Fix buffer length handling in GnuTLS password encryption and decryption.

[claws.git] / src / password.c

diff --git a/src/password.c b/src/password.c
index 2040698caa9c6330efc616de59483d41716f2562..9e66a92253fca1acbc2e04bad8251197c143f10f 100644 (file)
--- a/src/password.c
+++ b/src/password.c
@@ -110,7 +110,7 @@ static guchar *_make_key_deriv(const gchar *passphrase, guint rounds,
        return NULL;
 }
 
-static const gchar *master_passphrase()
+const gchar *master_passphrase()
 {
        gchar *input;
        gboolean end = FALSE;
@@ -145,7 +145,7 @@ static const gchar *master_passphrase()
        return _master_passphrase;
 }
 
-const gboolean master_passphrase_is_set()
+gboolean master_passphrase_is_set()
 {
        if (prefs_common_get_prefs()->master_passphrase == NULL
                        || strlen(prefs_common_get_prefs()->master_passphrase) == 0)
@@ -154,7 +154,7 @@ const gboolean master_passphrase_is_set()
        return TRUE;
 }
 
-const gboolean master_passphrase_is_correct(const gchar *input)
+gboolean master_passphrase_is_correct(const gchar *input)
 {
        guchar *kd, *input_kd;
        gchar **tokens;
@@ -266,11 +266,6 @@ void master_passphrase_change(const gchar *oldp, const gchar *newp)
        debug_print("Reencrypting all account passwords...\n");
        passwd_store_reencrypt_all(oldp, newp);
 
-       /* Now reencrypt all plugins passwords fields 
-        * FIXME: Unloaded plugins won't be able to update their stored passwords
-        */
-       plugins_master_passphrase_change(oldp, newp);
-
        master_passphrase_forget();
 }
 #endif
@@ -321,9 +316,6 @@ gchar *password_decrypt_old(const gchar *password)
 gchar *password_encrypt_gnutls(const gchar *password,
                const gchar *encryption_passphrase)
 {
-       /* Another, slightly inferior combination is AES-128-CBC + SHA-256.
-        * Any block cipher in CBC mode with keysize N and a hash algo with
-        * digest length 2*N would do. */
        gnutls_cipher_algorithm_t algo = GNUTLS_CIPHER_AES_256_CBC;
        gnutls_cipher_hd_t handle;
        gnutls_datum_t key, iv;
@@ -364,7 +356,7 @@ gchar *password_encrypt_gnutls(const gchar *password,
        /* Fill buf with one block of random data, our password, pad the
         * rest with zero bytes. */
        buf = malloc(BUFSIZE + blocklen);
-       memset(buf, 0, BUFSIZE);
+       memset(buf, 0, BUFSIZE + blocklen);
        if (!get_random_bytes(buf, blocklen)) {
                g_free(buf);
                g_free(key.data);
@@ -397,7 +389,7 @@ gchar *password_encrypt_gnutls(const gchar *password,
 
        /* And finally prepare the resulting string:
         * "{algorithm,rounds}base64encodedciphertext" */
-       base = g_base64_encode(encbuf, BUFSIZE);
+       base = g_base64_encode(encbuf, BUFSIZE + blocklen);
        g_free(encbuf);
        output = g_strdup_printf("{%s,%d}%s",
                        gnutls_cipher_get_name(algo), rounds, base);
@@ -479,6 +471,15 @@ gchar *password_decrypt_gnutls(const gchar *password,
        /* Prepare encrypted password string for decryption. */
        tmp = g_base64_decode(tokens[2], &len);
        g_strfreev(tokens);
+       if (tmp == NULL || len == 0) {
+               debug_print("Failed base64-decoding of stored password string\n");
+               g_free(key.data);
+               g_free(iv.data);
+               if (tmp != NULL)
+                       g_free(tmp);
+               return NULL;
+       }
+       debug_print("Encrypted password string length: %lu\n", len);
 
        /* Initialize the decryption */
        ret = gnutls_cipher_init(&handle, algo, &key, &iv);
@@ -486,13 +487,18 @@ gchar *password_decrypt_gnutls(const gchar *password,
                debug_print("Cipher init failed: %s\n", gnutls_strerror(ret));
                g_free(key.data);
                g_free(iv.data);
+               g_free(tmp);
                return NULL;
        }
 
-       buf = malloc(BUFSIZE + blocklen);
-       memset(buf, 0, BUFSIZE + blocklen);
+       /* Allocate the buffer to store decrypted plaintext in. */
+       buf = malloc(len);
+       memset(buf, 0, len);
+
+       /* Decrypt! */
        ret = gnutls_cipher_decrypt2(handle, tmp, len,
-                       buf, BUFSIZE + blocklen);
+                       buf, len);
+       g_free(tmp);
        if (ret < 0) {
                debug_print("Decryption failed: %s\n", gnutls_strerror(ret));
                g_free(key.data);
@@ -507,8 +513,12 @@ gchar *password_decrypt_gnutls(const gchar *password,
        g_free(key.data);
        g_free(iv.data);
 
+       /* 'buf+blocklen' should now be pointing to the plaintext
+        * password string. The first block contains random data from the IV. */
        tmp = g_strndup(buf + blocklen, MIN(strlen(buf + blocklen), BUFSIZE));
+       memset(buf, 0, len);
        g_free(buf);
+
        return tmp;
 }