/* Inspired by generic filldir in fs/readdir.c */
static int
ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct ecryptfs_getdents_callback *buf =
(struct ecryptfs_getdents_callback *)dirent;
size_t name_size;
char *name;
int rc;
buf->filldir_called++;
rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
buf->dentry, lower_name,
lower_namelen);
if (rc) {
printk(KERN_ERR "%s: Error attempting to decode and decrypt "
"filename [%s]; rc = [%d]\n", __func__, lower_name,
rc);
goto out;
}
rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
kfree(name);
if (rc >= 0)
buf->entries_written++;
out:
return rc;
}
static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
size_t *bufsiz)
{
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
char *lower_buf;
size_t lower_bufsiz = PATH_MAX;
mm_segment_t old_fs;
int rc;
lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
if (!lower_buf) {
rc = -ENOMEM;
goto out;
}
old_fs = get_fs();
set_fs(get_ds());
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
lower_bufsiz);
set_fs(old_fs);
if (rc < 0)
goto out;
lower_bufsiz = rc;
rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
lower_buf, lower_bufsiz);
out:
kfree(lower_buf);
return rc;
}
static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
{
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
char *lower_buf;
char *buf;
mm_segment_t old_fs;
int rc;
lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
if (!lower_buf)
return ERR_PTR(-ENOMEM);
old_fs = get_fs();
set_fs(get_ds());
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
PATH_MAX);
set_fs(old_fs);
if (rc < 0)
goto out;
rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
lower_buf, rc);
out:
kfree(lower_buf);
return rc ? ERR_PTR(rc) : buf;
}
static int
ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
char *lower_buf;
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) {
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());
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
bufsiz);
set_fs(old_fs);
if (rc >= 0) {
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;
}
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);
out:
return rc;
}
static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
{
DEFINE_DELAYED_CALL(done);
struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
const char *link;
char *buf;
int rc;
link = vfs_get_link(lower_dentry, &done);
if (IS_ERR(link))
return ERR_CAST(link);
rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
link, strlen(link));
do_delayed_call(&done);
if (rc)
return ERR_PTR(rc);
return buf;
}
static int
ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
{
char *lower_buf;
size_t lower_bufsiz;
struct dentry *lower_dentry;
struct ecryptfs_mount_crypt_stat *mount_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;
}
mount_crypt_stat = &ecryptfs_superblock_to_private(
dentry->d_sb)->mount_crypt_stat;
/*
* If the lower filename is encrypted, it will result in a significantly
* longer name. If needed, truncate the name after decode and decrypt.
*/
if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
lower_bufsiz = PATH_MAX;
else
lower_bufsiz = bufsiz;
/* Released in this function */
lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
if (lower_buf == NULL) {
printk(KERN_ERR "%s: Out of memory whilst attempting to "
"kmalloc [%zd] bytes\n", __func__, lower_bufsiz);
rc = -ENOMEM;
goto out;
}
old_fs = get_fs();
set_fs(get_ds());
rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
(char __user *)lower_buf,
lower_bufsiz);
set_fs(old_fs);
if (rc >= 0) {
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;
}
/* Check for bufsiz <= 0 done in sys_readlinkat() */
rc = copy_to_user(buf, plaintext_name,
min((size_t) bufsiz, 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);
out:
return rc;
}