diff options
| author | Miklos Szeredi <mszeredi@redhat.com> | 2020-06-02 22:20:26 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2020-06-03 09:45:22 +0200 |
| commit | 05acefb4872dae89e772729efb194af754c877e8 (patch) | |
| tree | 9a53947fdb6ac28bca724cfb7a05090fea1f3b8d | |
| parent | 292f902a40c11f043a5ca1305a114da0e523eaa3 (diff) | |
ovl: check permission to open real file
Call inode_permission() on real inode before opening regular file on one of
the underlying layers.
In some cases ovl_permission() already checks access to an underlying file,
but it misses the metacopy case, and possibly other ones as well.
Removing the redundant permission check from ovl_permission() should be
considered later.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
| -rw-r--r-- | fs/overlayfs/file.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 1860e220c82d..0f83c8dfec46 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -40,10 +40,22 @@ static struct file *ovl_open_realfile(const struct file *file, struct file *realfile; const struct cred *old_cred; int flags = file->f_flags | O_NOATIME | FMODE_NONOTIFY; + int acc_mode = ACC_MODE(flags); + int err; + + if (flags & O_APPEND) + acc_mode |= MAY_APPEND; old_cred = ovl_override_creds(inode->i_sb); - realfile = open_with_fake_path(&file->f_path, flags, realinode, - current_cred()); + err = inode_permission(realinode, MAY_OPEN | acc_mode); + if (err) { + realfile = ERR_PTR(err); + } else if (!inode_owner_or_capable(realinode)) { + realfile = ERR_PTR(-EPERM); + } else { + realfile = open_with_fake_path(&file->f_path, flags, realinode, + current_cred()); + } revert_creds(old_cred); pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n", |