integrity: IMA display

Make the measurement lists available through securityfs.
- removed test for NULL return code from securityfs_create_file/dir

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 296 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
new file mode 100644
index 000000000000..4f25be768b50
--- /dev/null
+++ b/security/integrity/ima/ima_fs.c
@@ -0,0 +1,296 @@
+/*
+ * 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/module.h>
+#include <linux/seq_file.h>
+#include <linux/rculist.h>
+#include <linux/rcupdate.h>
+
+#include "ima.h"
+
+#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 struct file_operations ima_htable_violations_ops = {
+        .read = ima_show_htable_violations
+};
+
+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 struct file_operations ima_measurements_count_ops = {
+        .read = ima_show_measurements_count
+};
+
+/* 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_dereference(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)
+{
+}
+
+static 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[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;
+
+        /* 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, IMA_DIGEST_SIZE);
+
+        /* 3rd: template name size */
+        namelen = strlen(e->template_name);
+        ima_putc(m, &namelen, sizeof namelen);
+
+        /* 4th:  template name */
+        ima_putc(m, e->template_name, namelen);
+
+        /* 5th:  template specific data */
+        ima_template_show(m, (struct ima_template_data *)&e->template,
+                          IMA_SHOW_BINARY);
+        return 0;
+}
+
+static 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 struct file_operations ima_measurements_ops = {
+        .open = ima_measurements_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
+static void ima_print_digest(struct seq_file *m, u8 *digest)
+{
+        int i;
+
+        for (i = 0; i < IMA_DIGEST_SIZE; i++)
+                seq_printf(m, "%02x", *(digest + i));
+}
+
+void ima_template_show(struct seq_file *m, void *e, enum ima_show_type show)
+{
+        struct ima_template_data *entry = e;
+        int namelen;
+
+        switch (show) {
+        case IMA_SHOW_ASCII:
+                ima_print_digest(m, entry->digest);
+                seq_printf(m, " %s\n", entry->file_name);
+                break;
+        case IMA_SHOW_BINARY:
+                ima_putc(m, entry->digest, IMA_DIGEST_SIZE);
+
+                namelen = strlen(entry->file_name);
+                ima_putc(m, &namelen, sizeof namelen);
+                ima_putc(m, entry->file_name, namelen);
+        default:
+                break;
+        }
+}
+
+/* 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;
+
+        /* 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);
+
+        /* 3th:  template name */
+        seq_printf(m, " %s ", e->template_name);
+
+        /* 4th:  template specific data */
+        ima_template_show(m, (struct ima_template_data *)&e->template,
+                          IMA_SHOW_ASCII);
+        return 0;
+}
+
+static 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 struct file_operations ima_ascii_measurements_ops = {
+        .open = ima_ascii_measurements_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
+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;
+
+int 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;
+
+        return 0;
+
+out:
+        securityfs_remove(runtime_measurements_count);
+        securityfs_remove(ascii_runtime_measurements);
+        securityfs_remove(binary_runtime_measurements);
+        securityfs_remove(ima_dir);
+        return -1;
+}
+
+void __exit ima_fs_cleanup(void)
+{
+        securityfs_remove(violations);
+        securityfs_remove(runtime_measurements_count);
+        securityfs_remove(ascii_runtime_measurements);
+        securityfs_remove(binary_runtime_measurements);
+        securityfs_remove(ima_dir);
+}