0002-v1-remove-function-path_contains_parent_reference.patch

From bb099a079d6cbd3fe5a0eab1170ec9e6c91f278b Mon Sep 17 00:00:00 2001
From: Shenhao Wang <wangsh.fnst@fujitsu.com>
Date: Sun, 26 Sep 2021 15:44:42 +0800
Subject: [PATCH 2/3] v1 remove function path_contains_parent_reference

---
 contrib/adminpack/adminpack.c            |  6 ----
 contrib/adminpack/expected/adminpack.out |  4 +--
 contrib/adminpack/sql/adminpack.sql      |  2 +-
 src/backend/utils/adt/genfile.c          |  6 ----
 src/include/port.h                       |  1 -
 src/port/path.c                          | 36 ++----------------------
 6 files changed, 5 insertions(+), 50 deletions(-)

diff --git a/contrib/adminpack/adminpack.c b/contrib/adminpack/adminpack.c
index 48c1746910..d5660da669 100644
--- a/contrib/adminpack/adminpack.c
+++ b/contrib/adminpack/adminpack.c
@@ -88,12 +88,6 @@ convert_and_check_filename(text *arg)
 	 */
 	if (is_absolute_path(filename))
 	{
-		/* Disallow '/a/b/data/..' */
-		if (path_contains_parent_reference(filename))
-			ereport(ERROR,
-					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-					 errmsg("reference to parent directory (\"..\") not allowed")));
-
 		/* Allow absolute paths if within DataDir */
 		if (!path_is_prefix_of_path(DataDir, filename))
 			ereport(ERROR,
diff --git a/contrib/adminpack/expected/adminpack.out b/contrib/adminpack/expected/adminpack.out
index edf3ebfcba..ad683ba964 100644
--- a/contrib/adminpack/expected/adminpack.out
+++ b/contrib/adminpack/expected/adminpack.out
@@ -50,8 +50,8 @@ SELECT pg_file_write(current_setting('data_directory') || '/test_file4', 'test4'
              5
 (1 row)
 
-SELECT pg_file_write(current_setting('data_directory') || '/../test_file4', 'test4', false);
-ERROR:  reference to parent directory ("..") not allowed
+SELECT pg_file_write('abc/../../test_file4', 'test4', false);
+ERROR:  path must be in or below the current directory
 RESET ROLE;
 REVOKE EXECUTE ON FUNCTION pg_file_write(text,text,bool) FROM regress_user1;
 REVOKE pg_read_all_settings FROM regress_user1;
diff --git a/contrib/adminpack/sql/adminpack.sql b/contrib/adminpack/sql/adminpack.sql
index 918d0bdc65..87ec827bef 100644
--- a/contrib/adminpack/sql/adminpack.sql
+++ b/contrib/adminpack/sql/adminpack.sql
@@ -23,7 +23,7 @@ SET ROLE regress_user1;
 SELECT pg_file_write('../test_file0', 'test0', false);
 SELECT pg_file_write('/tmp/test_file0', 'test0', false);
 SELECT pg_file_write(current_setting('data_directory') || '/test_file4', 'test4', false);
-SELECT pg_file_write(current_setting('data_directory') || '/../test_file4', 'test4', false);
+SELECT pg_file_write('abc/../../test_file4', 'test4', false);
 RESET ROLE;
 REVOKE EXECUTE ON FUNCTION pg_file_write(text,text,bool) FROM regress_user1;
 REVOKE pg_read_all_settings FROM regress_user1;
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index c436d9318b..1ad7fb644c 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -71,12 +71,6 @@ convert_and_check_filename(text *arg)
 	 */
 	if (is_absolute_path(filename))
 	{
-		/* Disallow '/a/b/data/..' */
-		if (path_contains_parent_reference(filename))
-			ereport(ERROR,
-					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-					 errmsg("reference to parent directory (\"..\") not allowed")));
-
 		/*
 		 * Allow absolute paths if within DataDir or Log_directory, even
 		 * though Log_directory might be outside DataDir.
diff --git a/src/include/port.h b/src/include/port.h
index 82f63de325..024f2fb21b 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -52,7 +52,6 @@ extern void join_path_components(char *ret_path,
 extern void canonicalize_path(char *path);
 extern void make_native_path(char *path);
 extern void cleanup_path(char *path);
-extern bool path_contains_parent_reference(const char *path);
 extern bool path_is_relative_and_below_cwd(const char *path);
 extern bool path_is_prefix_of_path(const char *path1, const char *path2);
 extern char *make_absolute_path(const char *path);
diff --git a/src/port/path.c b/src/port/path.c
index d6741181ba..b32eeb5fde 100644
--- a/src/port/path.c
+++ b/src/port/path.c
@@ -386,42 +386,10 @@ canonicalize_path(char *path)
 	free(tmppath);
 }
 
-/*
- * Detect whether a path contains any parent-directory references ("..")
- *
- * The input *must* have been put through canonicalize_path previously.
- *
- * This is a bit tricky because we mustn't be fooled by "..a.." (legal)
- * nor "C:.." (legal on Unix but not Windows).
- */
-bool
-path_contains_parent_reference(const char *path)
-{
-	int			path_len;
-
-	path = skip_drive(path);	/* C: shouldn't affect our conclusion */
-
-	path_len = strlen(path);
-
-	/*
-	 * ".." could be the whole path; otherwise, if it's present it must be at
-	 * the beginning, in the middle, or at the end.
-	 */
-	if (strcmp(path, "..") == 0 ||
-		strncmp(path, "../", 3) == 0 ||
-		strstr(path, "/../") != NULL ||
-		(path_len >= 3 && strcmp(path + path_len - 3, "/..") == 0))
-		return true;
-
-	return false;
-}
-
 /*
  * Detect whether a path is only in or below the current working directory.
  * An absolute path that matches the current working directory should
- * return false (we only want relative to the cwd).  We don't allow
- * "/../" even if that would keep us under the cwd (it is too hard to
- * track that).
+ * return false (we only want relative to the cwd).
  */
 bool
 path_is_relative_and_below_cwd(const char *path)
@@ -429,7 +397,7 @@ path_is_relative_and_below_cwd(const char *path)
 	if (is_absolute_path(path))
 		return false;
 	/* don't allow anything above the cwd */
-	else if (path_contains_parent_reference(path))
+	else if (path_is_prefix_of_path("..", path))
 		return false;
 #ifdef WIN32
 
-- 
2.26.2