eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()
ecryptfs_lookup_interpose() has turned into spaghetti code over the
years. This is an effort to clean it up.
- Shorten overly descriptive variable names such as ecryptfs_dentry
- Simplify gotos and error paths
- Create helper function for reading plaintext i_size from metadata
It also includes an optimization when reading i_size from the metadata.
A complete page-sized kmem_cache_alloc() was being done to read in 16
bytes of metadata. The buffer for that is now statically declared.
Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 162f9ba..66d8e67 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1201,24 +1201,19 @@
return rc;
}
-int ecryptfs_read_and_validate_header_region(char *data,
- struct inode *ecryptfs_inode)
+int ecryptfs_read_and_validate_header_region(struct inode *inode)
{
- struct ecryptfs_crypt_stat *crypt_stat =
- &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
+ u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+ u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
int rc;
- if (crypt_stat->extent_size == 0)
- crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
- rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
- ecryptfs_inode);
- if (rc < 0) {
- printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
- __func__, rc);
- goto out;
- }
- rc = ecryptfs_validate_marker(data + ECRYPTFS_FILE_SIZE_BYTES);
-out:
+ rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
+ inode);
+ if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+ return rc >= 0 ? -EINVAL : rc;
+ rc = ecryptfs_validate_marker(marker);
+ if (!rc)
+ ecryptfs_i_size_init(file_size, inode);
return rc;
}
@@ -1562,19 +1557,21 @@
return rc;
}
-int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
struct inode *inode)
{
+ u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+ u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
int rc;
- rc = ecryptfs_read_xattr_region(page_virt, inode);
- if (rc)
- goto out;
- rc = ecryptfs_validate_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES);
- if (rc)
- printk(KERN_WARNING "Valid data found in [%s] xattr, but "
- "the marker is invalid\n", ECRYPTFS_XATTR_NAME);
-out:
+ rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
+ ECRYPTFS_XATTR_NAME, file_size,
+ ECRYPTFS_SIZE_AND_MARKER_BYTES);
+ if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+ return rc >= 0 ? -EINVAL : rc;
+ rc = ecryptfs_validate_marker(marker);
+ if (!rc)
+ ecryptfs_i_size_init(file_size, inode);
return rc;
}
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 72aa24a..8297dda 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -200,6 +200,8 @@
#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8 /* 4*2 */
#define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64))
+#define ECRYPTFS_SIZE_AND_MARKER_BYTES (ECRYPTFS_FILE_SIZE_BYTES \
+ + MAGIC_ECRYPTFS_MARKER_SIZE_BYTES)
#define ECRYPTFS_DEFAULT_CIPHER "aes"
#define ECRYPTFS_DEFAULT_KEY_BYTES 16
#define ECRYPTFS_DEFAULT_HASH "md5"
@@ -659,9 +661,8 @@
void ecryptfs_write_crypt_stat_flags(char *page_virt,
struct ecryptfs_crypt_stat *crypt_stat,
size_t *written);
-int ecryptfs_read_and_validate_header_region(char *data,
- struct inode *ecryptfs_inode);
-int ecryptfs_read_and_validate_xattr_region(char *page_virt,
+int ecryptfs_read_and_validate_header_region(struct inode *inode);
+int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
struct inode *inode);
u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes);
int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code);
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index f0ad965..7349ade 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -307,105 +307,90 @@
return rc;
}
-/**
- * ecryptfs_lookup_interpose - Dentry interposition for a lookup
- */
-static int ecryptfs_lookup_interpose(struct dentry *ecryptfs_dentry,
- struct dentry *lower_dentry,
- struct inode *ecryptfs_dir_inode)
+static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
{
- struct dentry *lower_dir_dentry;
- struct vfsmount *lower_mnt;
- struct inode *inode, *lower_inode;
struct ecryptfs_crypt_stat *crypt_stat;
- char *page_virt = NULL;
- int put_lower = 0, rc = 0;
+ int rc;
- lower_dir_dentry = lower_dentry->d_parent;
- lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
- ecryptfs_dentry->d_parent));
- lower_inode = lower_dentry->d_inode;
- fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
- BUG_ON(!lower_dentry->d_count);
- ecryptfs_set_dentry_private(ecryptfs_dentry,
- kmem_cache_alloc(ecryptfs_dentry_info_cache,
- GFP_KERNEL));
- if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
- rc = -ENOMEM;
- printk(KERN_ERR "%s: Out of memory whilst attempting "
- "to allocate ecryptfs_dentry_info struct\n",
- __func__);
- goto out_put;
- }
- ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
- ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
- if (!lower_dentry->d_inode) {
- /* We want to add because we couldn't find in lower */
- d_add(ecryptfs_dentry, NULL);
- goto out;
- }
- inode = __ecryptfs_get_inode(lower_inode, ecryptfs_dir_inode->i_sb);
- if (IS_ERR(inode)) {
- rc = PTR_ERR(inode);
- printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
- __func__, rc);
- goto out;
- }
- if (!S_ISREG(inode->i_mode)) {
- if (inode->i_state & I_NEW)
- unlock_new_inode(inode);
- d_add(ecryptfs_dentry, inode);
- goto out;
- }
- /* Released in this function */
- page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
- if (!page_virt) {
- printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
- __func__);
- rc = -ENOMEM;
- make_bad_inode(inode);
- goto out;
- }
- rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
+ rc = ecryptfs_get_lower_file(dentry, inode);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the lower file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
- ecryptfs_dentry->d_name.name, rc);
- make_bad_inode(inode);
- goto out_free_kmem;
+ dentry->d_name.name, rc);
+ return rc;
}
- put_lower = 1;
+
crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
/* TODO: lock for crypt_stat comparison */
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
- ecryptfs_set_default_sizes(crypt_stat);
- rc = ecryptfs_read_and_validate_header_region(page_virt, inode);
+ ecryptfs_set_default_sizes(crypt_stat);
+
+ rc = ecryptfs_read_and_validate_header_region(inode);
+ ecryptfs_put_lower_file(inode);
if (rc) {
- memset(page_virt, 0, PAGE_CACHE_SIZE);
- rc = ecryptfs_read_and_validate_xattr_region(page_virt,
- inode);
- if (rc) {
- rc = 0;
- goto unlock_inode;
- }
- crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+ rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
+ if (!rc)
+ crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
- ecryptfs_i_size_init(page_virt, inode);
-unlock_inode:
+
+ /* Must return 0 to allow non-eCryptfs files to be looked up, too */
+ return 0;
+}
+
+/**
+ * ecryptfs_lookup_interpose - Dentry interposition for a lookup
+ */
+static int ecryptfs_lookup_interpose(struct dentry *dentry,
+ struct dentry *lower_dentry,
+ struct inode *dir_inode)
+{
+ struct inode *inode, *lower_inode = lower_dentry->d_inode;
+ struct ecryptfs_dentry_info *dentry_info;
+ struct vfsmount *lower_mnt;
+ int rc = 0;
+
+ lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
+ fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
+ BUG_ON(!lower_dentry->d_count);
+
+ dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
+ ecryptfs_set_dentry_private(dentry, dentry_info);
+ if (!dentry_info) {
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to allocate ecryptfs_dentry_info struct\n",
+ __func__);
+ dput(lower_dentry);
+ mntput(lower_mnt);
+ d_drop(dentry);
+ return -ENOMEM;
+ }
+ ecryptfs_set_dentry_lower(dentry, lower_dentry);
+ ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
+
+ if (!lower_dentry->d_inode) {
+ /* We want to add because we couldn't find in lower */
+ d_add(dentry, NULL);
+ return 0;
+ }
+ inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
+ if (IS_ERR(inode)) {
+ printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
+ __func__, PTR_ERR(inode));
+ return PTR_ERR(inode);
+ }
+ if (S_ISREG(inode->i_mode)) {
+ rc = ecryptfs_i_size_read(dentry, inode);
+ if (rc) {
+ make_bad_inode(inode);
+ return rc;
+ }
+ }
+
if (inode->i_state & I_NEW)
unlock_new_inode(inode);
- d_add(ecryptfs_dentry, inode);
-out_free_kmem:
- kmem_cache_free(ecryptfs_header_cache_2, page_virt);
- goto out;
-out_put:
- dput(lower_dentry);
- mntput(lower_mnt);
- d_drop(ecryptfs_dentry);
-out:
- if (put_lower)
- ecryptfs_put_lower_file(inode);
+ d_add(dentry, inode);
+
return rc;
}