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() v4 - Rebase against The Great Reformatting Signed-off-by: David Sommerseth <dav...@openvpn.net> --- src/openvpn/ssl_verify.c | 46 ++++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 22 deletions(-) diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c index 54a3416..e901202 100644 --- a/src/openvpn/ssl_verify.c +++ b/src/openvpn/ssl_verify.c @@ -1213,6 +1213,21 @@ 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 */ @@ -1264,6 +1279,7 @@ 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; } @@ -1275,6 +1291,7 @@ 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; } @@ -1283,10 +1300,7 @@ 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); @@ -1374,30 +1388,18 @@ 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)) { set_common_name(session, up->username); } + #ifdef ENABLE_DEF_AUTH msg(D_HANDSHAKE, "TLS: Username/Password authentication %s for username '%s' %s", ks->auth_deferred ? "deferred" : "succeeded", -- 1.8.3.1 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Openvpn-devel mailing list Openvpn-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/openvpn-devel