![Eric Biggers](/assets/img/avatar_default.png)
Now that all filesystems have been converted to use fscrypt_prepare_new_inode() and fscrypt_set_context(), fscrypt_inherit_context() is no longer used. Remove it. Acked-by: Jeff Layton <jlayton@kernel.org> Link: https://lore.kernel.org/r/20200917041136.178600-8-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
872 lines
26 KiB
C
872 lines
26 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* fscrypt.h: declarations for per-file encryption
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*
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* Filesystems that implement per-file encryption must include this header
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* file.
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*
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* Copyright (C) 2015, Google, Inc.
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*
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* Written by Michael Halcrow, 2015.
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* Modified by Jaegeuk Kim, 2015.
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*/
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#ifndef _LINUX_FSCRYPT_H
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#define _LINUX_FSCRYPT_H
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/parser.h>
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#include <linux/slab.h>
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#include <uapi/linux/fscrypt.h>
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#define FS_CRYPTO_BLOCK_SIZE 16
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union fscrypt_context;
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struct fscrypt_info;
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struct seq_file;
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struct fscrypt_str {
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unsigned char *name;
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u32 len;
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};
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struct fscrypt_name {
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const struct qstr *usr_fname;
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struct fscrypt_str disk_name;
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u32 hash;
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u32 minor_hash;
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struct fscrypt_str crypto_buf;
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bool is_ciphertext_name;
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};
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#define FSTR_INIT(n, l) { .name = n, .len = l }
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#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
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#define fname_name(p) ((p)->disk_name.name)
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#define fname_len(p) ((p)->disk_name.len)
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/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
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#define FSCRYPT_SET_CONTEXT_MAX_SIZE 40
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#ifdef CONFIG_FS_ENCRYPTION
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/*
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* fscrypt superblock flags
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*/
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#define FS_CFLG_OWN_PAGES (1U << 1)
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/*
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* crypto operations for filesystems
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*/
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struct fscrypt_operations {
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unsigned int flags;
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const char *key_prefix;
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int (*get_context)(struct inode *inode, void *ctx, size_t len);
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int (*set_context)(struct inode *inode, const void *ctx, size_t len,
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void *fs_data);
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const union fscrypt_context *(*get_dummy_context)(
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struct super_block *sb);
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bool (*empty_dir)(struct inode *inode);
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unsigned int max_namelen;
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bool (*has_stable_inodes)(struct super_block *sb);
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void (*get_ino_and_lblk_bits)(struct super_block *sb,
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int *ino_bits_ret, int *lblk_bits_ret);
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int (*get_num_devices)(struct super_block *sb);
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void (*get_devices)(struct super_block *sb,
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struct request_queue **devs);
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};
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static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
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{
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/*
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* Pairs with the cmpxchg_release() in fscrypt_get_encryption_info().
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* I.e., another task may publish ->i_crypt_info concurrently, executing
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* a RELEASE barrier. We need to use smp_load_acquire() here to safely
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* ACQUIRE the memory the other task published.
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*/
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return smp_load_acquire(&inode->i_crypt_info);
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}
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/**
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* fscrypt_needs_contents_encryption() - check whether an inode needs
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* contents encryption
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* @inode: the inode to check
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*
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* Return: %true iff the inode is an encrypted regular file and the kernel was
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* built with fscrypt support.
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*
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* If you need to know whether the encrypt bit is set even when the kernel was
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* built without fscrypt support, you must use IS_ENCRYPTED() directly instead.
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*/
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static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
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{
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return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
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}
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static inline const union fscrypt_context *
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fscrypt_get_dummy_context(struct super_block *sb)
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{
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if (!sb->s_cop->get_dummy_context)
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return NULL;
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return sb->s_cop->get_dummy_context(sb);
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}
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/*
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* When d_splice_alias() moves a directory's encrypted alias to its decrypted
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* alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME
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* must be cleared. Note that we don't have to support arbitrary moves of this
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* flag because fscrypt doesn't allow encrypted aliases to be the source or
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* target of a rename().
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*/
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static inline void fscrypt_handle_d_move(struct dentry *dentry)
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{
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dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME;
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}
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/* crypto.c */
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void fscrypt_enqueue_decrypt_work(struct work_struct *);
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struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
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unsigned int len,
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unsigned int offs,
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gfp_t gfp_flags);
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int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page,
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unsigned int len, unsigned int offs,
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u64 lblk_num, gfp_t gfp_flags);
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int fscrypt_decrypt_pagecache_blocks(struct page *page, unsigned int len,
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unsigned int offs);
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int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page,
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unsigned int len, unsigned int offs,
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u64 lblk_num);
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static inline bool fscrypt_is_bounce_page(struct page *page)
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{
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return page->mapping == NULL;
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}
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static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
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{
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return (struct page *)page_private(bounce_page);
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}
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void fscrypt_free_bounce_page(struct page *bounce_page);
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/* policy.c */
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int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg);
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int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg);
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int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg);
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int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg);
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int fscrypt_has_permitted_context(struct inode *parent, struct inode *child);
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int fscrypt_set_context(struct inode *inode, void *fs_data);
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struct fscrypt_dummy_context {
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const union fscrypt_context *ctx;
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};
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int fscrypt_set_test_dummy_encryption(struct super_block *sb,
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const substring_t *arg,
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struct fscrypt_dummy_context *dummy_ctx);
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void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
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struct super_block *sb);
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static inline void
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fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx)
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{
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kfree(dummy_ctx->ctx);
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dummy_ctx->ctx = NULL;
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}
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/* keyring.c */
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void fscrypt_sb_free(struct super_block *sb);
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int fscrypt_ioctl_add_key(struct file *filp, void __user *arg);
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int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg);
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int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
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int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
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/* keysetup.c */
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int fscrypt_get_encryption_info(struct inode *inode);
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int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
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bool *encrypt_ret);
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void fscrypt_put_encryption_info(struct inode *inode);
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void fscrypt_free_inode(struct inode *inode);
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int fscrypt_drop_inode(struct inode *inode);
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/* fname.c */
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int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname,
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int lookup, struct fscrypt_name *fname);
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static inline void fscrypt_free_filename(struct fscrypt_name *fname)
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{
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kfree(fname->crypto_buf.name);
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}
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int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
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struct fscrypt_str *crypto_str);
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void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str);
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int fscrypt_fname_disk_to_usr(const struct inode *inode,
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u32 hash, u32 minor_hash,
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const struct fscrypt_str *iname,
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struct fscrypt_str *oname);
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bool fscrypt_match_name(const struct fscrypt_name *fname,
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const u8 *de_name, u32 de_name_len);
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u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name);
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/* bio.c */
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void fscrypt_decrypt_bio(struct bio *bio);
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int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
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sector_t pblk, unsigned int len);
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/* hooks.c */
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int fscrypt_file_open(struct inode *inode, struct file *filp);
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int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
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struct dentry *dentry);
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int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
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struct inode *new_dir, struct dentry *new_dentry,
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unsigned int flags);
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int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
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struct fscrypt_name *fname);
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int fscrypt_prepare_setflags(struct inode *inode,
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unsigned int oldflags, unsigned int flags);
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int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
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unsigned int max_len,
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struct fscrypt_str *disk_link);
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int __fscrypt_encrypt_symlink(struct inode *inode, const char *target,
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unsigned int len, struct fscrypt_str *disk_link);
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const char *fscrypt_get_symlink(struct inode *inode, const void *caddr,
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unsigned int max_size,
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struct delayed_call *done);
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static inline void fscrypt_set_ops(struct super_block *sb,
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const struct fscrypt_operations *s_cop)
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{
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sb->s_cop = s_cop;
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}
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#else /* !CONFIG_FS_ENCRYPTION */
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static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
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{
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return NULL;
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}
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static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
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{
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return false;
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}
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static inline const union fscrypt_context *
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fscrypt_get_dummy_context(struct super_block *sb)
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{
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return NULL;
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}
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static inline void fscrypt_handle_d_move(struct dentry *dentry)
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{
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}
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/* crypto.c */
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static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work)
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{
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}
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static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page,
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unsigned int len,
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unsigned int offs,
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gfp_t gfp_flags)
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{
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return ERR_PTR(-EOPNOTSUPP);
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}
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static inline int fscrypt_encrypt_block_inplace(const struct inode *inode,
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struct page *page,
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unsigned int len,
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unsigned int offs, u64 lblk_num,
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gfp_t gfp_flags)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_decrypt_pagecache_blocks(struct page *page,
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unsigned int len,
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unsigned int offs)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_decrypt_block_inplace(const struct inode *inode,
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struct page *page,
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unsigned int len,
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unsigned int offs, u64 lblk_num)
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{
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return -EOPNOTSUPP;
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}
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static inline bool fscrypt_is_bounce_page(struct page *page)
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{
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return false;
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}
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static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
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{
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WARN_ON_ONCE(1);
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return ERR_PTR(-EINVAL);
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}
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static inline void fscrypt_free_bounce_page(struct page *bounce_page)
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{
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}
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/* policy.c */
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static inline int fscrypt_ioctl_set_policy(struct file *filp,
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const void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_get_policy_ex(struct file *filp,
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void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_has_permitted_context(struct inode *parent,
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struct inode *child)
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{
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return 0;
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}
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static inline int fscrypt_set_context(struct inode *inode, void *fs_data)
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{
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return -EOPNOTSUPP;
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}
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struct fscrypt_dummy_context {
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};
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static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq,
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char sep,
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struct super_block *sb)
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{
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}
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static inline void
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fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx)
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{
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}
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/* keyring.c */
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static inline void fscrypt_sb_free(struct super_block *sb)
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{
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}
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static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp,
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void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_ioctl_get_key_status(struct file *filp,
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void __user *arg)
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{
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return -EOPNOTSUPP;
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}
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/* keysetup.c */
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static inline int fscrypt_get_encryption_info(struct inode *inode)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_prepare_new_inode(struct inode *dir,
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struct inode *inode,
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bool *encrypt_ret)
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{
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if (IS_ENCRYPTED(dir))
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return -EOPNOTSUPP;
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return 0;
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}
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static inline void fscrypt_put_encryption_info(struct inode *inode)
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{
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return;
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}
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static inline void fscrypt_free_inode(struct inode *inode)
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{
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}
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static inline int fscrypt_drop_inode(struct inode *inode)
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{
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return 0;
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}
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/* fname.c */
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static inline int fscrypt_setup_filename(struct inode *dir,
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const struct qstr *iname,
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int lookup, struct fscrypt_name *fname)
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{
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if (IS_ENCRYPTED(dir))
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return -EOPNOTSUPP;
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memset(fname, 0, sizeof(*fname));
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fname->usr_fname = iname;
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fname->disk_name.name = (unsigned char *)iname->name;
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fname->disk_name.len = iname->len;
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return 0;
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}
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static inline void fscrypt_free_filename(struct fscrypt_name *fname)
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{
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return;
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}
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static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len,
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struct fscrypt_str *crypto_str)
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{
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return -EOPNOTSUPP;
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}
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static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
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{
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return;
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}
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static inline int fscrypt_fname_disk_to_usr(const struct inode *inode,
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u32 hash, u32 minor_hash,
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const struct fscrypt_str *iname,
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struct fscrypt_str *oname)
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{
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return -EOPNOTSUPP;
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}
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static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
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const u8 *de_name, u32 de_name_len)
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{
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/* Encryption support disabled; use standard comparison */
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if (de_name_len != fname->disk_name.len)
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return false;
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return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
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}
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static inline u64 fscrypt_fname_siphash(const struct inode *dir,
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const struct qstr *name)
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{
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WARN_ON_ONCE(1);
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return 0;
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}
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/* bio.c */
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static inline void fscrypt_decrypt_bio(struct bio *bio)
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{
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}
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static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
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sector_t pblk, unsigned int len)
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{
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return -EOPNOTSUPP;
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}
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/* hooks.c */
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static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
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{
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if (IS_ENCRYPTED(inode))
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return -EOPNOTSUPP;
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return 0;
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}
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static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir,
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struct dentry *dentry)
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{
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return -EOPNOTSUPP;
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}
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static inline int __fscrypt_prepare_rename(struct inode *old_dir,
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struct dentry *old_dentry,
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struct inode *new_dir,
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struct dentry *new_dentry,
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unsigned int flags)
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{
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return -EOPNOTSUPP;
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}
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|
static inline int __fscrypt_prepare_lookup(struct inode *dir,
|
|
struct dentry *dentry,
|
|
struct fscrypt_name *fname)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
static inline int fscrypt_prepare_setflags(struct inode *inode,
|
|
unsigned int oldflags,
|
|
unsigned int flags)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline int __fscrypt_prepare_symlink(struct inode *dir,
|
|
unsigned int len,
|
|
unsigned int max_len,
|
|
struct fscrypt_str *disk_link)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
|
|
static inline int __fscrypt_encrypt_symlink(struct inode *inode,
|
|
const char *target,
|
|
unsigned int len,
|
|
struct fscrypt_str *disk_link)
|
|
{
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
static inline const char *fscrypt_get_symlink(struct inode *inode,
|
|
const void *caddr,
|
|
unsigned int max_size,
|
|
struct delayed_call *done)
|
|
{
|
|
return ERR_PTR(-EOPNOTSUPP);
|
|
}
|
|
|
|
static inline void fscrypt_set_ops(struct super_block *sb,
|
|
const struct fscrypt_operations *s_cop)
|
|
{
|
|
}
|
|
|
|
#endif /* !CONFIG_FS_ENCRYPTION */
|
|
|
|
/* inline_crypt.c */
|
|
#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
|
|
|
|
bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode);
|
|
|
|
void fscrypt_set_bio_crypt_ctx(struct bio *bio,
|
|
const struct inode *inode, u64 first_lblk,
|
|
gfp_t gfp_mask);
|
|
|
|
void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio,
|
|
const struct buffer_head *first_bh,
|
|
gfp_t gfp_mask);
|
|
|
|
bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode,
|
|
u64 next_lblk);
|
|
|
|
bool fscrypt_mergeable_bio_bh(struct bio *bio,
|
|
const struct buffer_head *next_bh);
|
|
|
|
#else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
|
|
|
|
static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode)
|
|
{
|
|
return false;
|
|
}
|
|
|
|
static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio,
|
|
const struct inode *inode,
|
|
u64 first_lblk, gfp_t gfp_mask) { }
|
|
|
|
static inline void fscrypt_set_bio_crypt_ctx_bh(
|
|
struct bio *bio,
|
|
const struct buffer_head *first_bh,
|
|
gfp_t gfp_mask) { }
|
|
|
|
static inline bool fscrypt_mergeable_bio(struct bio *bio,
|
|
const struct inode *inode,
|
|
u64 next_lblk)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
static inline bool fscrypt_mergeable_bio_bh(struct bio *bio,
|
|
const struct buffer_head *next_bh)
|
|
{
|
|
return true;
|
|
}
|
|
#endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
|
|
|
|
/**
|
|
* fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline
|
|
* encryption
|
|
* @inode: an inode. If encrypted, its key must be set up.
|
|
*
|
|
* Return: true if the inode requires file contents encryption and if the
|
|
* encryption should be done in the block layer via blk-crypto rather
|
|
* than in the filesystem layer.
|
|
*/
|
|
static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode)
|
|
{
|
|
return fscrypt_needs_contents_encryption(inode) &&
|
|
__fscrypt_inode_uses_inline_crypto(inode);
|
|
}
|
|
|
|
/**
|
|
* fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer
|
|
* encryption
|
|
* @inode: an inode. If encrypted, its key must be set up.
|
|
*
|
|
* Return: true if the inode requires file contents encryption and if the
|
|
* encryption should be done in the filesystem layer rather than in the
|
|
* block layer via blk-crypto.
|
|
*/
|
|
static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode)
|
|
{
|
|
return fscrypt_needs_contents_encryption(inode) &&
|
|
!__fscrypt_inode_uses_inline_crypto(inode);
|
|
}
|
|
|
|
/**
|
|
* fscrypt_has_encryption_key() - check whether an inode has had its key set up
|
|
* @inode: the inode to check
|
|
*
|
|
* Return: %true if the inode has had its encryption key set up, else %false.
|
|
*
|
|
* Usually this should be preceded by fscrypt_get_encryption_info() to try to
|
|
* set up the key first.
|
|
*/
|
|
static inline bool fscrypt_has_encryption_key(const struct inode *inode)
|
|
{
|
|
return fscrypt_get_info(inode) != NULL;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_require_key() - require an inode's encryption key
|
|
* @inode: the inode we need the key for
|
|
*
|
|
* If the inode is encrypted, set up its encryption key if not already done.
|
|
* Then require that the key be present and return -ENOKEY otherwise.
|
|
*
|
|
* No locks are needed, and the key will live as long as the struct inode --- so
|
|
* it won't go away from under you.
|
|
*
|
|
* Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
|
|
* if a problem occurred while setting up the encryption key.
|
|
*/
|
|
static inline int fscrypt_require_key(struct inode *inode)
|
|
{
|
|
if (IS_ENCRYPTED(inode)) {
|
|
int err = fscrypt_get_encryption_info(inode);
|
|
|
|
if (err)
|
|
return err;
|
|
if (!fscrypt_has_encryption_key(inode))
|
|
return -ENOKEY;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted
|
|
* directory
|
|
* @old_dentry: an existing dentry for the inode being linked
|
|
* @dir: the target directory
|
|
* @dentry: negative dentry for the target filename
|
|
*
|
|
* A new link can only be added to an encrypted directory if the directory's
|
|
* encryption key is available --- since otherwise we'd have no way to encrypt
|
|
* the filename. Therefore, we first set up the directory's encryption key (if
|
|
* not already done) and return an error if it's unavailable.
|
|
*
|
|
* We also verify that the link will not violate the constraint that all files
|
|
* in an encrypted directory tree use the same encryption policy.
|
|
*
|
|
* Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
|
|
* -EXDEV if the link would result in an inconsistent encryption policy, or
|
|
* another -errno code.
|
|
*/
|
|
static inline int fscrypt_prepare_link(struct dentry *old_dentry,
|
|
struct inode *dir,
|
|
struct dentry *dentry)
|
|
{
|
|
if (IS_ENCRYPTED(dir))
|
|
return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted
|
|
* directories
|
|
* @old_dir: source directory
|
|
* @old_dentry: dentry for source file
|
|
* @new_dir: target directory
|
|
* @new_dentry: dentry for target location (may be negative unless exchanging)
|
|
* @flags: rename flags (we care at least about %RENAME_EXCHANGE)
|
|
*
|
|
* Prepare for ->rename() where the source and/or target directories may be
|
|
* encrypted. A new link can only be added to an encrypted directory if the
|
|
* directory's encryption key is available --- since otherwise we'd have no way
|
|
* to encrypt the filename. A rename to an existing name, on the other hand,
|
|
* *is* cryptographically possible without the key. However, we take the more
|
|
* conservative approach and just forbid all no-key renames.
|
|
*
|
|
* We also verify that the rename will not violate the constraint that all files
|
|
* in an encrypted directory tree use the same encryption policy.
|
|
*
|
|
* Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the
|
|
* rename would cause inconsistent encryption policies, or another -errno code.
|
|
*/
|
|
static inline int fscrypt_prepare_rename(struct inode *old_dir,
|
|
struct dentry *old_dentry,
|
|
struct inode *new_dir,
|
|
struct dentry *new_dentry,
|
|
unsigned int flags)
|
|
{
|
|
if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir))
|
|
return __fscrypt_prepare_rename(old_dir, old_dentry,
|
|
new_dir, new_dentry, flags);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted
|
|
* directory
|
|
* @dir: directory being searched
|
|
* @dentry: filename being looked up
|
|
* @fname: (output) the name to use to search the on-disk directory
|
|
*
|
|
* Prepare for ->lookup() in a directory which may be encrypted by determining
|
|
* the name that will actually be used to search the directory on-disk. Lookups
|
|
* can be done with or without the directory's encryption key; without the key,
|
|
* filenames are presented in encrypted form. Therefore, we'll try to set up
|
|
* the directory's encryption key, but even without it the lookup can continue.
|
|
*
|
|
* This also installs a custom ->d_revalidate() method which will invalidate the
|
|
* dentry if it was created without the key and the key is later added.
|
|
*
|
|
* Return: 0 on success; -ENOENT if key is unavailable but the filename isn't a
|
|
* correctly formed encoded ciphertext name, so a negative dentry should be
|
|
* created; or another -errno code.
|
|
*/
|
|
static inline int fscrypt_prepare_lookup(struct inode *dir,
|
|
struct dentry *dentry,
|
|
struct fscrypt_name *fname)
|
|
{
|
|
if (IS_ENCRYPTED(dir))
|
|
return __fscrypt_prepare_lookup(dir, dentry, fname);
|
|
|
|
memset(fname, 0, sizeof(*fname));
|
|
fname->usr_fname = &dentry->d_name;
|
|
fname->disk_name.name = (unsigned char *)dentry->d_name.name;
|
|
fname->disk_name.len = dentry->d_name.len;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's
|
|
* attributes
|
|
* @dentry: dentry through which the inode is being changed
|
|
* @attr: attributes to change
|
|
*
|
|
* Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file,
|
|
* most attribute changes are allowed even without the encryption key. However,
|
|
* without the encryption key we do have to forbid truncates. This is needed
|
|
* because the size being truncated to may not be a multiple of the filesystem
|
|
* block size, and in that case we'd have to decrypt the final block, zero the
|
|
* portion past i_size, and re-encrypt it. (We *could* allow truncating to a
|
|
* filesystem block boundary, but it's simpler to just forbid all truncates ---
|
|
* and we already forbid all other contents modifications without the key.)
|
|
*
|
|
* Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
|
|
* if a problem occurred while setting up the encryption key.
|
|
*/
|
|
static inline int fscrypt_prepare_setattr(struct dentry *dentry,
|
|
struct iattr *attr)
|
|
{
|
|
if (attr->ia_valid & ATTR_SIZE)
|
|
return fscrypt_require_key(d_inode(dentry));
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink
|
|
* @dir: directory in which the symlink is being created
|
|
* @target: plaintext symlink target
|
|
* @len: length of @target excluding null terminator
|
|
* @max_len: space the filesystem has available to store the symlink target
|
|
* @disk_link: (out) the on-disk symlink target being prepared
|
|
*
|
|
* This function computes the size the symlink target will require on-disk,
|
|
* stores it in @disk_link->len, and validates it against @max_len. An
|
|
* encrypted symlink may be longer than the original.
|
|
*
|
|
* Additionally, @disk_link->name is set to @target if the symlink will be
|
|
* unencrypted, but left NULL if the symlink will be encrypted. For encrypted
|
|
* symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the
|
|
* on-disk target later. (The reason for the two-step process is that some
|
|
* filesystems need to know the size of the symlink target before creating the
|
|
* inode, e.g. to determine whether it will be a "fast" or "slow" symlink.)
|
|
*
|
|
* Return: 0 on success, -ENAMETOOLONG if the symlink target is too long,
|
|
* -ENOKEY if the encryption key is missing, or another -errno code if a problem
|
|
* occurred while setting up the encryption key.
|
|
*/
|
|
static inline int fscrypt_prepare_symlink(struct inode *dir,
|
|
const char *target,
|
|
unsigned int len,
|
|
unsigned int max_len,
|
|
struct fscrypt_str *disk_link)
|
|
{
|
|
if (IS_ENCRYPTED(dir) || fscrypt_get_dummy_context(dir->i_sb) != NULL)
|
|
return __fscrypt_prepare_symlink(dir, len, max_len, disk_link);
|
|
|
|
disk_link->name = (unsigned char *)target;
|
|
disk_link->len = len + 1;
|
|
if (disk_link->len > max_len)
|
|
return -ENAMETOOLONG;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* fscrypt_encrypt_symlink() - encrypt the symlink target if needed
|
|
* @inode: symlink inode
|
|
* @target: plaintext symlink target
|
|
* @len: length of @target excluding null terminator
|
|
* @disk_link: (in/out) the on-disk symlink target being prepared
|
|
*
|
|
* If the symlink target needs to be encrypted, then this function encrypts it
|
|
* into @disk_link->name. fscrypt_prepare_symlink() must have been called
|
|
* previously to compute @disk_link->len. If the filesystem did not allocate a
|
|
* buffer for @disk_link->name after calling fscrypt_prepare_link(), then one
|
|
* will be kmalloc()'ed and the filesystem will be responsible for freeing it.
|
|
*
|
|
* Return: 0 on success, -errno on failure
|
|
*/
|
|
static inline int fscrypt_encrypt_symlink(struct inode *inode,
|
|
const char *target,
|
|
unsigned int len,
|
|
struct fscrypt_str *disk_link)
|
|
{
|
|
if (IS_ENCRYPTED(inode))
|
|
return __fscrypt_encrypt_symlink(inode, target, len, disk_link);
|
|
return 0;
|
|
}
|
|
|
|
/* If *pagep is a bounce page, free it and set *pagep to the pagecache page */
|
|
static inline void fscrypt_finalize_bounce_page(struct page **pagep)
|
|
{
|
|
struct page *page = *pagep;
|
|
|
|
if (fscrypt_is_bounce_page(page)) {
|
|
*pagep = fscrypt_pagecache_page(page);
|
|
fscrypt_free_bounce_page(page);
|
|
}
|
|
}
|
|
|
|
#endif /* _LINUX_FSCRYPT_H */
|