Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754760Ab2JNPJo (ORCPT ); Sun, 14 Oct 2012 11:09:44 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:46250 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754426Ab2JNOmU (ORCPT ); Sun, 14 Oct 2012 10:42:20 -0400 Message-Id: <20121014143550.246339786@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 14 Oct 2012 15:37:35 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Tyler Hicks , John Johansen , Colin Ian King Subject: [ 122/147] eCryptfs: Initialize empty lower files when opening them In-Reply-To: <20121014143533.742627615@decadent.org.uk> X-SA-Exim-Connect-IP: 77.75.106.1 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5883 Lines: 167 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tyler Hicks commit e3ccaa9761200952cc269b1f4b7d7bb77a5e071b upstream. Historically, eCryptfs has only initialized lower files in the ecryptfs_create() path. Lower file initialization is the act of writing the cryptographic metadata from the inode's crypt_stat to the header of the file. The ecryptfs_open() path already expects that metadata to be in the header of the file. A number of users have reported empty lower files in beneath their eCryptfs mounts. Most of the causes for those empty files being left around have been addressed, but the presence of empty files causes problems due to the lack of proper cryptographic metadata. To transparently solve this problem, this patch initializes empty lower files in the ecryptfs_open() error path. If the metadata is unreadable due to the lower inode size being 0, plaintext passthrough support is not in use, and the metadata is stored in the header of the file (as opposed to the user.ecryptfs extended attribute), the lower file will be initialized. The number of nested conditionals in ecryptfs_open() was getting out of hand, so a helper function was created. To avoid the same nested conditional problem, the conditional logic was reversed inside of the helper function. https://launchpad.net/bugs/911507 Signed-off-by: Tyler Hicks Cc: John Johansen Cc: Colin Ian King Signed-off-by: Ben Hutchings --- fs/ecryptfs/ecryptfs_kernel.h | 2 ++ fs/ecryptfs/file.c | 71 ++++++++++++++++++++++++++--------------- fs/ecryptfs/inode.c | 4 +-- 3 files changed, 49 insertions(+), 28 deletions(-) diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index 0deb4f2..9f77ff8 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -563,6 +563,8 @@ struct ecryptfs_open_req { struct inode *ecryptfs_get_inode(struct inode *lower_inode, struct super_block *sb); void ecryptfs_i_size_init(const char *page_virt, struct inode *inode); +int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry, + struct inode *ecryptfs_inode); int ecryptfs_decode_and_decrypt_filename(char **decrypted_name, size_t *decrypted_name_size, struct dentry *ecryptfs_dentry, diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index 2b17f2f..baf8b05 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -161,6 +161,48 @@ static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma) struct kmem_cache *ecryptfs_file_info_cache; +static int read_or_initialize_metadata(struct dentry *dentry) +{ + struct inode *inode = dentry->d_inode; + struct ecryptfs_mount_crypt_stat *mount_crypt_stat; + struct ecryptfs_crypt_stat *crypt_stat; + int rc; + + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + mount_crypt_stat = &ecryptfs_superblock_to_private( + inode->i_sb)->mount_crypt_stat; + mutex_lock(&crypt_stat->cs_mutex); + + if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED && + crypt_stat->flags & ECRYPTFS_KEY_VALID) { + rc = 0; + goto out; + } + + rc = ecryptfs_read_metadata(dentry); + if (!rc) + goto out; + + if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) { + crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED + | ECRYPTFS_ENCRYPTED); + rc = 0; + goto out; + } + + if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) && + !i_size_read(ecryptfs_inode_to_lower(inode))) { + rc = ecryptfs_initialize_file(dentry, inode); + if (!rc) + goto out; + } + + rc = -EIO; +out: + mutex_unlock(&crypt_stat->cs_mutex); + return rc; +} + /** * ecryptfs_open * @inode: inode speciying file to open @@ -236,32 +278,9 @@ static int ecryptfs_open(struct inode *inode, struct file *file) rc = 0; goto out; } - mutex_lock(&crypt_stat->cs_mutex); - if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) - || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { - rc = ecryptfs_read_metadata(ecryptfs_dentry); - if (rc) { - ecryptfs_printk(KERN_DEBUG, - "Valid headers not found\n"); - if (!(mount_crypt_stat->flags - & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { - rc = -EIO; - printk(KERN_WARNING "Either the lower file " - "is not in a valid eCryptfs format, " - "or the key could not be retrieved. " - "Plaintext passthrough mode is not " - "enabled; returning -EIO\n"); - mutex_unlock(&crypt_stat->cs_mutex); - goto out_put; - } - rc = 0; - crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED - | ECRYPTFS_ENCRYPTED); - mutex_unlock(&crypt_stat->cs_mutex); - goto out; - } - } - mutex_unlock(&crypt_stat->cs_mutex); + rc = read_or_initialize_metadata(ecryptfs_dentry); + if (rc) + goto out_put; ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = " "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino, (unsigned long long)i_size_read(inode)); diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 65efe5f..2d4143f 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -227,8 +227,8 @@ out: * * Returns zero on success */ -static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry, - struct inode *ecryptfs_inode) +int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry, + struct inode *ecryptfs_inode) { struct ecryptfs_crypt_stat *crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/