Unprivileged users are normally restricted from mounting with the allow_other option by system policy, but this could be bypassed for a mount done with user namespace root permissions. In such cases allow_other should not allow users outside the userns to access the mount as doing so would give the unprivileged user the ability to manipulate processes it would otherwise be unable to manipulate. Restrict allow_other to apply to users in the same userns used at mount or a descendant of that namespace. Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx> --- fs/fuse/dir.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 8fd9fe4dcd43..24e4cdb554f1 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1015,7 +1015,7 @@ int fuse_allow_current_process(struct fuse_conn *fc) const struct cred *cred; if (fc->flags & FUSE_ALLOW_OTHER) - return 1; + return current_in_userns(fc->user_ns); cred = current_cred(); if (uid_eq(cred->euid, fc->user_id) && -- 1.9.1 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
