security/keys/proc.c

   1 /* proc.c: proc files for key database enumeration
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/sched.h>
  15 #include <linux/slab.h>
  16 #include <linux/fs.h>
  17 #include <linux/proc_fs.h>
  18 #include <linux/seq_file.h>
  19 #include <asm/errno.h>
  20 #include "internal.h"
  21
  22 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  23 static int proc_keys_open(struct inode *inode, struct file *file);
  24 static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
  25 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
  26 static void proc_keys_stop(struct seq_file *p, void *v);
  27 static int proc_keys_show(struct seq_file *m, void *v);
  28
  29 static const struct seq_operations proc_keys_ops = {
  30         .start  = proc_keys_start,
  31         .next   = proc_keys_next,
  32         .stop   = proc_keys_stop,
  33         .show   = proc_keys_show,
  34 };
  35
  36 static const struct file_operations proc_keys_fops = {
  37         .open           = proc_keys_open,
  38         .read           = seq_read,
  39         .llseek         = seq_lseek,
  40         .release        = seq_release,
  41 };
  42 #endif
  43
  44 static int proc_key_users_open(struct inode *inode, struct file *file);
  45 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
  46 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
  47 static void proc_key_users_stop(struct seq_file *p, void *v);
  48 static int proc_key_users_show(struct seq_file *m, void *v);
  49
  50 static const struct seq_operations proc_key_users_ops = {
  51         .start  = proc_key_users_start,
  52         .next   = proc_key_users_next,
  53         .stop   = proc_key_users_stop,
  54         .show   = proc_key_users_show,
  55 };
  56
  57 static const struct file_operations proc_key_users_fops = {
  58         .open           = proc_key_users_open,
  59         .read           = seq_read,
  60         .llseek         = seq_lseek,
  61         .release        = seq_release,
  62 };
  63
  64 /*****************************************************************************/
  65 /*
  66  * declare the /proc files
  67  */
  68 static int __init key_proc_init(void)
  69 {
  70         struct proc_dir_entry *p;
  71
  72 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  73         p = proc_create("keys", 0, NULL, &proc_keys_fops);
  74         if (!p)
  75                 panic("Cannot create /proc/keys\n");
  76 #endif
  77
  78         p = proc_create("key-users", 0, NULL, &proc_key_users_fops);
  79         if (!p)
  80                 panic("Cannot create /proc/key-users\n");
  81
  82         return 0;
  83
  84 } /* end key_proc_init() */
  85
  86 __initcall(key_proc_init);
  87
  88 /*****************************************************************************/
  89 /*
  90  * implement "/proc/keys" to provides a list of the keys on the system
  91  */
  92 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  93
  94 static struct rb_node *key_serial_next(struct rb_node *n)
  95 {
  96         struct user_namespace *user_ns = current_user_ns();
  97
  98         n = rb_next(n);
  99         while (n) {
 100                 struct key *key = rb_entry(n, struct key, serial_node);
 101                 if (key->user->user_ns == user_ns)
 102                         break;
 103                 n = rb_next(n);
 104         }
 105         return n;
 106 }
 107
 108 static int proc_keys_open(struct inode *inode, struct file *file)
 109 {
 110         return seq_open(file, &proc_keys_ops);
 111 }
 112
 113 static struct key *find_ge_key(key_serial_t id)
 114 {
 115         struct user_namespace *user_ns = current_user_ns();
 116         struct rb_node *n = key_serial_tree.rb_node;
 117         struct key *minkey = NULL;
 118
 119         while (n) {
 120                 struct key *key = rb_entry(n, struct key, serial_node);
 121                 if (id < key->serial) {
 122                         if (!minkey || minkey->serial > key->serial)
 123                                 minkey = key;
 124                         n = n->rb_left;
 125                 } else if (id > key->serial) {
 126                         n = n->rb_right;
 127                 } else {
 128                         minkey = key;
 129                         break;
 130                 }
 131                 key = NULL;
 132         }
 133
 134         if (!minkey)
 135                 return NULL;
 136
 137         for (;;) {
 138                 if (minkey->user->user_ns == user_ns)
 139                         return minkey;
 140                 n = rb_next(&minkey->serial_node);
 141                 if (!n)
 142                         return NULL;
 143                 minkey = rb_entry(n, struct key, serial_node);
 144         }
 145 }
 146
 147 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
 148         __acquires(key_serial_lock)
 149 {
 150         key_serial_t pos = *_pos;
 151         struct key *key;
 152
 153         spin_lock(&key_serial_lock);
 154
 155         if (*_pos > INT_MAX)
 156                 return NULL;
 157         key = find_ge_key(pos);
 158         if (!key)
 159                 return NULL;
 160         *_pos = key->serial;
 161         return &key->serial_node;
 162 }
 163
 164 static inline key_serial_t key_node_serial(struct rb_node *n)
 165 {
 166         struct key *key = rb_entry(n, struct key, serial_node);
 167         return key->serial;
 168 }
 169
 170 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
 171 {
 172         struct rb_node *n;
 173
 174         n = key_serial_next(v);
 175         if (n)
 176                 *_pos = key_node_serial(n);
 177         return n;
 178 }
 179
 180 static void proc_keys_stop(struct seq_file *p, void *v)
 181         __releases(key_serial_lock)
 182 {
 183         spin_unlock(&key_serial_lock);
 184 }
 185
 186 static int proc_keys_show(struct seq_file *m, void *v)
 187 {
 188         struct rb_node *_p = v;
 189         struct key *key = rb_entry(_p, struct key, serial_node);
 190         struct timespec now;
 191         unsigned long timo;
 192         char xbuf[12];
 193         int rc;
 194
 195         /* check whether the current task is allowed to view the key (assuming
 196          * non-possession)
 197          * - the caller holds a spinlock, and thus the RCU read lock, making our
 198          *   access to __current_cred() safe
 199          */
 200         rc = key_task_permission(make_key_ref(key, 0), current_cred(),
 201                                  KEY_VIEW);
 202         if (rc < 0)
 203                 return 0;
 204
 205         now = current_kernel_time();
 206
 207         rcu_read_lock();
 208
 209         /* come up with a suitable timeout value */
 210         if (key->expiry == 0) {
 211                 memcpy(xbuf, "perm", 5);
 212         } else if (now.tv_sec >= key->expiry) {
 213                 memcpy(xbuf, "expd", 5);
 214         } else {
 215                 timo = key->expiry - now.tv_sec;
 216
 217                 if (timo < 60)
 218                         sprintf(xbuf, "%lus", timo);
 219                 else if (timo < 60*60)
 220                         sprintf(xbuf, "%lum", timo / 60);
 221                 else if (timo < 60*60*24)
 222                         sprintf(xbuf, "%luh", timo / (60*60));
 223                 else if (timo < 60*60*24*7)
 224                         sprintf(xbuf, "%lud", timo / (60*60*24));
 225                 else
 226                         sprintf(xbuf, "%luw", timo / (60*60*24*7));
 227         }
 228
 229 #define showflag(KEY, LETTER, FLAG) \
 230         (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')
 231
 232         seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
 233                    key->serial,
 234                    showflag(key, 'I', KEY_FLAG_INSTANTIATED),
 235                    showflag(key, 'R', KEY_FLAG_REVOKED),
 236                    showflag(key, 'D', KEY_FLAG_DEAD),
 237                    showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
 238                    showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
 239                    showflag(key, 'N', KEY_FLAG_NEGATIVE),
 240                    atomic_read(&key->usage),
 241                    xbuf,
 242                    key->perm,
 243                    key->uid,
 244                    key->gid,
 245                    key->type->name);
 246
 247 #undef showflag
 248
 249         if (key->type->describe)
 250                 key->type->describe(key, m);
 251         seq_putc(m, '\n');
 252
 253         rcu_read_unlock();
 254         return 0;
 255 }
 256
 257 #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
 258
 259 static struct rb_node *__key_user_next(struct rb_node *n)
 260 {
 261         while (n) {
 262                 struct key_user *user = rb_entry(n, struct key_user, node);
 263                 if (user->user_ns == current_user_ns())
 264                         break;
 265                 n = rb_next(n);
 266         }
 267         return n;
 268 }
 269
 270 static struct rb_node *key_user_next(struct rb_node *n)
 271 {
 272         return __key_user_next(rb_next(n));
 273 }
 274
 275 static struct rb_node *key_user_first(struct rb_root *r)
 276 {
 277         struct rb_node *n = rb_first(r);
 278         return __key_user_next(n);
 279 }
 280
 281 /*****************************************************************************/
 282 /*
 283  * implement "/proc/key-users" to provides a list of the key users
 284  */
 285 static int proc_key_users_open(struct inode *inode, struct file *file)
 286 {
 287         return seq_open(file, &proc_key_users_ops);
 288 }
 289
 290 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
 291         __acquires(key_user_lock)
 292 {
 293         struct rb_node *_p;
 294         loff_t pos = *_pos;
 295
 296         spin_lock(&key_user_lock);
 297
 298         _p = key_user_first(&key_user_tree);
 299         while (pos > 0 && _p) {
 300                 pos--;
 301                 _p = key_user_next(_p);
 302         }
 303
 304         return _p;
 305 }
 306
 307 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
 308 {
 309         (*_pos)++;
 310         return key_user_next((struct rb_node *) v);
 311 }
 312
 313 static void proc_key_users_stop(struct seq_file *p, void *v)
 314         __releases(key_user_lock)
 315 {
 316         spin_unlock(&key_user_lock);
 317 }
 318
 319 static int proc_key_users_show(struct seq_file *m, void *v)
 320 {
 321         struct rb_node *_p = v;
 322         struct key_user *user = rb_entry(_p, struct key_user, node);
 323         unsigned maxkeys = (user->uid == 0) ?
 324                 key_quota_root_maxkeys : key_quota_maxkeys;
 325         unsigned maxbytes = (user->uid == 0) ?
 326                 key_quota_root_maxbytes : key_quota_maxbytes;
 327
 328         seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
 329                    user->uid,
 330                    atomic_read(&user->usage),
 331                    atomic_read(&user->nkeys),
 332                    atomic_read(&user->nikeys),
 333                    user->qnkeys,
 334                    maxkeys,
 335                    user->qnbytes,
 336                    maxbytes);
 337
 338         return 0;
 339
 340 }