Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security layer updates from James Morris:
 "In terms of changes, there's general maintenance to the Smack,
  SELinux, and integrity code.

  The IMA code adds a new kconfig option, IMA_APPRAISE_SIGNED_INIT,
  which allows IMA appraisal to require signatures.  Support for reading
  keys from rootfs before init is call is also added"

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (23 commits)
  selinux: Remove security_ops extern
  security: smack: fix out-of-bounds access in smk_parse_smack()
  VFS: refactor vfs_read()
  ima: require signature based appraisal
  integrity: provide a hook to load keys when rootfs is ready
  ima: load x509 certificate from the kernel
  integrity: provide a function to load x509 certificate from the kernel
  integrity: define a new function integrity_read_file()
  Security: smack: replace kzalloc with kmem_cache for inode_smack
  Smack: Lock mode for the floor and hat labels
  ima: added support for new kernel cmdline parameter ima_template_fmt
  ima: allocate field pointers array on demand in template_desc_init_fields()
  ima: don't allocate a copy of template_fmt in template_desc_init_fields()
  ima: display template format in meas. list if template name length is zero
  ima: added error messages to template-related functions
  ima: use atomic bit operations to protect policy update interface
  ima: ignore empty and with whitespaces policy lines
  ima: no need to allocate entry for comment
  ima: report policy load status
  ima: use path names cache
  ...

8 files changed, 164 insertions, 107 deletions

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index e099875..b80a93e 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -131,3 +131,28 @@ config IMA_TRUSTED_KEYRING
 	help
 	   This option requires that all keys added to the .ima
 	   keyring be signed by a key on the system trusted keyring.
+
+config IMA_LOAD_X509
+	bool "Load X509 certificate onto the '.ima' trusted keyring"
+	depends on IMA_TRUSTED_KEYRING
+	default n
+	help
+	   File signature verification is based on the public keys
+	   loaded on the .ima trusted keyring. These public keys are
+	   X509 certificates signed by a trusted key on the
+	   .system keyring.  This option enables X509 certificate
+	   loading from the kernel onto the '.ima' trusted keyring.
+
+config IMA_X509_PATH
+	string "IMA X509 certificate path"
+	depends on IMA_LOAD_X509
+	default "/etc/keys/x509_ima.der"
+	help
+	   This option defines IMA X509 certificate path.
+
+config IMA_APPRAISE_SIGNED_INIT
+	bool "Require signed user-space initialization"
+	depends on IMA_LOAD_X509
+	default n
+	help
+	   This option requires user-space init to be signed.
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index f92be1b..b8a27c5 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -173,8 +173,7 @@ int ima_get_action(struct inode *inode, int mask, int function)
 {
 	int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE;
 
-	if (!ima_appraise)
-		flags &= ~IMA_APPRAISE;
+	flags &= ima_policy_flag;
 
 	return ima_match_policy(inode, function, mask, flags);
 }
@@ -325,11 +324,11 @@ const char *ima_d_path(struct path *path, char **pathbuf)
 {
 	char *pathname = NULL;
 
-	*pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+	*pathbuf = __getname();
 	if (*pathbuf) {
 		pathname = d_absolute_path(path, *pathbuf, PATH_MAX);
 		if (IS_ERR(pathname)) {
-			kfree(*pathbuf);
+			__putname(*pathbuf);
 			*pathbuf = NULL;
 			pathname = NULL;
 		}
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 78d66da..686355f 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -67,36 +67,6 @@ MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
 static struct crypto_shash *ima_shash_tfm;
 static struct crypto_ahash *ima_ahash_tfm;
 
-/**
- * ima_kernel_read - read file content
- *
- * This is a function for reading file content instead of kernel_read().
- * It does not perform locking checks to ensure it cannot be blocked.
- * It does not perform security checks because it is irrelevant for IMA.
- *
- */
-static int ima_kernel_read(struct file *file, loff_t offset,
-			   char *addr, unsigned long count)
-{
-	mm_segment_t old_fs;
-	char __user *buf = addr;
-	ssize_t ret = -EINVAL;
-
-	if (!(file->f_mode & FMODE_READ))
-		return -EBADF;
-
-	old_fs = get_fs();
-	set_fs(get_ds());
-	if (file->f_op->read)
-		ret = file->f_op->read(file, buf, count, &offset);
-	else if (file->f_op->aio_read)
-		ret = do_sync_read(file, buf, count, &offset);
-	else if (file->f_op->read_iter)
-		ret = new_sync_read(file, buf, count, &offset);
-	set_fs(old_fs);
-	return ret;
-}
-
 int __init ima_init_crypto(void)
 {
 	long rc;
@@ -324,7 +294,8 @@ static int ima_calc_file_hash_atfm(struct file *file,
 		}
 		/* read buffer */
 		rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
-		rc = ima_kernel_read(file, offset, rbuf[active], rbuf_len);
+		rc = integrity_kernel_read(file, offset, rbuf[active],
+					   rbuf_len);
 		if (rc != rbuf_len)
 			goto out3;
 
@@ -414,7 +385,7 @@ static int ima_calc_file_hash_tfm(struct file *file,
 	while (offset < i_size) {
 		int rbuf_len;
 
-		rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);
+		rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE);
 		if (rbuf_len < 0) {
 			rc = rbuf_len;
 			break;
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index da92fcc..461215e 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -118,6 +118,7 @@ static int ima_measurements_show(struct seq_file *m, void *v)
 	/* the list never shrinks, so we don't need a lock here */
 	struct ima_queue_entry *qe = v;
 	struct ima_template_entry *e;
+	char *template_name;
 	int namelen;
 	u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 	bool is_ima_template = false;
@@ -128,6 +129,9 @@ static int ima_measurements_show(struct seq_file *m, void *v)
 	if (e == NULL)
 		return -1;
 
+	template_name = (e->template_desc->name[0] != '\0') ?
+	    e->template_desc->name : e->template_desc->fmt;
+
 	/*
 	 * 1st: PCRIndex
 	 * PCR used is always the same (config option) in
@@ -139,14 +143,14 @@ static int ima_measurements_show(struct seq_file *m, void *v)
 	ima_putc(m, e->digest, TPM_DIGEST_SIZE);
 
 	/* 3rd: template name size */
-	namelen = strlen(e->template_desc->name);
+	namelen = strlen(template_name);
 	ima_putc(m, &namelen, sizeof(namelen));
 
 	/* 4th:  template name */
-	ima_putc(m, e->template_desc->name, namelen);
+	ima_putc(m, template_name, namelen);
 
 	/* 5th:  template length (except for 'ima' template) */
-	if (strcmp(e->template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0)
+	if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0)
 		is_ima_template = true;
 
 	if (!is_ima_template)
@@ -200,6 +204,7 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	/* the list never shrinks, so we don't need a lock here */
 	struct ima_queue_entry *qe = v;
 	struct ima_template_entry *e;
+	char *template_name;
 	int i;
 
 	/* get entry */
@@ -207,6 +212,9 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	if (e == NULL)
 		return -1;
 
+	template_name = (e->template_desc->name[0] != '\0') ?
+	    e->template_desc->name : e->template_desc->fmt;
+
 	/* 1st: PCR used (config option) */
 	seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
 
@@ -214,7 +222,7 @@ static int ima_ascii_measurements_show(struct seq_file *m, void *v)
 	ima_print_digest(m, e->digest, TPM_DIGEST_SIZE);
 
 	/* 3th:  template name */
-	seq_printf(m, " %s", e->template_desc->name);
+	seq_printf(m, " %s", template_name);
 
 	/* 4th:  template specific data */
 	for (i = 0; i < e->template_desc->num_fields; i++) {
@@ -288,7 +296,12 @@ static struct dentry *runtime_measurements_count;
 static struct dentry *violations;
 static struct dentry *ima_policy;
 
-static atomic_t policy_opencount = ATOMIC_INIT(1);
+enum ima_fs_flags {
+	IMA_FS_BUSY,
+};
+
+static unsigned long ima_fs_flags;
+
 /*
  * ima_open_policy: sequentialize access to the policy file
  */
@@ -297,9 +310,9 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
 	/* No point in being allowed to open it if you aren't going to write */
 	if (!(filp->f_flags & O_WRONLY))
 		return -EACCES;
-	if (atomic_dec_and_test(&policy_opencount))
-		return 0;
-	return -EBUSY;
+	if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags))
+		return -EBUSY;
+	return 0;
 }
 
 /*
@@ -311,10 +324,16 @@ static int ima_open_policy(struct inode *inode, struct file *filp)
  */
 static int ima_release_policy(struct inode *inode, struct file *file)
 {
+	const char *cause = valid_policy ? "completed" : "failed";
+
+	pr_info("IMA: policy update %s\n", cause);
+	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
+			    "policy_update", cause, !valid_policy, 0);
+
 	if (!valid_policy) {
 		ima_delete_rules();
 		valid_policy = 1;
-		atomic_set(&policy_opencount, 1);
+		clear_bit(IMA_FS_BUSY, &ima_fs_flags);
 		return 0;
 	}
 	ima_update_policy();
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 9164fc8..5e4c29d 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -24,6 +24,12 @@
 #include <crypto/hash_info.h>
 #include "ima.h"
 
+#ifdef CONFIG_IMA_X509_PATH
+#define IMA_X509_PATH	CONFIG_IMA_X509_PATH
+#else
+#define IMA_X509_PATH	"/etc/keys/x509_ima.der"
+#endif
+
 /* name for boot aggregate entry */
 static const char *boot_aggregate_name = "boot_aggregate";
 int ima_used_chip;
@@ -91,6 +97,17 @@ err_out:
 	return result;
 }
 
+#ifdef CONFIG_IMA_LOAD_X509
+void __init ima_load_x509(void)
+{
+	int unset_flags = ima_policy_flag & IMA_APPRAISE;
+
+	ima_policy_flag &= ~unset_flags;
+	integrity_load_x509(INTEGRITY_KEYRING_IMA, IMA_X509_PATH);
+	ima_policy_flag |= unset_flags;
+}
+#endif
+
 int __init ima_init(void)
 {
 	u8 pcr_i[TPM_DIGEST_SIZE];
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 62f59ec..eeee00dc 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -143,7 +143,7 @@ void ima_file_free(struct file *file)
 	struct inode *inode = file_inode(file);
 	struct integrity_iint_cache *iint;
 
-	if (!iint_initialized || !S_ISREG(inode->i_mode))
+	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
 		return;
 
 	iint = integrity_iint_find(inode);
@@ -246,7 +246,8 @@ out_digsig:
 		rc = -EACCES;
 	kfree(xattr_value);
 out_free:
-	kfree(pathbuf);
+	if (pathbuf)
+		__putname(pathbuf);
 out:
 	mutex_unlock(&inode->i_mutex);
 	if ((rc && must_appraise) && (ima_appraise & IMA_APPRAISE_ENFORCE))
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index cdc620b..d1eefb9 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -100,7 +100,13 @@ static struct ima_rule_entry default_appraise_rules[] = {
 	{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 	{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 	{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
+#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
+#else
+	/* force signature */
+	{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
+	 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
+#endif
 };
 
 static LIST_HEAD(ima_default_rules);
@@ -356,19 +362,8 @@ void __init ima_init_policy(void)
  */
 void ima_update_policy(void)
 {
-	static const char op[] = "policy_update";
-	const char *cause = "already-exists";
-	int result = 1;
-	int audit_info = 0;
-
-	if (ima_rules == &ima_default_rules) {
-		ima_rules = &ima_policy_rules;
-		ima_update_policy_flag();
-		cause = "complete";
-		result = 0;
-	}
-	integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
-			    NULL, op, cause, result, audit_info);
+	ima_rules = &ima_policy_rules;
+	ima_update_policy_flag();
 }
 
 enum {
@@ -686,13 +681,12 @@ ssize_t ima_parse_add_rule(char *rule)
 	ssize_t result, len;
 	int audit_info = 0;
 
-	/* Prevent installed policy from changing */
-	if (ima_rules != &ima_default_rules) {
-		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
-				    NULL, op, "already-exists",
-				    -EACCES, audit_info);
-		return -EACCES;
-	}
+	p = strsep(&rule, "\n");
+	len = strlen(p) + 1;
+	p += strspn(p, " \t");
+
+	if (*p == '#' || *p == '\0')
+		return len;
 
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry) {
@@ -703,14 +697,6 @@ ssize_t ima_parse_add_rule(char *rule)
 
 	INIT_LIST_HEAD(&entry->list);
 
-	p = strsep(&rule, "\n");
-	len = strlen(p) + 1;
-
-	if (*p == '#') {
-		kfree(entry);
-		return len;
-	}
-
 	result = ima_parse_rule(p, entry);
 	if (result) {
 		kfree(entry);
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index e854862..0b7404e 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -24,6 +24,7 @@ static struct ima_template_desc defined_templates[] = {
 	{.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT},
 	{.name = "ima-ng", .fmt = "d-ng|n-ng"},
 	{.name = "ima-sig", .fmt = "d-ng|n-ng|sig"},
+	{.name = "", .fmt = ""},	/* placeholder for a custom format */
 };
 
 static struct ima_template_field supported_fields[] = {
@@ -41,19 +42,28 @@ static struct ima_template_field supported_fields[] = {
 
 static struct ima_template_desc *ima_template;
 static struct ima_template_desc *lookup_template_desc(const char *name);
+static int template_desc_init_fields(const char *template_fmt,
+				     struct ima_template_field ***fields,
+				     int *num_fields);
 
 static int __init ima_template_setup(char *str)
 {
 	struct ima_template_desc *template_desc;
 	int template_len = strlen(str);
 
+	if (ima_template)
+		return 1;
+
 	/*
 	 * Verify that a template with the supplied name exists.
 	 * If not, use CONFIG_IMA_DEFAULT_TEMPLATE.
 	 */
 	template_desc = lookup_template_desc(str);
-	if (!template_desc)
+	if (!template_desc) {
+		pr_err("template %s not found, using %s\n",
+		       str, CONFIG_IMA_DEFAULT_TEMPLATE);
 		return 1;
+	}
 
 	/*
 	 * Verify whether the current hash algorithm is supported
@@ -70,6 +80,25 @@ static int __init ima_template_setup(char *str)
 }
 __setup("ima_template=", ima_template_setup);
 
+static int __init ima_template_fmt_setup(char *str)
+{
+	int num_templates = ARRAY_SIZE(defined_templates);
+
+	if (ima_template)
+		return 1;
+
+	if (template_desc_init_fields(str, NULL, NULL) < 0) {
+		pr_err("format string '%s' not valid, using template %s\n",
+		       str, CONFIG_IMA_DEFAULT_TEMPLATE);
+		return 1;
+	}
+
+	defined_templates[num_templates - 1].fmt = str;
+	ima_template = defined_templates + num_templates - 1;
+	return 1;
+}
+__setup("ima_template_fmt=", ima_template_fmt_setup);
+
 static struct ima_template_desc *lookup_template_desc(const char *name)
 {
 	int i;
@@ -113,43 +142,46 @@ static int template_desc_init_fields(const char *template_fmt,
 				     struct ima_template_field ***fields,
 				     int *num_fields)
 {
-	char *c, *template_fmt_copy, *template_fmt_ptr;
+	const char *template_fmt_ptr;
+	struct ima_template_field *found_fields[IMA_TEMPLATE_NUM_FIELDS_MAX];
 	int template_num_fields = template_fmt_size(template_fmt);
-	int i, result = 0;
+	int i, len;
 
-	if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX)
+	if (template_num_fields > IMA_TEMPLATE_NUM_FIELDS_MAX) {
+		pr_err("format string '%s' contains too many fields\n",
+		       template_fmt);
 		return -EINVAL;
-
-	/* copying is needed as strsep() modifies the original buffer */
-	template_fmt_copy = kstrdup(template_fmt, GFP_KERNEL);
-	if (template_fmt_copy == NULL)
-		return -ENOMEM;
-
-	*fields = kzalloc(template_num_fields * sizeof(*fields), GFP_KERNEL);
-	if (*fields == NULL) {
-		result = -ENOMEM;
-		goto out;
 	}
 
-	template_fmt_ptr = template_fmt_copy;
-	for (i = 0; (c = strsep(&template_fmt_ptr, "|")) != NULL &&
-	     i < template_num_fields; i++) {
-		struct ima_template_field *f = lookup_template_field(c);
+	for (i = 0, template_fmt_ptr = template_fmt; i < template_num_fields;
+	     i++, template_fmt_ptr += len + 1) {
+		char tmp_field_id[IMA_TEMPLATE_FIELD_ID_MAX_LEN + 1];
+
+		len = strchrnul(template_fmt_ptr, '|') - template_fmt_ptr;
+		if (len == 0 || len > IMA_TEMPLATE_FIELD_ID_MAX_LEN) {
+			pr_err("Invalid field with length %d\n", len);
+			return -EINVAL;
+		}
 
-		if (!f) {
-			result = -ENOENT;
-			goto out;
+		memcpy(tmp_field_id, template_fmt_ptr, len);
+		tmp_field_id[len] = '\0';
+		found_fields[i] = lookup_template_field(tmp_field_id);
+		if (!found_fields[i]) {
+			pr_err("field '%s' not found\n", tmp_field_id);
+			return -ENOENT;
 		}
-		(*fields)[i] = f;
 	}
-	*num_fields = i;
-out:
-	if (result < 0) {
-		kfree(*fields);
-		*fields = NULL;
+
+	if (fields && num_fields) {
+		*fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL);
+		if (*fields == NULL)
+			return -ENOMEM;
+
+		memcpy(*fields, found_fields, i * sizeof(*fields));
+		*num_fields = i;
 	}
-	kfree(template_fmt_copy);
-	return result;
+
+	return 0;
 }
 
 struct ima_template_desc *ima_template_desc_current(void)
@@ -163,8 +195,15 @@ struct ima_template_desc *ima_template_desc_current(void)
 int __init ima_init_template(void)
 {
 	struct ima_template_desc *template = ima_template_desc_current();
+	int result;
+
+	result = template_desc_init_fields(template->fmt,
+					   &(template->fields),
+					   &(template->num_fields));
+	if (result < 0)
+		pr_err("template %s init failed, result: %d\n",
+		       (strlen(template->name) ?
+		       template->name : template->fmt), result);
 
-	return template_desc_init_fields(template->fmt,
-					 &(template->fields),
-					 &(template->num_fields));
+	return result;
 }