eCryptfs: Filename Encryption: filldir, lookup, and readlink
Make the requisite modifications to ecryptfs_filldir(), ecryptfs_lookup(),
and ecryptfs_readlink() to call out to filename encryption functions.
Propagate filename encryption policy flags from mount-wide crypt_stat to
inode crypt_stat.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Dustin Kirkland <dustin.kirkland@gmail.com>
Cc: Eric Sandeen <sandeen@redhat.com>
Cc: Tyler Hicks <tchicks@us.ibm.com>
Cc: David Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index 0111906..38309ce 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -228,8 +228,7 @@
{
int rc;
- /* ecryptfs_do_create() calls ecryptfs_interpose(), which opens
- * the crypt_stat->lower_file (persistent file) */
+ /* ecryptfs_do_create() calls ecryptfs_interpose() */
rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
if (unlikely(rc)) {
ecryptfs_printk(KERN_WARNING, "Failed to create file in"
@@ -244,141 +243,91 @@
}
/**
- * ecryptfs_lookup
- * @dir: inode
- * @dentry: The dentry
- * @nd: nameidata, may be NULL
- *
- * Find a file on disk. If the file does not exist, then we'll add it to the
- * dentry cache and continue on to read it from the disk.
+ * ecryptfs_lookup_and_interpose_lower - Perform a lookup
*/
-static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd)
+int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
+ struct dentry *lower_dentry,
+ struct ecryptfs_crypt_stat *crypt_stat,
+ struct inode *ecryptfs_dir_inode,
+ struct nameidata *ecryptfs_nd)
{
- int rc = 0;
struct dentry *lower_dir_dentry;
- struct dentry *lower_dentry;
struct vfsmount *lower_mnt;
- char *encoded_name;
- int encoded_namelen;
- struct ecryptfs_crypt_stat *crypt_stat = NULL;
+ struct inode *lower_inode;
struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
char *page_virt = NULL;
- struct inode *lower_inode;
u64 file_size;
+ int rc = 0;
- lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
- dentry->d_op = &ecryptfs_dops;
- if ((dentry->d_name.len == 1 && !strcmp(dentry->d_name.name, "."))
- || (dentry->d_name.len == 2
- && !strcmp(dentry->d_name.name, ".."))) {
- d_drop(dentry);
- goto out;
- }
- encoded_namelen = ecryptfs_encode_filename(crypt_stat,
- dentry->d_name.name,
- dentry->d_name.len,
- &encoded_name);
- if (encoded_namelen < 0) {
- rc = encoded_namelen;
- d_drop(dentry);
- goto out;
- }
- ecryptfs_printk(KERN_DEBUG, "encoded_name = [%s]; encoded_namelen "
- "= [%d]\n", encoded_name, encoded_namelen);
- lower_dentry = lookup_one_len(encoded_name, lower_dir_dentry,
- encoded_namelen - 1);
- kfree(encoded_name);
- if (IS_ERR(lower_dentry)) {
- ecryptfs_printk(KERN_ERR, "ERR from lower_dentry\n");
- rc = PTR_ERR(lower_dentry);
- d_drop(dentry);
- goto out;
- }
- lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
- ecryptfs_printk(KERN_DEBUG, "lower_dentry = [%p]; lower_dentry->"
- "d_name.name = [%s]\n", lower_dentry,
- lower_dentry->d_name.name);
+ 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(dir, lower_dir_dentry->d_inode);
+ fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
BUG_ON(!atomic_read(&lower_dentry->d_count));
- ecryptfs_set_dentry_private(dentry,
+ ecryptfs_set_dentry_private(ecryptfs_dentry,
kmem_cache_alloc(ecryptfs_dentry_info_cache,
GFP_KERNEL));
- if (!ecryptfs_dentry_to_private(dentry)) {
+ if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
rc = -ENOMEM;
- ecryptfs_printk(KERN_ERR, "Out of memory whilst attempting "
- "to allocate ecryptfs_dentry_info struct\n");
+ printk(KERN_ERR "%s: Out of memory whilst attempting "
+ "to allocate ecryptfs_dentry_info struct\n",
+ __func__);
goto out_dput;
}
- ecryptfs_set_dentry_lower(dentry, lower_dentry);
- ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
+ 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(dentry, NULL);
+ d_add(ecryptfs_dentry, NULL);
goto out;
}
- rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb,
- ECRYPTFS_INTERPOSE_FLAG_D_ADD);
+ rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
+ ecryptfs_dir_inode->i_sb, 1);
if (rc) {
- ecryptfs_printk(KERN_ERR, "Error interposing\n");
+ printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
+ __func__, rc);
goto out;
}
- if (S_ISDIR(lower_inode->i_mode)) {
- ecryptfs_printk(KERN_DEBUG, "Is a directory; returning\n");
+ if (S_ISDIR(lower_inode->i_mode))
goto out;
- }
- if (S_ISLNK(lower_inode->i_mode)) {
- ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
+ if (S_ISLNK(lower_inode->i_mode))
goto out;
- }
- if (special_file(lower_inode->i_mode)) {
- ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
+ if (special_file(lower_inode->i_mode))
goto out;
- }
- if (!nd) {
- ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
- "as we *think* we are about to unlink\n");
+ if (!ecryptfs_nd)
goto out;
- }
/* Released in this function */
- page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2,
- GFP_USER);
+ 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;
- ecryptfs_printk(KERN_ERR,
- "Cannot ecryptfs_kmalloc a page\n");
goto out;
}
- crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
- if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
- ecryptfs_set_default_sizes(crypt_stat);
- if (!ecryptfs_inode_to_private(dentry->d_inode)->lower_file) {
- rc = ecryptfs_init_persistent_file(dentry);
+ if (!ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->lower_file) {
+ rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
if (rc) {
printk(KERN_ERR "%s: Error attempting to initialize "
"the persistent file for the dentry with name "
"[%s]; rc = [%d]\n", __func__,
- dentry->d_name.name, rc);
- goto out;
+ ecryptfs_dentry->d_name.name, rc);
+ goto out_free_kmem;
}
}
rc = ecryptfs_read_and_validate_header_region(page_virt,
- dentry->d_inode);
+ ecryptfs_dentry->d_inode);
if (rc) {
- rc = ecryptfs_read_and_validate_xattr_region(page_virt, dentry);
+ rc = ecryptfs_read_and_validate_xattr_region(page_virt,
+ ecryptfs_dentry);
if (rc) {
- printk(KERN_DEBUG "Valid metadata not found in header "
- "region or xattr region; treating file as "
- "unencrypted\n");
rc = 0;
- kmem_cache_free(ecryptfs_header_cache_2, page_virt);
- goto out;
+ goto out_free_kmem;
}
crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
}
mount_crypt_stat = &ecryptfs_superblock_to_private(
- dentry->d_sb)->mount_crypt_stat;
+ ecryptfs_dentry->d_sb)->mount_crypt_stat;
if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
file_size = (crypt_stat->num_header_bytes_at_front
@@ -388,14 +337,103 @@
} else {
file_size = get_unaligned_be64(page_virt);
}
- i_size_write(dentry->d_inode, (loff_t)file_size);
+ i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
+out_free_kmem:
kmem_cache_free(ecryptfs_header_cache_2, page_virt);
goto out;
-
out_dput:
dput(lower_dentry);
- d_drop(dentry);
+ d_drop(ecryptfs_dentry);
out:
+ return rc;
+}
+
+/**
+ * ecryptfs_lookup
+ * @ecryptfs_dir_inode: The eCryptfs directory inode
+ * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
+ * @ecryptfs_nd: nameidata; may be NULL
+ *
+ * Find a file on disk. If the file does not exist, then we'll add it to the
+ * dentry cache and continue on to read it from the disk.
+ */
+static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
+ struct dentry *ecryptfs_dentry,
+ struct nameidata *ecryptfs_nd)
+{
+ char *encrypted_and_encoded_name = NULL;
+ int encrypted_and_encoded_name_size;
+ struct ecryptfs_crypt_stat *crypt_stat = NULL;
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
+ struct ecryptfs_inode_info *inode_info;
+ struct dentry *lower_dir_dentry, *lower_dentry;
+ int rc = 0;
+
+ ecryptfs_dentry->d_op = &ecryptfs_dops;
+ if ((ecryptfs_dentry->d_name.len == 1
+ && !strcmp(ecryptfs_dentry->d_name.name, "."))
+ || (ecryptfs_dentry->d_name.len == 2
+ && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
+ goto out_d_drop;
+ }
+ lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
+ lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
+ lower_dir_dentry,
+ ecryptfs_dentry->d_name.len);
+ if (IS_ERR(lower_dentry)) {
+ rc = PTR_ERR(lower_dentry);
+ printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
+ "lower_dentry = [%s]\n", __func__, rc,
+ ecryptfs_dentry->d_name.name);
+ goto out_d_drop;
+ }
+ if (lower_dentry->d_inode)
+ goto lookup_and_interpose;
+ inode_info = ecryptfs_inode_to_private(ecryptfs_dentry->d_inode);
+ if (inode_info) {
+ crypt_stat = &inode_info->crypt_stat;
+ /* TODO: lock for crypt_stat comparison */
+ if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
+ ecryptfs_set_default_sizes(crypt_stat);
+ }
+ if (crypt_stat)
+ mount_crypt_stat = crypt_stat->mount_crypt_stat;
+ else
+ mount_crypt_stat = &ecryptfs_superblock_to_private(
+ ecryptfs_dentry->d_sb)->mount_crypt_stat;
+ if (!(crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
+ && !(mount_crypt_stat && (mount_crypt_stat->flags
+ & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
+ goto lookup_and_interpose;
+ dput(lower_dentry);
+ rc = ecryptfs_encrypt_and_encode_filename(
+ &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
+ crypt_stat, mount_crypt_stat, ecryptfs_dentry->d_name.name,
+ ecryptfs_dentry->d_name.len);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to encrypt and encode "
+ "filename; rc = [%d]\n", __func__, rc);
+ goto out_d_drop;
+ }
+ lower_dentry = lookup_one_len(encrypted_and_encoded_name,
+ lower_dir_dentry,
+ encrypted_and_encoded_name_size - 1);
+ if (IS_ERR(lower_dentry)) {
+ rc = PTR_ERR(lower_dentry);
+ printk(KERN_ERR "%s: lookup_one_len() returned [%d] on "
+ "lower_dentry = [%s]\n", __func__, rc,
+ encrypted_and_encoded_name);
+ goto out_d_drop;
+ }
+lookup_and_interpose:
+ rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
+ crypt_stat, ecryptfs_dir_inode,
+ ecryptfs_nd);
+ goto out;
+out_d_drop:
+ d_drop(ecryptfs_dentry);
+out:
+ kfree(encrypted_and_encoded_name);
return ERR_PTR(rc);
}
@@ -466,19 +504,21 @@
struct dentry *lower_dentry;
struct dentry *lower_dir_dentry;
char *encoded_symname;
- int encoded_symlen;
- struct ecryptfs_crypt_stat *crypt_stat = NULL;
+ size_t encoded_symlen;
+ struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
lower_dentry = ecryptfs_dentry_to_lower(dentry);
dget(lower_dentry);
lower_dir_dentry = lock_parent(lower_dentry);
- encoded_symlen = ecryptfs_encode_filename(crypt_stat, symname,
- strlen(symname),
- &encoded_symname);
- if (encoded_symlen < 0) {
- rc = encoded_symlen;
+ mount_crypt_stat = &ecryptfs_superblock_to_private(
+ dir->i_sb)->mount_crypt_stat;
+ rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
+ &encoded_symlen,
+ NULL,
+ mount_crypt_stat, symname,
+ strlen(symname));
+ if (rc)
goto out_lock;
- }
rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
encoded_symname);
kfree(encoded_symname);
@@ -602,52 +642,54 @@
}
static int
-ecryptfs_readlink(struct dentry *dentry, char __user * buf, int bufsiz)
+ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
- int rc;
- struct dentry *lower_dentry;
- char *decoded_name;
char *lower_buf;
- mm_segment_t old_fs;
+ struct dentry *lower_dentry;
struct ecryptfs_crypt_stat *crypt_stat;
+ char *plaintext_name;
+ size_t plaintext_name_size;
+ mm_segment_t old_fs;
+ int rc;
lower_dentry = ecryptfs_dentry_to_lower(dentry);
if (!lower_dentry->d_inode->i_op->readlink) {
rc = -EINVAL;
goto out;
}
+ crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
/* Released in this function */
lower_buf = kmalloc(bufsiz, GFP_KERNEL);
if (lower_buf == NULL) {
- ecryptfs_printk(KERN_ERR, "Out of memory\n");
+ printk(KERN_ERR "%s: Out of memory whilst attempting to "
+ "kmalloc [%d] bytes\n", __func__, bufsiz);
rc = -ENOMEM;
goto out;
}
old_fs = get_fs();
set_fs(get_ds());
- ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
- "lower_dentry->d_name.name = [%s]\n",
- lower_dentry->d_name.name);
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
bufsiz);
set_fs(old_fs);
if (rc >= 0) {
- crypt_stat = NULL;
- rc = ecryptfs_decode_filename(crypt_stat, lower_buf, rc,
- &decoded_name);
- if (rc == -ENOMEM)
+ rc = ecryptfs_decode_and_decrypt_filename(&plaintext_name,
+ &plaintext_name_size,
+ dentry, lower_buf,
+ rc);
+ if (rc) {
+ printk(KERN_ERR "%s: Error attempting to decode and "
+ "decrypt filename; rc = [%d]\n", __func__,
+ rc);
goto out_free_lower_buf;
- if (rc > 0) {
- ecryptfs_printk(KERN_DEBUG, "Copying [%d] bytes "
- "to userspace: [%*s]\n", rc,
- decoded_name);
- if (copy_to_user(buf, decoded_name, rc))
- rc = -EFAULT;
}
- kfree(decoded_name);
- fsstack_copy_attr_atime(dentry->d_inode,
- lower_dentry->d_inode);
+ rc = copy_to_user(buf, plaintext_name, plaintext_name_size);
+ if (rc)
+ rc = -EFAULT;
+ else
+ rc = plaintext_name_size;
+ kfree(plaintext_name);
+ fsstack_copy_attr_atime(dentry->d_inode, lower_dentry->d_inode);
}
out_free_lower_buf:
kfree(lower_buf);
@@ -669,8 +711,6 @@
}
old_fs = get_fs();
set_fs(get_ds());
- ecryptfs_printk(KERN_DEBUG, "Calling readlink w/ "
- "dentry->d_name.name = [%s]\n", dentry->d_name.name);
rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
set_fs(old_fs);
if (rc < 0)