From 11a9f4d807a0d71dc6eff51bb87baf4ca2cccf1d Mon Sep 17 00:00:00 2001 From: Jeff King Date: Sun, 13 May 2018 12:09:42 -0400 Subject: [PATCH] is_ntfs_dotgit: use a size_t for traversing string We walk through the "name" string using an int, which can wrap to a negative value and cause us to read random memory before our array (e.g., by creating a tree with a name >2GB, since "int" is still 32 bits even on most 64-bit platforms). Worse, this is easy to trigger during the fsck_tree() check, which is supposed to be protecting us from malicious garbage. Note one bit of trickiness in the existing code: we sometimes assign -1 to "len" at the end of the loop, and then rely on the "len++" in the for-loop's increment to take it back to 0. This is still legal with a size_t, since assigning -1 will turn into SIZE_MAX, which then wraps around to 0 on increment. Signed-off-by: Jeff King --- path.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/path.c b/path.c index 0349a0ab7b..9018aa0ac0 100644 --- a/path.c +++ b/path.c @@ -1224,7 +1224,7 @@ static int only_spaces_and_periods(const char *path, size_t len, size_t skip) int is_ntfs_dotgit(const char *name) { - int len; + size_t len; for (len = 0; ; len++) if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {