ecryptfs: initialize private persistent file before dereferencing pointer

commit e27759d7a3 upstream.

Ecryptfs_open dereferences a pointer to the private lower file (the one
stored in the ecryptfs inode), without checking if the pointer is NULL.
Right afterward, it initializes that pointer if it is NULL.  Swap order of
statements to first initialize.  Bug discovered by Duckjin Kang.

Signed-off-by: Duckjin Kang <fromdj2k@gmail.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Erez Zadok
2009-12-03 13:35:27 -05:00
committed by Greg Kroah-Hartman
parent 3621216258
commit 8c53542618

View File

@@ -191,13 +191,6 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
| ECRYPTFS_ENCRYPTED);
}
mutex_unlock(&crypt_stat->cs_mutex);
if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
&& !(file->f_flags & O_RDONLY)) {
rc = -EPERM;
printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
"file must hence be opened RO\n", __func__);
goto out;
}
if (!ecryptfs_inode_to_private(inode)->lower_file) {
rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
if (rc) {
@@ -208,6 +201,13 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
goto out;
}
}
if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
&& !(file->f_flags & O_RDONLY)) {
rc = -EPERM;
printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
"file must hence be opened RO\n", __func__);
goto out;
}
ecryptfs_set_file_lower(
file, ecryptfs_inode_to_private(inode)->lower_file);
if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {