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