Check for interrupts and stack overflow in TParserGet().

tglsfdc · tglsfdc · commit c7f33a197bf2 · 2023-06-24T17:18:08.000-04:00
TParserGet() recurses for some token types, meaning it's possible to drive it to stack overflow. Since this is a minority behavior, I chose to add the check_stack_depth() call to the two places that recurse rather than doing it during every single call. While at it, add CHECK_FOR_INTERRUPTS(), because this can run unpleasantly long for long inputs. Per bug #17995 from Zuming Jiang. This is old, so back-patch to all supported branches. Discussion: https://postgr.es/m/17995-9f20ff3e6389db4c@postgresql.org
diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
@@ -18,6 +18,7 @@
 
 #include "catalog/pg_collation.h"
 #include "commands/defrem.h"
+#include "miscadmin.h"
 #include "tsearch/ts_locale.h"
 #include "tsearch/ts_public.h"
 #include "tsearch/ts_type.h"
@@ -639,6 +640,12 @@ p_ishost(TParser *prs)
 
 	tmpprs->wanthost = true;
 
+	/*
+	 * Check stack depth before recursing.  (Since TParserGet() doesn't
+	 * normally recurse, we put the cost of checking here not there.)
+	 */
+	check_stack_depth();
+
 	if (TParserGet(tmpprs) && tmpprs->type == HOST)
 	{
 		prs->state->posbyte += tmpprs->lenbytetoken;
@@ -662,6 +669,12 @@ p_isURLPath(TParser *prs)
 	tmpprs->state = newTParserPosition(tmpprs->state);
 	tmpprs->state->state = TPS_InURLPathFirst;
 
+	/*
+	 * Check stack depth before recursing.  (Since TParserGet() doesn't
+	 * normally recurse, we put the cost of checking here not there.)
+	 */
+	check_stack_depth();
+
 	if (TParserGet(tmpprs) && tmpprs->type == URLPATH)
 	{
 		prs->state->posbyte += tmpprs->lenbytetoken;
@@ -1705,6 +1718,8 @@ TParserGet(TParser *prs)
 {
 	const TParserStateActionItem *item = NULL;
 
+	CHECK_FOR_INTERRUPTS();
+
 	Assert(prs->state);
 
 	if (prs->state->posbyte >= prs->lenstr)
