[PATCH 6/11] eCryptfs: Update metadata read/write functions

From: Michael Halcrow
Date: Mon Sep 17 2007 - 17:53:45 EST

Update the metadata read/write functions and grow_file() to use the
read_write.c routines. Do not open another lower file; use the
persistent lower file instead. Provide a separate function for
crypto.c::ecryptfs_read_xattr_region() to get to the lower xattr
without having to go through the eCryptfs getxattr.

Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
---
fs/ecryptfs/crypto.c | 126 +++++++++++++++++++----------------------
fs/ecryptfs/ecryptfs_kernel.h | 15 +++--
fs/ecryptfs/file.c | 2 +-
fs/ecryptfs/inode.c | 101 +++++++++++++++------------------
fs/ecryptfs/mmap.c | 2 +-
5 files changed, 113 insertions(+), 133 deletions(-)

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index d6a0680..6b4d310 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1344,21 +1344,28 @@ out:
return rc;
}

-int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
- struct vfsmount *mnt)
+int ecryptfs_read_and_validate_header_region(char *data,
+ struct inode *ecryptfs_inode)
{
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
int rc;

- rc = ecryptfs_read_header_region(data, dentry, mnt);
- if (rc)
+ rc = ecryptfs_read_lower(data, 0, crypt_stat->extent_size,
+ ecryptfs_inode);
+ if (rc) {
+ printk(KERN_ERR "%s: Error reading header region; rc = [%d]\n",
+ __FUNCTION__, rc);
goto out;
- if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES))
+ }
+ if (!contains_ecryptfs_marker(data + ECRYPTFS_FILE_SIZE_BYTES)) {
rc = -EINVAL;
+ ecryptfs_printk(KERN_DEBUG, "Valid marker not found\n");
+ }
out:
return rc;
}

-
void
ecryptfs_write_header_metadata(char *virt,
struct ecryptfs_crypt_stat *crypt_stat,
@@ -1443,24 +1450,18 @@ static int ecryptfs_write_headers_virt(char *page_virt, size_t *size,

static int
ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
- struct file *lower_file, char *page_virt)
+ struct dentry *ecryptfs_dentry,
+ char *page_virt)
{
- mm_segment_t oldfs;
int current_header_page;
int header_pages;
- ssize_t size;
- int rc = 0;
+ int rc;

- lower_file->f_pos = 0;
- oldfs = get_fs();
- set_fs(get_ds());
- size = vfs_write(lower_file, (char __user *)page_virt, PAGE_CACHE_SIZE,
- &lower_file->f_pos);
- if (size < 0) {
- rc = (int)size;
- printk(KERN_ERR "Error attempting to write lower page; "
- "rc = [%d]\n", rc);
- set_fs(oldfs);
+ if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, page_virt,
+ 0, PAGE_CACHE_SIZE))) {
+ printk(KERN_ERR "%s: Error attempting to write header "
+ "information to lower file; rc = [%d]\n", __FUNCTION__,
+ rc);
goto out;
}
header_pages = ((crypt_stat->extent_size
@@ -1469,18 +1470,19 @@ ecryptfs_write_metadata_to_contents(struct ecryptfs_crypt_stat *crypt_stat,
memset(page_virt, 0, PAGE_CACHE_SIZE);
current_header_page = 1;
while (current_header_page < header_pages) {
- size = vfs_write(lower_file, (char __user *)page_virt,
- PAGE_CACHE_SIZE, &lower_file->f_pos);
- if (size < 0) {
- rc = (int)size;
- printk(KERN_ERR "Error attempting to write lower page; "
- "rc = [%d]\n", rc);
- set_fs(oldfs);
+ loff_t offset;
+
+ offset = (current_header_page << PAGE_CACHE_SHIFT);
+ if ((rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode,
+ page_virt, offset,
+ PAGE_CACHE_SIZE))) {
+ printk(KERN_ERR "%s: Error attempting to write header "
+ "information to lower file; rc = [%d]\n",
+ __FUNCTION__, rc);
goto out;
}
current_header_page++;
}
- set_fs(oldfs);
out:
return rc;
}
@@ -1500,7 +1502,6 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
/**
* ecryptfs_write_metadata
* @ecryptfs_dentry: The eCryptfs dentry
- * @lower_file: The lower file struct, which was returned from dentry_open
*
* Write the file headers out. This will likely involve a userspace
* callout, in which the session key is encrypted with one or more
@@ -1508,22 +1509,21 @@ ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
* retrieved via a prompt. Exactly what happens at this point should
* be policy-dependent.
*
+ * TODO: Support header information spanning multiple pages
+ *
* Returns zero on success; non-zero on error
*/
-int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
- struct file *lower_file)
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
{
- struct ecryptfs_crypt_stat *crypt_stat;
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
char *page_virt;
- size_t size;
+ size_t size = 0;
int rc = 0;

- crypt_stat = &ecryptfs_inode_to_private(
- ecryptfs_dentry->d_inode)->crypt_stat;
if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
- ecryptfs_printk(KERN_DEBUG, "Key is "
- "invalid; bailing out\n");
+ printk(KERN_ERR "Key is invalid; bailing out\n");
rc = -EINVAL;
goto out;
}
@@ -1552,7 +1552,8 @@ int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
crypt_stat, page_virt,
size);
else
- rc = ecryptfs_write_metadata_to_contents(crypt_stat, lower_file,
+ rc = ecryptfs_write_metadata_to_contents(crypt_stat,
+ ecryptfs_dentry,
page_virt);
if (rc) {
printk(KERN_ERR "Error writing metadata out to lower file; "
@@ -1680,15 +1681,17 @@ out:
*
* Returns zero on success; non-zero on error
*/
-int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry)
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
{
+ struct dentry *lower_dentry =
+ ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
ssize_t size;
int rc = 0;

- size = ecryptfs_getxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME,
- page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+ size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
+ page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
if (size < 0) {
- printk(KERN_DEBUG "Error attempting to read the [%s] "
+ printk(KERN_ERR "Error attempting to read the [%s] "
"xattr from the lower file; return value = [%zd]\n",
ECRYPTFS_XATTR_NAME, size);
rc = -EINVAL;
@@ -1703,7 +1706,7 @@ int ecryptfs_read_and_validate_xattr_region(char *page_virt,
{
int rc;

- rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry);
+ rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_dentry->d_inode);
if (rc)
goto out;
if (!contains_ecryptfs_marker(page_virt + ECRYPTFS_FILE_SIZE_BYTES)) {
@@ -1717,8 +1720,6 @@ out:

/**
* ecryptfs_read_metadata
- * @ecryptfs_dentry: The eCryptfs dentry
- * @lower_file: The lower file from which to read the metadata
*
* Common entry point for reading file metadata. From here, we could
* retrieve the header information from the header region of the file,
@@ -1729,15 +1730,13 @@ out:
*
* Returns zero if valid headers found and parsed; non-zero otherwise
*/
-int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
- struct file *lower_file)
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
{
int rc = 0;
char *page_virt = NULL;
- mm_segment_t oldfs;
- ssize_t bytes_read;
+ struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
struct ecryptfs_crypt_stat *crypt_stat =
- &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
+ &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
&ecryptfs_superblock_to_private(
ecryptfs_dentry->d_sb)->mount_crypt_stat;
@@ -1748,27 +1747,18 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER);
if (!page_virt) {
rc = -ENOMEM;
- ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n");
+ printk(KERN_ERR "%s: Unable to allocate page_virt\n",
+ __FUNCTION__);
goto out;
}
- lower_file->f_pos = 0;
- oldfs = get_fs();
- set_fs(get_ds());
- bytes_read = lower_file->f_op->read(lower_file,
- (char __user *)page_virt,
- ECRYPTFS_DEFAULT_EXTENT_SIZE,
- &lower_file->f_pos);
- set_fs(oldfs);
- if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) {
- rc = -EINVAL;
- goto out;
- }
- rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
- ecryptfs_dentry,
- ECRYPTFS_VALIDATE_HEADER_SIZE);
+ rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
+ ecryptfs_inode);
+ if (!rc)
+ rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+ ecryptfs_dentry,
+ ECRYPTFS_VALIDATE_HEADER_SIZE);
if (rc) {
- rc = ecryptfs_read_xattr_region(page_virt,
- ecryptfs_dentry);
+ rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
if (rc) {
printk(KERN_DEBUG "Valid eCryptfs headers not found in "
"file header region or xattr region\n");
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
index 65f7ddf..3e52b42 100644
--- a/fs/ecryptfs/ecryptfs_kernel.h
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -570,13 +570,11 @@ int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
struct writeback_control *wbc);
int ecryptfs_encrypt_page(struct page *page);
int ecryptfs_decrypt_page(struct page *page);
-int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
- struct file *lower_file);
-int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry,
- struct file *lower_file);
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry);
-int ecryptfs_read_and_validate_header_region(char *data, struct dentry *dentry,
- struct vfsmount *mnt);
+int ecryptfs_read_and_validate_header_region(char *data,
+ struct inode *ecryptfs_inode);
int ecryptfs_read_and_validate_xattr_region(char *page_virt,
struct dentry *ecryptfs_dentry);
u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat);
@@ -599,10 +597,13 @@ int ecryptfs_open_lower_file(struct file **lower_file,
int ecryptfs_close_lower_file(struct file *lower_file);
ssize_t ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
size_t size);
+ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
+ void *value, size_t size);
int
ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags);
-int ecryptfs_read_xattr_region(char *page_virt, struct dentry *ecryptfs_dentry);
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
int ecryptfs_process_helo(unsigned int transport, uid_t uid, pid_t pid);
int ecryptfs_process_quit(uid_t uid, pid_t pid);
int ecryptfs_process_response(struct ecryptfs_message *msg, uid_t uid,
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 59c846d..df70bfa 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -248,7 +248,7 @@ static int ecryptfs_open(struct inode *inode, struct file *file)
mutex_lock(&crypt_stat->cs_mutex);
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
|| !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
- rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file);
+ rc = ecryptfs_read_metadata(ecryptfs_dentry);
if (rc) {
ecryptfs_printk(KERN_DEBUG,
"Valid headers not found\n");
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index c746b5d..a29dc31 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -153,37 +153,30 @@ out:

/**
* grow_file
- * @ecryptfs_dentry: the ecryptfs dentry
- * @lower_file: The lower file
- * @inode: The ecryptfs inode
- * @lower_inode: The lower inode
+ * @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 file *lower_file,
- struct inode *inode, struct inode *lower_inode)
+static int grow_file(struct dentry *ecryptfs_dentry)
{
- int rc = 0;
+ struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
struct file fake_file;
struct ecryptfs_file_info tmp_file_info;
+ char zero_virt[] = { 0x00 };
+ int rc = 0;

memset(&fake_file, 0, sizeof(fake_file));
fake_file.f_path.dentry = ecryptfs_dentry;
memset(&tmp_file_info, 0, sizeof(tmp_file_info));
ecryptfs_set_file_private(&fake_file, &tmp_file_info);
- ecryptfs_set_file_lower(&fake_file, lower_file);
- rc = ecryptfs_fill_zeros(&fake_file, 1);
- if (rc) {
- ecryptfs_inode_to_private(inode)->crypt_stat.flags |=
- ECRYPTFS_SECURITY_WARNING;
- ecryptfs_printk(KERN_WARNING, "Error attempting to fill zeros "
- "in file; rc = [%d]\n", rc);
- goto out;
- }
- i_size_write(inode, 0);
- rc = ecryptfs_write_inode_size_to_metadata(inode);
- ecryptfs_inode_to_private(inode)->crypt_stat.flags |= ECRYPTFS_NEW_FILE;
-out:
+ ecryptfs_set_file_lower(
+ &fake_file,
+ ecryptfs_inode_to_private(ecryptfs_inode)->lower_file);
+ rc = ecryptfs_write(&fake_file, 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;
}

@@ -197,53 +190,31 @@ out:
*/
static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
{
+ struct ecryptfs_crypt_stat *crypt_stat =
+ &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
int rc = 0;
- int lower_flags;
- struct ecryptfs_crypt_stat *crypt_stat;
- struct dentry *lower_dentry;
- struct file *lower_file;
- struct inode *inode, *lower_inode;
- struct vfsmount *lower_mnt;

- lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
- ecryptfs_printk(KERN_DEBUG, "lower_dentry->d_name.name = [%s]\n",
- lower_dentry->d_name.name);
- inode = ecryptfs_dentry->d_inode;
- crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
- lower_flags = ((O_CREAT | O_TRUNC) & O_ACCMODE) | O_RDWR;
- lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
- /* Corresponding fput() at end of this function */
- rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
- lower_flags);
- if (rc) {
- ecryptfs_printk(KERN_ERR,
- "Error opening dentry; rc = [%i]\n", rc);
- goto out;
- }
- lower_inode = lower_dentry->d_inode;
if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
- goto out_fput;
+ goto out;
}
crypt_stat->flags |= ECRYPTFS_NEW_FILE;
ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
rc = ecryptfs_new_file_context(ecryptfs_dentry);
if (rc) {
- ecryptfs_printk(KERN_DEBUG, "Error creating new file "
- "context\n");
- goto out_fput;
+ ecryptfs_printk(KERN_ERR, "Error creating new file "
+ "context; rc = [%d]\n", rc);
+ goto out;
}
- rc = ecryptfs_write_metadata(ecryptfs_dentry, lower_file);
+ rc = ecryptfs_write_metadata(ecryptfs_dentry);
if (rc) {
- ecryptfs_printk(KERN_DEBUG, "Error writing headers\n");
- goto out_fput;
+ printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
+ goto out;
}
- rc = grow_file(ecryptfs_dentry, lower_file, inode, lower_inode);
-out_fput:
- rc = ecryptfs_close_lower_file(lower_file);
+ rc = grow_file(ecryptfs_dentry);
if (rc)
- printk(KERN_ERR "Error closing lower_file\n");
+ printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
out:
return rc;
}
@@ -389,8 +360,8 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
ecryptfs_set_default_sizes(crypt_stat);
- rc = ecryptfs_read_and_validate_header_region(page_virt, lower_dentry,
- nd->mnt);
+ rc = ecryptfs_read_and_validate_header_region(page_virt,
+ dentry->d_inode);
if (rc) {
rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
if (rc) {
@@ -941,7 +912,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
}
mount_crypt_stat = &ecryptfs_superblock_to_private(
dentry->d_sb)->mount_crypt_stat;
- rc = ecryptfs_read_metadata(dentry, lower_file);
+ rc = ecryptfs_read_metadata(dentry);
if (rc) {
if (!(mount_crypt_stat->flags
& ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
@@ -1003,6 +974,24 @@ out:
}

ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
+ void *value, size_t size)
+{
+ int rc = 0;
+
+ if (!lower_dentry->d_inode->i_op->getxattr) {
+ rc = -ENOSYS;
+ goto out;
+ }
+ mutex_lock(&lower_dentry->d_inode->i_mutex);
+ rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
+ size);
+ mutex_unlock(&lower_dentry->d_inode->i_mutex);
+out:
+ return rc;
+}
+
+ssize_t
ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
size_t size)
{
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index 9b62110..60e635e 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -307,7 +307,7 @@ static int ecryptfs_readpage(struct file *file, struct page *page)
memset(page_virt, 0, PAGE_CACHE_SIZE);
if (page->index == 0) {
rc = ecryptfs_read_xattr_region(
- page_virt, file->f_path.dentry);
+ page_virt, page->mapping->host);
set_header_info(page_virt, crypt_stat);
}
kunmap_atomic(page_virt, KM_USER0);
--
1.5.1.6

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