Add fallible lcfs_node_try_set_mode()

Previously I added code to validate this but it happened much later. The mode (type) of a file is a very fundamental property and we should constrain its state as early as possible. Signed-off-by: Colin Walters <[email protected]>
cgwalters · Sep 9, 2024 · 9da2423 · 9da2423
1 parent ab45b87
commit 9da2423
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Showing 3 changed files with 13 additions and 1 deletion.
diff --git a/libcomposefs/lcfs-writer.c b/libcomposefs/lcfs-writer.c
@@ -989,6 +989,15 @@ void lcfs_node_set_mode(struct lcfs_node_s *node, uint32_t mode)
 	node->inode.st_mode = mode;
 }
 
+int lcfs_node_try_set_mode(struct lcfs_node_s *node, uint32_t mode)
+{
+	if (lcfs_validate_mode(mode) < 0) {
+		return -1;
+	}
+	node->inode.st_mode = mode;
+	return 0;
+}
+
 uint32_t lcfs_node_get_uid(struct lcfs_node_s *node)
 {
 	return node->inode.st_uid;

diff --git a/libcomposefs/lcfs-writer.h b/libcomposefs/lcfs-writer.h
@@ -131,6 +131,7 @@ LCFS_EXTERN struct lcfs_node_s *lcfs_node_get_hardlink_target(struct lcfs_node_s
 LCFS_EXTERN bool lcfs_node_dirp(struct lcfs_node_s *node);
 LCFS_EXTERN uint32_t lcfs_node_get_mode(struct lcfs_node_s *node);
 LCFS_EXTERN void lcfs_node_set_mode(struct lcfs_node_s *node, uint32_t mode);
+LCFS_EXTERN int lcfs_node_try_set_mode(struct lcfs_node_s *node, uint32_t mode);
 LCFS_EXTERN uint32_t lcfs_node_get_uid(struct lcfs_node_s *node);
 LCFS_EXTERN void lcfs_node_set_uid(struct lcfs_node_s *node, uint32_t uid);
 LCFS_EXTERN uint32_t lcfs_node_get_gid(struct lcfs_node_s *node);

diff --git a/tools/mkcomposefs.c b/tools/mkcomposefs.c
@@ -437,7 +437,9 @@ static char *tree_from_dump_line(dump_info *info, const char *line, size_t line_
 	if (node == NULL) {
 		oom();
 	}
-	lcfs_node_set_mode(node, mode);
+	if (lcfs_node_try_set_mode(node, mode) < 0) {
+		return make_error("Invalid mode %o", (unsigned int)mode);
+	}
 
 	err = tree_add_node(info, path, node);
 	if (err)