From bd4f0fe8bb7c73c738e1e11bc90d6e2cf9c6e20e Mon Sep 17 00:00:00 2001 From: Tyler Hicks Date: Wed, 23 Feb 2011 00:14:19 -0600 Subject: [PATCH] eCryptfs: Remove unnecessary grow_file() function When creating a new eCryptfs file, the crypto metadata is written out and then the lower file was being "grown" with 4 kB of encrypted zeroes. I suspect that growing the encrypted file was to prevent an information leak that the unencrypted file was empty. However, the unencrypted file size is stored, in plaintext, in the metadata so growing the file is unnecessary. Signed-off-by: Tyler Hicks --- fs/ecryptfs/crypto.c | 1 + fs/ecryptfs/inode.c | 23 ----------------------- 2 files changed, 1 insertion(+), 23 deletions(-) diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index bfd8b680e648..98a2a314ea68 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -1389,6 +1389,7 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry) rc = -ENOMEM; goto out; } + /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, ecryptfs_dentry); if (unlikely(rc)) { diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index b592938a84bc..8fa365acb789 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -142,26 +142,6 @@ out: return rc; } -/** - * grow_file - * @ecryptfs_dentry: the eCryptfs dentry - * - * This is the code which will grow the file to its correct size. - */ -static int grow_file(struct dentry *ecryptfs_dentry) -{ - struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; - char zero_virt[] = { 0x00 }; - int rc = 0; - - rc = ecryptfs_write(ecryptfs_inode, zero_virt, 0, 1); - i_size_write(ecryptfs_inode, 0); - rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); - ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |= - ECRYPTFS_NEW_FILE; - return rc; -} - /** * ecryptfs_initialize_file * @@ -202,9 +182,6 @@ static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry) printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc); goto out; } - rc = grow_file(ecryptfs_dentry); - if (rc) - printk(KERN_ERR "Error growing file; rc = [%d]\n", rc); out: return rc; }