1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
|
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <unistd.h>
#include <keyutils.h>
#include <linux/random.h>
#include <sodium/crypto_pwhash_scryptsalsa208sha256.h>
#include <uuid/uuid.h>
#include "libbcachefs/checksum.h"
#include "crypto.h"
char *read_passphrase(const char *prompt)
{
char *buf = NULL;
size_t buflen = 0;
ssize_t len;
if (isatty(STDIN_FILENO)) {
struct termios old, new;
fprintf(stderr, "%s", prompt);
fflush(stderr);
if (tcgetattr(STDIN_FILENO, &old))
die("error getting terminal attrs");
new = old;
new.c_lflag &= ~ECHO;
if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &new))
die("error setting terminal attrs");
len = getline(&buf, &buflen, stdin);
tcsetattr(STDIN_FILENO, TCSAFLUSH, &old);
fprintf(stderr, "\n");
} else {
len = getline(&buf, &buflen, stdin);
}
if (len < 0)
die("error reading passphrase");
if (len && buf[len - 1] == '\n')
buf[len - 1] = '\0';
return buf;
}
char *read_passphrase_twice(const char *prompt)
{
char *pass = read_passphrase(prompt);
if (!isatty(STDIN_FILENO))
return pass;
char *pass2 = read_passphrase("Enter same passphrase again: ");
if (strcmp(pass, pass2)) {
memzero_explicit(pass, strlen(pass));
memzero_explicit(pass2, strlen(pass2));
die("Passphrases do not match");
}
memzero_explicit(pass2, strlen(pass2));
free(pass2);
return pass;
}
struct bch_key derive_passphrase(struct bch_sb_field_crypt *crypt,
const char *passphrase)
{
const unsigned char salt[] = "bcache";
struct bch_key key;
int ret;
switch (BCH_CRYPT_KDF_TYPE(crypt)) {
case BCH_KDF_SCRYPT:
ret = crypto_pwhash_scryptsalsa208sha256_ll(
(void *) passphrase, strlen(passphrase),
salt, sizeof(salt),
1ULL << BCH_KDF_SCRYPT_N(crypt),
1ULL << BCH_KDF_SCRYPT_R(crypt),
1ULL << BCH_KDF_SCRYPT_P(crypt),
(void *) &key, sizeof(key));
if (ret)
die("scrypt error: %i", ret);
break;
default:
die("unknown kdf type %llu", BCH_CRYPT_KDF_TYPE(crypt));
}
return key;
}
bool bch2_sb_is_encrypted(struct bch_sb *sb)
{
struct bch_sb_field_crypt *crypt;
return (crypt = bch2_sb_field_get(sb, crypt)) &&
bch2_key_is_encrypted(&crypt->key);
}
void bch2_passphrase_check(struct bch_sb *sb, const char *passphrase,
struct bch_key *passphrase_key,
struct bch_encrypted_key *sb_key)
{
struct bch_sb_field_crypt *crypt = bch2_sb_field_get(sb, crypt);
if (!crypt)
die("filesystem is not encrypted");
*sb_key = crypt->key;
if (!bch2_key_is_encrypted(sb_key))
die("filesystem does not have encryption key");
*passphrase_key = derive_passphrase(crypt, passphrase);
/* Check if the user supplied the correct passphrase: */
if (bch2_chacha_encrypt_key(passphrase_key, __bch2_sb_key_nonce(sb),
sb_key, sizeof(*sb_key)))
die("error encrypting key");
if (bch2_key_is_encrypted(sb_key))
die("incorrect passphrase");
}
void bch2_add_key(struct bch_sb *sb,
const char *type,
const char *keyring_str,
const char *passphrase)
{
struct bch_key passphrase_key;
struct bch_encrypted_key sb_key;
int keyring;
if (!strcmp(keyring_str, "session"))
keyring = KEY_SPEC_SESSION_KEYRING;
else if (!strcmp(keyring_str, "user"))
keyring = KEY_SPEC_USER_KEYRING;
else if (!strcmp(keyring_str, "user_session"))
keyring = KEY_SPEC_USER_SESSION_KEYRING;
else
die("unknown keyring %s", keyring_str);
bch2_passphrase_check(sb, passphrase,
&passphrase_key,
&sb_key);
char uuid[40];
uuid_unparse_lower(sb->user_uuid.b, uuid);
char *description = mprintf("bcachefs:%s", uuid);
if (add_key(type,
description,
&passphrase_key, sizeof(passphrase_key),
keyring) < 0)
die("add_key error: %m");
memzero_explicit(description, strlen(description));
free(description);
memzero_explicit(&passphrase_key, sizeof(passphrase_key));
memzero_explicit(&sb_key, sizeof(sb_key));
}
void bch_sb_crypt_init(struct bch_sb *sb,
struct bch_sb_field_crypt *crypt,
const char *passphrase)
{
crypt->key.magic = BCH_KEY_MAGIC;
get_random_bytes(&crypt->key.key, sizeof(crypt->key.key));
if (passphrase) {
SET_BCH_CRYPT_KDF_TYPE(crypt, BCH_KDF_SCRYPT);
SET_BCH_KDF_SCRYPT_N(crypt, ilog2(16384));
SET_BCH_KDF_SCRYPT_R(crypt, ilog2(8));
SET_BCH_KDF_SCRYPT_P(crypt, ilog2(16));
struct bch_key passphrase_key = derive_passphrase(crypt, passphrase);
assert(!bch2_key_is_encrypted(&crypt->key));
if (bch2_chacha_encrypt_key(&passphrase_key, __bch2_sb_key_nonce(sb),
&crypt->key, sizeof(crypt->key)))
die("error encrypting key");
assert(bch2_key_is_encrypted(&crypt->key));
memzero_explicit(&passphrase_key, sizeof(passphrase_key));
}
}
|
