From 3feb3b8a605b6f98eb5b3397bcc84348f25d052c Mon Sep 17 00:00:00 2001
From: Daniele Lacamera <dan@danielinux.net>
Date: Mon, 21 Oct 2019 23:04:14 +0200
Subject: [PATCH] Key changed to password-based

---
 src/usecfs.c | 29 +++++++++++++++++++++--------
 src/usecfs.h |  2 +-
 test/main.c  |  2 +-
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/usecfs.c b/src/usecfs.c
index 0caaf56..16e06dc 100644
--- a/src/usecfs.c
+++ b/src/usecfs.c
@@ -27,15 +27,12 @@ uint8_t crypto_tmp[CRYPTO_BLOCK_SIZE];
 uint8_t crypto_iv[CRYPTO_BLOCK_SIZE];
 
 #include <wolfssl/wolfcrypt/chacha.h>
+#include <wolfssl/wolfcrypt/pwdbased.h>
+#include <wolfssl/wolfcrypt/sha256.h>
 
 static ChaCha chacha;
 #define CRYPTO_KEY_SIZE 32
 
-const uint8_t chacha20_key[] = {
-  0xe7, 0xa1, 0x9c, 0xb0, 0x48, 0xa8, 0x30, 0xf9, 0x37, 0xda, 0x8e, 0xde,
-  0xff, 0xb2, 0x62, 0x03, 0x24, 0x55, 0xb8, 0x8b, 0x7b, 0x18, 0x68, 0x57,
-  0x7d, 0x35, 0xbe, 0xbd, 0xf6, 0x0e, 0xc1, 0x2c
-};
 
 #endif
 
@@ -87,7 +84,6 @@ static void cache_commit(void)
                 memcpy(&crypto_iv[0], &cached_block, sizeof(uint32_t));
                 memcpy(&crypto_iv[4], &i, sizeof(uint32_t));
                 memcpy(crypto_tmp, cache + (i * CRYPTO_BLOCK_SIZE), CRYPTO_BLOCK_SIZE);
-                wc_Chacha_SetKey(&chacha, chacha20_key, CRYPTO_KEY_SIZE);
                 wc_Chacha_SetIV(&chacha, crypto_iv, CRYPTO_BLOCK_SIZE);
                 wc_Chacha_Process(&chacha, cache + i * CRYPTO_BLOCK_SIZE, crypto_tmp, CRYPTO_BLOCK_SIZE);
             }
@@ -113,7 +109,6 @@ static void cache_load(uint32_t blk)
                 memcpy(&crypto_iv[0], &blk, sizeof(uint32_t));
                 memcpy(&crypto_iv[4], &i, sizeof(uint32_t));
                 memcpy(crypto_tmp, cache + (i * CRYPTO_BLOCK_SIZE), CRYPTO_BLOCK_SIZE);
-                wc_Chacha_SetKey(&chacha, chacha20_key, CRYPTO_KEY_SIZE);
                 wc_Chacha_SetIV(&chacha, crypto_iv, CRYPTO_BLOCK_SIZE);
                 wc_Chacha_Process(&chacha, cache + i * CRYPTO_BLOCK_SIZE, crypto_tmp, CRYPTO_BLOCK_SIZE);
             }
@@ -482,11 +477,29 @@ int usecfs_close(int fd)
     }
 }
 
-int usecfs_init(void)
+
+#ifdef CRYPTO
+#define SALT_LEN 32
+const uint8_t password_salt[SALT_LEN] = {
+  0xe7, 0xa1, 0x9c, 0xb0, 0x48, 0xa8, 0x30, 0xf9, 0x37, 0xda, 0x8e, 0xde,
+  0xff, 0xb2, 0x62, 0x03, 0x24, 0x55, 0xb8, 0x8b, 0x7b, 0x18, 0x68, 0x57,
+  0x7d, 0x35, 0xbe, 0xbd, 0xf6, 0x0e, 0xc1, 0x2c
+};
+#endif
+
+int usecfs_init(const char *password)
 {
     blockdev = block_open(BLOCKDEV_OPEN_ARGS);
     if (!blockdev)
         return -1;
     memset(OpenFiles, 0xFF, MAX_OPEN_FILES * sizeof(struct openfile));
+#ifdef CRYPTO
+    {
+        uint8_t chacha_key[CRYPTO_KEY_SIZE];
+        int ret = 0;
+        ret = wc_PBKDF2(chacha_key, password, strlen(password), password_salt, SALT_LEN, 2048, CRYPTO_KEY_SIZE, SHA256);
+        wc_Chacha_SetKey(&chacha, chacha_key, CRYPTO_KEY_SIZE);
+    }
+#endif
     return 0;
 }
diff --git a/src/usecfs.h b/src/usecfs.h
index 26b3c91..cfadbde 100644
--- a/src/usecfs.h
+++ b/src/usecfs.h
@@ -4,7 +4,7 @@
 #define MAX_OPEN_FILES 16
 #include <stdint.h>
 
-int usecfs_init(void);
+int usecfs_init(const char *password);
 int usecfs_open(const char *name);
 int usecfs_creat(const char *name);
 int usecfs_read(int fd, void *data, uint32_t len);
diff --git a/test/main.c b/test/main.c
index e927a71..befc705 100644
--- a/test/main.c
+++ b/test/main.c
@@ -7,7 +7,7 @@ int main(void)
     int fd;
     int buf[40] = { };
 
-    if (usecfs_init() < 0)
+    if (usecfs_init("sEcret") < 0)
     {
         printf("error.\n");
         return 1;