1 files changed, 522 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
new file mode 100644
index 000000000..cd1683dad
--- /dev/null
+++ b/security/integrity/ima/ima_fs.c
@@ -0,0 +1,522 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2005,2006,2007,2008 IBM Corporation
+ *
+ * Authors:
+ * Kylene Hall <kjhall@us.ibm.com>
+ * Reiner Sailer <sailer@us.ibm.com>
+ * Mimi Zohar <zohar@us.ibm.com>
+ *
+ * File: ima_fs.c
+ *	implemenents security file system for reporting
+ *	current measurement list and IMA statistics
+ */
+
+#include <linux/fcntl.h>
+#include <linux/kernel_read_file.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/parser.h>
+#include <linux/vmalloc.h>
+
+#include "ima.h"
+
+static DEFINE_MUTEX(ima_write_mutex);
+
+bool ima_canonical_fmt;
+static int __init default_canonical_fmt_setup(char *str)
+{
+#ifdef __BIG_ENDIAN
+	ima_canonical_fmt = true;
+#endif
+	return 1;
+}
+__setup("ima_canonical_fmt", default_canonical_fmt_setup);
+
+static int valid_policy = 1;
+
+static ssize_t ima_show_htable_value(char __user *buf, size_t count,
+				     loff_t *ppos, atomic_long_t *val)
+{
+	char tmpbuf[32];	/* greater than largest 'long' string value */
+	ssize_t len;
+
+	len = scnprintf(tmpbuf, sizeof(tmpbuf), "%li\n", atomic_long_read(val));
+	return simple_read_from_buffer(buf, count, ppos, tmpbuf, len);
+}
+
+static ssize_t ima_show_htable_violations(struct file *filp,
+					  char __user *buf,
+					  size_t count, loff_t *ppos)
+{
+	return ima_show_htable_value(buf, count, ppos, &ima_htable.violations);
+}
+
+static const struct file_operations ima_htable_violations_ops = {
+	.read = ima_show_htable_violations,
+	.llseek = generic_file_llseek,
+};
+
+static ssize_t ima_show_measurements_count(struct file *filp,
+					   char __user *buf,
+					   size_t count, loff_t *ppos)
+{
+	return ima_show_htable_value(buf, count, ppos, &ima_htable.len);
+
+}
+
+static const struct file_operations ima_measurements_count_ops = {
+	.read = ima_show_measurements_count,
+	.llseek = generic_file_llseek,
+};
+
+/* returns pointer to hlist_node */
+static void *ima_measurements_start(struct seq_file *m, loff_t *pos)
+{
+	loff_t l = *pos;
+	struct ima_queue_entry *qe;
+
+	/* we need a lock since pos could point beyond last element */
+	rcu_read_lock();
+	list_for_each_entry_rcu(qe, &ima_measurements, later) {
+		if (!l--) {
+			rcu_read_unlock();
+			return qe;
+		}
+	}
+	rcu_read_unlock();
+	return NULL;
+}
+
+static void *ima_measurements_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct ima_queue_entry *qe = v;
+
+	/* lock protects when reading beyond last element
+	 * against concurrent list-extension
+	 */
+	rcu_read_lock();
+	qe = list_entry_rcu(qe->later.next, struct ima_queue_entry, later);
+	rcu_read_unlock();
+	(*pos)++;
+
+	return (&qe->later == &ima_measurements) ? NULL : qe;
+}
+
+static void ima_measurements_stop(struct seq_file *m, void *v)
+{
+}
+
+void ima_putc(struct seq_file *m, void *data, int datalen)
+{
+	while (datalen--)
+		seq_putc(m, *(char *)data++);
+}
+
+/* print format:
+ *       32bit-le=pcr#
+ *       char[20]=template digest
+ *       32bit-le=template name size
+ *       char[n]=template name
+ *       [eventdata length]
+ *       eventdata[n]=template specific data
+ */
+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;
+	u32 pcr, namelen, template_data_len; /* temporary fields */
+	bool is_ima_template = false;
+	int i;
+
+	/* get entry */
+	e = qe->entry;
+	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 defaults to the same (config option) in
+	 * little-endian format, unless set in policy
+	 */
+	pcr = !ima_canonical_fmt ? e->pcr : (__force u32)cpu_to_le32(e->pcr);
+	ima_putc(m, &pcr, sizeof(e->pcr));
+
+	/* 2nd: template digest */
+	ima_putc(m, e->digests[ima_sha1_idx].digest, TPM_DIGEST_SIZE);
+
+	/* 3rd: template name size */
+	namelen = !ima_canonical_fmt ? strlen(template_name) :
+		(__force u32)cpu_to_le32(strlen(template_name));
+	ima_putc(m, &namelen, sizeof(namelen));
+
+	/* 4th:  template name */
+	ima_putc(m, template_name, strlen(template_name));
+
+	/* 5th:  template length (except for 'ima' template) */
+	if (strcmp(template_name, IMA_TEMPLATE_IMA_NAME) == 0)
+		is_ima_template = true;
+
+	if (!is_ima_template) {
+		template_data_len = !ima_canonical_fmt ? e->template_data_len :
+			(__force u32)cpu_to_le32(e->template_data_len);
+		ima_putc(m, &template_data_len, sizeof(e->template_data_len));
+	}
+
+	/* 6th:  template specific data */
+	for (i = 0; i < e->template_desc->num_fields; i++) {
+		enum ima_show_type show = IMA_SHOW_BINARY;
+		const struct ima_template_field *field =
+			e->template_desc->fields[i];
+
+		if (is_ima_template && strcmp(field->field_id, "d") == 0)
+			show = IMA_SHOW_BINARY_NO_FIELD_LEN;
+		if (is_ima_template && strcmp(field->field_id, "n") == 0)
+			show = IMA_SHOW_BINARY_OLD_STRING_FMT;
+		field->field_show(m, show, &e->template_data[i]);
+	}
+	return 0;
+}
+
+static const struct seq_operations ima_measurments_seqops = {
+	.start = ima_measurements_start,
+	.next = ima_measurements_next,
+	.stop = ima_measurements_stop,
+	.show = ima_measurements_show
+};
+
+static int ima_measurements_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &ima_measurments_seqops);
+}
+
+static const struct file_operations ima_measurements_ops = {
+	.open = ima_measurements_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+void ima_print_digest(struct seq_file *m, u8 *digest, u32 size)
+{
+	u32 i;
+
+	for (i = 0; i < size; i++)
+		seq_printf(m, "%02x", *(digest + i));
+}
+
+/* print in ascii */
+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 */
+	e = qe->entry;
+	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 ", e->pcr);
+
+	/* 2nd: SHA1 template hash */
+	ima_print_digest(m, e->digests[ima_sha1_idx].digest, TPM_DIGEST_SIZE);
+
+	/* 3th:  template name */
+	seq_printf(m, " %s", template_name);
+
+	/* 4th:  template specific data */
+	for (i = 0; i < e->template_desc->num_fields; i++) {
+		seq_puts(m, " ");
+		if (e->template_data[i].len == 0)
+			continue;
+
+		e->template_desc->fields[i]->field_show(m, IMA_SHOW_ASCII,
+							&e->template_data[i]);
+	}
+	seq_puts(m, "\n");
+	return 0;
+}
+
+static const struct seq_operations ima_ascii_measurements_seqops = {
+	.start = ima_measurements_start,
+	.next = ima_measurements_next,
+	.stop = ima_measurements_stop,
+	.show = ima_ascii_measurements_show
+};
+
+static int ima_ascii_measurements_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &ima_ascii_measurements_seqops);
+}
+
+static const struct file_operations ima_ascii_measurements_ops = {
+	.open = ima_ascii_measurements_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release,
+};
+
+static ssize_t ima_read_policy(char *path)
+{
+	void *data = NULL;
+	char *datap;
+	size_t size;
+	int rc, pathlen = strlen(path);
+
+	char *p;
+
+	/* remove \n */
+	datap = path;
+	strsep(&datap, "\n");
+
+	rc = kernel_read_file_from_path(path, 0, &data, INT_MAX, NULL,
+					READING_POLICY);
+	if (rc < 0) {
+		pr_err("Unable to open file: %s (%d)", path, rc);
+		return rc;
+	}
+	size = rc;
+	rc = 0;
+
+	datap = data;
+	while (size > 0 && (p = strsep(&datap, "\n"))) {
+		pr_debug("rule: %s\n", p);
+		rc = ima_parse_add_rule(p);
+		if (rc < 0)
+			break;
+		size -= rc;
+	}
+
+	vfree(data);
+	if (rc < 0)
+		return rc;
+	else if (size)
+		return -EINVAL;
+	else
+		return pathlen;
+}
+
+static ssize_t ima_write_policy(struct file *file, const char __user *buf,
+				size_t datalen, loff_t *ppos)
+{
+	char *data;
+	ssize_t result;
+
+	if (datalen >= PAGE_SIZE)
+		datalen = PAGE_SIZE - 1;
+
+	/* No partial writes. */
+	result = -EINVAL;
+	if (*ppos != 0)
+		goto out;
+
+	data = memdup_user_nul(buf, datalen);
+	if (IS_ERR(data)) {
+		result = PTR_ERR(data);
+		goto out;
+	}
+
+	result = mutex_lock_interruptible(&ima_write_mutex);
+	if (result < 0)
+		goto out_free;
+
+	if (data[0] == '/') {
+		result = ima_read_policy(data);
+	} else if (ima_appraise & IMA_APPRAISE_POLICY) {
+		pr_err("signed policy file (specified as an absolute pathname) required\n");
+		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
+				    "policy_update", "signed policy required",
+				    1, 0);
+		result = -EACCES;
+	} else {
+		result = ima_parse_add_rule(data);
+	}
+	mutex_unlock(&ima_write_mutex);
+out_free:
+	kfree(data);
+out:
+	if (result < 0)
+		valid_policy = 0;
+
+	return result;
+}
+
+static struct dentry *ima_dir;
+static struct dentry *ima_symlink;
+static struct dentry *binary_runtime_measurements;
+static struct dentry *ascii_runtime_measurements;
+static struct dentry *runtime_measurements_count;
+static struct dentry *violations;
+static struct dentry *ima_policy;
+
+enum ima_fs_flags {
+	IMA_FS_BUSY,
+};
+
+static unsigned long ima_fs_flags;
+
+#ifdef	CONFIG_IMA_READ_POLICY
+static const struct seq_operations ima_policy_seqops = {
+		.start = ima_policy_start,
+		.next = ima_policy_next,
+		.stop = ima_policy_stop,
+		.show = ima_policy_show,
+};
+#endif
+
+/*
+ * ima_open_policy: sequentialize access to the policy file
+ */
+static int ima_open_policy(struct inode *inode, struct file *filp)
+{
+	if (!(filp->f_flags & O_WRONLY)) {
+#ifndef	CONFIG_IMA_READ_POLICY
+		return -EACCES;
+#else
+		if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
+			return -EACCES;
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		return seq_open(filp, &ima_policy_seqops);
+#endif
+	}
+	if (test_and_set_bit(IMA_FS_BUSY, &ima_fs_flags))
+		return -EBUSY;
+	return 0;
+}
+
+/*
+ * ima_release_policy - start using the new measure policy rules.
+ *
+ * Initially, ima_measure points to the default policy rules, now
+ * point to the new policy rules, and remove the securityfs policy file,
+ * assuming a valid policy.
+ */
+static int ima_release_policy(struct inode *inode, struct file *file)
+{
+	const char *cause = valid_policy ? "completed" : "failed";
+
+	if ((file->f_flags & O_ACCMODE) == O_RDONLY)
+		return seq_release(inode, file);
+
+	if (valid_policy && ima_check_policy() < 0) {
+		cause = "failed";
+		valid_policy = 0;
+	}
+
+	pr_info("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;
+		clear_bit(IMA_FS_BUSY, &ima_fs_flags);
+		return 0;
+	}
+
+	ima_update_policy();
+#if !defined(CONFIG_IMA_WRITE_POLICY) && !defined(CONFIG_IMA_READ_POLICY)
+	securityfs_remove(ima_policy);
+	ima_policy = NULL;
+#elif defined(CONFIG_IMA_WRITE_POLICY)
+	clear_bit(IMA_FS_BUSY, &ima_fs_flags);
+#elif defined(CONFIG_IMA_READ_POLICY)
+	inode->i_mode &= ~S_IWUSR;
+#endif
+	return 0;
+}
+
+static const struct file_operations ima_measure_policy_ops = {
+	.open = ima_open_policy,
+	.write = ima_write_policy,
+	.read = seq_read,
+	.release = ima_release_policy,
+	.llseek = generic_file_llseek,
+};
+
+int __init ima_fs_init(void)
+{
+	int ret;
+
+	ima_dir = securityfs_create_dir("ima", integrity_dir);
+	if (IS_ERR(ima_dir))
+		return PTR_ERR(ima_dir);
+
+	ima_symlink = securityfs_create_symlink("ima", NULL, "integrity/ima",
+						NULL);
+	if (IS_ERR(ima_symlink)) {
+		ret = PTR_ERR(ima_symlink);
+		goto out;
+	}
+
+	binary_runtime_measurements =
+	    securityfs_create_file("binary_runtime_measurements",
+				   S_IRUSR | S_IRGRP, ima_dir, NULL,
+				   &ima_measurements_ops);
+	if (IS_ERR(binary_runtime_measurements)) {
+		ret = PTR_ERR(binary_runtime_measurements);
+		goto out;
+	}
+
+	ascii_runtime_measurements =
+	    securityfs_create_file("ascii_runtime_measurements",
+				   S_IRUSR | S_IRGRP, ima_dir, NULL,
+				   &ima_ascii_measurements_ops);
+	if (IS_ERR(ascii_runtime_measurements)) {
+		ret = PTR_ERR(ascii_runtime_measurements);
+		goto out;
+	}
+
+	runtime_measurements_count =
+	    securityfs_create_file("runtime_measurements_count",
+				   S_IRUSR | S_IRGRP, ima_dir, NULL,
+				   &ima_measurements_count_ops);
+	if (IS_ERR(runtime_measurements_count)) {
+		ret = PTR_ERR(runtime_measurements_count);
+		goto out;
+	}
+
+	violations =
+	    securityfs_create_file("violations", S_IRUSR | S_IRGRP,
+				   ima_dir, NULL, &ima_htable_violations_ops);
+	if (IS_ERR(violations)) {
+		ret = PTR_ERR(violations);
+		goto out;
+	}
+
+	ima_policy = securityfs_create_file("policy", POLICY_FILE_FLAGS,
+					    ima_dir, NULL,
+					    &ima_measure_policy_ops);
+	if (IS_ERR(ima_policy)) {
+		ret = PTR_ERR(ima_policy);
+		goto out;
+	}
+
+	return 0;
+out:
+	securityfs_remove(ima_policy);
+	securityfs_remove(violations);
+	securityfs_remove(runtime_measurements_count);
+	securityfs_remove(ascii_runtime_measurements);
+	securityfs_remove(binary_runtime_measurements);
+	securityfs_remove(ima_symlink);
+	securityfs_remove(ima_dir);
+
+	return ret;
+}