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-rw-r--r--crypto/lollipop/cryptfs.c71
1 files changed, 66 insertions, 5 deletions
diff --git a/crypto/lollipop/cryptfs.c b/crypto/lollipop/cryptfs.c
index fe075c4ad..56f10b92b 100644
--- a/crypto/lollipop/cryptfs.c
+++ b/crypto/lollipop/cryptfs.c
@@ -842,6 +842,49 @@ errout:
return rc;
}
+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) {
+ printf("Trying to convert ascii string of odd length\n");
+ return NULL;
+ }
+
+ unsigned char* master_key = (unsigned char*) malloc(size / 2);
+ if (master_key == 0) {
+ printf("Cannot allocate\n");
+ 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) {
+ printf("Invalid hex string\n");
+ 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
*/
@@ -1114,9 +1157,14 @@ static int pbkdf2(const char *passwd, const unsigned char *salt,
printf("Using pbkdf2 for cryptfs KDF\n");
/* Turn the password into a key and IV that can decrypt the master key */
- PKCS5_PBKDF2_HMAC_SHA1(passwd, strlen(passwd), salt, SALT_LEN,
+ 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,
HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey);
+ memset(master_key, 0, keysize);
+ free (master_key);
return 0;
}
@@ -1132,9 +1180,14 @@ static int scrypt(const char *passwd, const unsigned char *salt,
int p = 1 << ftr->p_factor;
/* Turn the password into a key and IV that can decrypt the master key */
- crypto_scrypt((const uint8_t *)passwd, strlen(passwd), salt, SALT_LEN,
- N, r, p, ikey, KEY_LEN_BYTES + IV_LEN_BYTES);
-
+ 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);
+
+ memset(master_key, 0, keysize);
+ free (master_key);
return 0;
}
@@ -1153,8 +1206,16 @@ static int scrypt_keymaster(const char *passwd, const unsigned char *salt,
int r = 1 << ftr->r_factor;
int p = 1 << ftr->p_factor;
- rc = crypto_scrypt((const uint8_t *)passwd, strlen(passwd), salt, SALT_LEN,
+ unsigned char* master_key = convert_hex_ascii_to_key(passwd, &key_size);
+ if (!master_key) {
+ printf("Failed to convert passwd from hex\n");
+ 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);
if (rc) {
printf("scrypt failed\n");