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.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'dir-iterator.c') diff --git a/dir-iterator.c b/dir-iterator.c index b17e9f970a..3764dd81a1 100644 --- a/dir-iterator.c +++ b/dir-iterator.c @@ -203,7 +203,7 @@ struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags) { struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter)); struct dir_iterator *dir_iterator = &iter->base; - int saved_errno; + int saved_errno, err; strbuf_init(&iter->base.path, PATH_MAX); strbuf_addstr(&iter->base.path, path); @@ -213,10 +213,15 @@ struct dir_iterator *dir_iterator_begin(const char *path, unsigned int flags) iter->flags = flags; /* - * Note: stat already checks for NULL or empty strings and - * inexistent paths. + * Note: stat/lstat already checks for NULL or empty strings and + * nonexistent paths. */ - if (stat(iter->base.path.buf, &iter->base.st) < 0) { + if (iter->flags & DIR_ITERATOR_FOLLOW_SYMLINKS) + err = stat(iter->base.path.buf, &iter->base.st); + else + err = lstat(iter->base.path.buf, &iter->base.st); + + if (err < 0) { saved_errno = errno; goto error_out; } -- cgit v1.2.3