Size accounting + alloc() overflow checking, round #2

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 8 insertions, 1 deletions

diff --git a/lib/fstree/fstree_from_dir.c b/lib/fstree/fstree_from_dir.c
index 9aab5df..d6fac86 100644
--- a/lib/fstree/fstree_from_dir.c
+++ b/lib/fstree/fstree_from_dir.c
@@ -25,6 +25,7 @@
 static char *get_file_path(tree_node_t *n, const char *name)
 {
 	char *ptr, *new;
+	size_t len;
 	int ret;
 
 	if (n->parent == NULL) {
@@ -41,7 +42,13 @@ static char *get_file_path(tree_node_t *n, const char *name)
 	ret = canonicalize_name(ptr);
 	assert(ret == 0);
 
-	new = realloc(ptr, strlen(ptr) + strlen(name) + 2);
+	if (SZ_ADD_OV(strlen(ptr), strlen(name), &len) ||
+	    SZ_ADD_OV(len, 2, &len)) {
+		errno = EOVERFLOW;
+		goto fail;
+	}
+
+	new = realloc(ptr, len);
 	if (new == NULL)
 		goto fail;