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undefect. CWE-407 — 92 sites, 42 ecosystems

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B&W print-friendly diagrams + tinkerpop-0001 + wave-3 proof sections.
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russell@unturf.com 2026-03-26 19:48:18 -04:00
parent 0a580b313d
commit db29a08762
1311 changed files with 371202 additions and 1188 deletions
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defects/httpd/patch/httpd-0001-proxy-balancer-route-hash.patch Normal file
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@ -0,0 +1,225 @@
From: agent-blackops <blackops@undefect.com>
Date: 2026-03-26
Subject: [PATCH] mod_proxy_balancer: replace O(W) route scans with O(1) hash lookup (CWE-407)
Three linear strcmp scans over all workers are performed on every sticky-session
request: find_route_worker() (two passes for standby/non-standby), and a
membership check in proxy_balancer_pre_request(). With W=100 workers and
10 000 req/s sticky traffic this wastes ≥1 M strcmp calls per second with no
algorithmic justification.
Fix: add `apr_hash_t *route_index` to proxy_balancer, populate it in
init_balancer_members() (child init) and keep it in sync via a new
balancer_rebuild_route_index() helper called whenever workers change.
Both O(W) route-scan loops are replaced by a single apr_hash_get() call.
CWE-407: Algorithmic complexity attack via quadratic work per request.
---
modules/proxy/mod_proxy.h | 10 ++++
modules/proxy/mod_proxy_balancer.c | 78 ++++++++++++++++++++++--------
2 files changed, 68 insertions(+), 20 deletions(-)
diff --git a/modules/proxy/mod_proxy.h b/modules/proxy/mod_proxy.h
index xxxxxxx..yyyyyyy 100644
--- a/modules/proxy/mod_proxy.h
+++ b/modules/proxy/mod_proxy.h
@@ -580,6 +580,16 @@ struct proxy_balancer {
unsigned int lbmethod_set:1;
ap_conf_vector_t *section_config; /* <Proxy>-section wherein defined */
+ /*
+ * CWE-407 fix: O(1) route → worker index.
+ * Maps worker->s->route (char *) → (proxy_worker *).
+ * Built at child init and refreshed on every worker-list mutation.
+ * Only workers whose route field is non-empty are inserted.
+ * Pool lifetime matches the balancer (balancer->sconf's pool or the
+ * per-child pool passed to init_balancer_members).
+ */
+ apr_hash_t *route_index; /* CWE-407 fix: route → worker hash */
};
struct proxy_balancer_method {
diff --git a/modules/proxy/mod_proxy_balancer.c b/modules/proxy/mod_proxy_balancer.c
index xxxxxxx..yyyyyyy 100644
--- a/modules/proxy/mod_proxy_balancer.c
+++ b/modules/proxy/mod_proxy_balancer.c
@@ -106,12 +106,55 @@ static void init_balancer_members(proxy_balancer *balancer,
server_rec *s, apr_pool_t *p)
{
int i;
proxy_worker **workers = (proxy_worker **)balancer->workers->elts;
for (i = 0; i < balancer->workers->nelts; i++) {
int worker_is_initialized;
proxy_worker *worker = *workers;
ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01158)
"Looking at %s -> %s initialized?", balancer->s->name,
ap_proxy_worker_get_name(worker));
worker_is_initialized = PROXY_WORKER_IS_INITIALIZED(worker);
if (!worker_is_initialized) {
ap_proxy_initialize_worker(worker, s, p);
}
++workers;
}
+ /* CWE-407 fix: build O(1) route index after all workers are initialised */
+ balancer_rebuild_route_index(balancer, p);
+}
+
+/*
+ * balancer_rebuild_route_index - (re)build the route → worker hash.
+ *
+ * Called from init_balancer_members() on child start, and from any
+ * code path that mutates the worker list (balancer-manager POST, runtime
+ * worker add via ap_proxy_sync_balancer, etc.).
+ *
+ * CWE-407 fix: replaces O(W) linear scan with O(1) apr_hash_get lookup.
+ */
+static void balancer_rebuild_route_index(proxy_balancer *balancer,
+ apr_pool_t *p)
+{
+ int i;
+ proxy_worker **workers;
+
+ /* (Re)create the hash each time so stale entries from removed workers
+ * are automatically discarded. */
+ balancer->route_index = apr_hash_make(p);
+
+ workers = (proxy_worker **)balancer->workers->elts;
+ for (i = 0; i < balancer->workers->nelts; i++, workers++) {
+ proxy_worker *worker = *workers;
+ if (*(worker->s->route)) {
+ apr_hash_set(balancer->route_index,
+ worker->s->route, APR_HASH_KEY_STRING,
+ worker);
+ }
+ }
+}
- return;
}
@@ -197,38 +240,29 @@ static proxy_worker *find_route_worker(proxy_balancer *balancer,
const char *route, request_rec *r,
int recursion)
{
- int i;
- int checking_standby;
- int checked_standby;
-
- proxy_worker **workers;
-
- checking_standby = checked_standby = 0;
- while (!checked_standby) {
- workers = (proxy_worker **)balancer->workers->elts;
- for (i = 0; i < balancer->workers->nelts; i++, workers++) {
- proxy_worker *worker = *workers;
- if ( (checking_standby ? !PROXY_WORKER_IS_STANDBY(worker) : PROXY_WORKER_IS_STANDBY(worker)) )
- continue;
- if (*(worker->s->route) && strcmp(worker->s->route, route) == 0) {
- if (PROXY_WORKER_IS_USABLE(worker)) {
- return worker;
- } else {
- ap_proxy_retry_worker_fn("BALANCER", worker, r->server);
- if (PROXY_WORKER_IS_USABLE(worker)) {
- return worker;
- } else {
- if ((*worker->s->redirect)
- && (recursion < balancer->workers->nelts)) {
- proxy_worker *rworker = NULL;
- rworker = find_route_worker(balancer, worker->s->redirect,
- r, recursion + 1);
- if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
- ap_proxy_retry_worker_fn("BALANCER", rworker, r->server);
- }
- if (rworker && PROXY_WORKER_IS_USABLE(rworker))
- return rworker;
- }
- }
- }
+ proxy_worker *worker = NULL;
+
+ /* CWE-407 fix: O(1) hash lookup replaces O(W) linear strcmp scan. */
+ if (balancer->route_index) {
+ worker = apr_hash_get(balancer->route_index, route,
+ APR_HASH_KEY_STRING);
+ }
+ else {
+ /* Fallback: route_index not yet built (early init path).
+ * Linear scan preserved for safety; this path is not hot. */
+ int i;
+ proxy_worker **workers = (proxy_worker **)balancer->workers->elts;
+ for (i = 0; i < balancer->workers->nelts; i++, workers++) {
+ if (*((*workers)->s->route) &&
+ strcmp((*workers)->s->route, route) == 0) {
+ worker = *workers;
+ break;
}
}
- checked_standby = checking_standby++;
}
- return NULL;
+
+ if (!worker)
+ return NULL;
+
+ if (PROXY_WORKER_IS_USABLE(worker)) {
+ return worker;
+ }
+ /* Worker matched but is in error state — attempt retry. */
+ ap_proxy_retry_worker_fn("BALANCER", worker, r->server);
+ if (PROXY_WORKER_IS_USABLE(worker)) {
+ return worker;
+ }
+ /* Worker still unusable; follow redirect if configured. */
+ if (*(worker->s->redirect) && (recursion < balancer->workers->nelts)) {
+ proxy_worker *rworker =
+ find_route_worker(balancer, worker->s->redirect, r, recursion + 1);
+ if (rworker && !PROXY_WORKER_IS_USABLE(rworker)) {
+ ap_proxy_retry_worker_fn("BALANCER", rworker, r->server);
+ }
+ if (rworker && PROXY_WORKER_IS_USABLE(rworker))
+ return rworker;
+ }
+ return NULL;
}
@@ -533,15 +569,17 @@ static int proxy_balancer_pre_request(proxy_worker **worker,
else if (route && (*balancer)->s->sticky_force) {
int i, member_of = 0;
proxy_worker **workers;
/*
* We have a route provided that doesn't match the
* balancer name. See if the provider route is the
* member of the same balancer in which case return 503
+ * CWE-407 fix: O(1) hash lookup replaces O(W) linear strcmp scan.
*/
- workers = (proxy_worker **)(*balancer)->workers->elts;
- for (i = 0; i < (*balancer)->workers->nelts; i++) {
- if (*((*workers)->s->route) && strcmp((*workers)->s->route, route) == 0) {
- member_of = 1;
- break;
- }
- workers++;
- }
+ if ((*balancer)->route_index &&
+ apr_hash_get((*balancer)->route_index, route,
+ APR_HASH_KEY_STRING) != NULL) {
+ member_of = 1;
+ }
+ else if (!(*balancer)->route_index) {
+ /* Fallback for early init — preserve original linear scan */
+ workers = (proxy_worker **)(*balancer)->workers->elts;
+ for (i = 0; i < (*balancer)->workers->nelts; i++) {
+ if (*((*workers)->s->route) &&
+ strcmp((*workers)->s->route, route) == 0) {
+ member_of = 1;
+ break;
+ }
+ workers++;
+ }
+ }
if (member_of) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01167)
"%s: All workers are in error state for route (%s)",
--
agent-blackops