From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 58CEC7D089 for ; Mon, 5 Nov 2018 18:22:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387714AbeKFDnC (ORCPT ); Mon, 5 Nov 2018 22:43:02 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:45130 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387705AbeKFDnC (ORCPT ); Mon, 5 Nov 2018 22:43:02 -0500 Received: by mail-pg1-f196.google.com with SMTP id y4so4146821pgc.12 for ; Mon, 05 Nov 2018 10:22:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=IcHeJPDy1T6WJ8Fq/KWMAHt8XXMgVqCQgxCpPKbKBJs=; b=M9wXyYqIKEgqQIEmct5wd2kPiiSHE43E9Lkvrp7BmJdE9NKWkYx3+QVjmoU0tCY9uk M+wRAz4dAVV+MkuPtJ7+hPsAb2/On0bruoOvwk0/A3DGI4ZX0qg3siPeJrJwF4aOSt/6 sk/MXZNbtGWdPd6udNfraOmG5pTpChd1Yc2ayv/EhfyZsuMvlpcsedktv7YAoOpG5gAe 4mEkvdOKN1edoo+LaV9Uk4IgLd2+hFuqYj4cDNfukkyddBk4z7L1wYH4fklyLzq0deYA U0sQbHUuJTgDPhZOYqfdpKV3l1Cv0oJfo/0P/Rcogh/MF/1yzLlaz1vnufZbJU0B9Xxp n5Sw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IcHeJPDy1T6WJ8Fq/KWMAHt8XXMgVqCQgxCpPKbKBJs=; b=uJHXow8/B0SXv44iyWZB63LJFVu3CEnmR1IcUM9uLFMlvVxSnphnxIlxWEBDvlYPxh geaLKdgzaBP6psRXh0tfyke9JNSufcUcXZf2Z5KiK0IzlJFSXK2PIud8G7w0faWeP6M7 DCTQtfbqTlZG6YpQc5V2zvJmla/ekPj02PbNOv2EGSicch1KqeRDA5cML248fopY+rdJ gBm0pF/ToR/l+ApUW4i3ZoavJOoC7tl5h0fVpbnceOuBQQKS8KbpY8yL/yAdYcERnhDw CcUDJFi+E72NCARtqhCwF7afJAtT6X/7dowi8BzVibJ7O3Orf0Plgz5XwgHMF7Lnl0Sh bJsw== X-Gm-Message-State: AGRZ1gJA//bdmqmoc1QGHCuYMt2KbKhuKrmdz+FZ1wRwE5wOJIdi1qLq krbrA5x4mQ4Rfe2Tzq7XqU/ieA== X-Google-Smtp-Source: AJdET5dPPg2osdD85x9UsEy7rRMx/EolrukFiEW+nL0YW6oFDOO7veYp8k3xlVrauHis73nim8zf5A== X-Received: by 2002:a62:7d10:: with SMTP id y16-v6mr22939181pfc.245.1541442127796; Mon, 05 Nov 2018 10:22:07 -0800 (PST) Received: from nebulus.mtv.corp.google.com ([2620:0:1000:1612:b4fb:6752:f21f:3502]) by smtp.gmail.com with ESMTPSA id s184-v6sm53788626pfb.46.2018.11.05.10.22.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Nov 2018 10:22:07 -0800 (PST) From: Mark Salyzyn To: linux-kernel@vger.kernel.org Cc: Mark Salyzyn , Miklos Szeredi , Jonathan Corbet , Vivek Goyal , "Eric W . Biederman" , Amir Goldstein , Randy Dunlap , Stephen Smalley , linux-unionfs@vger.kernel.org, linux-doc@vger.kernel.org, kernel-team@android.com Subject: [PATCH v6 1/2] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh Date: Mon, 5 Nov 2018 10:21:41 -0800 Message-Id: <20181105182146.233025-2-salyzyn@android.com> X-Mailer: git-send-email 2.19.1.930.g4563a0d9d0-goog In-Reply-To: <20181105182146.233025-1-salyzyn@android.com> References: <20181105182146.233025-1-salyzyn@android.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Assumption never checked, should fail if the mounter creds are not sufficient. Signed-off-by: Mark Salyzyn Cc: Miklos Szeredi Cc: Jonathan Corbet Cc: Vivek Goyal Cc: Eric W. Biederman Cc: Amir Goldstein Cc: Randy Dunlap Cc: Stephen Smalley Cc: linux-unionfs@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: kernel-team@android.com v5: - dependency of "overlayfs: override_creds=off option bypass creator_cred" v6: - rebase --- fs/overlayfs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index efd372312ef1..aa012b6bd46e 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -163,6 +163,11 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid)) return NULL; + if (!capable(CAP_DAC_READ_SEARCH)) { + origin = ERR_PTR(-EPERM); + goto out; + } + bytes = (fh->len - offsetof(struct ovl_fh, fid)); real = exportfs_decode_fh(mnt, (struct fid *)fh->fid, bytes >> 2, (int)fh->type, -- 2.19.1.930.g4563a0d9d0-goog