security/tomoyo/audit.c

   1 /*
   2  * security/tomoyo/audit.c
   3  *
   4  * Pathname restriction functions.
   5  *
   6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
   7  */
   8
   9 #include "common.h"
  10 #include <linux/slab.h>
  11
  12 /**
  13  * tomoyo_convert_time - Convert time_t to YYYY/MM/DD hh/mm/ss.
  14  *
  15  * @time:  Seconds since 1970/01/01 00:00:00.
  16  * @stamp: Pointer to "struct tomoyo_time".
  17  *
  18  * Returns nothing.
  19  *
  20  * This function does not handle Y2038 problem.
  21  */
  22 static void tomoyo_convert_time(time_t time, struct tomoyo_time *stamp)
  23 {
  24         static const u16 tomoyo_eom[2][12] = {
  25                 { 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
  26                 { 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
  27         };
  28         u16 y;
  29         u8 m;
  30         bool r;
  31         stamp->sec = time % 60;
  32         time /= 60;
  33         stamp->min = time % 60;
  34         time /= 60;
  35         stamp->hour = time % 24;
  36         time /= 24;
  37         for (y = 1970; ; y++) {
  38                 const unsigned short days = (y & 3) ? 365 : 366;
  39                 if (time < days)
  40                         break;
  41                 time -= days;
  42         }
  43         r = (y & 3) == 0;
  44         for (m = 0; m < 11 && time >= tomoyo_eom[r][m]; m++)
  45                 ;
  46         if (m)
  47                 time -= tomoyo_eom[r][m - 1];
  48         stamp->year = y;
  49         stamp->month = ++m;
  50         stamp->day = ++time;
  51 }
  52
  53 /**
  54  * tomoyo_print_header - Get header line of audit log.
  55  *
  56  * @r: Pointer to "struct tomoyo_request_info".
  57  *
  58  * Returns string representation.
  59  *
  60  * This function uses kmalloc(), so caller must kfree() if this function
  61  * didn't return NULL.
  62  */
  63 static char *tomoyo_print_header(struct tomoyo_request_info *r)
  64 {
  65         struct tomoyo_time stamp;
  66         const pid_t gpid = task_pid_nr(current);
  67         static const int tomoyo_buffer_len = 4096;
  68         char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
  69         pid_t ppid;
  70         if (!buffer)
  71                 return NULL;
  72         {
  73                 struct timeval tv;
  74                 do_gettimeofday(&tv);
  75                 tomoyo_convert_time(tv.tv_sec, &stamp);
  76         }
  77         rcu_read_lock();
  78         ppid = task_tgid_vnr(current->real_parent);
  79         rcu_read_unlock();
  80         snprintf(buffer, tomoyo_buffer_len - 1,
  81                  "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
  82                  "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
  83                  "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
  84                  "fsuid=%u fsgid=%u }",
  85                  stamp.year, stamp.month, stamp.day, stamp.hour,
  86                  stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
  87                  tomoyo_yesno(r->granted), gpid, task_tgid_vnr(current), ppid,
  88                  current_uid(), current_gid(), current_euid(), current_egid(),
  89                  current_suid(), current_sgid(), current_fsuid(),
  90                  current_fsgid());
  91         return buffer;
  92 }
  93
  94 /**
  95  * tomoyo_init_log - Allocate buffer for audit logs.
  96  *
  97  * @r:    Pointer to "struct tomoyo_request_info".
  98  * @len:  Buffer size needed for @fmt and @args.
  99  * @fmt:  The printf()'s format string.
 100  * @args: va_list structure for @fmt.
 101  *
 102  * Returns pointer to allocated memory.
 103  *
 104  * This function uses kzalloc(), so caller must kfree() if this function
 105  * didn't return NULL.
 106  */
 107 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
 108                       va_list args)
 109 {
 110         char *buf = NULL;
 111         const char *header = NULL;
 112         int pos;
 113         const char *domainname = tomoyo_domain()->domainname->name;
 114         header = tomoyo_print_header(r);
 115         if (!header)
 116                 return NULL;
 117         /* +10 is for '\n' etc. and '\0'. */
 118         len += strlen(domainname) + strlen(header) + 10;
 119         len = tomoyo_round2(len);
 120         buf = kzalloc(len, GFP_NOFS);
 121         if (!buf)
 122                 goto out;
 123         len--;
 124         pos = snprintf(buf, len, "%s", header);
 125         pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 126         vsnprintf(buf + pos, len - pos, fmt, args);
 127 out:
 128         kfree(header);
 129         return buf;
 130 }
 131
 132 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
 133 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
 134
 135 /* Structure for audit log. */
 136 struct tomoyo_log {
 137         struct list_head list;
 138         char *log;
 139         int size;
 140 };
 141
 142 /* The list for "struct tomoyo_log". */
 143 static LIST_HEAD(tomoyo_log);
 144
 145 /* Lock for "struct list_head tomoyo_log". */
 146 static DEFINE_SPINLOCK(tomoyo_log_lock);
 147
 148 /* Length of "stuct list_head tomoyo_log". */
 149 static unsigned int tomoyo_log_count;
 150
 151 /**
 152  * tomoyo_get_audit - Get audit mode.
 153  *
 154  * @ns:          Pointer to "struct tomoyo_policy_namespace".
 155  * @profile:     Profile number.
 156  * @index:       Index number of functionality.
 157  * @is_granted:  True if granted log, false otherwise.
 158  *
 159  * Returns true if this request should be audited, false otherwise.
 160  */
 161 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
 162                              const u8 profile, const u8 index,
 163                              const bool is_granted)
 164 {
 165         u8 mode;
 166         const u8 category = TOMOYO_MAC_CATEGORY_FILE + TOMOYO_MAX_MAC_INDEX;
 167         struct tomoyo_profile *p;
 168         if (!tomoyo_policy_loaded)
 169                 return false;
 170         p = tomoyo_profile(ns, profile);
 171         if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
 172                 return false;
 173         mode = p->config[index];
 174         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 175                 mode = p->config[category];
 176         if (mode == TOMOYO_CONFIG_USE_DEFAULT)
 177                 mode = p->default_config;
 178         if (is_granted)
 179                 return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
 180         return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
 181 }
 182
 183 /**
 184  * tomoyo_write_log2 - Write an audit log.
 185  *
 186  * @r:    Pointer to "struct tomoyo_request_info".
 187  * @len:  Buffer size needed for @fmt and @args.
 188  * @fmt:  The printf()'s format string.
 189  * @args: va_list structure for @fmt.
 190  *
 191  * Returns nothing.
 192  */
 193 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
 194                        va_list args)
 195 {
 196         char *buf;
 197         struct tomoyo_log *entry;
 198         bool quota_exceeded = false;
 199         if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type, r->granted))
 200                 goto out;
 201         buf = tomoyo_init_log(r, len, fmt, args);
 202         if (!buf)
 203                 goto out;
 204         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 205         if (!entry) {
 206                 kfree(buf);
 207                 goto out;
 208         }
 209         entry->log = buf;
 210         len = tomoyo_round2(strlen(buf) + 1);
 211         /*
 212          * The entry->size is used for memory quota checks.
 213          * Don't go beyond strlen(entry->log).
 214          */
 215         entry->size = len + tomoyo_round2(sizeof(*entry));
 216         spin_lock(&tomoyo_log_lock);
 217         if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
 218             tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
 219             tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
 220                 quota_exceeded = true;
 221         } else {
 222                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
 223                 list_add_tail(&entry->list, &tomoyo_log);
 224                 tomoyo_log_count++;
 225         }
 226         spin_unlock(&tomoyo_log_lock);
 227         if (quota_exceeded) {
 228                 kfree(buf);
 229                 kfree(entry);
 230                 goto out;
 231         }
 232         wake_up(&tomoyo_log_wait);
 233 out:
 234         return;
 235 }
 236
 237 /**
 238  * tomoyo_write_log - Write an audit log.
 239  *
 240  * @r:   Pointer to "struct tomoyo_request_info".
 241  * @fmt: The printf()'s format string, followed by parameters.
 242  *
 243  * Returns nothing.
 244  */
 245 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
 246 {
 247         va_list args;
 248         int len;
 249         va_start(args, fmt);
 250         len = vsnprintf((char *) &len, 1, fmt, args) + 1;
 251         va_end(args);
 252         va_start(args, fmt);
 253         tomoyo_write_log2(r, len, fmt, args);
 254         va_end(args);
 255 }
 256
 257 /**
 258  * tomoyo_read_log - Read an audit log.
 259  *
 260  * @head: Pointer to "struct tomoyo_io_buffer".
 261  *
 262  * Returns nothing.
 263  */
 264 void tomoyo_read_log(struct tomoyo_io_buffer *head)
 265 {
 266         struct tomoyo_log *ptr = NULL;
 267         if (head->r.w_pos)
 268                 return;
 269         kfree(head->read_buf);
 270         head->read_buf = NULL;
 271         spin_lock(&tomoyo_log_lock);
 272         if (!list_empty(&tomoyo_log)) {
 273                 ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
 274                 list_del(&ptr->list);
 275                 tomoyo_log_count--;
 276                 tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
 277         }
 278         spin_unlock(&tomoyo_log_lock);
 279         if (ptr) {
 280                 head->read_buf = ptr->log;
 281                 head->r.w[head->r.w_pos++] = head->read_buf;
 282                 kfree(ptr);
 283         }
 284 }
 285
 286 /**
 287  * tomoyo_poll_log - Wait for an audit log.
 288  *
 289  * @file: Pointer to "struct file".
 290  * @wait: Pointer to "poll_table".
 291  *
 292  * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 293  */
 294 int tomoyo_poll_log(struct file *file, poll_table *wait)
 295 {
 296         if (tomoyo_log_count)
 297                 return POLLIN | POLLRDNORM;
 298         poll_wait(file, &tomoyo_log_wait, wait);
 299         if (tomoyo_log_count)
 300                 return POLLIN | POLLRDNORM;
 301         return 0;
 302 }