From: Theodore Ts'o Subject: Re: [PATCH] ext4 crypto: handle ENOKEY correctly Date: Sun, 31 May 2015 11:03:42 -0400 Message-ID: <20150531150342.GB11642@thunk.org> References: <1432917543-26495-1-git-send-email-dmonakhov@openvz.org> <20150529204429.GH18540@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Dmitry Monakhov , G@thunk.org Return-path: Received: from imap.thunk.org ([74.207.234.97]:39295 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758259AbbEaPDr (ORCPT ); Sun, 31 May 2015 11:03:47 -0400 Content-Disposition: inline In-Reply-To: <20150529204429.GH18540@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, May 29, 2015 at 04:44:29PM -0400, Theodore Ts'o wrote: > I don't think that's the right way to go. We should add checks to > ext4_file_open, sure. But the problem is that i_crypt_info can get > set to NULL after the file is succesfully opened. So we need to > handle i_crypt_info being NULL everywhere. So the BUG_ON() in > ext4_get_crypto_ctx() needs to be replaced with: > > if (ci == NULL) > return ERR_PTR(-ENOKEY); This is what I had in mind.... - Ted commit 3cde0c5d3125697c4b02c32054a378dc71ebfdb5 Author: Theodore Ts'o Date: Sun May 31 08:12:34 2015 -0400 ext4 crypto: handle unexpected lack of encryption keys Fix up attempts by users to try to write to a file when they don't have access to the encryption key. Signed-off-by: Theodore Ts'o diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c index ac2419c..6634478 100644 --- a/fs/ext4/crypto.c +++ b/fs/ext4/crypto.c @@ -104,7 +104,8 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode) unsigned long flags; struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info; - BUG_ON(ci == NULL); + if (ci == NULL) + return ERR_PTR(-ENOKEY); /* * We first try getting the ctx from a free list because in diff --git a/fs/ext4/crypto_policy.c b/fs/ext4/crypto_policy.c index a1d434d..02c4e5d 100644 --- a/fs/ext4/crypto_policy.c +++ b/fs/ext4/crypto_policy.c @@ -183,7 +183,8 @@ int ext4_inherit_context(struct inode *parent, struct inode *child) if (res < 0) return res; ci = EXT4_I(parent)->i_crypt_info; - BUG_ON(ci == NULL); + if (ci == NULL) + return -ENOKEY; ctx.format = EXT4_ENCRYPTION_CONTEXT_FORMAT_V1; if (DUMMY_ENCRYPTION_ENABLED(EXT4_SB(parent->i_sb))) { diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 875ca6b..ac517f1 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -226,6 +226,8 @@ static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) int err = ext4_get_encryption_info(inode); if (err) return 0; + if (ext4_encryption_info(inode) == NULL) + return -ENOKEY; } file_accessed(file); if (IS_DAX(file_inode(file))) { @@ -278,6 +280,13 @@ static int ext4_file_open(struct inode * inode, struct file * filp) ext4_journal_stop(handle); } } + if (ext4_encrypted_inode(inode)) { + ret = ext4_get_encryption_info(inode); + if (ret) + return -EACCES; + if (ext4_encryption_info(inode) == NULL) + return -ENOKEY; + } /* * Set up the jbd2_inode if we are opening the inode for * writing and the journal is present @@ -287,13 +296,7 @@ static int ext4_file_open(struct inode * inode, struct file * filp) if (ret < 0) return ret; } - ret = dquot_file_open(inode, filp); - if (!ret && ext4_encrypted_inode(inode)) { - ret = ext4_get_encryption_info(inode); - if (ret) - ret = -EACCES; - } - return ret; + return dquot_file_open(inode, filp); } /*