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- From 4a600dabd5e2799bf0c3048859ee4f00808b7d89 Mon Sep 17 00:00:00 2001
- From: Glenn Strauss <gstrauss@gluelogic.com>
- Date: Sat, 6 Feb 2021 08:29:41 -0500
- Subject: [PATCH] [mod_auth] close HTTP/2 connection after bad pass
-
- mitigation slows down brute force password attacks
-
- x-ref:
- "Possible feature: authentication brute force hardening"
- https://redmine.lighttpd.net/boards/3/topics/8885
-
- Signed-off-by: Glenn Strauss <gstrauss@gluelogic.com>
- ---
- src/connections.c | 22 +++++++++++++++++++++-
- src/mod_accesslog.c | 2 +-
- src/mod_auth.c | 6 +++---
- src/reqpool.c | 1 +
- src/request.h | 2 +-
- src/response.c | 4 ++--
- 6 files changed, 29 insertions(+), 8 deletions(-)
-
- --- a/src/connections.c
- +++ b/src/connections.c
- @@ -228,7 +228,7 @@ static void connection_handle_response_e
- }
- }
-
- - if (r->keep_alive) {
- + if (r->keep_alive > 0) {
- request_reset(r);
- config_reset_config(r);
- con->is_readable = 1; /* potentially trigger optimistic read */
- @@ -1265,6 +1265,19 @@ connection_set_fdevent_interest (request
- }
-
-
- +__attribute_cold__
- +static void
- +connection_request_end_h2 (request_st * const h2r, connection * const con)
- +{
- + if (h2r->keep_alive >= 0) {
- + h2r->keep_alive = -1;
- + h2_send_goaway(con, H2_E_NO_ERROR);
- + }
- + else /*(abort connection upon second request to close h2 connection)*/
- + h2_send_goaway(con, H2_E_ENHANCE_YOUR_CALM);
- +}
- +
- +
- static void
- connection_state_machine_h2 (request_st * const h2r, connection * const con)
- {
- @@ -1359,8 +1372,15 @@ connection_state_machine_h2 (request_st
- && !chunkqueue_is_empty(con->read_queue))
- resched |= 1;
- h2_send_end_stream(r, con);
- + const int alive = r->keep_alive;
- h2_retire_stream(r, con);/*r invalidated;removed from h2c->r[]*/
- --i;/* adjust loop i; h2c->rused was modified to retire r */
- + /*(special-case: allow *stream* to set r->keep_alive = -1 to
- + * trigger goaway on h2 connection, e.g. after mod_auth failure
- + * in attempt to mitigate brute force attacks by forcing a
- + * reconnect and (somewhat) slowing down retries)*/
- + if (alive < 0)
- + connection_request_end_h2(h2r, con);
- }
- }
- }
- --- a/src/mod_accesslog.c
- +++ b/src/mod_accesslog.c
- @@ -1108,7 +1108,7 @@ static int log_access_record (const requ
- break;
- case FORMAT_CONNECTION_STATUS:
- if (r->state == CON_STATE_RESPONSE_END) {
- - if (0 == r->keep_alive) {
- + if (r->keep_alive <= 0) {
- buffer_append_string_len(b, CONST_STR_LEN("-"));
- } else {
- buffer_append_string_len(b, CONST_STR_LEN("+"));
- --- a/src/mod_auth.c
- +++ b/src/mod_auth.c
- @@ -828,7 +828,7 @@ static handler_t mod_auth_check_basic(re
- log_error(r->conf.errh, __FILE__, __LINE__,
- "password doesn't match for %s username: %s IP: %s",
- r->uri.path.ptr, username->ptr, r->con->dst_addr_buf->ptr);
- - r->keep_alive = 0; /*(disable keep-alive if bad password)*/
- + r->keep_alive = -1; /*(disable keep-alive if bad password)*/
- rc = HANDLER_UNSET;
- break;
- }
- @@ -1461,7 +1461,7 @@ static handler_t mod_auth_check_digest(r
- return HANDLER_FINISHED;
- case HANDLER_ERROR:
- default:
- - r->keep_alive = 0; /*(disable keep-alive if unknown user)*/
- + r->keep_alive = -1; /*(disable keep-alive if unknown user)*/
- buffer_free(b);
- return mod_auth_send_401_unauthorized_digest(r, require, 0);
- }
- @@ -1482,7 +1482,7 @@ static handler_t mod_auth_check_digest(r
- log_error(r->conf.errh, __FILE__, __LINE__,
- "digest: auth failed for %s: wrong password, IP: %s",
- username, r->con->dst_addr_buf->ptr);
- - r->keep_alive = 0; /*(disable keep-alive if bad password)*/
- + r->keep_alive = -1; /*(disable keep-alive if bad password)*/
-
- buffer_free(b);
- return mod_auth_send_401_unauthorized_digest(r, require, 0);
- --- a/src/reqpool.c
- +++ b/src/reqpool.c
- @@ -58,6 +58,7 @@ request_reset (request_st * const r)
- http_response_reset(r);
-
- r->loops_per_request = 0;
- + r->keep_alive = 0;
-
- r->h2state = 0; /* H2_STATE_IDLE */
- r->h2id = 0;
- --- a/src/request.h
- +++ b/src/request.h
- @@ -175,7 +175,7 @@ struct request_st {
- char resp_header_repeated;
-
- char loops_per_request; /* catch endless loops in a single request */
- - char keep_alive; /* only request.c can enable it, all other just disable */
- + int8_t keep_alive; /* only request.c can enable it, all other just disable */
- char async_callback;
-
- buffer *tmp_buf; /* shared; same as srv->tmp_buf */
- --- a/src/response.c
- +++ b/src/response.c
- @@ -103,9 +103,9 @@ http_response_write_header (request_st *
- if (light_btst(r->resp_htags, HTTP_HEADER_UPGRADE)
- && r->http_version == HTTP_VERSION_1_1) {
- http_header_response_set(r, HTTP_HEADER_CONNECTION, CONST_STR_LEN("Connection"), CONST_STR_LEN("upgrade"));
- - } else if (0 == r->keep_alive) {
- + } else if (r->keep_alive <= 0) {
- http_header_response_set(r, HTTP_HEADER_CONNECTION, CONST_STR_LEN("Connection"), CONST_STR_LEN("close"));
- - } else if (r->http_version == HTTP_VERSION_1_0) {/*(&& r->keep_alive != 0)*/
- + } else if (r->http_version == HTTP_VERSION_1_0) {/*(&& r->keep_alive > 0)*/
- http_header_response_set(r, HTTP_HEADER_CONNECTION, CONST_STR_LEN("Connection"), CONST_STR_LEN("keep-alive"));
- }
-
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