From patchwork Tue Mar 2 20:04:19 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 392606 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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 E1C30C4646F for ; Wed, 3 Mar 2021 01:02:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ACD5964FA0 for ; Wed, 3 Mar 2021 01:02:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343929AbhCCAx4 (ORCPT ); Tue, 2 Mar 2021 19:53:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:57768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350532AbhCBUGA (ORCPT ); Tue, 2 Mar 2021 15:06:00 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3CF6164F21; Tue, 2 Mar 2021 20:05:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614715504; bh=PsxMo4HzObRVzmAihudWFkfU25b1OePLRuCHAZt3lws=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gFYkSokSkZIrOsAhufSj4OgDGiZzR1QFqw6ap7Q8lsdWmzsGRrm8FoKp4gA60lJcp mPW8rZYuJQlmL7QpSElzGmJ5ikWWo6rNVZvfm0eFqML5xylkOrq4XWgt0/zxFZM2/M v1GR4H0YUyQb7pBds78dOcYpSyi9ffAnm2Wjv75UUIpTN74QHFX06e34cvRhC+JJEo q8v/BnsoP+QZdjN9ZZiNAxnc1a5LIaaWYyEwtCsGBju9Bnlx/s/5MY6nzMrtpfqqrR bV7j415NAb9Jq/xdjU/nSBcAxBT0enq51G2Hv3tb68MnP4TxLAX8IVg86vMwT9Rs5M 4B/dWwkV/klVw== From: Eric Biggers To: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: linux-fscrypt@vger.kernel.org, Yunlei He , bintian.wang@hihonor.com, stable@vger.kernel.org Subject: [PATCH 1/2] ext4: fix error handling in ext4_end_enable_verity() Date: Tue, 2 Mar 2021 12:04:19 -0800 Message-Id: <20210302200420.137977-2-ebiggers@kernel.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210302200420.137977-1-ebiggers@kernel.org> References: <20210302200420.137977-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Biggers ext4 didn't properly clean up if verity failed to be enabled on a file: - It left verity metadata (pages past EOF) in the page cache, which would be exposed to userspace if the file was later extended. - It didn't truncate the verity metadata at all (either from cache or from disk) if an error occurred while setting the verity bit. Fix these bugs by adding a call to truncate_inode_pages() and ensuring that we truncate the verity metadata (both from cache and from disk) in all error paths. Also rework the code to cleanly separate the success path from the error paths, which makes it much easier to understand. Reported-by: Yunlei He Fixes: c93d8f885809 ("ext4: add basic fs-verity support") Cc: # v5.4+ Signed-off-by: Eric Biggers --- fs/ext4/verity.c | 90 ++++++++++++++++++++++++++++++------------------ 1 file changed, 56 insertions(+), 34 deletions(-) diff --git a/fs/ext4/verity.c b/fs/ext4/verity.c index 5b7ba8f711538..acb12441c549b 100644 --- a/fs/ext4/verity.c +++ b/fs/ext4/verity.c @@ -201,55 +201,77 @@ static int ext4_end_enable_verity(struct file *filp, const void *desc, struct inode *inode = file_inode(filp); const int credits = 2; /* superblock and inode for ext4_orphan_del() */ handle_t *handle; + struct ext4_iloc iloc; int err = 0; - int err2; - if (desc != NULL) { - /* Succeeded; write the verity descriptor. */ - err = ext4_write_verity_descriptor(inode, desc, desc_size, - merkle_tree_size); - - /* Write all pages before clearing VERITY_IN_PROGRESS. */ - if (!err) - err = filemap_write_and_wait(inode->i_mapping); - } + /* + * If an error already occurred (which fs/verity/ signals by passing + * desc == NULL), then only clean-up is needed. + */ + if (desc == NULL) + goto cleanup; - /* If we failed, truncate anything we wrote past i_size. */ - if (desc == NULL || err) - ext4_truncate(inode); + /* Append the verity descriptor. */ + err = ext4_write_verity_descriptor(inode, desc, desc_size, + merkle_tree_size); + if (err) + goto cleanup; /* - * We must always clean up by clearing EXT4_STATE_VERITY_IN_PROGRESS and - * deleting the inode from the orphan list, even if something failed. - * If everything succeeded, we'll also set the verity bit in the same - * transaction. + * Write all pages (both data and verity metadata). Note that this must + * happen before clearing EXT4_STATE_VERITY_IN_PROGRESS; otherwise pages + * beyond i_size won't be written properly. For crash consistency, this + * also must happen before the verity inode flag gets persisted. */ + err = filemap_write_and_wait(inode->i_mapping); + if (err) + goto cleanup; - ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); + /* + * Finally, set the verity inode flag and remove the inode from the + * orphan list (in a single transaction). + */ handle = ext4_journal_start(inode, EXT4_HT_INODE, credits); if (IS_ERR(handle)) { - ext4_orphan_del(NULL, inode); - return PTR_ERR(handle); + err = PTR_ERR(handle); + goto cleanup; } - err2 = ext4_orphan_del(handle, inode); - if (err2) - goto out_stop; + err = ext4_orphan_del(handle, inode); + if (err) + goto stop_and_cleanup; - if (desc != NULL && !err) { - struct ext4_iloc iloc; + err = ext4_reserve_inode_write(handle, inode, &iloc); + if (err) + goto stop_and_cleanup; + + ext4_set_inode_flag(inode, EXT4_INODE_VERITY); + ext4_set_inode_flags(inode, false); + err = ext4_mark_iloc_dirty(handle, inode, &iloc); + if (err) + goto stop_and_cleanup; - err = ext4_reserve_inode_write(handle, inode, &iloc); - if (err) - goto out_stop; - ext4_set_inode_flag(inode, EXT4_INODE_VERITY); - ext4_set_inode_flags(inode, false); - err = ext4_mark_iloc_dirty(handle, inode, &iloc); - } -out_stop: ext4_journal_stop(handle); - return err ?: err2; + + ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); + return 0; + + +stop_and_cleanup: + ext4_journal_stop(handle); +cleanup: + /* + * Verity failed to be enabled, so clean up by truncating any verity + * metadata that was written beyond i_size (both from cache and from + * disk), removing the inode from the orphan list (if it wasn't done + * already), and clearing EXT4_STATE_VERITY_IN_PROGRESS. + */ + truncate_inode_pages(inode->i_mapping, inode->i_size); + ext4_truncate(inode); + ext4_orphan_del(NULL, inode); + ext4_clear_inode_state(inode, EXT4_STATE_VERITY_IN_PROGRESS); + return err; } static int ext4_get_verity_descriptor_location(struct inode *inode,