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         struct rb_node *_p = v;
 188         struct key *key = rb_entry(_p, struct key, serial_node);
 189         struct timespec now;
 190         unsigned long timo;
 191         char xbuf[12];
 192         int rc;
 193
 194         /* check whether the current task is allowed to view the key (assuming
 195          * non-possession)
 196          * - the caller holds a spinlock, and thus the RCU read lock, making our
 197          *   access to __current_cred() safe
 198          */
 199         rc = key_task_permission(make_key_ref(key, 0), current_cred(),
 200                                  KEY_VIEW);
 201         if (rc < 0)
 202                 return 0;
 203
 204         now = current_kernel_time();
 205
 206         rcu_read_lock();
 207
 208         /* come up with a suitable timeout value */
 209         if (key->expiry == 0) {
 210                 memcpy(xbuf, "perm", 5);
 211         } else if (now.tv_sec >= key->expiry) {
 212                 memcpy(xbuf, "expd", 5);
 213         } else {
 214                 timo = key->expiry - now.tv_sec;
 215
 216                 if (timo < 60)
 217                         sprintf(xbuf, "%lus", timo);
 218                 else if (timo < 60*60)
 219                         sprintf(xbuf, "%lum", timo / 60);
 220                 else if (timo < 60*60*24)
 221                         sprintf(xbuf, "%luh", timo / (60*60));
 222                 else if (timo < 60*60*24*7)
 223                         sprintf(xbuf, "%lud", timo / (60*60*24));
 224                 else
 225                         sprintf(xbuf, "%luw", timo / (60*60*24*7));
 226         }
 227
 228 #define showflag(KEY, LETTER, FLAG) \
 229         (test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')
 230
 231         seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
 232                    key->serial,
 233                    showflag(key, 'I', KEY_FLAG_INSTANTIATED),
 234                    showflag(key, 'R', KEY_FLAG_REVOKED),
 235                    showflag(key, 'D', KEY_FLAG_DEAD),
 236                    showflag(key, 'Q', KEY_FLAG_IN_QUOTA),
 237                    showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
 238                    showflag(key, 'N', KEY_FLAG_NEGATIVE),
 239                    atomic_read(&key->usage),
 240                    xbuf,
 241                    key->perm,
 242                    key->uid,
 243                    key->gid,
 244                    key->type->name);
 245
 246 #undef showflag
 247
 248         if (key->type->describe)
 249                 key->type->describe(key, m);
 250         seq_putc(m, '\n');
 251
 252         rcu_read_unlock();
 253         return 0;
 254 }
 255
 256 #endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
 257
 258 static struct rb_node *__key_user_next(struct rb_node *n)
 259 {
 260         while (n) {
 261                 struct key_user *user = rb_entry(n, struct key_user, node);
 262                 if (user->user_ns == current_user_ns())
 263                         break;
 264                 n = rb_next(n);
 265         }
 266         return n;
 267 }
 268
 269 static struct rb_node *key_user_next(struct rb_node *n)
 270 {
 271         return __key_user_next(rb_next(n));
 272 }
 273
 274 static struct rb_node *key_user_first(struct rb_root *r)
 275 {
 276         struct rb_node *n = rb_first(r);
 277         return __key_user_next(n);
 278 }
 279
 280 /*****************************************************************************/
 281 /*
 282  * implement "/proc/key-users" to provides a list of the key users
 283  */
 284 static int proc_key_users_open(struct inode *inode, struct file *file)
 285 {
 286         return seq_open(file, &proc_key_users_ops);
 287 }
 288
 289 static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
 290         __acquires(key_user_lock)
 291 {
 292         struct rb_node *_p;
 293         loff_t pos = *_pos;
 294
 295         spin_lock(&key_user_lock);
 296
 297         _p = key_user_first(&key_user_tree);
 298         while (pos > 0 && _p) {
 299                 pos--;
 300                 _p = key_user_next(_p);
 301         }
 302
 303         return _p;
 304 }
 305
 306 static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
 307 {
 308         (*_pos)++;
 309         return key_user_next((struct rb_node *)v);
 310 }
 311
 312 static void proc_key_users_stop(struct seq_file *p, void *v)
 313         __releases(key_user_lock)
 314 {
 315         spin_unlock(&key_user_lock);
 316 }
 317
 318 static int proc_key_users_show(struct seq_file *m, void *v)
 319 {
 320         struct rb_node *_p = v;
 321         struct key_user *user = rb_entry(_p, struct key_user, node);
 322         unsigned maxkeys = (user->uid == 0) ?
 323                 key_quota_root_maxkeys : key_quota_maxkeys;
 324         unsigned maxbytes = (user->uid == 0) ?
 325                 key_quota_root_maxbytes : key_quota_maxbytes;
 326
 327         seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
 328                    user->uid,
 329                    atomic_read(&user->usage),
 330                    atomic_read(&user->nkeys),
 331                    atomic_read(&user->nikeys),
 332                    user->qnkeys,
 333                    maxkeys,
 334                    user->qnbytes,
 335                    maxbytes);
 336
 337         return 0;
 338
 339 }