* eet: Zero cipher material as soon as possible. Prevent information

	leak of temporary data in memory, so improve security.

git-svn-id: http://svn.enlightenment.org/svn/e/trunk/eet@45630 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

diff --git a/ChangeLog b/ChangeLog
index ff52139..2f1d054 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -321,3 +321,7 @@
 2010-01-22  Cedric BAIL
 
        * Add VAR_ARRAY tests.
+
+2010-01-27  Cedric BAIL
+
+       * Improve security by zeroying cipher material as soon as possible.

diff --git a/src/lib/eet_cipher.c b/src/lib/eet_cipher.c
index 34df38b..a4e9880 100644 (file)
--- a/src/lib/eet_cipher.c
+++ b/src/lib/eet_cipher.c
@@ -769,11 +769,19 @@ eet_cipher(const void *data, unsigned int size, const char *key, unsigned int le
    memcpy(iv, key_material, MAX_IV_LEN);
    memcpy(ik, key_material + MAX_IV_LEN, MAX_KEY_LEN);
 
+   memset(key_material, 0, sizeof (key_material));
+
    crypted_length = ((((size + sizeof (unsigned int)) >> 5) + 1) << 5);
    ret = malloc(crypted_length + sizeof(unsigned int));
-   if (!ret) return EET_ERROR_OUT_OF_MEMORY;
+   if (!ret) {
+      memset(iv, 0, sizeof (iv));
+      memset(ik, 0, sizeof (ik));
+      memset(&salt, 0, sizeof (salt));
+      return EET_ERROR_OUT_OF_MEMORY;
+   }
 
    *ret = salt;
+   memset(&salt, 0, sizeof (salt));
    tmp = htonl(size);
 
 #ifdef HAVE_GNUTLS
@@ -790,6 +798,9 @@ eet_cipher(const void *data, unsigned int size, const char *key, unsigned int le
    err = gcry_cipher_setkey(cipher, ik, MAX_KEY_LEN);
    if (err) goto on_error;
 
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
    /* Gcrypt encrypt */
    err = gcry_cipher_encrypt(cipher, (unsigned char *)(ret + 1), crypted_length, NULL, 0);
    if (err) goto on_error;
@@ -808,6 +819,9 @@ eet_cipher(const void *data, unsigned int size, const char *key, unsigned int le
    if (!EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, ik, iv)) goto on_error;
    opened = 1;
 
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
    /* Openssl encrypt */
    if (!EVP_EncryptUpdate(&ctx, (unsigned char*)(ret + 1), &tmp_len, (unsigned char*) buffer, size + sizeof (unsigned int)))
      goto on_error;
@@ -826,6 +840,9 @@ eet_cipher(const void *data, unsigned int size, const char *key, unsigned int le
    return EET_ERROR_NONE;
 
  on_error:
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
 # ifdef HAVE_GNUTLS
    /* Gcrypt error */
    if (opened) gcry_cipher_close(cipher);
@@ -872,9 +889,13 @@ eet_decipher(const void *data, unsigned int size, const char *key, unsigned int
 
    /* Generate the iv and the key with the salt */
    eet_pbkdf2_sha1(key, length, (unsigned char *)&salt, sizeof(unsigned int), 2048, key_material, MAX_KEY_LEN + MAX_IV_LEN);
+
    memcpy(iv, key_material, MAX_IV_LEN);
    memcpy(ik, key_material + MAX_IV_LEN, MAX_KEY_LEN);
 
+   memset(key_material, 0, sizeof (key_material));
+   memset(&salt, 0, sizeof (salt));
+
    /* Align to AES block size if size is not align */
    tmp_len = size - sizeof (unsigned int);
    if ((tmp_len & 0x1F) != 0) goto on_error;
@@ -894,6 +915,9 @@ eet_decipher(const void *data, unsigned int size, const char *key, unsigned int
    err = gcry_cipher_setkey(cipher, ik, MAX_KEY_LEN);
    if (err) goto on_error;
 
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
    /* Gcrypt decrypt */
    err = gcry_cipher_decrypt(cipher, ret, tmp_len, ((unsigned int *)data) + 1, tmp_len);
    if (err) goto on_error;
@@ -912,6 +936,9 @@ eet_decipher(const void *data, unsigned int size, const char *key, unsigned int
    if (!EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, ik, iv))
      goto on_error;
 
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
    /* Openssl decrypt */
    if (!EVP_DecryptUpdate(&ctx, (unsigned char *) ret, &tmp,
                          (unsigned char *) (over + 1), tmp_len))
@@ -940,6 +967,9 @@ eet_decipher(const void *data, unsigned int size, const char *key, unsigned int
    return EET_ERROR_NONE;
 
  on_error:
+   memset(iv, 0, sizeof (iv));
+   memset(ik, 0, sizeof (ik));
+
 # ifdef HAVE_GNUTLS
 # else
    if (opened) EVP_CIPHER_CTX_cleanup(&ctx);