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/fs.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <asm/errno.h>
  19 #include "internal.h"
  20
  21 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  22 static int proc_keys_open(struct inode *inode, struct file *file);
  23 static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
  24 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
  25 static void proc_keys_stop(struct seq_file *p, void *v);
  26 static int proc_keys_show(struct seq_file *m, void *v);
  27
  28 static const struct seq_operations proc_keys_ops = {
  29         .start  = proc_keys_start,
  30         .next   = proc_keys_next,
  31         .stop   = proc_keys_stop,
  32         .show   = proc_keys_show,
  33 };
  34
  35 static const struct file_operations proc_keys_fops = {
  36         .open           = proc_keys_open,
  37         .read           = seq_read,
  38         .llseek         = seq_lseek,
  39         .release        = seq_release,
  40 };
  41 #endif
  42
  43 static int proc_key_users_open(struct inode *inode, struct file *file);
  44 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
  45 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
  46 static void proc_key_users_stop(struct seq_file *p, void *v);
  47 static int proc_key_users_show(struct seq_file *m, void *v);
  48
  49 static const struct seq_operations proc_key_users_ops = {
  50         .start  = proc_key_users_start,
  51         .next   = proc_key_users_next,
  52         .stop   = proc_key_users_stop,
  53         .show   = proc_key_users_show,
  54 };
  55
  56 static const struct file_operations proc_key_users_fops = {
  57         .open           = proc_key_users_open,
  58         .read           = seq_read,
  59         .llseek         = seq_lseek,
  60         .release        = seq_release,
  61 };
  62
  63 /*****************************************************************************/
  64 /*
  65  * declare the /proc files
  66  */
  67 static int __init key_proc_init(void)
  68 {
  69         struct proc_dir_entry *p;
  70
  71 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  72         p = proc_create("keys", 0, NULL, &proc_keys_fops);
  73         if (!p)
  74                 panic("Cannot create /proc/keys\n");
  75 #endif
  76
  77         p = proc_create("key-users", 0, NULL, &proc_key_users_fops);
  78         if (!p)
  79                 panic("Cannot create /proc/key-users\n");
  80
  81         return 0;
  82
  83 } /* end key_proc_init() */
  84
  85 __initcall(key_proc_init);
  86
  87 /*****************************************************************************/
  88 /*
  89  * implement "/proc/keys" to provides a list of the keys on the system
  90  */
  91 #ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
  92
  93 static struct rb_node *key_serial_next(struct rb_node *n)
  94 {
  95         struct user_namespace *user_ns = current_user_ns();
  96
  97         n = rb_next(n);
  98         while (n) {
  99                 struct key *key = rb_entry(n, struct key, serial_node);
 100                 if (key->user->user_ns == user_ns)
 101                         break;
 102                 n = rb_next(n);
 103         }
 104         return n;
 105 }
 106
 107 static int proc_keys_open(struct inode *inode, struct file *file)
 108 {
 109         return seq_open(file, &proc_keys_ops);
 110 }
 111
 112 static struct key *find_ge_key(key_serial_t id)
 113 {
 114         struct user_namespace *user_ns = current_user_ns();
 115         struct rb_node *n = key_serial_tree.rb_node;
 116         struct key *minkey = NULL;
 117
 118         while (n) {
 119                 struct key *key = rb_entry(n, struct key, serial_node);
 120                 if (id < key->serial) {
 121                         if (!minkey || minkey->serial > key->serial)
 122                                 minkey = key;
 123                         n = n->rb_left;
 124                 } else if (id > key->serial) {
 125                         n = n->rb_right;
 126                 } else {
 127                         minkey = key;
 128                         break;
 129                 }
 130                 key = NULL;
 131         }
 132
 133         if (!minkey)
 134                 return NULL;
 135
 136         for (;;) {
 137                 if (minkey->user->user_ns == user_ns)
 138                         return minkey;
 139                 n = rb_next(&minkey->serial_node);
 140                 if (!n)
 141                         return NULL;
 142                 minkey = rb_entry(n, struct key, serial_node);
 143         }
 144 }
 145
 146 static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
 147         __acquires(key_serial_lock)
 148 {
 149         key_serial_t pos = *_pos;
 150         struct key *key;
 151
 152         spin_lock(&key_serial_lock);
 153
 154         if (*_pos > INT_MAX)
 155                 return NULL;
 156         key = find_ge_key(pos);
 157         if (!key)
 158                 return NULL;
 159         *_pos = key->serial;
 160         return &key->serial_node;
 161 }
 162
 163 static inline key_serial_t key_node_serial(struct rb_node *n)
 164 {
 165         struct key *key = rb_entry(n, struct key, serial_node);
 166         return key->serial;
 167 }
 168
 169 static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
 170 {
 171         struct rb_node *n;
 172
 173         n = key_serial_next(v);
 174         if (n)
 175                 *_pos = key_node_serial(n);
 176         return n;
 177 }
 178
 179 static void proc_keys_stop(struct seq_file *p, void *v)
 180         __releases(key_serial_lock)
 181 {
 182         spin_unlock(&key_serial_lock);
 183 }
 184
 185 static int proc_keys_show(struct seq_file *m, void *v)
 186 {
 187         const struct cred *cred = current_cred();
 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         key_ref_t key_ref, skey_ref;
 193         char xbuf[12];
 194         int rc;
 195
 196         key_ref = make_key_ref(key, 0);
 197
 198         /* determine if the key is possessed by this process (a test we can
 199          * skip if the key does not indicate the possessor can view it
 200          */
 201         if (key->perm & KEY_POS_VIEW) {
 202                 skey_ref = search_my_process_keyrings(key->type, key,
 203                                                       lookup_user_key_possessed,
 204                                                       cred);
 205                 if (!IS_ERR(skey_ref)) {
 206                         key_ref_put(skey_ref);
 207                         key_ref = make_key_ref(key, 1);
 208                 }
 209         }
 210
 211         /* check whether the current task is allowed to view the key (assuming
 212          * non-possession)
 213          * - the caller holds a spinlock, and thus the RCU read lock, making our
 214          *   access to __current_cred() safe
 215          */
 216         rc = key_task_permission(key_ref, cred, KEY_VIEW);
 217         if (rc < 0)
 218                 return 0;
 219
 220         now = current_kernel_time();
 221
 222         rcu_read_lock();
 223
 224         /* come up with a suitable timeout value */
 225         if (key->expiry == 0) {
 226                 memcpy(xbuf, "perm", 5);
 227         } else if (now.tv_sec >= key->expiry) {
 228                 memcpy(xbuf, "expd", 5);
 229         } else {
 230                 timo = key->expiry - now.tv_sec;
 231
 232                 if (timo < 60)
 233                         sprintf(xbuf, "%lus", timo);
 234                 else if (timo < 60*60)
 235                         sprintf(xbuf, "%lum", timo / 60);
 236                 else if (timo < 60*60*24)
 237                         sprintf(xbuf, "%luh", timo / (60*60));
 238                 else if (timo < 60*60*24*7)
 239                         sprintf(xbuf, "%lud", timo / (60*60*24));
 240                 else
 241                         sprintf(xbuf, "%luw", timo / (60*60*24*7));
 242         }
 243
 244 #define showflag(KEY, LETTER, FLAG) \
 245         (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')
 246
 247         seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
 248                    key->serial,
 249                    showflag(key, 'I', KEY_FLAG_INSTANTIATED),
 250                    showflag(key, 'R', KEY_FLAG_REVOKED),
 251                    showflag(key, 'D', KEY_FLAG_DEAD),
 252                    showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
 253                    showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
 254                    showflag(key, 'N', KEY_FLAG_NEGATIVE),
 255                    atomic_read(&key->usage),
 256                    xbuf,
 257                    key->perm,
 258                    key->uid,
 259                    key->gid,
 260                    key->type->name);
 261
 262 #undef showflag
 263
 264         if (key->type->describe)
 265                 key->type->describe(key, m);
 266         seq_putc(m, '\n');
 267
 268         rcu_read_unlock();
 269         return 0;
 270 }
 271
 272 #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
 273
 274 static struct rb_node *__key_user_next(struct rb_node *n)
 275 {
 276         while (n) {
 277                 struct key_user *user = rb_entry(n, struct key_user, node);
 278                 if (user->user_ns == current_user_ns())
 279                         break;
 280                 n = rb_next(n);
 281         }
 282         return n;
 283 }
 284
 285 static struct rb_node *key_user_next(struct rb_node *n)
 286 {
 287         return __key_user_next(rb_next(n));
 288 }
 289
 290 static struct rb_node *key_user_first(struct rb_root *r)
 291 {
 292         struct rb_node *n = rb_first(r);
 293         return __key_user_next(n);
 294 }
 295
 296 /*****************************************************************************/
 297 /*
 298  * implement "/proc/key-users" to provides a list of the key users
 299  */
 300 static int proc_key_users_open(struct inode *inode, struct file *file)
 301 {
 302         return seq_open(file, &proc_key_users_ops);
 303 }
 304
 305 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
 306         __acquires(key_user_lock)
 307 {
 308         struct rb_node *_p;
 309         loff_t pos = *_pos;
 310
 311         spin_lock(&key_user_lock);
 312
 313         _p = key_user_first(&key_user_tree);
 314         while (pos > 0 && _p) {
 315                 pos--;
 316                 _p = key_user_next(_p);
 317         }
 318
 319         return _p;
 320 }
 321
 322 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
 323 {
 324         (*_pos)++;
 325         return key_user_next((struct rb_node *)v);
 326 }
 327
 328 static void proc_key_users_stop(struct seq_file *p, void *v)
 329         __releases(key_user_lock)
 330 {
 331         spin_unlock(&key_user_lock);
 332 }
 333
 334 static int proc_key_users_show(struct seq_file *m, void *v)
 335 {
 336         struct rb_node *_p = v;
 337         struct key_user *user = rb_entry(_p, struct key_user, node);
 338         unsigned maxkeys = (user->uid == 0) ?
 339                 key_quota_root_maxkeys : key_quota_maxkeys;
 340         unsigned maxbytes = (user->uid == 0) ?
 341                 key_quota_root_maxbytes : key_quota_maxbytes;
 342
 343         seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
 344                    user->uid,
 345                    atomic_read(&user->usage),
 346                    atomic_read(&user->nkeys),
 347                    atomic_read(&user->nikeys),
 348                    user->qnkeys,
 349                    maxkeys,
 350                    user->qnbytes,
 351                    maxbytes);
 352
 353         return 0;
 354
 355 }