Code modifications to integrate Ledger HW device into monero-wallet-cli.

The basic approach it to delegate all sensitive data (master key, secret
ephemeral key, key derivation, ....) and related operations to the device.
As device has low memory, it does not keep itself the values
(except for view/spend keys) but once computed there are encrypted (with AES
are equivalent) and return back to monero-wallet-cli. When they need to be
manipulated by the device, they are decrypted on receive.

Moreover, using the client for storing the value in encrypted form limits
the modification in the client code. Those values are transfered from one
C-structure to another one as previously.

The code modification has been done with the wishes to be open to any
other hardware wallet. To achieve that a C++ class hw::Device has been
introduced. Two initial implementations are provided: the "default", which
remaps all calls to initial Monero code, and  the "Ledger", which delegates
all calls to Ledger device.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/crypto/slow-hash.c b/src/crypto/slow-hash.c
index f921b2455..36bfba9fd 100644
--- a/src/crypto/slow-hash.c
+++ b/src/crypto/slow-hash.c
@@ -515,8 +515,11 @@ void slow_hash_free_state(void)
  * @param length the length in bytes of the data
  * @param hash a pointer to a buffer in which the final 256 bit hash will be stored
  */
+void cn_slow_hash(const void *data, size_t length, char *hash) {
+    cn_slow_hash_pre(data,length,hash,false);
+}
 
-void cn_slow_hash(const void *data, size_t length, char *hash)
+void cn_slow_hash_pre(const void *data, size_t length, char *hash, bool prehashed)
 {
     RDATA_ALIGN16 uint8_t expandedKey[240];  /* These buffers are aligned to use later with SSE functions */
 
@@ -543,8 +546,11 @@ void cn_slow_hash(const void *data, size_t length, char *hash)
         slow_hash_allocate_state();
 
     /* CryptoNight Step 1:  Use Keccak1600 to initialize the 'state' (and 'text') buffers from the data. */
-
-    hash_process(&state.hs, data, length);
+    if (prehashed) {
+        memcpy(&state.hs, data, length);
+    } else {
+        hash_process(&state.hs, data, length);
+    }
     memcpy(text, state.init, INIT_SIZE_BYTE);
 
     /* CryptoNight Step 2:  Iteratively encrypt the results from Keccak to fill