// SPDX-License-Identifier: GPL-2.0
#include <linux/quotaops.h>
#include <linux/uuid.h>
#include "ext4.h"
#include "xattr.h"
#include "ext4_jbd2.h"
static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst,
const struct fscrypt_name *src)
{
memset(dst, 0, sizeof(*dst));
dst->usr_fname = src->usr_fname;
dst->disk_name = src->disk_name;
dst->hinfo.hash = src->hash;
dst->hinfo.minor_hash = src->minor_hash;
dst->crypto_buf = src->crypto_buf;
}
int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname,
int lookup, struct ext4_filename *fname)
{
struct fscrypt_name name;
int err;
err = fscrypt_setup_filename(dir, iname, lookup, &name);
if (err)
return err;
ext4_fname_from_fscrypt_name(fname, &name);
err = ext4_fname_setup_ci_filename(dir, iname, fname);
if (err)
ext4_fname_free_filename(fname);
return err;
}
int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct ext4_filename *fname)
{
struct fscrypt_name name;
int err;
err = fscrypt_prepare_lookup(dir, dentry, &name);
if (err)
return err;
ext4_fname_from_fscrypt_name(fname, &name);
err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname);
if (err)
ext4_fname_free_filename(fname);
return err;
}
void ext4_fname_free_filename(struct ext4_filename *fname)
{
struct fscrypt_name name;
name.crypto_buf = fname->crypto_buf;
fscrypt_free_filename(&name);
fname->crypto_buf.name = NULL;
fname->usr_fname = NULL;
fname->disk_name.name = NULL;
ext4_fname_free_ci_filename(fname);
}
static bool uuid_is_zero(__u8 u[16])
{
int i;
for (i = 0; i < 16; i++)
if (u[i])
return false;
return true;
}
int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg)
{
struct super_block *sb = file_inode(filp)->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
int err, err2;
handle_t *handle;
if (!ext4_has_feature_encrypt(sb))
return -EOPNOTSUPP;
if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) {
err = mnt_want_write_file(filp);
if (err)
return err;
handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
if (IS_ERR(handle)) {
err = PTR_ERR(handle);
goto pwsalt_err_exit;
}
err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
EXT4_JTR_NONE);
if (err)
goto pwsalt_err_journal;
lock_buffer(sbi->s_sbh);
generate_random_uuid(sbi->s_es->s_encrypt_pw_salt);
ext4_superblock_csum_set(sb);
unlock_buffer(sbi->s_sbh);
err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
pwsalt_err_journal:
err2 = ext4_journal_stop(handle);
if (err2 && !err)
err = err2;
pwsalt_err_exit:
mnt_drop_write_file(filp);
if (err)
return err;
}
if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16))
return -EFAULT;
return 0;
}
static int ext4_get_context(struct inode *inode, void *ctx, size_t len)
{
return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION,
EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len);
}
static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
void *fs_data)
{
handle_t *handle = fs_data;
int res, res2, credits, retries = 0;
/*
* Encrypting the root directory is not allowed because e2fsck expects
* lost+found to exist and be unencrypted, and encrypting the root
* directory would imply encrypting the lost+found directory as well as
* the filename "lost+found" itself.
*/
if (inode->i_ino == EXT4_ROOT_INO)
return -EPERM;
if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode)))
return -EINVAL;
if (ext4_test_inode_flag(inode, EXT4_INODE_DAX))
return -EOPNOTSUPP;
res = ext4_convert_inline_data(inode);
if (res)
return res;
/*
* If a journal handle was specified, then the encryption context is
* being set on a new inode via inheritance and is part of a larger
* transaction to create the inode. Otherwise the encryption context is
* being set on an existing inode in its own transaction. Only in the
* latter case should the "retry on ENOSPC" logic be used.
*/
if (handle) {
res = ext4_xattr_set_handle(handle, inode,
EXT4_XATTR_INDEX_ENCRYPTION,
EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
ctx, len, 0);
if (!res) {
ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
ext4_clear_inode_state(inode,
EXT4_STATE_MAY_INLINE_DATA);
/*
* Update inode->i_flags - S_ENCRYPTED will be enabled,
* S_DAX may be disabled
*/
ext4_set_inode_flags(inode, false);
}
return res;
}
res = dquot_initialize(inode);
if (res)
return res;
retry:
res = ext4_xattr_set_credits(inode, len, false /* is_create */,
&credits);
if (res)
return res;
handle = ext4_journal_start(inode, EXT4_HT_MISC, credits);
if (IS_ERR(handle))
return PTR_ERR(handle);
res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION,
EXT4_XATTR_NAME_ENCRYPTION_CONTEXT,
ctx, len, 0);
if (!res) {
ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
/*
* Update inode->i_flags - S_ENCRYPTED will be enabled,
* S_DAX may be disabled
*/
ext4_set_inode_flags(inode, false);
res = ext4_mark_inode_dirty(handle, inode);
if (res)
EXT4_ERROR_INODE(inode, "Failed to mark inode dirty");
}
res2 = ext4_journal_stop(handle);
if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry;
if (!res)
res = res2;
return res;
}
static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb)
{
return EXT4_SB(sb)->s_dummy_enc_policy.policy;
}
static bool ext4_has_stable_inodes(struct super_block *sb)
{
return ext4_has_feature_stable_inodes(sb);
}
const struct fscrypt_operations ext4_cryptops = {
.needs_bounce_pages = 1,
.has_32bit_inodes = 1,
.supports_subblock_data_units = 1,
.legacy_key_prefix = "ext4:",
.get_context = ext4_get_context,
.set_context = ext4_set_context,
.get_dummy_policy = ext4_get_dummy_policy,
.empty_dir = ext4_empty_dir,
.has_stable_inodes = ext4_has_stable_inodes,
};
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