Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
9pfs: local: lstat: don't follow symlinks
The local_lstat() callback is vulnerable to symlink attacks because it calls: (1) lstat() which follows symbolic links in all path elements but the rightmost one (2) getxattr() which follows symbolic links in all path elements (3) local_mapped_file_attr()->local_fopen()->openat(O_NOFOLLOW) which follows symbolic links in all path elements but the rightmost one This patch converts local_lstat() to rely on opendir_nofollow() and fstatat(AT_SYMLINK_NOFOLLOW) to fix (1), fgetxattrat_nofollow() to fix (2). A new local_fopenat() helper is introduced as a replacement to local_fopen() to fix (3). No effort is made to factor out code because local_fopen() will be dropped when all users have been converted to call local_fopenat(). This partly fixes CVE-2016-9602. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
- Loading branch information
Showing
1 changed file
with
61 additions
and
17 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters