22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 1) // SPDX-License-Identifier: GPL-2.0
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 2) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 3) * Filesystem-level keyring for fscrypt
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 4) *
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 5) * Copyright 2019 Google LLC
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 6) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 7)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 8) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 9) * This file implements management of fscrypt master keys in the
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 10) * filesystem-level keyring, including the ioctls:
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 11) *
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 12) * - FS_IOC_ADD_ENCRYPTION_KEY
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 13) * - FS_IOC_REMOVE_ENCRYPTION_KEY
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 14) * - FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 15) * - FS_IOC_GET_ENCRYPTION_KEY_STATUS
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 16) *
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 17) * See the "User API" section of Documentation/filesystems/fscrypt.rst for more
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 18) * information about these ioctls.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 19) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 20)
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 21) #include <crypto/skcipher.h>
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 22) #include <linux/key-type.h>
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 23) #include <linux/random.h>
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 24) #include <linux/seq_file.h>
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 25)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 26) #include "fscrypt_private.h"
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 27)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 28) static void wipe_master_key_secret(struct fscrypt_master_key_secret *secret)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 29) {
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 30) fscrypt_destroy_hkdf(&secret->hkdf);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 31) memzero_explicit(secret, sizeof(*secret));
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 32) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 33)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 34) static void move_master_key_secret(struct fscrypt_master_key_secret *dst,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 35) struct fscrypt_master_key_secret *src)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 36) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 37) memcpy(dst, src, sizeof(*dst));
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 38) memzero_explicit(src, sizeof(*src));
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 39) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 40)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 41) static void free_master_key(struct fscrypt_master_key *mk)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 42) {
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 43) size_t i;
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 44)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 45) wipe_master_key_secret(&mk->mk_secret);
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 46)
3ceb6543e9cf6 (Eric Biggers 2020-10-23 17:51:31 -0700 47) for (i = 0; i <= FSCRYPT_MODE_MAX; i++) {
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 48) fscrypt_destroy_prepared_key(&mk->mk_direct_keys[i]);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 49) fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_64_keys[i]);
5fee36095cda4 (Satya Tangirala 2020-07-02 01:56:05 +0000 50) fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_32_keys[i]);
b103fb7653fff (Eric Biggers 2019-10-24 14:54:36 -0700 51) }
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 52)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 53) key_put(mk->mk_users);
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 54) kfree_sensitive(mk);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 55) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 56)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 57) static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 58) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 59) if (spec->__reserved)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 60) return false;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 61) return master_key_spec_len(spec) != 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 62) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 63)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 64) static int fscrypt_key_instantiate(struct key *key,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 65) struct key_preparsed_payload *prep)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 66) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 67) key->payload.data[0] = (struct fscrypt_master_key *)prep->data;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 68) return 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 69) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 70)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 71) static void fscrypt_key_destroy(struct key *key)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 72) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 73) free_master_key(key->payload.data[0]);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 74) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 75)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 76) static void fscrypt_key_describe(const struct key *key, struct seq_file *m)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 77) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 78) seq_puts(m, key->description);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 79)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 80) if (key_is_positive(key)) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 81) const struct fscrypt_master_key *mk = key->payload.data[0];
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 82)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 83) if (!is_master_key_secret_present(&mk->mk_secret))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 84) seq_puts(m, ": secret removed");
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 85) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 86) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 87)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 88) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 89) * Type of key in ->s_master_keys. Each key of this type represents a master
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 90) * key which has been added to the filesystem. Its payload is a
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 91) * 'struct fscrypt_master_key'. The "." prefix in the key type name prevents
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 92) * users from adding keys of this type via the keyrings syscalls rather than via
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 93) * the intended method of FS_IOC_ADD_ENCRYPTION_KEY.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 94) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 95) static struct key_type key_type_fscrypt = {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 96) .name = "._fscrypt",
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 97) .instantiate = fscrypt_key_instantiate,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 98) .destroy = fscrypt_key_destroy,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 99) .describe = fscrypt_key_describe,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 100) };
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 101)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 102) static int fscrypt_user_key_instantiate(struct key *key,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 103) struct key_preparsed_payload *prep)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 104) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 105) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 106) * We just charge FSCRYPT_MAX_KEY_SIZE bytes to the user's key quota for
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 107) * each key, regardless of the exact key size. The amount of memory
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 108) * actually used is greater than the size of the raw key anyway.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 109) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 110) return key_payload_reserve(key, FSCRYPT_MAX_KEY_SIZE);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 111) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 112)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 113) static void fscrypt_user_key_describe(const struct key *key, struct seq_file *m)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 114) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 115) seq_puts(m, key->description);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 116) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 117)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 118) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 119) * Type of key in ->mk_users. Each key of this type represents a particular
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 120) * user who has added a particular master key.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 121) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 122) * Note that the name of this key type really should be something like
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 123) * ".fscrypt-user" instead of simply ".fscrypt". But the shorter name is chosen
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 124) * mainly for simplicity of presentation in /proc/keys when read by a non-root
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 125) * user. And it is expected to be rare that a key is actually added by multiple
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 126) * users, since users should keep their encryption keys confidential.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 127) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 128) static struct key_type key_type_fscrypt_user = {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 129) .name = ".fscrypt",
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 130) .instantiate = fscrypt_user_key_instantiate,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 131) .describe = fscrypt_user_key_describe,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 132) };
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 133)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 134) /* Search ->s_master_keys or ->mk_users */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 135) static struct key *search_fscrypt_keyring(struct key *keyring,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 136) struct key_type *type,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 137) const char *description)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 138) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 139) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 140) * We need to mark the keyring reference as "possessed" so that we
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 141) * acquire permission to search it, via the KEY_POS_SEARCH permission.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 142) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 143) key_ref_t keyref = make_key_ref(keyring, true /* possessed */);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 144)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 145) keyref = keyring_search(keyref, type, description, false);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 146) if (IS_ERR(keyref)) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 147) if (PTR_ERR(keyref) == -EAGAIN || /* not found */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 148) PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 149) keyref = ERR_PTR(-ENOKEY);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 150) return ERR_CAST(keyref);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 151) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 152) return key_ref_to_ptr(keyref);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 153) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 154)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 155) #define FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE \
c593642c8be04 (Pankaj Bharadiya 2019-12-09 10:31:43 -0800 156) (CONST_STRLEN("fscrypt-") + sizeof_field(struct super_block, s_id))
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 157)
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 158) #define FSCRYPT_MK_DESCRIPTION_SIZE (2 * FSCRYPT_KEY_IDENTIFIER_SIZE + 1)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 159)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 160) #define FSCRYPT_MK_USERS_DESCRIPTION_SIZE \
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 161) (CONST_STRLEN("fscrypt-") + 2 * FSCRYPT_KEY_IDENTIFIER_SIZE + \
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 162) CONST_STRLEN("-users") + 1)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 163)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 164) #define FSCRYPT_MK_USER_DESCRIPTION_SIZE \
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 165) (2 * FSCRYPT_KEY_IDENTIFIER_SIZE + CONST_STRLEN(".uid.") + 10 + 1)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 166)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 167) static void format_fs_keyring_description(
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 168) char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE],
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 169) const struct super_block *sb)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 170) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 171) sprintf(description, "fscrypt-%s", sb->s_id);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 172) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 173)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 174) static void format_mk_description(
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 175) char description[FSCRYPT_MK_DESCRIPTION_SIZE],
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 176) const struct fscrypt_key_specifier *mk_spec)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 177) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 178) sprintf(description, "%*phN",
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 179) master_key_spec_len(mk_spec), (u8 *)&mk_spec->u);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 180) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 181)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 182) static void format_mk_users_keyring_description(
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 183) char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE],
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 184) const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 185) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 186) sprintf(description, "fscrypt-%*phN-users",
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 187) FSCRYPT_KEY_IDENTIFIER_SIZE, mk_identifier);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 188) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 189)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 190) static void format_mk_user_description(
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 191) char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE],
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 192) const u8 mk_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 193) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 194)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 195) sprintf(description, "%*phN.uid.%u", FSCRYPT_KEY_IDENTIFIER_SIZE,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 196) mk_identifier, __kuid_val(current_fsuid()));
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 197) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 198)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 199) /* Create ->s_master_keys if needed. Synchronized by fscrypt_add_key_mutex. */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 200) static int allocate_filesystem_keyring(struct super_block *sb)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 201) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 202) char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE];
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 203) struct key *keyring;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 204)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 205) if (sb->s_master_keys)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 206) return 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 207)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 208) format_fs_keyring_description(description, sb);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 209) keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 210) current_cred(), KEY_POS_SEARCH |
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 211) KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 212) KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 213) if (IS_ERR(keyring))
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 214) return PTR_ERR(keyring);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 215)
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 216) /*
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 217) * Pairs with the smp_load_acquire() in fscrypt_find_master_key().
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 218) * I.e., here we publish ->s_master_keys with a RELEASE barrier so that
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 219) * concurrent tasks can ACQUIRE it.
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 220) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 221) smp_store_release(&sb->s_master_keys, keyring);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 222) return 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 223) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 224)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 225) void fscrypt_sb_free(struct super_block *sb)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 226) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 227) key_put(sb->s_master_keys);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 228) sb->s_master_keys = NULL;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 229) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 230)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 231) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 232) * Find the specified master key in ->s_master_keys.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 233) * Returns ERR_PTR(-ENOKEY) if not found.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 234) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 235) struct key *fscrypt_find_master_key(struct super_block *sb,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 236) const struct fscrypt_key_specifier *mk_spec)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 237) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 238) struct key *keyring;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 239) char description[FSCRYPT_MK_DESCRIPTION_SIZE];
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 240)
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 241) /*
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 242) * Pairs with the smp_store_release() in allocate_filesystem_keyring().
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 243) * I.e., another task can publish ->s_master_keys concurrently,
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 244) * executing a RELEASE barrier. We need to use smp_load_acquire() here
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 245) * to safely ACQUIRE the memory the other task published.
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 246) */
777afe4e68d7a (Eric Biggers 2020-07-21 15:59:18 -0700 247) keyring = smp_load_acquire(&sb->s_master_keys);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 248) if (keyring == NULL)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 249) return ERR_PTR(-ENOKEY); /* No keyring yet, so no keys yet. */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 250)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 251) format_mk_description(description, mk_spec);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 252) return search_fscrypt_keyring(keyring, &key_type_fscrypt, description);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 253) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 254)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 255) static int allocate_master_key_users_keyring(struct fscrypt_master_key *mk)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 256) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 257) char description[FSCRYPT_MK_USERS_DESCRIPTION_SIZE];
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 258) struct key *keyring;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 259)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 260) format_mk_users_keyring_description(description,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 261) mk->mk_spec.u.identifier);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 262) keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 263) current_cred(), KEY_POS_SEARCH |
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 264) KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 265) KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 266) if (IS_ERR(keyring))
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 267) return PTR_ERR(keyring);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 268)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 269) mk->mk_users = keyring;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 270) return 0;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 271) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 272)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 273) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 274) * Find the current user's "key" in the master key's ->mk_users.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 275) * Returns ERR_PTR(-ENOKEY) if not found.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 276) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 277) static struct key *find_master_key_user(struct fscrypt_master_key *mk)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 278) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 279) char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 280)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 281) format_mk_user_description(description, mk->mk_spec.u.identifier);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 282) return search_fscrypt_keyring(mk->mk_users, &key_type_fscrypt_user,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 283) description);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 284) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 285)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 286) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 287) * Give the current user a "key" in ->mk_users. This charges the user's quota
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 288) * and marks the master key as added by the current user, so that it cannot be
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 289) * removed by another user with the key. Either the master key's key->sem must
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 290) * be held for write, or the master key must be still undergoing initialization.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 291) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 292) static int add_master_key_user(struct fscrypt_master_key *mk)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 293) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 294) char description[FSCRYPT_MK_USER_DESCRIPTION_SIZE];
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 295) struct key *mk_user;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 296) int err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 297)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 298) format_mk_user_description(description, mk->mk_spec.u.identifier);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 299) mk_user = key_alloc(&key_type_fscrypt_user, description,
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 300) current_fsuid(), current_gid(), current_cred(),
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 301) KEY_POS_SEARCH | KEY_USR_VIEW, 0, NULL);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 302) if (IS_ERR(mk_user))
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 303) return PTR_ERR(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 304)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 305) err = key_instantiate_and_link(mk_user, NULL, 0, mk->mk_users, NULL);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 306) key_put(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 307) return err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 308) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 309)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 310) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 311) * Remove the current user's "key" from ->mk_users.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 312) * The master key's key->sem must be held for write.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 313) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 314) * Returns 0 if removed, -ENOKEY if not found, or another -errno code.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 315) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 316) static int remove_master_key_user(struct fscrypt_master_key *mk)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 317) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 318) struct key *mk_user;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 319) int err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 320)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 321) mk_user = find_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 322) if (IS_ERR(mk_user))
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 323) return PTR_ERR(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 324) err = key_unlink(mk->mk_users, mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 325) key_put(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 326) return err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 327) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 328)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 329) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 330) * Allocate a new fscrypt_master_key which contains the given secret, set it as
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 331) * the payload of a new 'struct key' of type fscrypt, and link the 'struct key'
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 332) * into the given keyring. Synchronized by fscrypt_add_key_mutex.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 333) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 334) static int add_new_master_key(struct fscrypt_master_key_secret *secret,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 335) const struct fscrypt_key_specifier *mk_spec,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 336) struct key *keyring)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 337) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 338) struct fscrypt_master_key *mk;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 339) char description[FSCRYPT_MK_DESCRIPTION_SIZE];
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 340) struct key *key;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 341) int err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 342)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 343) mk = kzalloc(sizeof(*mk), GFP_KERNEL);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 344) if (!mk)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 345) return -ENOMEM;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 346)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 347) mk->mk_spec = *mk_spec;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 348)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 349) move_master_key_secret(&mk->mk_secret, secret);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 350)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 351) refcount_set(&mk->mk_refcount, 1); /* secret is present */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 352) INIT_LIST_HEAD(&mk->mk_decrypted_inodes);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 353) spin_lock_init(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 354)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 355) if (mk_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 356) err = allocate_master_key_users_keyring(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 357) if (err)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 358) goto out_free_mk;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 359) err = add_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 360) if (err)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 361) goto out_free_mk;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 362) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 363)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 364) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 365) * Note that we don't charge this key to anyone's quota, since when
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 366) * ->mk_users is in use those keys are charged instead, and otherwise
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 367) * (when ->mk_users isn't in use) only root can add these keys.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 368) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 369) format_mk_description(description, mk_spec);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 370) key = key_alloc(&key_type_fscrypt, description,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 371) GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 372) KEY_POS_SEARCH | KEY_USR_SEARCH | KEY_USR_VIEW,
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 373) KEY_ALLOC_NOT_IN_QUOTA, NULL);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 374) if (IS_ERR(key)) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 375) err = PTR_ERR(key);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 376) goto out_free_mk;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 377) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 378) err = key_instantiate_and_link(key, mk, sizeof(*mk), keyring, NULL);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 379) key_put(key);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 380) if (err)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 381) goto out_free_mk;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 382)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 383) return 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 384)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 385) out_free_mk:
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 386) free_master_key(mk);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 387) return err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 388) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 389)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 390) #define KEY_DEAD 1
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 391)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 392) static int add_existing_master_key(struct fscrypt_master_key *mk,
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 393) struct fscrypt_master_key_secret *secret)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 394) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 395) struct key *mk_user;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 396) bool rekey;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 397) int err;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 398)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 399) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 400) * If the current user is already in ->mk_users, then there's nothing to
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 401) * do. (Not applicable for v1 policy keys, which have NULL ->mk_users.)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 402) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 403) if (mk->mk_users) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 404) mk_user = find_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 405) if (mk_user != ERR_PTR(-ENOKEY)) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 406) if (IS_ERR(mk_user))
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 407) return PTR_ERR(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 408) key_put(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 409) return 0;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 410) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 411) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 412)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 413) /* If we'll be re-adding ->mk_secret, try to take the reference. */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 414) rekey = !is_master_key_secret_present(&mk->mk_secret);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 415) if (rekey && !refcount_inc_not_zero(&mk->mk_refcount))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 416) return KEY_DEAD;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 417)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 418) /* Add the current user to ->mk_users, if applicable. */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 419) if (mk->mk_users) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 420) err = add_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 421) if (err) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 422) if (rekey && refcount_dec_and_test(&mk->mk_refcount))
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 423) return KEY_DEAD;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 424) return err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 425) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 426) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 427)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 428) /* Re-add the secret if needed. */
4a4b8721f1a5e (Eric Biggers 2020-11-16 19:26:26 -0800 429) if (rekey)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 430) move_master_key_secret(&mk->mk_secret, secret);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 431) return 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 432) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 433)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 434) static int do_add_master_key(struct super_block *sb,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 435) struct fscrypt_master_key_secret *secret,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 436) const struct fscrypt_key_specifier *mk_spec)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 437) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 438) static DEFINE_MUTEX(fscrypt_add_key_mutex);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 439) struct key *key;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 440) int err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 441)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 442) mutex_lock(&fscrypt_add_key_mutex); /* serialize find + link */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 443) retry:
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 444) key = fscrypt_find_master_key(sb, mk_spec);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 445) if (IS_ERR(key)) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 446) err = PTR_ERR(key);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 447) if (err != -ENOKEY)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 448) goto out_unlock;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 449) /* Didn't find the key in ->s_master_keys. Add it. */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 450) err = allocate_filesystem_keyring(sb);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 451) if (err)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 452) goto out_unlock;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 453) err = add_new_master_key(secret, mk_spec, sb->s_master_keys);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 454) } else {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 455) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 456) * Found the key in ->s_master_keys. Re-add the secret if
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 457) * needed, and add the user to ->mk_users if needed.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 458) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 459) down_write(&key->sem);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 460) err = add_existing_master_key(key->payload.data[0], secret);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 461) up_write(&key->sem);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 462) if (err == KEY_DEAD) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 463) /* Key being removed or needs to be removed */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 464) key_invalidate(key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 465) key_put(key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 466) goto retry;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 467) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 468) key_put(key);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 469) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 470) out_unlock:
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 471) mutex_unlock(&fscrypt_add_key_mutex);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 472) return err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 473) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 474)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 475) static int add_master_key(struct super_block *sb,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 476) struct fscrypt_master_key_secret *secret,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 477) struct fscrypt_key_specifier *key_spec)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 478) {
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 479) int err;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 480)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 481) if (key_spec->type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 482) err = fscrypt_init_hkdf(&secret->hkdf, secret->raw,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 483) secret->size);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 484) if (err)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 485) return err;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 486)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 487) /*
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 488) * Now that the HKDF context is initialized, the raw key is no
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 489) * longer needed.
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 490) */
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 491) memzero_explicit(secret->raw, secret->size);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 492)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 493) /* Calculate the key identifier */
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 494) err = fscrypt_hkdf_expand(&secret->hkdf,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 495) HKDF_CONTEXT_KEY_IDENTIFIER, NULL, 0,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 496) key_spec->u.identifier,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 497) FSCRYPT_KEY_IDENTIFIER_SIZE);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 498) if (err)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 499) return err;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 500) }
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 501) return do_add_master_key(sb, secret, key_spec);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 502) }
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 503)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 504) static int fscrypt_provisioning_key_preparse(struct key_preparsed_payload *prep)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 505) {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 506) const struct fscrypt_provisioning_key_payload *payload = prep->data;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 507)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 508) if (prep->datalen < sizeof(*payload) + FSCRYPT_MIN_KEY_SIZE ||
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 509) prep->datalen > sizeof(*payload) + FSCRYPT_MAX_KEY_SIZE)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 510) return -EINVAL;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 511)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 512) if (payload->type != FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 513) payload->type != FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 514) return -EINVAL;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 515)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 516) if (payload->__reserved)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 517) return -EINVAL;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 518)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 519) prep->payload.data[0] = kmemdup(payload, prep->datalen, GFP_KERNEL);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 520) if (!prep->payload.data[0])
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 521) return -ENOMEM;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 522)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 523) prep->quotalen = prep->datalen;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 524) return 0;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 525) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 526)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 527) static void fscrypt_provisioning_key_free_preparse(
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 528) struct key_preparsed_payload *prep)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 529) {
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 530) kfree_sensitive(prep->payload.data[0]);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 531) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 532)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 533) static void fscrypt_provisioning_key_describe(const struct key *key,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 534) struct seq_file *m)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 535) {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 536) seq_puts(m, key->description);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 537) if (key_is_positive(key)) {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 538) const struct fscrypt_provisioning_key_payload *payload =
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 539) key->payload.data[0];
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 540)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 541) seq_printf(m, ": %u [%u]", key->datalen, payload->type);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 542) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 543) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 544)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 545) static void fscrypt_provisioning_key_destroy(struct key *key)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 546) {
453431a54934d (Waiman Long 2020-08-06 23:18:13 -0700 547) kfree_sensitive(key->payload.data[0]);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 548) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 549)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 550) static struct key_type key_type_fscrypt_provisioning = {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 551) .name = "fscrypt-provisioning",
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 552) .preparse = fscrypt_provisioning_key_preparse,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 553) .free_preparse = fscrypt_provisioning_key_free_preparse,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 554) .instantiate = generic_key_instantiate,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 555) .describe = fscrypt_provisioning_key_describe,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 556) .destroy = fscrypt_provisioning_key_destroy,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 557) };
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 558)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 559) /*
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 560) * Retrieve the raw key from the Linux keyring key specified by 'key_id', and
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 561) * store it into 'secret'.
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 562) *
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 563) * The key must be of type "fscrypt-provisioning" and must have the field
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 564) * fscrypt_provisioning_key_payload::type set to 'type', indicating that it's
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 565) * only usable with fscrypt with the particular KDF version identified by
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 566) * 'type'. We don't use the "logon" key type because there's no way to
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 567) * completely restrict the use of such keys; they can be used by any kernel API
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 568) * that accepts "logon" keys and doesn't require a specific service prefix.
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 569) *
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 570) * The ability to specify the key via Linux keyring key is intended for cases
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 571) * where userspace needs to re-add keys after the filesystem is unmounted and
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 572) * re-mounted. Most users should just provide the raw key directly instead.
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 573) */
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 574) static int get_keyring_key(u32 key_id, u32 type,
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 575) struct fscrypt_master_key_secret *secret)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 576) {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 577) key_ref_t ref;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 578) struct key *key;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 579) const struct fscrypt_provisioning_key_payload *payload;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 580) int err;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 581)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 582) ref = lookup_user_key(key_id, 0, KEY_NEED_SEARCH);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 583) if (IS_ERR(ref))
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 584) return PTR_ERR(ref);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 585) key = key_ref_to_ptr(ref);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 586)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 587) if (key->type != &key_type_fscrypt_provisioning)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 588) goto bad_key;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 589) payload = key->payload.data[0];
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 590)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 591) /* Don't allow fscrypt v1 keys to be used as v2 keys and vice versa. */
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 592) if (payload->type != type)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 593) goto bad_key;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 594)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 595) secret->size = key->datalen - sizeof(*payload);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 596) memcpy(secret->raw, payload->raw, secret->size);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 597) err = 0;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 598) goto out_put;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 599)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 600) bad_key:
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 601) err = -EKEYREJECTED;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 602) out_put:
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 603) key_ref_put(ref);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 604) return err;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 605) }
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 606)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 607) /*
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 608) * Add a master encryption key to the filesystem, causing all files which were
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 609) * encrypted with it to appear "unlocked" (decrypted) when accessed.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 610) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 611) * When adding a key for use by v1 encryption policies, this ioctl is
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 612) * privileged, and userspace must provide the 'key_descriptor'.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 613) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 614) * When adding a key for use by v2+ encryption policies, this ioctl is
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 615) * unprivileged. This is needed, in general, to allow non-root users to use
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 616) * encryption without encountering the visibility problems of process-subscribed
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 617) * keyrings and the inability to properly remove keys. This works by having
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 618) * each key identified by its cryptographically secure hash --- the
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 619) * 'key_identifier'. The cryptographic hash ensures that a malicious user
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 620) * cannot add the wrong key for a given identifier. Furthermore, each added key
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 621) * is charged to the appropriate user's quota for the keyrings service, which
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 622) * prevents a malicious user from adding too many keys. Finally, we forbid a
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 623) * user from removing a key while other users have added it too, which prevents
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 624) * a user who knows another user's key from causing a denial-of-service by
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 625) * removing it at an inopportune time. (We tolerate that a user who knows a key
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 626) * can prevent other users from removing it.)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 627) *
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 628) * For more details, see the "FS_IOC_ADD_ENCRYPTION_KEY" section of
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 629) * Documentation/filesystems/fscrypt.rst.
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 630) */
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 631) int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 632) {
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 633) struct super_block *sb = file_inode(filp)->i_sb;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 634) struct fscrypt_add_key_arg __user *uarg = _uarg;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 635) struct fscrypt_add_key_arg arg;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 636) struct fscrypt_master_key_secret secret;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 637) int err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 638)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 639) if (copy_from_user(&arg, uarg, sizeof(arg)))
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 640) return -EFAULT;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 641)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 642) if (!valid_key_spec(&arg.key_spec))
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 643) return -EINVAL;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 644)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 645) if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 646) return -EINVAL;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 647)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 648) /*
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 649) * Only root can add keys that are identified by an arbitrary descriptor
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 650) * rather than by a cryptographic hash --- since otherwise a malicious
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 651) * user could add the wrong key.
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 652) */
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 653) if (arg.key_spec.type == FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 654) !capable(CAP_SYS_ADMIN))
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 655) return -EACCES;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 656)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 657) memset(&secret, 0, sizeof(secret));
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 658) if (arg.key_id) {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 659) if (arg.raw_size != 0)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 660) return -EINVAL;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 661) err = get_keyring_key(arg.key_id, arg.key_spec.type, &secret);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 662) if (err)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 663) goto out_wipe_secret;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 664) } else {
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 665) if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE ||
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 666) arg.raw_size > FSCRYPT_MAX_KEY_SIZE)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 667) return -EINVAL;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 668) secret.size = arg.raw_size;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 669) err = -EFAULT;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 670) if (copy_from_user(secret.raw, uarg->raw, secret.size))
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 671) goto out_wipe_secret;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 672) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 673)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 674) err = add_master_key(sb, &secret, &arg.key_spec);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 675) if (err)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 676) goto out_wipe_secret;
5dae460c2292d (Eric Biggers 2019-08-04 19:35:47 -0700 677)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 678) /* Return the key identifier to userspace, if applicable */
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 679) err = -EFAULT;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 680) if (arg.key_spec.type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER &&
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 681) copy_to_user(uarg->key_spec.u.identifier, arg.key_spec.u.identifier,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 682) FSCRYPT_KEY_IDENTIFIER_SIZE))
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 683) goto out_wipe_secret;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 684) err = 0;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 685) out_wipe_secret:
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 686) wipe_master_key_secret(&secret);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 687) return err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 688) }
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 689) EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key);
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 690)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 691) /*
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 692) * Add the key for '-o test_dummy_encryption' to the filesystem keyring.
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 693) *
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 694) * Use a per-boot random key to prevent people from misusing this option.
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 695) */
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 696) int fscrypt_add_test_dummy_key(struct super_block *sb,
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 697) struct fscrypt_key_specifier *key_spec)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 698) {
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 699) static u8 test_key[FSCRYPT_MAX_KEY_SIZE];
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 700) struct fscrypt_master_key_secret secret;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 701) int err;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 702)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 703) get_random_once(test_key, FSCRYPT_MAX_KEY_SIZE);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 704)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 705) memset(&secret, 0, sizeof(secret));
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 706) secret.size = FSCRYPT_MAX_KEY_SIZE;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 707) memcpy(secret.raw, test_key, FSCRYPT_MAX_KEY_SIZE);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 708)
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 709) err = add_master_key(sb, &secret, key_spec);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 710) wipe_master_key_secret(&secret);
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 711) return err;
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 712) }
cdeb21da1783a (Eric Biggers 2020-05-12 16:32:49 -0700 713)
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 714) /*
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 715) * Verify that the current user has added a master key with the given identifier
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 716) * (returns -ENOKEY if not). This is needed to prevent a user from encrypting
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 717) * their files using some other user's key which they don't actually know.
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 718) * Cryptographically this isn't much of a problem, but the semantics of this
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 719) * would be a bit weird, so it's best to just forbid it.
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 720) *
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 721) * The system administrator (CAP_FOWNER) can override this, which should be
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 722) * enough for any use cases where encryption policies are being set using keys
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 723) * that were chosen ahead of time but aren't available at the moment.
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 724) *
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 725) * Note that the key may have already removed by the time this returns, but
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 726) * that's okay; we just care whether the key was there at some point.
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 727) *
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 728) * Return: 0 if the key is added, -ENOKEY if it isn't, or another -errno code
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 729) */
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 730) int fscrypt_verify_key_added(struct super_block *sb,
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 731) const u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE])
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 732) {
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 733) struct fscrypt_key_specifier mk_spec;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 734) struct key *key, *mk_user;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 735) struct fscrypt_master_key *mk;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 736) int err;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 737)
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 738) mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 739) memcpy(mk_spec.u.identifier, identifier, FSCRYPT_KEY_IDENTIFIER_SIZE);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 740)
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 741) key = fscrypt_find_master_key(sb, &mk_spec);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 742) if (IS_ERR(key)) {
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 743) err = PTR_ERR(key);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 744) goto out;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 745) }
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 746) mk = key->payload.data[0];
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 747) mk_user = find_master_key_user(mk);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 748) if (IS_ERR(mk_user)) {
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 749) err = PTR_ERR(mk_user);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 750) } else {
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 751) key_put(mk_user);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 752) err = 0;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 753) }
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 754) key_put(key);
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 755) out:
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 756) if (err == -ENOKEY && capable(CAP_FOWNER))
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 757) err = 0;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 758) return err;
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 759) }
5ab7189a31bad (Eric Biggers 2019-08-04 19:35:48 -0700 760)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 761) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 762) * Try to evict the inode's dentries from the dentry cache. If the inode is a
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 763) * directory, then it can have at most one dentry; however, that dentry may be
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 764) * pinned by child dentries, so first try to evict the children too.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 765) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 766) static void shrink_dcache_inode(struct inode *inode)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 767) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 768) struct dentry *dentry;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 769)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 770) if (S_ISDIR(inode->i_mode)) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 771) dentry = d_find_any_alias(inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 772) if (dentry) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 773) shrink_dcache_parent(dentry);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 774) dput(dentry);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 775) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 776) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 777) d_prune_aliases(inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 778) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 779)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 780) static void evict_dentries_for_decrypted_inodes(struct fscrypt_master_key *mk)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 781) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 782) struct fscrypt_info *ci;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 783) struct inode *inode;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 784) struct inode *toput_inode = NULL;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 785)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 786) spin_lock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 787)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 788) list_for_each_entry(ci, &mk->mk_decrypted_inodes, ci_master_key_link) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 789) inode = ci->ci_inode;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 790) spin_lock(&inode->i_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 791) if (inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW)) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 792) spin_unlock(&inode->i_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 793) continue;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 794) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 795) __iget(inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 796) spin_unlock(&inode->i_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 797) spin_unlock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 798)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 799) shrink_dcache_inode(inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 800) iput(toput_inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 801) toput_inode = inode;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 802)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 803) spin_lock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 804) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 805)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 806) spin_unlock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 807) iput(toput_inode);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 808) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 809)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 810) static int check_for_busy_inodes(struct super_block *sb,
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 811) struct fscrypt_master_key *mk)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 812) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 813) struct list_head *pos;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 814) size_t busy_count = 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 815) unsigned long ino;
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 816) char ino_str[50] = "";
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 817)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 818) spin_lock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 819)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 820) list_for_each(pos, &mk->mk_decrypted_inodes)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 821) busy_count++;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 822)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 823) if (busy_count == 0) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 824) spin_unlock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 825) return 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 826) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 827)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 828) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 829) /* select an example file to show for debugging purposes */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 830) struct inode *inode =
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 831) list_first_entry(&mk->mk_decrypted_inodes,
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 832) struct fscrypt_info,
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 833) ci_master_key_link)->ci_inode;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 834) ino = inode->i_ino;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 835) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 836) spin_unlock(&mk->mk_decrypted_inodes_lock);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 837)
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 838) /* If the inode is currently being created, ino may still be 0. */
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 839) if (ino)
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 840) snprintf(ino_str, sizeof(ino_str), ", including ino %lu", ino);
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 841)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 842) fscrypt_warn(NULL,
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 843) "%s: %zu inode(s) still busy after removing key with %s %*phN%s",
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 844) sb->s_id, busy_count, master_key_spec_type(&mk->mk_spec),
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 845) master_key_spec_len(&mk->mk_spec), (u8 *)&mk->mk_spec.u,
ae9ff8ad81b13 (Eric Biggers 2020-09-16 21:11:29 -0700 846) ino_str);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 847) return -EBUSY;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 848) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 849)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 850) static int try_to_lock_encrypted_files(struct super_block *sb,
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 851) struct fscrypt_master_key *mk)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 852) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 853) int err1;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 854) int err2;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 855)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 856) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 857) * An inode can't be evicted while it is dirty or has dirty pages.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 858) * Thus, we first have to clean the inodes in ->mk_decrypted_inodes.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 859) *
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 860) * Just do it the easy way: call sync_filesystem(). It's overkill, but
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 861) * it works, and it's more important to minimize the amount of caches we
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 862) * drop than the amount of data we sync. Also, unprivileged users can
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 863) * already call sync_filesystem() via sys_syncfs() or sys_sync().
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 864) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 865) down_read(&sb->s_umount);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 866) err1 = sync_filesystem(sb);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 867) up_read(&sb->s_umount);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 868) /* If a sync error occurs, still try to evict as much as possible. */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 869)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 870) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 871) * Inodes are pinned by their dentries, so we have to evict their
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 872) * dentries. shrink_dcache_sb() would suffice, but would be overkill
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 873) * and inappropriate for use by unprivileged users. So instead go
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 874) * through the inodes' alias lists and try to evict each dentry.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 875) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 876) evict_dentries_for_decrypted_inodes(mk);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 877)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 878) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 879) * evict_dentries_for_decrypted_inodes() already iput() each inode in
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 880) * the list; any inodes for which that dropped the last reference will
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 881) * have been evicted due to fscrypt_drop_inode() detecting the key
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 882) * removal and telling the VFS to evict the inode. So to finish, we
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 883) * just need to check whether any inodes couldn't be evicted.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 884) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 885) err2 = check_for_busy_inodes(sb, mk);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 886)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 887) return err1 ?: err2;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 888) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 889)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 890) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 891) * Try to remove an fscrypt master encryption key.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 892) *
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 893) * FS_IOC_REMOVE_ENCRYPTION_KEY (all_users=false) removes the current user's
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 894) * claim to the key, then removes the key itself if no other users have claims.
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 895) * FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS (all_users=true) always removes the
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 896) * key itself.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 897) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 898) * To "remove the key itself", first we wipe the actual master key secret, so
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 899) * that no more inodes can be unlocked with it. Then we try to evict all cached
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 900) * inodes that had been unlocked with the key.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 901) *
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 902) * If all inodes were evicted, then we unlink the fscrypt_master_key from the
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 903) * keyring. Otherwise it remains in the keyring in the "incompletely removed"
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 904) * state (without the actual secret key) where it tracks the list of remaining
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 905) * inodes. Userspace can execute the ioctl again later to retry eviction, or
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 906) * alternatively can re-add the secret key again.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 907) *
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 908) * For more details, see the "Removing keys" section of
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 909) * Documentation/filesystems/fscrypt.rst.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 910) */
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 911) static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 912) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 913) struct super_block *sb = file_inode(filp)->i_sb;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 914) struct fscrypt_remove_key_arg __user *uarg = _uarg;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 915) struct fscrypt_remove_key_arg arg;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 916) struct key *key;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 917) struct fscrypt_master_key *mk;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 918) u32 status_flags = 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 919) int err;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 920) bool dead;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 921)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 922) if (copy_from_user(&arg, uarg, sizeof(arg)))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 923) return -EFAULT;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 924)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 925) if (!valid_key_spec(&arg.key_spec))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 926) return -EINVAL;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 927)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 928) if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 929) return -EINVAL;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 930)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 931) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 932) * Only root can add and remove keys that are identified by an arbitrary
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 933) * descriptor rather than by a cryptographic hash.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 934) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 935) if (arg.key_spec.type == FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR &&
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 936) !capable(CAP_SYS_ADMIN))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 937) return -EACCES;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 938)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 939) /* Find the key being removed. */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 940) key = fscrypt_find_master_key(sb, &arg.key_spec);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 941) if (IS_ERR(key))
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 942) return PTR_ERR(key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 943) mk = key->payload.data[0];
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 944)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 945) down_write(&key->sem);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 946)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 947) /* If relevant, remove current user's (or all users) claim to the key */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 948) if (mk->mk_users && mk->mk_users->keys.nr_leaves_on_tree != 0) {
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 949) if (all_users)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 950) err = keyring_clear(mk->mk_users);
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 951) else
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 952) err = remove_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 953) if (err) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 954) up_write(&key->sem);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 955) goto out_put_key;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 956) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 957) if (mk->mk_users->keys.nr_leaves_on_tree != 0) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 958) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 959) * Other users have still added the key too. We removed
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 960) * the current user's claim to the key, but we still
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 961) * can't remove the key itself.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 962) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 963) status_flags |=
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 964) FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 965) err = 0;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 966) up_write(&key->sem);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 967) goto out_put_key;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 968) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 969) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 970)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 971) /* No user claims remaining. Go ahead and wipe the secret. */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 972) dead = false;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 973) if (is_master_key_secret_present(&mk->mk_secret)) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 974) wipe_master_key_secret(&mk->mk_secret);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 975) dead = refcount_dec_and_test(&mk->mk_refcount);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 976) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 977) up_write(&key->sem);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 978) if (dead) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 979) /*
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 980) * No inodes reference the key, and we wiped the secret, so the
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 981) * key object is free to be removed from the keyring.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 982) */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 983) key_invalidate(key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 984) err = 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 985) } else {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 986) /* Some inodes still reference this key; try to evict them. */
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 987) err = try_to_lock_encrypted_files(sb, mk);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 988) if (err == -EBUSY) {
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 989) status_flags |=
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 990) FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 991) err = 0;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 992) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 993) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 994) /*
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 995) * We return 0 if we successfully did something: removed a claim to the
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 996) * key, wiped the secret, or tried locking the files again. Users need
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 997) * to check the informational status flags if they care whether the key
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 998) * has been fully removed including all files locked.
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 999) */
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1000) out_put_key:
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1001) key_put(key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1002) if (err == 0)
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1003) err = put_user(status_flags, &uarg->removal_status_flags);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1004) return err;
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1005) }
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1006)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1007) int fscrypt_ioctl_remove_key(struct file *filp, void __user *uarg)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1008) {
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1009) return do_remove_key(filp, uarg, false);
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1010) }
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1011) EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key);
b1c0ec3599f42 (Eric Biggers 2019-08-04 19:35:46 -0700 1012)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1013) int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *uarg)
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1014) {
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1015) if (!capable(CAP_SYS_ADMIN))
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1016) return -EACCES;
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1017) return do_remove_key(filp, uarg, true);
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1018) }
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1019) EXPORT_SYMBOL_GPL(fscrypt_ioctl_remove_key_all_users);
78a1b96bcf7a0 (Eric Biggers 2019-08-04 19:35:47 -0700 1020)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1021) /*
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1022) * Retrieve the status of an fscrypt master encryption key.
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1023) *
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1024) * We set ->status to indicate whether the key is absent, present, or
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1025) * incompletely removed. "Incompletely removed" means that the master key
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1026) * secret has been removed, but some files which had been unlocked with it are
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1027) * still in use. This field allows applications to easily determine the state
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1028) * of an encrypted directory without using a hack such as trying to open a
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1029) * regular file in it (which can confuse the "incompletely removed" state with
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1030) * absent or present).
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1031) *
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1032) * In addition, for v2 policy keys we allow applications to determine, via
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1033) * ->status_flags and ->user_count, whether the key has been added by the
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1034) * current user, by other users, or by both. Most applications should not need
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1035) * this, since ordinarily only one user should know a given key. However, if a
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1036) * secret key is shared by multiple users, applications may wish to add an
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1037) * already-present key to prevent other users from removing it. This ioctl can
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1038) * be used to check whether that really is the case before the work is done to
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1039) * add the key --- which might e.g. require prompting the user for a passphrase.
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1040) *
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1041) * For more details, see the "FS_IOC_GET_ENCRYPTION_KEY_STATUS" section of
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1042) * Documentation/filesystems/fscrypt.rst.
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1043) */
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1044) int fscrypt_ioctl_get_key_status(struct file *filp, void __user *uarg)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1045) {
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1046) struct super_block *sb = file_inode(filp)->i_sb;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1047) struct fscrypt_get_key_status_arg arg;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1048) struct key *key;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1049) struct fscrypt_master_key *mk;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1050) int err;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1051)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1052) if (copy_from_user(&arg, uarg, sizeof(arg)))
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1053) return -EFAULT;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1054)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1055) if (!valid_key_spec(&arg.key_spec))
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1056) return -EINVAL;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1057)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1058) if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved)))
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1059) return -EINVAL;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1060)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1061) arg.status_flags = 0;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1062) arg.user_count = 0;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1063) memset(arg.__out_reserved, 0, sizeof(arg.__out_reserved));
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1064)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1065) key = fscrypt_find_master_key(sb, &arg.key_spec);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1066) if (IS_ERR(key)) {
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1067) if (key != ERR_PTR(-ENOKEY))
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1068) return PTR_ERR(key);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1069) arg.status = FSCRYPT_KEY_STATUS_ABSENT;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1070) err = 0;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1071) goto out;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1072) }
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1073) mk = key->payload.data[0];
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1074) down_read(&key->sem);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1075)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1076) if (!is_master_key_secret_present(&mk->mk_secret)) {
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1077) arg.status = FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1078) err = 0;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1079) goto out_release_key;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1080) }
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1081)
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1082) arg.status = FSCRYPT_KEY_STATUS_PRESENT;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1083) if (mk->mk_users) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1084) struct key *mk_user;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1085)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1086) arg.user_count = mk->mk_users->keys.nr_leaves_on_tree;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1087) mk_user = find_master_key_user(mk);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1088) if (!IS_ERR(mk_user)) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1089) arg.status_flags |=
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1090) FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1091) key_put(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1092) } else if (mk_user != ERR_PTR(-ENOKEY)) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1093) err = PTR_ERR(mk_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1094) goto out_release_key;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1095) }
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1096) }
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1097) err = 0;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1098) out_release_key:
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1099) up_read(&key->sem);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1100) key_put(key);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1101) out:
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1102) if (!err && copy_to_user(uarg, &arg, sizeof(arg)))
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1103) err = -EFAULT;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1104) return err;
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1105) }
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1106) EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_key_status);
5a7e29924dac3 (Eric Biggers 2019-08-04 19:35:46 -0700 1107)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 1108) int __init fscrypt_init_keyring(void)
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 1109) {
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1110) int err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1111)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1112) err = register_key_type(&key_type_fscrypt);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1113) if (err)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1114) return err;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1115)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1116) err = register_key_type(&key_type_fscrypt_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1117) if (err)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1118) goto err_unregister_fscrypt;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1119)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1120) err = register_key_type(&key_type_fscrypt_provisioning);
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1121) if (err)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1122) goto err_unregister_fscrypt_user;
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1123)
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1124) return 0;
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1125)
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1126) err_unregister_fscrypt_user:
93edd392cad74 (Eric Biggers 2019-11-19 14:24:47 -0800 1127) unregister_key_type(&key_type_fscrypt_user);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1128) err_unregister_fscrypt:
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1129) unregister_key_type(&key_type_fscrypt);
23c688b54016e (Eric Biggers 2019-08-04 19:35:47 -0700 1130) return err;
22d94f493bfb4 (Eric Biggers 2019-08-04 19:35:46 -0700 1131) }
VisionFive2 Linux kernel
StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)
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