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eCryptfs: Unlink lower inode when ecryptfs_create() fails

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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 <tyhicks@canonical.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Colin Ian King <colin.king@canonical.com>
This commit is contained in:
Tyler Hicks 2012-05-22 15:09:50 -05:00
parent 2ecaf55db6
commit 8bc2d3cf61
1 changed files with 32 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
fs/ecryptfs/inode.c
View File

@ -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,