From 8bc2d3cf612994a960c2e8eaea37f6676f67082a Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 22 May 2012 15:09:50 -0500 Subject: eCryptfs: Unlink lower inode when ecryptfs_create() fails ecryptfs_create() creates a lower inode, allocates an eCryptfs inode, initializes the eCryptfs inode and cryptographic metadata attached to the inode, and then writes the metadata to the header of the file. If an error was to occur after the lower inode was created, an empty lower file would be left in the lower filesystem. This is a problem because ecryptfs_open() refuses to open any lower files which do not have the appropriate metadata in the file header. This patch properly unlinks the lower inode when an error occurs in the later stages of ecryptfs_create(), reducing the chance that an empty lower file will be left in the lower filesystem. https://launchpad.net/bugs/872905 Signed-off-by: Tyler Hicks Cc: John Johansen Cc: Colin Ian King --- fs/ecryptfs/inode.c | 55 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 32 insertions(+), 23 deletions(-) (limited to 'fs/ecryptfs/inode.c') diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index a07441a..65efe5f 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -143,6 +143,31 @@ static int ecryptfs_interpose(struct dentry *lower_dentry, return 0; } +static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry, + struct inode *inode) +{ + struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); + struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); + struct dentry *lower_dir_dentry; + int rc; + + dget(lower_dentry); + lower_dir_dentry = lock_parent(lower_dentry); + rc = vfs_unlink(lower_dir_inode, lower_dentry); + if (rc) { + printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); + goto out_unlock; + } + fsstack_copy_attr_times(dir, lower_dir_inode); + set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink); + inode->i_ctime = dir->i_ctime; + d_drop(dentry); +out_unlock: + unlock_dir(lower_dir_dentry); + dput(lower_dentry); + return rc; +} + /** * ecryptfs_do_create * @directory_inode: inode of the new file's dentry's parent in ecryptfs @@ -182,8 +207,10 @@ ecryptfs_do_create(struct inode *directory_inode, } inode = __ecryptfs_get_inode(lower_dentry->d_inode, directory_inode->i_sb); - if (IS_ERR(inode)) + if (IS_ERR(inode)) { + vfs_unlink(lower_dir_dentry->d_inode, lower_dentry); goto out_lock; + } fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode); fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode); out_lock: @@ -265,7 +292,9 @@ ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry, * that this on disk file is prepared to be an ecryptfs file */ rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode); if (rc) { - drop_nlink(ecryptfs_inode); + ecryptfs_do_unlink(directory_inode, ecryptfs_dentry, + ecryptfs_inode); + make_bad_inode(ecryptfs_inode); unlock_new_inode(ecryptfs_inode); iput(ecryptfs_inode); goto out; @@ -477,27 +506,7 @@ out_lock: static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry) { - int rc = 0; - struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); - struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir); - struct dentry *lower_dir_dentry; - - dget(lower_dentry); - lower_dir_dentry = lock_parent(lower_dentry); - rc = vfs_unlink(lower_dir_inode, lower_dentry); - if (rc) { - printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc); - goto out_unlock; - } - fsstack_copy_attr_times(dir, lower_dir_inode); - set_nlink(dentry->d_inode, - ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink); - dentry->d_inode->i_ctime = dir->i_ctime; - d_drop(dentry); -out_unlock: - unlock_dir(lower_dir_dentry); - dput(lower_dentry); - return rc; + return ecryptfs_do_unlink(dir, dentry, dentry->d_inode); } static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry, -- cgit v1.1 From e3ccaa9761200952cc269b1f4b7d7bb77a5e071b Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Wed, 20 Jun 2012 23:50:59 -0700 Subject: eCryptfs: Initialize empty lower files when opening them 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 --- fs/ecryptfs/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ecryptfs/inode.c') 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; -- cgit v1.1 From 821f7494a77627fb1ab539591c57b22cdca702d6 Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Tue, 3 Jul 2012 16:50:57 -0700 Subject: eCryptfs: Revert to a writethrough cache model A change was made about a year ago to get eCryptfs to better utilize its page cache during writes. The idea was to do the page encryption operations during page writeback, rather than doing them when initially writing into the page cache, to reduce the number of page encryption operations during sequential writes. This meant that the encrypted page would only be written to the lower filesystem during page writeback, which was a change from how eCryptfs had previously wrote to the lower filesystem in ecryptfs_write_end(). The change caused a few eCryptfs-internal bugs that were shook out. Unfortunately, more grave side effects have been identified that will force changes outside of eCryptfs. Because the lower filesystem isn't consulted until page writeback, eCryptfs has no way to pass lower write errors (ENOSPC, mainly) back to userspace. Additionaly, it was reported that quotas could be bypassed because of the way eCryptfs may sometimes open the lower filesystem using a privileged kthread. It would be nice to resolve the latest issues, but it is best if the eCryptfs commits be reverted to the old behavior in the meantime. This reverts: 32001d6f "eCryptfs: Flush file in vma close" 5be79de2 "eCryptfs: Flush dirty pages in setattr" 57db4e8d "ecryptfs: modify write path to encrypt page in writepage" Signed-off-by: Tyler Hicks Tested-by: Colin King Cc: Colin King Cc: Thieu Le --- fs/ecryptfs/inode.c | 6 ------ 1 file changed, 6 deletions(-) (limited to 'fs/ecryptfs/inode.c') diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 2d4143f..769fb85 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -981,12 +981,6 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) goto out; } - if (S_ISREG(inode->i_mode)) { - rc = filemap_write_and_wait(inode->i_mapping); - if (rc) - goto out; - fsstack_copy_attr_all(inode, lower_inode); - } memcpy(&lower_ia, ia, sizeof(lower_ia)); if (ia->ia_valid & ATTR_FILE) lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file); -- cgit v1.1