Further improve the memory management when a clients --auth-token
fails the server side token authentication enabled via --auth-gen-token.
v2 - Add ASSERT() if base64 encoding of token fails
v3 - Use proper boolean logic in ASSERT()
Signed-off-by: David Sommerseth <dav...@openvpn.net>
---
src/openvpn/ssl_verify.c | 45 +++++++++++++++++++++++----------------------
1 file changed, 23 insertions(+), 22 deletions(-)
diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c
index 4328828..d661473 100644
--- a/src/openvpn/ssl_verify.c
+++ b/src/openvpn/ssl_verify.c
@@ -1108,6 +1108,21 @@ verify_user_pass_management (struct tls_session
*session, const struct user_pass
}
#endif
+/**
+ * Wipes the authentication token out of the memory, frees and cleans up
related buffers and flags
+ *
+ * @param multi Pointer to a multi object holding the auth_token variables
+ */
+static void
+wipe_auth_token(struct tls_multi *multi)
+{
+ secure_memzero (multi->auth_token, AUTH_TOKEN_SIZE);
+ free (multi->auth_token);
+ multi->auth_token = NULL;
+ multi->auth_token_sent = false;
+}
+
+
/*
* Main username/password verification entry point
*/
@@ -1157,6 +1172,7 @@ verify_user_pass(struct user_pass *up, struct tls_multi
*multi,
/* Ensure that the username has not changed */
if (!tls_lock_username(multi, up->username))
{
+ wipe_auth_token(multi);
ks->authenticated = false;
goto done;
}
@@ -1168,6 +1184,7 @@ verify_user_pass(struct user_pass *up, struct tls_multi
*multi,
&& (multi->auth_token_tstamp + session->opt->auth_token_lifetime) <
now)
{
msg (D_HANDSHAKE, "Auth-token for client expired\n");
+ wipe_auth_token(multi);
ks->authenticated = false;
goto done;
}
@@ -1176,10 +1193,7 @@ verify_user_pass(struct user_pass *up, struct tls_multi
*multi,
if (memcmp_constant_time(multi->auth_token, up->password,
strlen(multi->auth_token)) != 0)
{
- secure_memzero (multi->auth_token, AUTH_TOKEN_SIZE);
- free (multi->auth_token);
- multi->auth_token = NULL;
- multi->auth_token_sent = false;
+ wipe_auth_token(multi);
ks->authenticated = false;
tls_deauthenticate (multi);
@@ -1255,24 +1269,11 @@ verify_user_pass(struct user_pass *up, struct tls_multi
*multi,
/* The token should be longer than the input when
* being base64 encoded
*/
- if( openvpn_base64_encode(tok, AUTH_TOKEN_SIZE,
- &multi->auth_token) < AUTH_TOKEN_SIZE)
- {
- msg(D_TLS_ERRORS, "BASE64 encoding of token failed. "
- "No auth-token will be activated now");
- if (multi->auth_token)
- {
- secure_memzero (multi->auth_token, AUTH_TOKEN_SIZE);
- free (multi->auth_token);
- multi->auth_token = NULL;
- }
- }
- else
- {
- multi->auth_token_tstamp = now;
- dmsg (D_SHOW_KEYS, "Generated token for client: %s",
- multi->auth_token);
- }
+ ASSERT(openvpn_base64_encode(tok, AUTH_TOKEN_SIZE,
+ &multi->auth_token) > AUTH_TOKEN_SIZE);
+ multi->auth_token_tstamp = now;
+ dmsg (D_SHOW_KEYS, "Generated token for client: %s",
+ multi->auth_token);
}
if ((session->opt->ssl_flags & SSLF_USERNAME_AS_COMMON_NAME))
--
1.8.3.1
------------------------------------------------------------------------------
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