From 438c84c2f0c794f75ab55ce65c505b01bfce4480 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 11 Dec 2017 11:28:10 +0100 Subject: ovl: don't follow redirects if redirect_dir=off Overlayfs is following redirects even when redirects are disabled. If this is unintentional (probably the majority of cases) then this can be a problem. E.g. upper layer comes from untrusted USB drive, and attacker crafts a redirect to enable read access to otherwise unreadable directories. If "redirect_dir=off", then turn off following as well as creation of redirects. If "redirect_dir=follow", then turn on following, but turn off creation of redirects (which is what "redirect_dir=off" does now). This is a backward incompatible change, so make it dependent on a config option. Reported-by: David Howells Signed-off-by: Miklos Szeredi --- fs/overlayfs/ovl_entry.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/overlayfs/ovl_entry.h') diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h index 752bab645879..9d0bc03bf6e4 100644 --- a/fs/overlayfs/ovl_entry.h +++ b/fs/overlayfs/ovl_entry.h @@ -14,6 +14,8 @@ struct ovl_config { char *workdir; bool default_permissions; bool redirect_dir; + bool redirect_follow; + const char *redirect_mode; bool index; }; -- cgit v1.2.3