Perform secure erase of expanded keys also

1 files changed, 13 insertions, 4 deletions

diff --git a/fish.c b/fish.c
index a7c3cfc..437174d 100644
--- a/fish.c
+++ b/fish.c
@@ -31,6 +31,7 @@
 
 #include "keystore.h"
 #include "fish.h"
+#include "misc.h"
 
 #define IB 64
 static const char fish_base64[64] = "./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
@@ -58,6 +59,10 @@ static const signed char fish_unbase64[256] = {
     *((dest)++) = (source) & 0xFF; \
 } while (0);
 
+static void secure_erase_key(BF_KEY *bfkey) {
+    secure_erase(bfkey, sizeof(*bfkey));
+}
+
 /**
  * Encrypts a message in ECB mode.
  */
@@ -71,7 +76,6 @@ char *fish_encrypt_ecb(const char *key, size_t keylen, const char *message) {
     unsigned char bit;
     unsigned char word;
     unsigned char d;
-    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     
     messagelen = strlen(message);
     if (messagelen == 0) return NULL;
@@ -79,6 +83,7 @@ char *fish_encrypt_ecb(const char *key, size_t keylen, const char *message) {
     end = encrypted;
     if (!encrypted) return NULL;
      
+    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     while (*message) {
         // Read 8 bytes (a Blowfish block)
         BF_LONG binary[2] = { 0, 0 };
@@ -109,6 +114,7 @@ char *fish_encrypt_ecb(const char *key, size_t keylen, const char *message) {
         // Stop if a null terminator was found
         if (c == '\0') break;
     }
+    secure_erase_key(&bfkey);
     *end = '\0';
     return encrypted;
 }
@@ -120,7 +126,6 @@ char *fish_encrypt_cbc(const char *key, size_t keylen, const char *message) {
     BF_KEY bfkey;
     unsigned char *encrypted = NULL;
     BIO *b64 = NULL;
-    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     
     size_t messagelen = strlen(message);
     if (messagelen == 0) goto err;
@@ -136,7 +141,9 @@ char *fish_encrypt_cbc(const char *key, size_t keylen, const char *message) {
     memcpy(encrypted, iv, 8);
     
     // Encrypt in CBC mode. The IV is overwritten
+    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     BF_cbc_encrypt((const unsigned char*)message, encrypted+8, messagelen, &bfkey, iv, BF_ENCRYPT);
+    secure_erase_key(&bfkey);
     
     // Base64 encode
     b64 = BIO_new(BIO_f_base64());
@@ -178,7 +185,6 @@ static char *fish_decrypt_cbc(const char *key, size_t keylen, const char *data)
     BF_KEY bfkey;
     unsigned char *decrypted, *bindata = NULL;
     BIO *b64 = NULL;
-    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     
     // Skip leading "*" that indicates that the message is using CBC byte
     if (*data != '*') goto err;
@@ -209,7 +215,9 @@ static char *fish_decrypt_cbc(const char *key, size_t keylen, const char *data)
     if (outlen) {
         unsigned char *iv = &bindata[0];
         unsigned char *enc = &bindata[8];
+        BF_set_key(&bfkey, keylen, (const unsigned char*)key);
         BF_cbc_encrypt(enc, decrypted, outlen, &bfkey, iv, BF_DECRYPT);
+        secure_erase_key(&bfkey);
     }
     BIO_free_all(b64);
     decrypted[outlen] = '\0';
@@ -232,12 +240,12 @@ static char *fish_decrypt_ecb(const char *key, size_t keylen, const char *data)
     unsigned char bit;
     unsigned char word;
     unsigned char d;
-    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     
     decrypted = malloc(strlen(data)+1);
     end = decrypted;
     if (!decrypted) return NULL;
     
+    BF_set_key(&bfkey, keylen, (const unsigned char*)key);
     while (*data) {
         // Convert from FiSH-BASE64
         BF_LONG binary[2] = { 0, 0 };
@@ -263,6 +271,7 @@ static char *fish_decrypt_ecb(const char *key, size_t keylen, const char *data)
     }
     
   decrypt_end:
+    secure_erase_key(&bfkey);
     *end = '\0';
     return decrypted;
 }