From: Michael Paquier <michael@paquier.xyz>
Date: Mon, 11 May 2026 12:13:49 +0000 (-0700)
Subject: Fix overflows with ts_headline()
X-Git-Tag: REL_16_14~25
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=5919e0005b6f23292450a44f1db5c6b2e2bb0ddf;p=thirdparty%2Fpostgresql.git

Fix overflows with ts_headline()

The options "StartSel", "StopSel" and "FragmentDelimiter" given by a
caller of the SQL function ts_headline() have their lengths stored as
int16.  When providing values larger than PG_INT16_MAX, it was possible
to overflow the length values stored, leading to incorrect behaviors in
generateHeadline(), in most cases translating to a crash.

Attempting to use values for these options larger than PG_INT16_MAX is
now blocked.  Some test cases are added to cover our tracks.

Reported-by: Xint Code
Author: Michael Paquier <michael@paquier.xyz>
Backpatch-through: 14
Security: CVE-2026-6473
---

diff --git a/src/backend/tsearch/wparser_def.c b/src/backend/tsearch/wparser_def.c
index 20c1b2dfb66..05d605ade51 100644
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -2627,6 +2627,9 @@ prsd_headline(PG_FUNCTION_ARGS)
 	int			max_fragments = 0;
 	bool		highlightall = false;
 	ListCell   *l;
+	size_t		startsellen;
+	size_t		stopsellen;
+	size_t		fragdelimlen;
 
 	/* Extract configuration option values */
 	prs->startsel = NULL;
@@ -2716,9 +2719,24 @@ prsd_headline(PG_FUNCTION_ARGS)
 		prs->fragdelim = pstrdup(" ... ");
 
 	/* Caller will need these lengths, too */
-	prs->startsellen = strlen(prs->startsel);
-	prs->stopsellen = strlen(prs->stopsel);
-	prs->fragdelimlen = strlen(prs->fragdelim);
+	startsellen = strlen(prs->startsel);
+	stopsellen = strlen(prs->stopsel);
+	fragdelimlen = strlen(prs->fragdelim);
+	if (startsellen > PG_INT16_MAX)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("value for \"%s\" is too long", "StartSel")));
+	if (stopsellen > PG_INT16_MAX)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("value for \"%s\" is too long", "StopSel")));
+	if (fragdelimlen > PG_INT16_MAX)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("value for \"%s\" is too long", "FragmentDelimiter")));
+	prs->startsellen = startsellen;
+	prs->stopsellen = stopsellen;
+	prs->fragdelimlen = fragdelimlen;
 
 	PG_RETURN_POINTER(prs);
 }
diff --git a/src/test/regress/expected/tsearch.out b/src/test/regress/expected/tsearch.out
index 9fad6c8b04b..38ddb7aa64e 100644
--- a/src/test/regress/expected/tsearch.out
+++ b/src/test/regress/expected/tsearch.out
@@ -2144,6 +2144,16 @@ NOTICE:  text-search query doesn't contain lexemes: ""
  foo bar
 (1 row)
 
+-- Test for large values of StartSel, StopSel and FragmentDelimiter
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'StartSel=' || repeat('x', 32768));
+ERROR:  value for "StartSel" is too long
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'StopSel=' || repeat('x', 32768));
+ERROR:  value for "StopSel" is too long
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'FragmentDelimiter=' || repeat('x', 32768));
+ERROR:  value for "FragmentDelimiter" is too long
 --Rewrite sub system
 CREATE TABLE test_tsquery (txtkeyword TEXT, txtsample TEXT);
 \set ECHO none
diff --git a/src/test/regress/sql/tsearch.sql b/src/test/regress/sql/tsearch.sql
index fbd26cdba45..bcaff947dca 100644
--- a/src/test/regress/sql/tsearch.sql
+++ b/src/test/regress/sql/tsearch.sql
@@ -646,6 +646,14 @@ SELECT ts_headline('english',
 SELECT ts_headline('english',
 'foo bar', to_tsquery('english', ''));
 
+-- Test for large values of StartSel, StopSel and FragmentDelimiter
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'StartSel=' || repeat('x', 32768));
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'StopSel=' || repeat('x', 32768));
+SELECT ts_headline('english', 'foo barbar', to_tsquery('english', 'foo'),
+  'FragmentDelimiter=' || repeat('x', 32768));
+
 --Rewrite sub system
 
 CREATE TABLE test_tsquery (txtkeyword TEXT, txtsample TEXT);