memcpy(keys->authentication_key, outbuf, sizeof(keys->authentication_key));
}
+/* A boolean: are blocks of the specified type encrypted in the BlueSky file
+ * system? */
+gboolean bluesky_crypt_block_needs_encryption(uint8_t type)
+{
+ type -= '0';
+
+ switch (type) {
+ case LOGTYPE_DATA:
+ case LOGTYPE_INODE:
+ return TRUE;
+ case LOGTYPE_INODE_MAP:
+ case LOGTYPE_CHECKPOINT:
+ return FALSE;
+ default:
+ g_warning("Unknown log item type in crypto layer: %d!\n",
+ type);
+ return TRUE;
+ }
+}
+
void bluesky_crypt_block_encrypt(gchar *cloud_block, size_t len,
BlueSkyCryptKeys *keys)
{
gcry_strerror(status));
}
- bluesky_crypt_random_bytes(header->crypt_iv, sizeof(header->crypt_iv));
- status = gcry_cipher_setctr(handle, header->crypt_iv,
- sizeof(header->crypt_iv));
- if (status) {
- g_error("gcrypt error setting IV: %s\n",
- gcry_strerror(status));
+ gboolean encrypted = bluesky_crypt_block_needs_encryption(header->type);
+
+ if (encrypted) {
+ header->magic[3] ^= 0x10;
+
+ bluesky_crypt_random_bytes(header->crypt_iv, sizeof(header->crypt_iv));
+ status = gcry_cipher_setctr(handle, header->crypt_iv,
+ sizeof(header->crypt_iv));
+ if (status) {
+ g_error("gcrypt error setting IV: %s\n",
+ gcry_strerror(status));
+ }
+
+ status = gcry_cipher_encrypt(handle,
+ cloud_block + sizeof(struct cloudlog_header),
+ GUINT32_FROM_LE(header->size1),
+ NULL, 0);
+ if (status) {
+ g_error("gcrypt error encrypting: %s\n",
+ gcry_strerror(status));
+ }
+ } else {
+ memset(header->crypt_iv, 0, sizeof(header->crypt_iv));
}
- status = gcry_cipher_encrypt(handle,
- cloud_block + sizeof(struct cloudlog_header),
- GUINT32_FROM_LE(header->size1),
- NULL, 0);
- if (status) {
- g_error("gcrypt error encrypting: %s\n",
- gcry_strerror(status));
+ bluesky_crypt_hmac((char *)&header->crypt_iv,
+ cloud_block + len - (char *)&header->crypt_iv,
+ keys->authentication_key,
+ header->crypt_auth);
+
+ gcry_cipher_close(handle);
+}
+
+gboolean bluesky_crypt_block_decrypt(gchar *cloud_block, size_t len,
+ BlueSkyCryptKeys *keys)
+{
+ gcry_error_t status;
+ uint8_t hmac_check[CRYPTO_HASH_SIZE];
+
+ gboolean encrypted = TRUE;
+
+ struct cloudlog_header *header = (struct cloudlog_header *)cloud_block;
+ if (memcmp(header->magic, CLOUDLOG_MAGIC,
+ sizeof(header->magic)) == 0)
+ encrypted = FALSE;
+ else
+ g_assert(memcmp(header->magic, CLOUDLOG_MAGIC_ENCRYPTED,
+ sizeof(header->magic)) == 0);
+
+ if (encrypted != bluesky_crypt_block_needs_encryption(header->type)) {
+ g_warning("Encrypted status of item does not match expected!\n");
}
bluesky_crypt_hmac((char *)&header->crypt_iv,
cloud_block + len - (char *)&header->crypt_iv,
keys->authentication_key,
- header->crypt_auth);
+ hmac_check);
+ if (memcmp(hmac_check, header->crypt_auth, CRYPTO_HASH_SIZE) != 0) {
+ g_warning("Cloud block HMAC does not match!\n");
+ return FALSE;
+ }
+
+ if (encrypted) {
+ gcry_cipher_hd_t handle;
+ status = gcry_cipher_open(&handle, GCRY_CIPHER_AES,
+ GCRY_CIPHER_MODE_CTR, 0);
+ if (status) {
+ g_error("gcrypt error setting up encryption: %s\n",
+ gcry_strerror(status));
+ }
+
+ gcry_cipher_setkey(handle, keys->encryption_key, CRYPTO_KEY_SIZE);
+ if (status) {
+ g_error("gcrypt error setting key: %s\n",
+ gcry_strerror(status));
+ }
+
+ status = gcry_cipher_setctr(handle, header->crypt_iv,
+ sizeof(header->crypt_iv));
+ if (status) {
+ g_error("gcrypt error setting IV: %s\n",
+ gcry_strerror(status));
+ }
+
+ status = gcry_cipher_decrypt(handle,
+ cloud_block + sizeof(struct cloudlog_header),
+ GUINT32_FROM_LE(header->size1),
+ NULL, 0);
+ if (status) {
+ g_error("gcrypt error decrypting: %s\n",
+ gcry_strerror(status));
+ }
+ header->magic[3] ^= 0x10;
+
+ gcry_cipher_close(handle);
+ }
+
+ return TRUE;
}
#if 0