From: Karl Fleischmann <karl.fleischmann@open-xchange.com>
Date: Mon, 19 Dec 2022 14:18:40 +0000 (+0100)
Subject: lib: Warn about unsupported inequality string comparisons in event filters
X-Git-Tag: 2.4.0~3239
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ea83fac1bcfedbb7a8f100dac62d322c8451f974;p=thirdparty%2Fdovecot%2Fcore.git

lib: Warn about unsupported inequality string comparisons in event filters
---

diff --git a/src/lib/event-filter-private.h b/src/lib/event-filter-private.h
index 2c80b1d14d..bb9b0f638a 100644
--- a/src/lib/event-filter-private.h
+++ b/src/lib/event-filter-private.h
@@ -87,6 +87,7 @@ struct event_filter_node {
 
 	bool ambiguous_unit:1;
 	bool warned_ambiguous_unit:1;
+	bool warned_string_inequality:1;
 	bool warned_type_mismatch:1;
 };
 
diff --git a/src/lib/event-filter.c b/src/lib/event-filter.c
index 335312f829..3bb52d6d2b 100644
--- a/src/lib/event-filter.c
+++ b/src/lib/event-filter.c
@@ -254,6 +254,7 @@ clone_expr(pool_t pool, struct event_filter_node *old)
 	new->ambiguous_unit = old->ambiguous_unit;
 	new->warned_ambiguous_unit = old->warned_ambiguous_unit;
 	new->warned_type_mismatch = old->warned_type_mismatch;
+	new->warned_string_inequality = old->warned_string_inequality;
 
 	return new;
 }
@@ -590,8 +591,21 @@ event_match_field(struct event *event, struct event_filter_node *node,
 
 	switch (field->value_type) {
 	case EVENT_FIELD_VALUE_TYPE_STR:
+		/* We only support string equality comparisons. */
 		if (node->op != EVENT_FILTER_OP_CMP_EQ) {
-			/* we only support string equality comparisons */
+			/* Warn about non-equality comparisons. */
+			if (!node->warned_string_inequality) {
+				const char *name = event->sending_name;
+				/* Use i_warning to prevent event filter recursions. */
+				i_warning("Event filter for string field '%s' "
+					  "only supports equality operation "
+					  "'=' not '%s'. (event=%s, source=%s:%u)",
+					  wanted_field->key,
+					  event_filter_export_query_expr_op(node->op),
+					  name != NULL ? name : "",
+					  source_filename, source_linenum);
+				node->warned_string_inequality = TRUE;
+			}
 			return FALSE;
 		}
 		if (field->value.str[0] == '\0') {