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am 3bd36d5e: Remove hex encoding and password adjusting now that patterns are \'1\' based

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* commit '3bd36d5e5f14dff4dadba88eb27664e495d0e16e':
  Remove hex encoding and password adjusting now that patterns are '1' based
This commit is contained in:
Paul Lawrence 2015-06-10 16:02:11 +00:00 committed by Android Git Automerger
commit 330f26baea
1 changed files with 25 additions and 190 deletions
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215
cryptfs.c
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@ -78,8 +78,7 @@
#define KEY_IN_FOOTER "footer"
// "default_password" encoded into hex (d=0x64 etc)
#define DEFAULT_PASSWORD "64656661756c745f70617373776f7264"
#define DEFAULT_PASSWORD "default_password"
#define EXT4_FS 1
#define F2FS_FS 2
@ -900,68 +899,25 @@ err:
return -1;
}
static int hexdigit (char c)
{
if (c >= '0' && c <= '9') return c - '0';
c = tolower(c);
if (c >= 'a' && c <= 'f') return c - 'a' + 10;
return -1;
}
static unsigned char* convert_hex_ascii_to_key(const char* master_key_ascii,
unsigned int* out_keysize)
{
unsigned int i;
*out_keysize = 0;
size_t size = strlen (master_key_ascii);
if (size % 2) {
SLOGE("Trying to convert ascii string of odd length");
return NULL;
}
unsigned char* master_key = (unsigned char*) malloc(size / 2);
if (master_key == 0) {
SLOGE("Cannot allocate");
return NULL;
}
for (i = 0; i < size; i += 2) {
int high_nibble = hexdigit (master_key_ascii[i]);
int low_nibble = hexdigit (master_key_ascii[i + 1]);
if(high_nibble < 0 || low_nibble < 0) {
SLOGE("Invalid hex string");
free (master_key);
return NULL;
}
master_key[*out_keysize] = high_nibble * 16 + low_nibble;
(*out_keysize)++;
}
return master_key;
}
/* Convert a binary key of specified length into an ascii hex string equivalent,
* without the leading 0x and with null termination
*/
static void convert_key_to_hex_ascii(const unsigned char *master_key,
unsigned int keysize, char *master_key_ascii) {
unsigned int i, a;
unsigned char nibble;
unsigned int keysize, char *master_key_ascii) {
unsigned int i, a;
unsigned char nibble;
for (i=0, a=0; i<keysize; i++, a+=2) {
/* For each byte, write out two ascii hex digits */
nibble = (master_key[i] >> 4) & 0xf;
master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30);
for (i=0, a=0; i<keysize; i++, a+=2) {
/* For each byte, write out two ascii hex digits */
nibble = (master_key[i] >> 4) & 0xf;
master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30);
nibble = master_key[i] & 0xf;
master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30);
}
nibble = master_key[i] & 0xf;
master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30);
}
/* Add the null termination */
master_key_ascii[a] = '\0';
/* Add the null termination */
master_key_ascii[a] = '\0';
}
@ -1162,14 +1118,10 @@ static int pbkdf2(const char *passwd, const unsigned char *salt,
SLOGI("Using pbkdf2 for cryptfs KDF");
/* Turn the password into a key and IV that can decrypt the master key */
unsigned int keysize;
char* master_key = (char*)convert_hex_ascii_to_key(passwd, &keysize);
if (!master_key) return -1;
PKCS5_PBKDF2_HMAC_SHA1(master_key, keysize, salt, SALT_LEN,
PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd),
salt, SALT_LEN,
HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey);
memset(master_key, 0, keysize);
free (master_key);
return 0;
}
@ -1186,14 +1138,11 @@ static int scrypt(const char *passwd, const unsigned char *salt,
/* Turn the password into a key and IV that can decrypt the master key */
unsigned int keysize;
unsigned char* master_key = convert_hex_ascii_to_key(passwd, &keysize);
if (!master_key) return -1;
crypto_scrypt(master_key, keysize, salt, SALT_LEN, N, r, p, ikey,
KEY_LEN_BYTES + IV_LEN_BYTES);
crypto_scrypt((const uint8_t*)passwd, strlen(passwd),
salt, SALT_LEN, N, r, p, ikey,
KEY_LEN_BYTES + IV_LEN_BYTES);
memset(master_key, 0, keysize);
free (master_key);
return 0;
return 0;
}
static int scrypt_keymaster(const char *passwd, const unsigned char *salt,
@ -1202,7 +1151,6 @@ static int scrypt_keymaster(const char *passwd, const unsigned char *salt,
SLOGI("Using scrypt with keymaster for cryptfs KDF");
int rc;
unsigned int key_size;
size_t signature_size;
unsigned char* signature;
struct crypt_mnt_ftr *ftr = (struct crypt_mnt_ftr *) params;
@ -1211,16 +1159,9 @@ static int scrypt_keymaster(const char *passwd, const unsigned char *salt,
int r = 1 << ftr->r_factor;
int p = 1 << ftr->p_factor;
unsigned char* master_key = convert_hex_ascii_to_key(passwd, &key_size);
if (!master_key) {
SLOGE("Failed to convert passwd from hex");
return -1;
}
rc = crypto_scrypt(master_key, key_size, salt, SALT_LEN,
N, r, p, ikey, KEY_LEN_BYTES + IV_LEN_BYTES);
memset(master_key, 0, key_size);
free(master_key);
rc = crypto_scrypt((const uint8_t*)passwd, strlen(passwd),
salt, SALT_LEN, N, r, p, ikey,
KEY_LEN_BYTES + IV_LEN_BYTES);
if (rc) {
SLOGE("scrypt failed");
@ -1949,68 +1890,6 @@ int check_unmounted_and_get_ftr(struct crypt_mnt_ftr* crypt_ftr)
return 0;
}
/*
* TODO - transition patterns to new format in calling code
* and remove this vile hack, and the use of hex in
* the password passing code.
*
* Patterns are passed in zero based (i.e. the top left dot
* is represented by zero, the top middle one etc), but we want
* to store them '1' based.
* This is to allow us to migrate the calling code to use this
* convention. It also solves a nasty problem whereby scrypt ignores
* trailing zeros, so patterns ending at the top left could be
* truncated, and similarly, you could add the top left to any
* pattern and still match.
* adjust_passwd is a hack function that returns the alternate representation
* if the password appears to be a pattern (hex numbers all less than 09)
* If it succeeds we need to try both, and in particular try the alternate
* first. If the original matches, then we need to update the footer
* with the alternate.
* All code that accepts passwords must adjust them first. Since
* cryptfs_check_passwd is always the first function called after a migration
* (and indeed on any boot) we only need to do the double try in this
* function.
*/
char* adjust_passwd(const char* passwd)
{
size_t index, length;
if (!passwd) {
return 0;
}
// Check even length. Hex encoded passwords are always
// an even length, since each character encodes to two characters.
length = strlen(passwd);
if (length % 2) {
SLOGW("Password not correctly hex encoded.");
return 0;
}
// Check password is old-style pattern - a collection of hex
// encoded bytes less than 9 (00 through 08)
for (index = 0; index < length; index +=2) {
if (passwd[index] != '0'
|| passwd[index + 1] < '0' || passwd[index + 1] > '8') {
return 0;
}
}
// Allocate room for adjusted passwd and null terminate
char* adjusted = malloc(length + 1);
adjusted[length] = 0;
// Add 0x31 ('1') to each character
for (index = 0; index < length; index += 2) {
// output is 31 through 39 so set first byte to three, second to src + 1
adjusted[index] = '3';
adjusted[index + 1] = passwd[index + 1] + 1;
}
return adjusted;
}
int cryptfs_check_passwd(char *passwd)
{
SLOGI("cryptfs_check_passwd");
@ -2025,31 +1904,8 @@ int cryptfs_check_passwd(char *passwd)
if (rc)
return rc;
char* adjusted_passwd = adjust_passwd(passwd);
if (adjusted_passwd) {
int failed_decrypt_count = crypt_ftr.failed_decrypt_count;
rc = test_mount_encrypted_fs(&crypt_ftr, adjusted_passwd,
DATA_MNT_POINT, "userdata");
// Maybe the original one still works?
if (rc) {
// Don't double count this failure
crypt_ftr.failed_decrypt_count = failed_decrypt_count;
rc = test_mount_encrypted_fs(&crypt_ftr, passwd,
DATA_MNT_POINT, "userdata");
if (!rc) {
// cryptfs_changepw also adjusts so pass original
// Note that adjust_passwd only recognises patterns
// so we can safely use CRYPT_TYPE_PATTERN
SLOGI("Updating pattern to new format");
cryptfs_changepw(CRYPT_TYPE_PATTERN, passwd);
}
}
free(adjusted_passwd);
} else {
rc = test_mount_encrypted_fs(&crypt_ftr, passwd,
DATA_MNT_POINT, "userdata");
}
rc = test_mount_encrypted_fs(&crypt_ftr, passwd,
DATA_MNT_POINT, "userdata");
if (rc == 0 && crypt_ftr.crypt_type != CRYPT_TYPE_DEFAULT) {
cryptfs_clear_password();
@ -2095,11 +1951,6 @@ int cryptfs_verify_passwd(char *passwd)
/* If the device has no password, then just say the password is valid */
rc = 0;
} else {
char* adjusted_passwd = adjust_passwd(passwd);
if (adjusted_passwd) {
passwd = adjusted_passwd;
}
decrypt_master_key(passwd, decrypted_master_key, &crypt_ftr, 0, 0);
if (!memcmp(decrypted_master_key, saved_master_key, crypt_ftr.keysize)) {
/* They match, the password is correct */
@ -2109,8 +1960,6 @@ int cryptfs_verify_passwd(char *passwd)
sleep(1);
rc = 1;
}
free(adjusted_passwd);
}
return rc;
@ -3241,15 +3090,7 @@ error_shutting_down:
int cryptfs_enable(char *howarg, int type, char *passwd, int allow_reboot)
{
char* adjusted_passwd = adjust_passwd(passwd);
if (adjusted_passwd) {
passwd = adjusted_passwd;
}
int rc = cryptfs_enable_internal(howarg, type, passwd, allow_reboot);
free(adjusted_passwd);
return rc;
return cryptfs_enable_internal(howarg, type, passwd, allow_reboot);
}
int cryptfs_enable_default(char *howarg, int allow_reboot)
@ -3286,18 +3127,12 @@ int cryptfs_changepw(int crypt_type, const char *newpw)
crypt_ftr.crypt_type = crypt_type;
char* adjusted_passwd = adjust_passwd(newpw);
if (adjusted_passwd) {
newpw = adjusted_passwd;
}
rc = encrypt_master_key(crypt_type == CRYPT_TYPE_DEFAULT ? DEFAULT_PASSWORD
: newpw,
crypt_ftr.salt,
saved_master_key,
crypt_ftr.master_key,
&crypt_ftr);
free(adjusted_passwd);
if (rc) {
SLOGE("Encrypt master key failed: %d", rc);
return -1;