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#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 <libscrypt.h>
#include <uuid/uuid.h>
#include "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;
}
void derive_passphrase(struct bch_sb_field_crypt *crypt,
struct bch_key *key,
const char *passphrase)
{
const unsigned char salt[] = "bcache";
int ret;
switch (BCH_CRYPT_KDF_TYPE(crypt)) {
case BCH_KDF_SCRYPT:
ret = libscrypt_scrypt((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));
}
}
void bch2_add_key(struct bch_sb *sb, const char *passphrase)
{
struct bch_sb_field_crypt *crypt = bch2_sb_get_crypt(sb);
if (!crypt)
die("filesystem is not encrypted");
struct bch_encrypted_key sb_key = crypt->key;
if (!bch2_key_is_encrypted(&sb_key))
die("filesystem does not have encryption key");
struct bch_key passphrase_key;
derive_passphrase(crypt, &passphrase_key, 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");
char uuid[40];
uuid_unparse_lower(sb->user_uuid.b, uuid);
char *description = mprintf("bcachefs:%s", uuid);
if (add_key("logon", description,
&passphrase_key, sizeof(passphrase_key),
KEY_SPEC_USER_KEYRING) < 0 ||
add_key("user", description,
&passphrase_key, sizeof(passphrase_key),
KEY_SPEC_USER_KEYRING) < 0)
die("add_key error: %s", strerror(errno));
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) {
struct bch_key passphrase_key;
SET_BCH_CRYPT_KDF_TYPE(crypt, BCH_KDF_SCRYPT);
SET_BCH_KDF_SCRYPT_N(crypt, ilog2(SCRYPT_N));
SET_BCH_KDF_SCRYPT_R(crypt, ilog2(SCRYPT_r));
SET_BCH_KDF_SCRYPT_P(crypt, ilog2(SCRYPT_p));
derive_passphrase(crypt, &passphrase_key, 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));
}
}
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