From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Fri, 27 Mar 2026 10:20:38 +0000 (+0200)
Subject: Avoid memory leak on error while parsing pg_stat_statements dump file
X-Git-Tag: REL_18_4~99
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=25b02320e13305a03fbcbbb0202053dbcb7540d1;p=thirdparty%2Fpostgresql.git

Avoid memory leak on error while parsing pg_stat_statements dump file

By using palloc() instead of raw malloc().

Reported-by: Gaurav Singh <gaurav.singh@yugabyte.com>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/CAEcQ1bYR9s4eQLFDjzzJHU8fj-MTbmRpW-9J-r2gsCn+HEsynw@mail.gmail.com
Backpatch-through: 14
---

diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c
index 9b3a33118f4..1c07acf231e 100644
--- a/contrib/pg_stat_statements/pg_stat_statements.c
+++ b/contrib/pg_stat_statements/pg_stat_statements.c
@@ -798,7 +798,7 @@ pgss_shmem_shutdown(int code, Datum arg)
 	if (fwrite(&pgss->stats, sizeof(pgssGlobalStats), 1, file) != 1)
 		goto error;
 
-	free(qbuffer);
+	pfree(qbuffer);
 	qbuffer = NULL;
 
 	if (FreeFile(file))
@@ -822,7 +822,8 @@ error:
 			(errcode_for_file_access(),
 			 errmsg("could not write file \"%s\": %m",
 					PGSS_DUMP_FILE ".tmp")));
-	free(qbuffer);
+	if (qbuffer)
+		pfree(qbuffer);
 	if (file)
 		FreeFile(file);
 	unlink(PGSS_DUMP_FILE ".tmp");
@@ -1791,7 +1792,8 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 			pgss->extent != extent ||
 			pgss->gc_count != gc_count)
 		{
-			free(qbuffer);
+			if (qbuffer)
+				pfree(qbuffer);
 			qbuffer = qtext_load_file(&qbuffer_size);
 		}
 	}
@@ -2006,7 +2008,8 @@ pg_stat_statements_internal(FunctionCallInfo fcinfo,
 
 	LWLockRelease(pgss->lock);
 
-	free(qbuffer);
+	if (qbuffer)
+		pfree(qbuffer);
 }
 
 /* Number of output arguments (columns) for pg_stat_statements_info */
@@ -2293,7 +2296,7 @@ error:
 }
 
 /*
- * Read the external query text file into a malloc'd buffer.
+ * Read the external query text file into a palloc'd buffer.
  *
  * Returns NULL (without throwing an error) if unable to read, eg
  * file not there or insufficient memory.
@@ -2335,7 +2338,7 @@ qtext_load_file(Size *buffer_size)
 
 	/* Allocate buffer; beware that off_t might be wider than size_t */
 	if (stat.st_size <= MaxAllocHugeSize)
-		buf = (char *) malloc(stat.st_size);
+		buf = (char *) palloc_extended(stat.st_size, MCXT_ALLOC_HUGE | MCXT_ALLOC_NO_OOM);
 	else
 		buf = NULL;
 	if (buf == NULL)
@@ -2374,7 +2377,7 @@ qtext_load_file(Size *buffer_size)
 						(errcode_for_file_access(),
 						 errmsg("could not read file \"%s\": %m",
 								PGSS_TEXT_FILE)));
-			free(buf);
+			pfree(buf);
 			CloseTransientFile(fd);
 			return NULL;
 		}
@@ -2585,7 +2588,7 @@ gc_qtexts(void)
 	else
 		pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
-	free(qbuffer);
+	pfree(qbuffer);
 
 	/*
 	 * OK, count a garbage collection cycle.  (Note: even though we have
@@ -2602,7 +2605,8 @@ gc_fail:
 	/* clean up resources */
 	if (qfile)
 		FreeFile(qfile);
-	free(qbuffer);
+	if (qbuffer)
+		pfree(qbuffer);
 
 	/*
 	 * Since the contents of the external file are now uncertain, mark all