Fixed MTP to work with TWRP

security/integrity/ima/ima_fs.c

@@ -0,0 +1,382 @@
+/*
+ * 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>
+ *
+ * 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.
+ *
+ * File: ima_fs.c
+ *	implemenents security file system for reporting
+ *	current measurement list and IMA statistics
+ */
+#include <linux/fcntl.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+#include <linux/parser.h>
+
+#include "ima.h"
+
+static int valid_policy = 1;
+#define TMPBUFLEN 12
+static ssize_t ima_show_htable_value(char __user *buf, size_t count,
+				     loff_t *ppos, atomic_long_t *val)
+{
+	char tmpbuf[TMPBUFLEN];
+	ssize_t len;
+
+	len = scnprintf(tmpbuf, TMPBUFLEN, "%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
+ */
+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;
+	int namelen;
+	u32 pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+	bool is_ima_template = false;
+	int i;
+
+	/* get entry */
+	e = qe->entry;
+	if (e == NULL)
+		return -1;
+
+	/*
+	 * 1st: PCRIndex
+	 * PCR used is always the same (config option) in
+	 * little-endian format
+	 */
+	ima_putc(m, &pcr, sizeof(pcr));
+
+	/* 2nd: template digest */
+	ima_putc(m, e->digest, TPM_DIGEST_SIZE);
+
+	/* 3rd: template name size */
+	namelen = strlen(e->template_desc->name);
+	ima_putc(m, &namelen, sizeof(namelen));
+
+	/* 4th:  template name */
+	ima_putc(m, e->template_desc->name, namelen);
+
+	/* 5th:  template length (except for 'ima' template) */
+	if (strcmp(e->template_desc->name, IMA_TEMPLATE_IMA_NAME) == 0)
+		is_ima_template = true;
+
+	if (!is_ima_template)
+		ima_putc(m, &e->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;
+		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, int size)
+{
+	int 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;
+	int i;
+
+	/* get entry */
+	e = qe->entry;
+	if (e == NULL)
+		return -1;
+
+	/* 1st: PCR used (config option) */
+	seq_printf(m, "%2d ", CONFIG_IMA_MEASURE_PCR_IDX);
+
+	/* 2nd: SHA1 template hash */
+	ima_print_digest(m, e->digest, TPM_DIGEST_SIZE);
+
+	/* 3th:  template name */
+	seq_printf(m, " %s", e->template_desc->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_write_policy(struct file *file, const char __user *buf,
+				size_t datalen, loff_t *ppos)
+{
+	char *data = NULL;
+	ssize_t result;
+
+	if (datalen >= PAGE_SIZE)
+		datalen = PAGE_SIZE - 1;
+
+	/* No partial writes. */
+	result = -EINVAL;
+	if (*ppos != 0)
+		goto out;
+
+	result = -ENOMEM;
+	data = kmalloc(datalen + 1, GFP_KERNEL);
+	if (!data)
+		goto out;
+
+	*(data + datalen) = '\0';
+
+	result = -EFAULT;
+	if (copy_from_user(data, buf, datalen))
+		goto out;
+
+	result = ima_parse_add_rule(data);
+out:
+	if (result < 0)
+		valid_policy = 0;
+	kfree(data);
+	return result;
+}
+
+static struct dentry *ima_dir;
+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;
+
+static atomic_t policy_opencount = ATOMIC_INIT(1);
+/*
+ * ima_open_policy: sequentialize access to the policy file
+ */
+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;
+}
+
+/*
+ * 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)
+{
+	if (!valid_policy) {
+		ima_delete_rules();
+		valid_policy = 1;
+		atomic_set(&policy_opencount, 1);
+		return 0;
+	}
+	ima_update_policy();
+	securityfs_remove(ima_policy);
+	ima_policy = NULL;
+	return 0;
+}
+
+static const struct file_operations ima_measure_policy_ops = {
+	.open = ima_open_policy,
+	.write = ima_write_policy,
+	.release = ima_release_policy,
+	.llseek = generic_file_llseek,
+};
+
+int __init ima_fs_init(void)
+{
+	ima_dir = securityfs_create_dir("ima", NULL);
+	if (IS_ERR(ima_dir))
+		return -1;
+
+	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))
+		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))
+		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))
+		goto out;
+
+	violations =
+	    securityfs_create_file("violations", S_IRUSR | S_IRGRP,
+				   ima_dir, NULL, &ima_htable_violations_ops);
+	if (IS_ERR(violations))
+		goto out;
+
+	ima_policy = securityfs_create_file("policy",
+					    S_IWUSR,
+					    ima_dir, NULL,
+					    &ima_measure_policy_ops);
+	if (IS_ERR(ima_policy))
+		goto out;
+
+	return 0;
+out:
+	securityfs_remove(violations);
+	securityfs_remove(runtime_measurements_count);
+	securityfs_remove(ascii_runtime_measurements);
+	securityfs_remove(binary_runtime_measurements);
+	securityfs_remove(ima_dir);
+	securityfs_remove(ima_policy);
+	return -1;
+}