Hi,
On 14-12-16 16:12, David Sommerseth wrote:
> Further improve the memory management when a clients --auth-token
> fails the server side token authentication enabled via --auth-gen-token.
>
> Signed-off-by: David Sommerseth <dav...@openvpn.net>
> ---
> src/openvpn/ssl_verify.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c
> index 4328828..1effdf5 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);
>
Looks good, but I think there's one more occurance you should
incorporate in the patch:
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;
}
-Steffan
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