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-rw-r--r--security/integrity/ima/ima_fs.c522
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;
+}
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