From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 624727D2F0 for ; Tue, 30 Jul 2019 17:29:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729386AbfG3R3P (ORCPT ); Tue, 30 Jul 2019 13:29:15 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:37295 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728271AbfG3R3P (ORCPT ); Tue, 30 Jul 2019 13:29:15 -0400 Received: by mail-pg1-f195.google.com with SMTP id i70so19675060pgd.4 for ; Tue, 30 Jul 2019 10:29:14 -0700 (PDT) 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=7bBFrWA52UIw86e3/QjeXJw/OCabcRoNRYCv3kxW+2M=; b=LQii4WieS2MDafhUA+OlKsskPWxI5YTobLOu88Z4ddha0lABd53i4WCZ7OxuKqKL2U 5omu44FjkhueJ2p2uUdil676QfB8AaWwVo/GXXW/8lB4YmyRYBxcOsjW6V1awdSxUZSB S5AU+5wN2JXSiw2ydg0XA7DLFJwleT9jZGTST0FBaPEKPLfQwGq2MgyoDnSKXJR/rkKx MekG+GWbYUQc2Fpm1vkEBYmn8SmzE1t+nNaI1gtgMNxfPF2shyvZWiW7wlqsan36Vyu+ 5Q7Pyu7gadXlpV24vvL4Un7FQr9SLj87xvYjKzU7/8jllMYuwH9SRNdirD0t6Ps6QVAh /FbQ== 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=7bBFrWA52UIw86e3/QjeXJw/OCabcRoNRYCv3kxW+2M=; b=XkCCL6yAP2QHP1CElv5nYsBJlqauvN8T0FU4wky95U6kxS7jV5gn24wmByhvh22c87 xduKjOnL6nCy2yE/J7ylgHd9hd8jPHPHemd1xw6ruXzGimwg2Mt0NRuzfYKU5xhme3MR xwsHGBBzsQk2Li9izo80+CB+uTSKTEaOlpOH2yp22OBAGgJ38Q07OakF/bNJYUHtpPb3 5WwDUh7GiuBletwYDv+K0DvgtmcmxNUGa2gkFyroR53r+WBuPAHPMziSBynpTGT/o2ZY 5TtT/ONcHaKHz1TMcdhTE7J2iOQJPi/K2aoNtTIpm9wEaabrL9nw/sJcE8HqauMTcqSv /NoQ== X-Gm-Message-State: APjAAAXoXli6iYkaJ62spu0y81KmEkDqduEc2m2W42/nYg6AfsCngzHC pf8SwW4446Iv9S5NYgJKaxg= X-Google-Smtp-Source: APXvYqy7O+JUNFiimggQGDjVBWO2oAeYvEamsKNDhzODd3L8yHiwF/P1sGG4hZNspXySynCEu0Z/Nw== X-Received: by 2002:a63:6c46:: with SMTP id h67mr102026443pgc.248.1564507754414; Tue, 30 Jul 2019 10:29:14 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.gmail.com with ESMTPSA id o129sm39856293pfg.1.2019.07.30.10.29.13 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 30 Jul 2019 10:29:13 -0700 (PDT) From: Mark Salyzyn To: linux-kernel@vger.kernel.org Cc: kernel-team@android.com, 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 Subject: [PATCH v12 1/5] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh Date: Tue, 30 Jul 2019 10:28:58 -0700 Message-Id: <20190730172904.79146-2-salyzyn@android.com> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog In-Reply-To: <20190730172904.79146-1-salyzyn@android.com> References: <20190730172904.79146-1-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 --- v11 + v12 - rebase v10: - return NULL rather than ERR_PTR(-EPERM) - did _not_ add it ovl_can_decode_fh() because of changes since last review, suspect needs to be added to ovl_lower_uuid_ok()? v8 + v9: - rebase v7: - This time for realz v6: - rebase v5: - dependency of "overlayfs: override_creds=off option bypass creator_cred" --- fs/overlayfs/namei.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index e9717c2f7d45..9702f0d5309d 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -161,6 +161,9 @@ 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)) + return NULL; + bytes = (fh->len - offsetof(struct ovl_fh, fid)); real = exportfs_decode_fh(mnt, (struct fid *)fh->fid, bytes >> 2, (int)fh->type, -- 2.22.0.770.g0f2c4a37fd-goog