From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7AB0C76186 for ; Wed, 24 Jul 2019 20:11:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 97FEB20665 for ; Wed, 24 Jul 2019 20:11:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="Ps3kbWjF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392641AbfGXULw (ORCPT ); Wed, 24 Jul 2019 16:11:52 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:42187 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392025AbfGXT5e (ORCPT ); Wed, 24 Jul 2019 15:57:34 -0400 Received: by mail-pl1-f193.google.com with SMTP id ay6so22435168plb.9 for ; Wed, 24 Jul 2019 12:57:34 -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=xWf1wqBywrzqDn4QoQmjv8h4FPdjfVbADD3ipadMdY0=; b=Ps3kbWjF13UPogwWSsC0j1C1LHTomES8Modx8qFda13HSsS2jZ4gUjMhQQyjIctloQ kr3kLXtMYRijIejm/ZHtQ4C3AqKPqY3ZHzBVoDk9iRt4R9cw06KEAYwmVxY3QZtIPjnq y+EnI9kd6drKRqNsuWKiEzoO/K332RFgL3+iVCi6iBhhkIitIXXG2sg5J8vY2z+5gHC2 SFovx1V4uzeTYGC4PQ0ipuH3uTpIWDyVbHQw6GcPjb+ZSgRIpmH/Eo7AUWg0/vEUUIuR Z87flKb7/uwvWhZWnxpSDZLnP2l+ZEp4A7ejy86spDsLIF9+9jWNQJ3ucUpLAUhnmW9s DlSQ== 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=xWf1wqBywrzqDn4QoQmjv8h4FPdjfVbADD3ipadMdY0=; b=tYhrTWOZi1LAzVlO32JhockdflVmAT4fAfbnSMKlMeCdld144INCwzbqEx4VpxTq+o SuCPBc/DI83IV/82msRHRFTDmBHoKUr22ayOW8gBtJ4LhOvXB5WyIc5uOligfZrsRC/n TxC503A6n+rkllEuR9H5/hEq3RSZtunx/z8GjD98iLeIPpoJk8YWbD4v4kMaKwB0W21U moTUkSckyyMiHFFxCi+1Zm8khrNOr4eUx/DncAHXBGtg1sx3fTGC6PyFTl/sSjr80eiG KuvTJuErXbQm+4B+ug9xfn0fzEwrfe2LoMX/tRyctl+MyQhCLqo0vlWfoJdR3yORAEGJ Gzww== X-Gm-Message-State: APjAAAXgSH0x68ekQWOpEd0f6tm1vkElnOPcrjfcQYPbJVSoqOlTcOFD ZMUQIekAPp8UJRTQGtLfJpJI/PEV X-Google-Smtp-Source: APXvYqyOM0dv0KNnlpru4O+Ku92Xy82BvYB2ri/rGxGwsQ32yP0CJ/DGZq3sRmE9fDxjNQjCUf4tBQ== X-Received: by 2002:a17:902:830c:: with SMTP id bd12mr89230023plb.237.1563998253455; Wed, 24 Jul 2019 12:57:33 -0700 (PDT) Received: from nebulus.mtv.corp.google.com ([2620:15c:211:200:5404:91ba:59dc:9400]) by smtp.gmail.com with ESMTPSA id f88sm46307394pjg.5.2019.07.24.12.57.32 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 24 Jul 2019 12:57:33 -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 v10 1/5] overlayfs: check CAP_DAC_READ_SEARCH before issuing exportfs_decode_fh Date: Wed, 24 Jul 2019 12:57:12 -0700 Message-Id: <20190724195719.218307-2-salyzyn@android.com> X-Mailer: git-send-email 2.22.0.657.g960e92d24f-goog In-Reply-To: <20190724195719.218307-1-salyzyn@android.com> References: <20190724195719.218307-1-salyzyn@android.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 --- 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, -- 2.22.0.657.g960e92d24f-goog