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 48f9a87523c6030d1f0f8bd12052db5b65d8cbf9..8ccee5883dcea11a0318eaa1a44dee55889290b2 100644 (file)
--- a/src/backend/tsearch/wparser_def.c
+++ b/src/backend/tsearch/wparser_def.c
@@ -2557,6 +2557,9 @@ prsd_headline(PG_FUNCTION_ARGS)
        bool            highlightall = false;
        int                     max_cover;
        ListCell   *l;
+       size_t          startsellen;
+       size_t          stopsellen;
+       size_t          fragdelimlen;
 
        /* Extract configuration option values */
        prs->startsel = NULL;
@@ -2642,9 +2645,24 @@ 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 629147c5b119455630c2eb7641c116630f6031cb..3204be7c60a6c59ef192e37f599d4cf20ab3ce12 100644 (file)
--- a/src/test/regress/expected/tsearch.out
+++ b/src/test/regress/expected/tsearch.out
@@ -2007,6 +2007,16 @@ 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 0a90c1b539d9e5cd91ee2a167eecb2c983ff2942..561656a6e5794de536ad6329da93de55c8a2fd13 100644 (file)
--- a/src/test/regress/sql/tsearch.sql
+++ b/src/test/regress/sql/tsearch.sql
@@ -555,6 +555,14 @@ 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);