	new_iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
-	if (!new_iint)
-		return -ENOMEM;
+	iint = integrity_iint_find(inode);
+	if (iint)
+		return iint;
 
-	new_iint->inode = inode;
-	new_node = &new_iint->rb_node;
+	iint = kmem_cache_alloc(iint_cache, GFP_NOFS);
+	if (!iint)
+		return NULL;
 
-	mutex_lock(&inode->i_mutex);	/* i_flags */
-	spin_lock(&integrity_iint_lock);
+	write_lock(&integrity_iint_lock);
 
 	p = &integrity_iint_tree.rb_node;
 	while (*p) {
 		parent = *p;
 		test_iint = rb_entry(parent, struct integrity_iint_cache,
 				     rb_node);
-		rc = -EEXIST;
 		if (inode < test_iint->inode)
 			p = &(*p)->rb_left;
-		else if (inode > test_iint->inode)
-			p = &(*p)->rb_right;
 		else
-			goto out_err;
+			p = &(*p)->rb_right;
 	}
 
+	iint->inode = inode;
+	node = &iint->rb_node;
 	inode->i_flags |= S_IMA;
-	rb_link_node(new_node, parent, p);
-	rb_insert_color(new_node, &integrity_iint_tree);
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, &integrity_iint_tree);
 
-	spin_unlock(&integrity_iint_lock);
-	mutex_unlock(&inode->i_mutex);	/* i_flags */
-
-	return 0;
-out_err:
-	spin_unlock(&integrity_iint_lock);
-	mutex_unlock(&inode->i_mutex);	/* i_flags */
-	iint_free(new_iint);
-
-	return rc;
+	write_unlock(&integrity_iint_lock);
+	return iint;
 }
 
 /**
@@ -143,10 +134,10 @@ void integrity_inode_free(struct inode *inode)
 	if (!IS_IMA(inode))
 		return;
 
-	spin_lock(&integrity_iint_lock);
+	write_lock(&integrity_iint_lock);
 	iint = __integrity_iint_find(inode);
 	rb_erase(&iint->rb_node, &integrity_iint_tree);
-	spin_unlock(&integrity_iint_lock);
+	write_unlock(&integrity_iint_lock);
 
 	iint_free(iint);
 }
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index f5d7f28..72e66fd 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -145,19 +145,14 @@ static int process_measurement(struct file *file, const unsigned char *filename,
 	if (!action)
 		return 0;
 
-retry:
-	iint = integrity_iint_find(inode);
-	if (!iint) {
-		rc = integrity_inode_alloc(inode);
-		if (!rc || rc == -EEXIST)
-			goto retry;
-		return rc;
-	}
-
 	must_appraise = action & IMA_APPRAISE;
 
 	mutex_lock(&inode->i_mutex);
 
+	iint = integrity_inode_get(inode);
+	if (!iint)
+		goto out;
+
 	/* Determine if already appraised/measured based on bitmask
 	 * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED) */
 	iint->flags |= action;
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 6/9] ima: add inode_post_setattr call
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (4 preceding siblings ...)
  2012-01-30 22:14 ` [RFC][PATCH v1 5/9] ima: allocating iint improvements Mimi Zohar
@ 2012-01-30 22:14 ` Mimi Zohar
  2012-01-30 22:14 ` [RFC][PATCH v1 7/9] ima: add ima_inode_setxattr/removexattr function and calls Mimi Zohar
                   ` (2 subsequent siblings)
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:14 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar

Changing an inode's metadata may result in our not needing to appraise
the file.  In such cases, we must remove 'security.ima'.

Changelog v1:
- use ima_inode_post_setattr() stub function, if IMA_APPRAISE not configured

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
 fs/attr.c           |    2 ++
 include/linux/ima.h |   10 ++++++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index d9bd7fc..f496bac 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -14,6 +14,7 @@
 #include <linux/fcntl.h>
 #include <linux/security.h>
 #include <linux/evm.h>
+#include <linux/ima.h>
 
 /**
  * inode_change_ok - check if attribute changes to an inode are allowed
@@ -245,6 +246,7 @@ int notify_change(struct dentry * dentry, struct iattr * attr)
 
 	if (!error) {
 		fsnotify_change(dentry, ia_valid);
+		ima_inode_post_setattr(dentry);
 		evm_inode_post_setattr(dentry, ia_valid);
 	}
 
diff --git a/include/linux/ima.h b/include/linux/ima.h
index 6ac8e50..e2bfbb1 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -39,5 +39,15 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 {
 	return 0;
 }
+
 #endif /* CONFIG_IMA_H */
+
+#ifdef CONFIG_IMA_APPRAISE
+extern void ima_inode_post_setattr(struct dentry *dentry);
+#else
+static inline void ima_inode_post_setattr(struct dentry *dentry)
+{
+	return;
+}
+#endif /* CONFIG_IMA_APPRAISE_H */
 #endif /* _LINUX_IMA_H */
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 7/9] ima: add ima_inode_setxattr/removexattr function and calls
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (5 preceding siblings ...)
  2012-01-30 22:14 ` [RFC][PATCH v1 6/9] ima: add inode_post_setattr call Mimi Zohar
@ 2012-01-30 22:14 ` Mimi Zohar
  2012-01-30 22:14 ` [RFC][PATCH v1 8/9] ima: add support for different security.ima data types Mimi Zohar
  2012-01-30 22:14 ` [RFC][PATCH v1 9/9] ima: digital signature verification support Mimi Zohar
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:14 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Mimi Zohar

Based on xattr_permission comments, the restriction to modify 'security'
xattr is left up to the underlying fs or lsm. Ensure that not just anyone
can modify or remove 'security.ima'.

Changelog v1:
- Unless IMA-APPRAISE is configured, use stub ima_inode_removexattr()/setxattr()
  functions.  (Moved ima_inode_removexattr()/setxattr() to ima_appraise.c)

Changelog:
  - take i_mutex to fix locking (Dmitry Kasatkin)
  - ima_reset_appraise_flags should only be called when modifying or
    removing the 'security.ima' xattr. Requires CAP_SYS_ADMIN privilege.
    (Incorporated fix from Roberto Sassu)
  - Even if allowed to update security.ima, reset the appraisal flags,
    forcing re-appraisal.
  - Replace CAP_MAC_ADMIN with CAP_SYS_ADMIN
  - static inline ima_inode_setxattr()/ima_inode_removexattr() stubs
  - ima_protect_xattr should be static

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
 include/linux/ima.h                   |   17 ++++++++++
 security/integrity/ima/ima_appraise.c |   57 +++++++++++++++++++++++++++++++++
 security/security.c                   |    6 +++
 3 files changed, 80 insertions(+), 0 deletions(-)

diff --git a/include/linux/ima.h b/include/linux/ima.h
index e2bfbb1..2c7223d 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -44,10 +44,27 @@ static inline int ima_file_mmap(struct file *file, unsigned long prot)
 
 #ifdef CONFIG_IMA_APPRAISE
 extern void ima_inode_post_setattr(struct dentry *dentry);
+extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
+		       const void *xattr_value, size_t xattr_value_len);
+extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
 #else
 static inline void ima_inode_post_setattr(struct dentry *dentry)
 {
 	return;
 }
+
+static inline int ima_inode_setxattr(struct dentry *dentry,
+				     const char *xattr_name,
+				     const void *xattr_value,
+				     size_t xattr_value_len)
+{
+	return 0;
+}
+
+static inline int ima_inode_removexattr(struct dentry *dentry,
+					const char *xattr_name)
+{
+	return 0;
+}
 #endif /* CONFIG_IMA_APPRAISE_H */
 #endif /* _LINUX_IMA_H */
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 392ceb2..5fd90fc 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -168,3 +168,60 @@ void ima_inode_post_setattr(struct dentry *dentry)
 		rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
 	return;
 }
+
+/*
+ * ima_protect_xattr - protect 'security.ima'
+ *
+ * Ensure that not just anyone can modify or remove 'security.ima'.
+ */
+static int ima_protect_xattr(struct dentry *dentry, const char *xattr_name,
+			     const void *xattr_value, size_t xattr_value_len)
+{
+	if (strcmp(xattr_name, XATTR_NAME_IMA) == 0) {
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		return 1;
+	}
+	return 0;
+}
+
+static void ima_reset_appraise_flags(struct inode *inode)
+{
+	struct integrity_iint_cache *iint;
+
+	if (!ima_initialized || !ima_appraise || !S_ISREG(inode->i_mode))
+		return;
+
+	iint = integrity_iint_find(inode);
+	if (!iint)
+		return;
+
+	iint->flags &= ~(IMA_COLLECTED | IMA_APPRAISED | IMA_MEASURED);
+	return;
+}
+
+int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
+		       const void *xattr_value, size_t xattr_value_len)
+{
+	int result;
+
+	result = ima_protect_xattr(dentry, xattr_name, xattr_value,
+				   xattr_value_len);
+	if (result == 1) {
+		ima_reset_appraise_flags(dentry->d_inode);
+		result = 0;
+	}
+	return result;
+}
+
+int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name)
+{
+	int result;
+
+	result = ima_protect_xattr(dentry, xattr_name, NULL, 0);
+	if (result == 1) {
+		ima_reset_appraise_flags(dentry->d_inode);
+		result = 0;
+	}
+	return result;
+}
diff --git a/security/security.c b/security/security.c
index 556c64c..1203077 100644
--- a/security/security.c
+++ b/security/security.c
@@ -569,6 +569,9 @@ int security_inode_setxattr(struct dentry *dentry, const char *name,
 	ret = security_ops->inode_setxattr(dentry, name, value, size, flags);
 	if (ret)
 		return ret;
+	ret = ima_inode_setxattr(dentry, name, value, size);
+	if (ret)
+		return ret;
 	return evm_inode_setxattr(dentry, name, value, size);
 }
 
@@ -604,6 +607,9 @@ int security_inode_removexattr(struct dentry *dentry, const char *name)
 	ret = security_ops->inode_removexattr(dentry, name);
 	if (ret)
 		return ret;
+	ret = ima_inode_removexattr(dentry, name);
+	if (ret)
+		return ret;
 	return evm_inode_removexattr(dentry, name);
 }
 
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 8/9] ima: add support for different security.ima data types
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (6 preceding siblings ...)
  2012-01-30 22:14 ` [RFC][PATCH v1 7/9] ima: add ima_inode_setxattr/removexattr function and calls Mimi Zohar
@ 2012-01-30 22:14 ` Mimi Zohar
  2012-01-30 22:14 ` [RFC][PATCH v1 9/9] ima: digital signature verification support Mimi Zohar
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:14 UTC (permalink / raw)
  To: linux-security-module
  Cc: Mimi Zohar, linux-kernel, linux-fsdevel, David Safford,
	Dmitry Kasatkin, Dmitry Kasatkin

IMA-appraisal currently verifies the integrity of a file based on a
known 'good' measurement value.  This patch reserves the first byte
of 'security.ima' as a place holder for the type of method used for
verifying file data integrity.

Changelog v1:
- Use the newly defined 'struct evm_ima_xattr_data'

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
 security/integrity/ima/ima_api.c      |    6 +++---
 security/integrity/ima/ima_appraise.c |   23 +++++++++++++----------
 security/integrity/integrity.h        |    2 +-
 3 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index d73b13e..e1f6019 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -147,8 +147,8 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 	if (!(iint->flags & IMA_COLLECTED)) {
 		u64 i_version = file->f_dentry->d_inode->i_version;
 
-		memset(iint->digest, 0, IMA_DIGEST_SIZE);
-		result = ima_calc_hash(file, iint->digest);
+		iint->ima_xattr.type = IMA_XATTR_DIGEST;
+		result = ima_calc_hash(file, iint->ima_xattr.digest);
 		if (!result) {
 			iint->version = i_version;
 			iint->flags |= IMA_COLLECTED;
@@ -195,7 +195,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
 		return;
 	}
 	memset(&entry->template, 0, sizeof(entry->template));
-	memcpy(entry->template.digest, iint->digest, IMA_DIGEST_SIZE);
+	memcpy(entry->template.digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE);
 	strncpy(entry->template.file_name, filename, IMA_EVENT_NAME_LEN_MAX);
 
 	result = ima_store_template(entry, violation, inode);
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 5fd90fc..3deb37f 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -47,9 +47,9 @@ int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask)
 static void ima_fix_xattr(struct dentry *dentry,
 			  struct integrity_iint_cache *iint)
 {
-	iint->digest[0] = IMA_XATTR_DIGEST;
-	__vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
-			      iint->digest, IMA_DIGEST_SIZE + 1, 0);
+	iint->ima_xattr.type = IMA_XATTR_DIGEST;
+	__vfs_setxattr_noperm(dentry, XATTR_NAME_IMA, (u8 *)&iint->ima_xattr,
+			      sizeof iint->ima_xattr, 0);
 }
 
 /*
@@ -65,7 +65,7 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 {
 	struct dentry *dentry = file->f_dentry;
 	struct inode *inode = dentry->d_inode;
-	u8 xattr_value[IMA_DIGEST_SIZE];
+	struct evm_ima_xattr_data xattr_value;
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	const char *op = "appraise_data";
 	char *cause = "unknown";
@@ -76,8 +76,8 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 	if (iint->flags & IMA_APPRAISED)
 		return iint->ima_status;
 
-	rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, xattr_value,
-				   IMA_DIGEST_SIZE);
+	rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
+				   sizeof xattr_value);
 	if (rc <= 0) {
 		if (rc && rc != -ENODATA)
 			goto out;
@@ -88,7 +88,8 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 		goto out;
 	}
 
-	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
+	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
+				 rc, iint);
 	if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
 		if ((status == INTEGRITY_NOLABEL)
 		    || (status == INTEGRITY_NOXATTRS))
@@ -98,14 +99,16 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 		goto out;
 	}
 
-	rc = memcmp(xattr_value, iint->digest, IMA_DIGEST_SIZE);
+	rc = memcmp(xattr_value.digest, iint->ima_xattr.digest,
+		    IMA_DIGEST_SIZE);
 	if (rc) {
 		status = INTEGRITY_FAIL;
 		cause = "invalid-hash";
 		print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE,
-				     xattr_value, IMA_DIGEST_SIZE);
+				     &xattr_value, sizeof xattr_value);
 		print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE,
-				     iint->digest, IMA_DIGEST_SIZE);
+				     (u8 *)&iint->ima_xattr,
+				     sizeof iint->ima_xattr);
 		goto out;
 	}
 	status = INTEGRITY_PASS;
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 295702d..c145331 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -39,7 +39,7 @@ struct integrity_iint_cache {
 	struct inode *inode;	/* back pointer to inode in question */
 	u64 version;		/* track inode changes */
 	unsigned char flags;
-	u8 digest[SHA1_DIGEST_SIZE];
+	struct evm_ima_xattr_data ima_xattr;
 	enum integrity_status ima_status;
 	enum integrity_status evm_status;
 };
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* [RFC][PATCH v1 9/9] ima: digital signature verification support
  2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
                   ` (7 preceding siblings ...)
  2012-01-30 22:14 ` [RFC][PATCH v1 8/9] ima: add support for different security.ima data types Mimi Zohar
@ 2012-01-30 22:14 ` Mimi Zohar
  8 siblings, 0 replies; 13+ messages in thread
From: Mimi Zohar @ 2012-01-30 22:14 UTC (permalink / raw)
  To: linux-security-module
  Cc: Dmitry Kasatkin, linux-kernel, linux-fsdevel, David Safford, Mimi Zohar

From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>

This patch adds support for digital signature based integrity appraisal.
With this patch, 'security.ima' contains either the file data hash or
a digital signature of the file data hash. The file data hash provides
the security attribute of file integrity. In addition to file integrity,
a digital signature provides the security attribute of authenticity.

Unlike EVM, when the file metadata changes, the digital signature is
replaced with an HMAC, modification of the file data does not cause the
'security.ima' digital signature to be replaced with a hash. As a
result, after any modification, subsequent file integrity appraisals
would fail.

Although digitally signed files can be modified, but by not updating
'security.ima' to reflect these modifications, in essence digitally
signed files could be considered 'immutable'.

IMA uses a different keyring than EVM. While the EVM keyring should not
be updated after initialization and locked, the IMA keyring should allow
updating or adding new keys when upgrading or installing packages.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
 security/integrity/ima/ima_appraise.c |   69 ++++++++++++++++++++++++---------
 security/integrity/integrity.h        |    1 +
 2 files changed, 51 insertions(+), 19 deletions(-)

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 3deb37f..fad87c3 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -65,7 +65,7 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 {
 	struct dentry *dentry = file->f_dentry;
 	struct inode *inode = dentry->d_inode;
-	struct evm_ima_xattr_data xattr_value;
+	struct evm_ima_xattr_data *xattr_value = NULL;
 	enum integrity_status status = INTEGRITY_UNKNOWN;
 	const char *op = "appraise_data";
 	char *cause = "unknown";
@@ -76,8 +76,8 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 	if (iint->flags & IMA_APPRAISED)
 		return iint->ima_status;
 
-	rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
-				   sizeof xattr_value);
+	rc = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)&xattr_value,
+				0, GFP_NOFS);
 	if (rc <= 0) {
 		if (rc && rc != -ENODATA)
 			goto out;
@@ -88,8 +88,7 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 		goto out;
 	}
 
-	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
-				 rc, iint);
+	status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
 	if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
 		if ((status == INTEGRITY_NOLABEL)
 		    || (status == INTEGRITY_NOXATTRS))
@@ -99,30 +98,57 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 		goto out;
 	}
 
-	rc = memcmp(xattr_value.digest, iint->ima_xattr.digest,
-		    IMA_DIGEST_SIZE);
-	if (rc) {
-		status = INTEGRITY_FAIL;
-		cause = "invalid-hash";
-		print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE,
-				     &xattr_value, sizeof xattr_value);
-		print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE,
-				     (u8 *)&iint->ima_xattr,
-				     sizeof iint->ima_xattr);
-		goto out;
+	switch (xattr_value->type) {
+	case IMA_XATTR_DIGEST:
+		rc = memcmp(xattr_value->digest, iint->ima_xattr.digest,
+			    IMA_DIGEST_SIZE);
+		if (rc) {
+			cause = "invalid-hash";
+			status = INTEGRITY_FAIL;
+			print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE,
+					     xattr_value, sizeof(*xattr_value));
+			print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE,
+					     (u8 *)&iint->ima_xattr,
+					     sizeof iint->ima_xattr);
+			break;
+		}
+		status = INTEGRITY_PASS;
+		break;
+	case EVM_IMA_XATTR_DIGSIG:
+		iint->flags |= IMA_DIGSIG;
+		rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
+					     xattr_value->digest, rc - 1,
+					     iint->ima_xattr.digest,
+					     IMA_DIGEST_SIZE);
+		if (rc == -EOPNOTSUPP) {
+			status = INTEGRITY_UNKNOWN;
+		} else if (rc) {
+			cause = "invalid-signature";
+			status = INTEGRITY_FAIL;
+		} else {
+			status = INTEGRITY_PASS;
+		}
+		break;
+	default:
+		status = INTEGRITY_UNKNOWN;
+		cause = "unknown-ima-data";
+		break;
 	}
-	status = INTEGRITY_PASS;
-	iint->flags |= IMA_APPRAISED;
+
 out:
 	if (status != INTEGRITY_PASS) {
-		if (ima_appraise & IMA_APPRAISE_FIX) {
+		if ((ima_appraise & IMA_APPRAISE_FIX) &&
+		    (xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
 			ima_fix_xattr(dentry, iint);
 			status = INTEGRITY_PASS;
 		}
 		integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
 				    op, cause, 1, 0);
+	} else {
+		iint->flags |= IMA_APPRAISED;
 	}
 	iint->ima_status = status;
+	kfree(xattr_value);
 	return status;
 }
 
@@ -134,9 +160,14 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
 	struct dentry *dentry = file->f_dentry;
 	int rc = 0;
 
+	/* do not collect and update hash for digital signatures */
+	if (iint->flags & IMA_DIGSIG)
+		return;
+
 	rc = ima_collect_measurement(iint, file);
 	if (rc < 0)
 		return;
+
 	ima_fix_xattr(dentry, iint);
 }
 
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index c145331..0594a57 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -21,6 +21,7 @@
 #define IMA_APPRAISE		4
 #define IMA_APPRAISED		8
 #define IMA_COLLECTED		16
+#define IMA_DIGSIG		32
 
 enum evm_ima_xattr_type {
 	IMA_XATTR_DIGEST = 0x01,
-- 
1.7.6.5


^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [RFC][PATCH v1 5/9] ima: allocating iint improvements
  2012-01-30 22:14 ` [RFC][PATCH v1 5/9] ima: allocating iint improvements Mimi Zohar
@ 2012-02-01 16:58   ` Eric Paris
  2012-02-01 18:46     ` Kasatkin, Dmitry
  0 siblings, 1 reply; 13+ messages in thread
From: Eric Paris @ 2012-02-01 16:58 UTC (permalink / raw)
  To: Mimi Zohar
  Cc: linux-security-module, Dmitry Kasatkin, linux-kernel,
	linux-fsdevel, David Safford, Mimi Zohar

On Mon, Jan 30, 2012 at 5:14 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
>

>  static struct rb_root integrity_iint_tree = RB_ROOT;
> -static DEFINE_SPINLOCK(integrity_iint_lock);
> +static DEFINE_RWLOCK(integrity_iint_lock);
>  static struct kmem_cache *iint_cache __read_mostly;

Has any profiling been done here?   rwlocks have been shown to
actually be slower on multi processor systems in a number of cases due
to the cache line bouncing required.  I believe the current kernel
logic is that if you have a short critical section and you can't show
profile data the rwlocks are better, just stick with a spinlock.

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [RFC][PATCH v1 5/9] ima: allocating iint improvements
  2012-02-01 16:58   ` Eric Paris
@ 2012-02-01 18:46     ` Kasatkin, Dmitry
  2012-02-09  9:40       ` Kasatkin, Dmitry
  0 siblings, 1 reply; 13+ messages in thread
From: Kasatkin, Dmitry @ 2012-02-01 18:46 UTC (permalink / raw)
  To: Eric Paris
  Cc: Mimi Zohar, linux-security-module, linux-kernel, linux-fsdevel,
	David Safford, Mimi Zohar

On Wed, Feb 1, 2012 at 6:58 PM, Eric Paris <eparis@parisplace.org> wrote:
> On Mon, Jan 30, 2012 at 5:14 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
>> From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
>>
>
>>  static struct rb_root integrity_iint_tree = RB_ROOT;
>> -static DEFINE_SPINLOCK(integrity_iint_lock);
>> +static DEFINE_RWLOCK(integrity_iint_lock);
>>  static struct kmem_cache *iint_cache __read_mostly;
>
> Has any profiling been done here?   rwlocks have been shown to
> actually be slower on multi processor systems in a number of cases due
> to the cache line bouncing required.  I believe the current kernel
> logic is that if you have a short critical section and you can't show
> profile data the rwlocks are better, just stick with a spinlock.

No, I have not done any profiling.
My assumption was that rwlocks are better when there many readers.
If what you say is true then rwlocks are useless...
With big sections it is necessary to use rw semaphores.

- Dmitry

^ permalink raw reply	[flat|nested] 13+ messages in thread

* Re: [RFC][PATCH v1 5/9] ima: allocating iint improvements
  2012-02-01 18:46     ` Kasatkin, Dmitry
@ 2012-02-09  9:40       ` Kasatkin, Dmitry
  0 siblings, 0 replies; 13+ messages in thread
From: Kasatkin, Dmitry @ 2012-02-09  9:40 UTC (permalink / raw)
  To: Eric Paris
  Cc: Mimi Zohar, linux-security-module, linux-kernel, linux-fsdevel,
	David Safford, Mimi Zohar

On Wed, Feb 1, 2012 at 8:46 PM, Kasatkin, Dmitry
<dmitry.kasatkin@intel.com> wrote:
> On Wed, Feb 1, 2012 at 6:58 PM, Eric Paris <eparis@parisplace.org> wrote:
>> On Mon, Jan 30, 2012 at 5:14 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
>>> From: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
>>>
>>
>>>  static struct rb_root integrity_iint_tree = RB_ROOT;
>>> -static DEFINE_SPINLOCK(integrity_iint_lock);
>>> +static DEFINE_RWLOCK(integrity_iint_lock);
>>>  static struct kmem_cache *iint_cache __read_mostly;
>>
>> Has any profiling been done here?   rwlocks have been shown to
>> actually be slower on multi processor systems in a number of cases due
>> to the cache line bouncing required.  I believe the current kernel
>> logic is that if you have a short critical section and you can't show
>> profile data the rwlocks are better, just stick with a spinlock.
>
> No, I have not done any profiling.
> My assumption was that rwlocks are better when there many readers.
> If what you say is true then rwlocks are useless...
> With big sections it is necessary to use rw semaphores.
>

Hello,

I and Mimi made performance measurements with rwlocks and spinlocks.
We used kernel compilation with multiple jobs as a test,
because it reads and creates lots of files..

In all cases rwlocks implementation performed better than spinlocks,
but very insignificantly. For example with total compilation time
around 6 minutes, with rwlocks time was 1 - 3 seconds shorter... But
always like that.

So as conclusion I can make, that usage of rwlocks is justified...

Thanks for bringing this up...

> - Dmitry

^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2012-02-09  9:40 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-01-30 22:13 [RFC][PATCH v1 0/9] ima: appraisal extension Mimi Zohar
2012-01-30 22:13 ` [RFC][PATCH v1 1/9] vfs: extend vfs_removexattr locking Mimi Zohar
2012-01-30 22:13 ` [RFC][PATCH v1 2/9] vfs: move ima_file_free before releasing the file Mimi Zohar
2012-01-30 22:13 ` [RFC][PATCH v1 3/9] ima: integrity appraisal extension Mimi Zohar
2012-01-30 22:13 ` [RFC][PATCH v1 4/9] ima: add appraise action keywords and default rules Mimi Zohar
2012-01-30 22:14 ` [RFC][PATCH v1 5/9] ima: allocating iint improvements Mimi Zohar
2012-02-01 16:58   ` Eric Paris
2012-02-01 18:46     ` Kasatkin, Dmitry
2012-02-09  9:40       ` Kasatkin, Dmitry
2012-01-30 22:14 ` [RFC][PATCH v1 6/9] ima: add inode_post_setattr call Mimi Zohar
2012-01-30 22:14 ` [RFC][PATCH v1 7/9] ima: add ima_inode_setxattr/removexattr function and calls Mimi Zohar
2012-01-30 22:14 ` [RFC][PATCH v1 8/9] ima: add support for different security.ima data types Mimi Zohar
2012-01-30 22:14 ` [RFC][PATCH v1 9/9] ima: digital signature verification support Mimi Zohar

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