TOMOYO: Add auditing interface.

Add /sys/kernel/security/tomoyo/audit interface. This interface generates audit
logs in the form of domain policy so that /usr/sbin/tomoyo-auditd can reuse
audit logs for appending to /sys/kernel/security/tomoyo/domain_policy
interface.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 300 insertions, 0 deletions

diff --git a/security/tomoyo/audit.c b/security/tomoyo/audit.c
new file mode 100644
index 000000000000..e882f17065f2
--- /dev/null
+++ b/security/tomoyo/audit.c
@@ -0,0 +1,300 @@
+/*
+ * security/tomoyo/audit.c
+ *
+ * Pathname restriction functions.
+ *
+ * Copyright (C) 2005-2010  NTT DATA CORPORATION
+ */
+
+#include "common.h"
+#include <linux/slab.h>
+
+/**
+ * tomoyo_convert_time - Convert time_t to YYYY/MM/DD hh/mm/ss.
+ *
+ * @time:  Seconds since 1970/01/01 00:00:00.
+ * @stamp: Pointer to "struct tomoyo_time".
+ *
+ * Returns nothing.
+ *
+ * This function does not handle Y2038 problem.
+ */
+static void tomoyo_convert_time(time_t time, struct tomoyo_time *stamp)
+{
+        static const u16 tomoyo_eom[2][12] = {
+                { 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
+                { 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
+        };
+        u16 y;
+        u8 m;
+        bool r;
+        stamp->sec = time % 60;
+        time /= 60;
+        stamp->min = time % 60;
+        time /= 60;
+        stamp->hour = time % 24;
+        time /= 24;
+        for (y = 1970; ; y++) {
+                const unsigned short days = (y & 3) ? 365 : 366;
+                if (time < days)
+                        break;
+                time -= days;
+        }
+        r = (y & 3) == 0;
+        for (m = 0; m < 11 && time >= tomoyo_eom[r][m]; m++)
+                ;
+        if (m)
+                time -= tomoyo_eom[r][m - 1];
+        stamp->year = y;
+        stamp->month = ++m;
+        stamp->day = ++time;
+}
+
+/**
+ * tomoyo_print_header - Get header line of audit log.
+ *
+ * @r: Pointer to "struct tomoyo_request_info".
+ *
+ * Returns string representation.
+ *
+ * This function uses kmalloc(), so caller must kfree() if this function
+ * didn't return NULL.
+ */
+static char *tomoyo_print_header(struct tomoyo_request_info *r)
+{
+        struct tomoyo_time stamp;
+        const pid_t gpid = task_pid_nr(current);
+        static const int tomoyo_buffer_len = 4096;
+        char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
+        pid_t ppid;
+        if (!buffer)
+                return NULL;
+        {
+                struct timeval tv;
+                do_gettimeofday(&tv);
+                tomoyo_convert_time(tv.tv_sec, &stamp);
+        }
+        rcu_read_lock();
+        ppid = task_tgid_vnr(current->real_parent);
+        rcu_read_unlock();
+        snprintf(buffer, tomoyo_buffer_len - 1,
+                 "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
+                 "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
+                 "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
+                 "fsuid=%u fsgid=%u }",
+                 stamp.year, stamp.month, stamp.day, stamp.hour,
+                 stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
+                 tomoyo_yesno(r->granted), gpid, task_tgid_vnr(current), ppid,
+                 current_uid(), current_gid(), current_euid(), current_egid(),
+                 current_suid(), current_sgid(), current_fsuid(),
+                 current_fsgid());
+        return buffer;
+}
+
+/**
+ * tomoyo_init_log - Allocate buffer for audit logs.
+ *
+ * @r:    Pointer to "struct tomoyo_request_info".
+ * @len:  Buffer size needed for @fmt and @args.
+ * @fmt:  The printf()'s format string.
+ * @args: va_list structure for @fmt.
+ *
+ * Returns pointer to allocated memory.
+ *
+ * This function uses kzalloc(), so caller must kfree() if this function
+ * didn't return NULL.
+ */
+char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
+                      va_list args)
+{
+        char *buf = NULL;
+        const char *header = NULL;
+        int pos;
+        const char *domainname = tomoyo_domain()->domainname->name;
+        header = tomoyo_print_header(r);
+        if (!header)
+                return NULL;
+        /* +10 is for '\n' etc. and '\0'. */
+        len += strlen(domainname) + strlen(header) + 10;
+        len = tomoyo_round2(len);
+        buf = kzalloc(len, GFP_NOFS);
+        if (!buf)
+                goto out;
+        len--;
+        pos = snprintf(buf, len, "%s", header);
+        pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
+        vsnprintf(buf + pos, len - pos, fmt, args);
+out:
+        kfree(header);
+        return buf;
+}
+
+/* Wait queue for /sys/kernel/security/tomoyo/audit. */
+static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
+
+/* Structure for audit log. */
+struct tomoyo_log {
+        struct list_head list;
+        char *log;
+        int size;
+};
+
+/* The list for "struct tomoyo_log". */
+static LIST_HEAD(tomoyo_log);
+
+/* Lock for "struct list_head tomoyo_log". */
+static DEFINE_SPINLOCK(tomoyo_log_lock);
+
+/* Length of "stuct list_head tomoyo_log". */
+static unsigned int tomoyo_log_count;
+
+/**
+ * tomoyo_get_audit - Get audit mode.
+ *
+ * @profile:     Profile number.
+ * @index:       Index number of functionality.
+ * @is_granted:  True if granted log, false otherwise.
+ *
+ * Returns true if this request should be audited, false otherwise.
+ */
+static bool tomoyo_get_audit(const u8 profile, const u8 index,
+                             const bool is_granted)
+{
+        u8 mode;
+        const u8 category = TOMOYO_MAC_CATEGORY_FILE + TOMOYO_MAX_MAC_INDEX;
+        struct tomoyo_profile *p;
+        if (!tomoyo_policy_loaded)
+                return false;
+        p = tomoyo_profile(profile);
+        if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
+                return false;
+        mode = p->config[index];
+        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
+                mode = p->config[category];
+        if (mode == TOMOYO_CONFIG_USE_DEFAULT)
+                mode = p->default_config;
+        if (is_granted)
+                return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
+        return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
+}
+
+/**
+ * tomoyo_write_log2 - Write an audit log.
+ *
+ * @r:    Pointer to "struct tomoyo_request_info".
+ * @len:  Buffer size needed for @fmt and @args.
+ * @fmt:  The printf()'s format string.
+ * @args: va_list structure for @fmt.
+ *
+ * Returns nothing.
+ */
+void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
+                       va_list args)
+{
+        char *buf;
+        struct tomoyo_log *entry;
+        bool quota_exceeded = false;
+        if (!tomoyo_get_audit(r->profile, r->type, r->granted))
+                goto out;
+        buf = tomoyo_init_log(r, len, fmt, args);
+        if (!buf)
+                goto out;
+        entry = kzalloc(sizeof(*entry), GFP_NOFS);
+        if (!entry) {
+                kfree(buf);
+                goto out;
+        }
+        entry->log = buf;
+        len = tomoyo_round2(strlen(buf) + 1);
+        /*
+         * The entry->size is used for memory quota checks.
+         * Don't go beyond strlen(entry->log).
+         */
+        entry->size = len + tomoyo_round2(sizeof(*entry));
+        spin_lock(&tomoyo_log_lock);
+        if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
+            tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
+            tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
+                quota_exceeded = true;
+        } else {
+                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
+                list_add_tail(&entry->list, &tomoyo_log);
+                tomoyo_log_count++;
+        }
+        spin_unlock(&tomoyo_log_lock);
+        if (quota_exceeded) {
+                kfree(buf);
+                kfree(entry);
+                goto out;
+        }
+        wake_up(&tomoyo_log_wait);
+out:
+        return;
+}
+
+/**
+ * tomoyo_write_log - Write an audit log.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @fmt: The printf()'s format string, followed by parameters.
+ *
+ * Returns nothing.
+ */
+void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
+{
+        va_list args;
+        int len;
+        va_start(args, fmt);
+        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
+        va_end(args);
+        va_start(args, fmt);
+        tomoyo_write_log2(r, len, fmt, args);
+        va_end(args);
+}
+
+/**
+ * tomoyo_read_log - Read an audit log.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns nothing.
+ */
+void tomoyo_read_log(struct tomoyo_io_buffer *head)
+{
+        struct tomoyo_log *ptr = NULL;
+        if (head->r.w_pos)
+                return;
+        kfree(head->read_buf);
+        head->read_buf = NULL;
+        spin_lock(&tomoyo_log_lock);
+        if (!list_empty(&tomoyo_log)) {
+                ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
+                list_del(&ptr->list);
+                tomoyo_log_count--;
+                tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
+        }
+        spin_unlock(&tomoyo_log_lock);
+        if (ptr) {
+                head->read_buf = ptr->log;
+                head->r.w[head->r.w_pos++] = head->read_buf;
+                kfree(ptr);
+        }
+}
+
+/**
+ * tomoyo_poll_log - Wait for an audit log.
+ *
+ * @file: Pointer to "struct file".
+ * @wait: Pointer to "poll_table".
+ *
+ * Returns POLLIN | POLLRDNORM when ready to read an audit log.
+ */
+int tomoyo_poll_log(struct file *file, poll_table *wait)
+{
+        if (tomoyo_log_count)
+                return POLLIN | POLLRDNORM;
+        poll_wait(file, &tomoyo_log_wait, wait);
+        if (tomoyo_log_count)
+                return POLLIN | POLLRDNORM;
+        return 0;
+}