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=unavailable 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 A1A7E7D90F for ; Tue, 22 Oct 2019 20:46:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388653AbfJVUqK (ORCPT ); Tue, 22 Oct 2019 16:46:10 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:44177 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732243AbfJVUqK (ORCPT ); Tue, 22 Oct 2019 16:46:10 -0400 Received: by mail-pg1-f195.google.com with SMTP id e10so10649958pgd.11 for ; Tue, 22 Oct 2019 13:46:08 -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=VTz2gA5Vgd+VWXyia7j9i0zhx2iVoEFHW3eopMIkCvw=; b=ZBFn+4JN6wTs5zPUNSPxP4riFuqh6MBDRoX+j6kfrK8y/X7XxJc2j+fQgzAcGNVdi3 REJvrkfBWPDoqKCA4NQiilOVQ0ivKN5ikZEKClEq3xMJUL5a+cCAxJrCfOlnUq4/zRIH IVbKLyKc88CrUF/Uwfjyph9zVHE9fl6s9qC4pIbI94M+x/Sd143vCmNSgV+8Fdi+r6IL +Y0iuDpYyzTXII+BzQwiLiL0yBH8ql9lH/ctLoxo85SP65/UypoDdrDSPb7rms2yUq/t RWaQBEAptheR2dnST5N0i2EhoeeLdwg2NnoIChw1yP36/idz3Q9bfv6xTWvqfwA1OexZ RbLg== 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=VTz2gA5Vgd+VWXyia7j9i0zhx2iVoEFHW3eopMIkCvw=; b=PIdoQsYri2J7K60WYmNkShuz4ApacJtWbp7w1y2RIYWevzZW2zSByeVylrFJwQrO0D jtWhr42XPeuXuCqRUYs6NuXZxjun6MOlETfTQvB4+WZdJihAozxR4FQbZZozvZjhtrCQ TVuNYoIyrjtH91u1O6Ddq828KGBnnphzS2dyDThcZ9bOSWI86Xvd8e69uH9f+uR5NGg/ wJCouxvH66UqmOxQx/iXSI1dHFnrxuXjzEVCGnxMt5dEZsL2eeutDXzYX3yp3NTM9Plk adIHcgdomsx+y6TAU5M7xU0/dM4pdL4C4ILE4cI/g0UEjOpZ74MeSx3BB3PP2IRAvjeH YhqA== X-Gm-Message-State: APjAAAWeL1vNfJYhv+RMYPGrJVNAjpOfIAbUZUK5vAadRENe9sJ4a+qe Ed60MUyGDbaRj3mb2LZAXfxDcQ== X-Google-Smtp-Source: APXvYqxZEe8zdF5s+ksC85SyvZGPDJkmKtKuSQPm6Cqk/w5iXIl6fu/fjEgRpdIi06VP7Gv4e5RUjg== X-Received: by 2002:a63:4556:: with SMTP id u22mr5662508pgk.2.1571777167769; Tue, 22 Oct 2019 13:46:07 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.gmail.com with ESMTPSA id l184sm19810903pfl.76.2019.10.22.13.46.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Oct 2019 13:46:07 -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 v14 2/5] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh Date: Tue, 22 Oct 2019 13:44:47 -0700 Message-Id: <20191022204453.97058-3-salyzyn@android.com> X-Mailer: git-send-email 2.23.0.866.gb869b98d4c-goog In-Reply-To: <20191022204453.97058-1-salyzyn@android.com> References: <20191022204453.97058-1-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 +v13 + v14 - 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, -- 2.23.0.866.gb869b98d4c-goog