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v1.1.5 - Fix CRITICAL segfault: Use wrapper nodes for no-kind-filter subscriptions

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The kind index optimization in v1.1.4 introduced a critical bug that caused
segmentation faults in production. The bug was in add_subscription_to_kind_index()
which directly assigned sub->next for no-kind-filter subscriptions, corrupting
the main active_subscriptions linked list.

Root Cause:
- subscription_t has only ONE 'next' pointer used by active_subscriptions list
- Code tried to reuse 'next' for no_kind_filter_subs list
- This overwrote the active_subscriptions linkage, breaking list traversal
- Result: segfaults when iterating subscriptions

Fix:
- Added no_kind_filter_node_t wrapper structure (like kind_subscription_node_t)
- Changed no_kind_filter_subs from subscription_t* to no_kind_filter_node_t*
- Updated add/remove functions to use wrapper nodes
- Updated broadcast function to iterate through wrapper nodes

This follows the same pattern already used for kind_index entries and
prevents any corruption of the subscription structure's next pointer.
This commit is contained in:
Your Name
2026-02-01 12:37:07 -04:00
parent a1928cc5d7
commit 30dc4bf67d
4 changed files with 30 additions and 15 deletions
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31
src/subscriptions.c
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@@ -100,10 +100,17 @@ void add_subscription_to_kind_index(subscription_t* sub) {
filter = filter->next;
}
// If subscription has no kind filter, add to no-kind-filter list
// If subscription has no kind filter, add to no-kind-filter list using wrapper node
if (!has_kind_filter) {
sub->next = g_subscription_manager.no_kind_filter_subs;
g_subscription_manager.no_kind_filter_subs = sub;
no_kind_filter_node_t* node = malloc(sizeof(no_kind_filter_node_t));
if (!node) {
DEBUG_ERROR("add_subscription_to_kind_index: failed to allocate no-kind-filter node");
return;
}
node->subscription = sub;
node->next = g_subscription_manager.no_kind_filter_subs;
g_subscription_manager.no_kind_filter_subs = node;
DEBUG_TRACE("KIND_INDEX: Added subscription '%s' to no-kind-filter list", sub->id);
}
}
@@ -130,11 +137,13 @@ void remove_subscription_from_kind_index(subscription_t* sub) {
}
}
// Remove from no-kind-filter list
subscription_t** current = &g_subscription_manager.no_kind_filter_subs;
// Remove from no-kind-filter list if present
no_kind_filter_node_t** current = &g_subscription_manager.no_kind_filter_subs;
while (*current) {
if (*current == sub) {
if ((*current)->subscription == sub) {
no_kind_filter_node_t* to_free = *current;
*current = (*current)->next;
free(to_free);
DEBUG_TRACE("KIND_INDEX: Removed subscription '%s' from no-kind-filter list", sub->id);
break;
}
@@ -797,12 +806,12 @@ int broadcast_event_to_subscriptions(cJSON* event) {
}
// Add subscriptions with no kind filter (must check against all events)
subscription_t* no_kind_sub = g_subscription_manager.no_kind_filter_subs;
while (no_kind_sub && candidate_count < MAX_TOTAL_SUBSCRIPTIONS) {
if (no_kind_sub->active) {
candidates_to_check[candidate_count++] = no_kind_sub;
no_kind_filter_node_t* no_kind_node = g_subscription_manager.no_kind_filter_subs;
while (no_kind_node && candidate_count < MAX_TOTAL_SUBSCRIPTIONS) {
if (no_kind_node->subscription && no_kind_node->subscription->active) {
candidates_to_check[candidate_count++] = no_kind_node->subscription;
}
no_kind_sub = no_kind_sub->next;
no_kind_node = no_kind_node->next;
}
DEBUG_TRACE("BROADCAST: Checking %d candidate subscriptions (kind index optimization)", candidate_count);