From bffc762f87ae8d18c6001bf0044a76004245754c Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Tue, 24 Jan 2023 19:43:51 -0500 Subject: dir-iterator: prevent top-level symlinks without FOLLOW_SYMLINKS When using the dir_iterator API, we first stat(2) the base path, and then use that as a starting point to enumerate the directory's contents. If the directory contains symbolic links, we will immediately die() upon encountering them without the `FOLLOW_SYMLINKS` flag. The same is not true when resolving the top-level directory, though. As explained in a previous commit, this oversight in 6f054f9fb3 (builtin/clone.c: disallow `--local` clones with symlinks, 2022-07-28) can be used as an attack vector to include arbitrary files on a victim's filesystem from outside of the repository. Prevent resolving top-level symlinks unless the FOLLOW_SYMLINKS flag is given, which will cause clones of a repository with a symlink'd "$GIT_DIR/objects" directory to fail. Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- dir-iterator.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'dir-iterator.h') diff --git a/dir-iterator.h b/dir-iterator.h index 08229157c6..e3b6ff2800 100644 --- a/dir-iterator.h +++ b/dir-iterator.h @@ -61,6 +61,11 @@ * not the symlinks themselves, which is the default behavior. Broken * symlinks are ignored. * + * Note: setting DIR_ITERATOR_FOLLOW_SYMLINKS affects resolving the + * starting path as well (e.g., attempting to iterate starting at a + * symbolic link pointing to a directory without FOLLOW_SYMLINKS will + * result in an error). + * * Warning: circular symlinks are also followed when * DIR_ITERATOR_FOLLOW_SYMLINKS is set. The iteration may end up with * an ELOOP if they happen and DIR_ITERATOR_PEDANTIC is set. -- cgit v1.2.3