Hi,
On 28-03-17 21:19, David Sommerseth wrote:
> If tls_deauthenticate() was called, it could in some scenarios leave the
> authentication token for a session in memory. This change just ensures
> auth-tokens are always wiped as soon as a TLS session is considered
> broken.
>
> Signed-off-by: David Sommerseth <[email protected]>
>
> ---
>
> The wipe_auth_token() function is otherwise moved to be declared before
> tls_deauthenticate() and the latter function is also slightly modified to
> make use of the C99 feature of inline declaration - mostly to have a more
> reasonable coding style when adding the wipe_auth_token() call.
> ---
> src/openvpn/ssl_verify.c | 44 ++++++++++++++++++++++++--------------------
> 1 file changed, 24 insertions(+), 20 deletions(-)
>
> diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c
> index a6e9be3..008a60d 100644
> --- a/src/openvpn/ssl_verify.c
> +++ b/src/openvpn/ssl_verify.c
> @@ -80,6 +80,26 @@ setenv_untrusted(struct tls_session *session)
> setenv_link_socket_actual(session->opt->es, "untrusted",
> &session->untrusted_addr, SA_IP_PORT);
> }
>
> +
> +/**
> + * 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)
> +{
> + if( multi ) {
> + if (multi->auth_token ) {
The spaces in theses lines look a bit odd.
> + secure_memzero(multi->auth_token, AUTH_TOKEN_SIZE);
> + free(multi->auth_token);
> + }
> + multi->auth_token = NULL;
> + multi->auth_token_sent = false;
> + }
> +}
> +
> +
> /*
> * Remove authenticated state from all sessions in the given tunnel
> */
> @@ -88,10 +108,10 @@ tls_deauthenticate(struct tls_multi *multi)
> {
> if (multi)
> {
> - int i, j;
> - for (i = 0; i < TM_SIZE; ++i)
> + wipe_auth_token(multi);
> + for (int i = 0; i < TM_SIZE; ++i)
> {
> - for (j = 0; j < KS_SIZE; ++j)
> + for (int j = 0; j < KS_SIZE; ++j)
> {
> multi->session[i].key[j].authenticated = false;
> }
> @@ -1219,21 +1239,6 @@ verify_user_pass_management(struct tls_session
> *session, const struct user_pass
> }
> #endif /* ifdef MANAGEMENT_DEF_AUTH */
>
> -/**
> - * 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
> */
> @@ -1285,7 +1290,7 @@ 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);
> + /* auth-token cleared in tls_lock_username() on failure */
> ks->authenticated = false;
> goto done;
> }
> @@ -1306,7 +1311,6 @@ 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)
> {
> - wipe_auth_token(multi);
> ks->authenticated = false;
> tls_deauthenticate(multi);
>
>
Shouldn't we also clear the token if the ccd authentication check in
verify_final_auth_checks() fails?
-Steffan
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