437 строки
11 KiB
C
437 строки
11 KiB
C
/*
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* General per-file encryption definition
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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_FSCRYPTO_H
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#define _LINUX_FSCRYPTO_H
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#include <linux/key.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/bio.h>
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#include <linux/dcache.h>
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#include <crypto/skcipher.h>
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#include <uapi/linux/fs.h>
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#define FS_KEY_DERIVATION_NONCE_SIZE 16
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#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
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#define FS_POLICY_FLAGS_PAD_4 0x00
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#define FS_POLICY_FLAGS_PAD_8 0x01
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#define FS_POLICY_FLAGS_PAD_16 0x02
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#define FS_POLICY_FLAGS_PAD_32 0x03
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#define FS_POLICY_FLAGS_PAD_MASK 0x03
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#define FS_POLICY_FLAGS_VALID 0x03
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/* Encryption algorithms */
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#define FS_ENCRYPTION_MODE_INVALID 0
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#define FS_ENCRYPTION_MODE_AES_256_XTS 1
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#define FS_ENCRYPTION_MODE_AES_256_GCM 2
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#define FS_ENCRYPTION_MODE_AES_256_CBC 3
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#define FS_ENCRYPTION_MODE_AES_256_CTS 4
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/**
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* Encryption context for inode
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*
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* Protector format:
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* 1 byte: Protector format (1 = this version)
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* 1 byte: File contents encryption mode
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* 1 byte: File names encryption mode
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* 1 byte: Flags
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* 8 bytes: Master Key descriptor
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* 16 bytes: Encryption Key derivation nonce
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*/
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struct fscrypt_context {
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u8 format;
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u8 contents_encryption_mode;
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u8 filenames_encryption_mode;
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u8 flags;
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u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
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u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
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} __packed;
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/* Encryption parameters */
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#define FS_XTS_TWEAK_SIZE 16
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#define FS_AES_128_ECB_KEY_SIZE 16
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#define FS_AES_256_GCM_KEY_SIZE 32
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#define FS_AES_256_CBC_KEY_SIZE 32
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#define FS_AES_256_CTS_KEY_SIZE 32
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#define FS_AES_256_XTS_KEY_SIZE 64
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#define FS_MAX_KEY_SIZE 64
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#define FS_KEY_DESC_PREFIX "fscrypt:"
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#define FS_KEY_DESC_PREFIX_SIZE 8
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/* This is passed in from userspace into the kernel keyring */
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struct fscrypt_key {
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u32 mode;
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u8 raw[FS_MAX_KEY_SIZE];
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u32 size;
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} __packed;
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struct fscrypt_info {
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u8 ci_data_mode;
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u8 ci_filename_mode;
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u8 ci_flags;
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struct crypto_skcipher *ci_ctfm;
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struct key *ci_keyring_key;
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u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
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};
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#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
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#define FS_WRITE_PATH_FL 0x00000002
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struct fscrypt_ctx {
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union {
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struct {
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struct page *bounce_page; /* Ciphertext page */
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struct page *control_page; /* Original page */
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} w;
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struct {
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struct bio *bio;
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struct work_struct work;
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} r;
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struct list_head free_list; /* Free list */
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};
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u8 flags; /* Flags */
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u8 mode; /* Encryption mode for tfm */
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};
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struct fscrypt_completion_result {
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struct completion completion;
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int res;
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};
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#define DECLARE_FS_COMPLETION_RESULT(ecr) \
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struct fscrypt_completion_result ecr = { \
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COMPLETION_INITIALIZER((ecr).completion), 0 }
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static inline int fscrypt_key_size(int mode)
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{
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switch (mode) {
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case FS_ENCRYPTION_MODE_AES_256_XTS:
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return FS_AES_256_XTS_KEY_SIZE;
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case FS_ENCRYPTION_MODE_AES_256_GCM:
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return FS_AES_256_GCM_KEY_SIZE;
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case FS_ENCRYPTION_MODE_AES_256_CBC:
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return FS_AES_256_CBC_KEY_SIZE;
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case FS_ENCRYPTION_MODE_AES_256_CTS:
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return FS_AES_256_CTS_KEY_SIZE;
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default:
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BUG();
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}
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return 0;
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}
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#define FS_FNAME_NUM_SCATTER_ENTRIES 4
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#define FS_CRYPTO_BLOCK_SIZE 16
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#define FS_FNAME_CRYPTO_DIGEST_SIZE 32
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/**
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* For encrypted symlinks, the ciphertext length is stored at the beginning
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* of the string in little-endian format.
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*/
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struct fscrypt_symlink_data {
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__le16 len;
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char encrypted_path[1];
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} __packed;
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/**
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* This function is used to calculate the disk space required to
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* store a filename of length l in encrypted symlink format.
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*/
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static inline u32 fscrypt_symlink_data_len(u32 l)
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{
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if (l < FS_CRYPTO_BLOCK_SIZE)
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l = FS_CRYPTO_BLOCK_SIZE;
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return (l + sizeof(struct fscrypt_symlink_data) - 1);
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}
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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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};
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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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/*
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* crypto opertions for filesystems
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*/
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struct fscrypt_operations {
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int (*get_context)(struct inode *, void *, size_t);
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int (*key_prefix)(struct inode *, u8 **);
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int (*prepare_context)(struct inode *);
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int (*set_context)(struct inode *, const void *, size_t, void *);
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int (*dummy_context)(struct inode *);
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bool (*is_encrypted)(struct inode *);
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bool (*empty_dir)(struct inode *);
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unsigned (*max_namelen)(struct inode *);
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};
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static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
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{
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if (inode->i_sb->s_cop->dummy_context &&
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inode->i_sb->s_cop->dummy_context(inode))
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return true;
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return false;
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}
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static inline bool fscrypt_valid_contents_enc_mode(u32 mode)
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{
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return (mode == FS_ENCRYPTION_MODE_AES_256_XTS);
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}
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static inline bool fscrypt_valid_filenames_enc_mode(u32 mode)
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{
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return (mode == FS_ENCRYPTION_MODE_AES_256_CTS);
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}
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static inline u32 fscrypt_validate_encryption_key_size(u32 mode, u32 size)
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{
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if (size == fscrypt_key_size(mode))
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return size;
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return 0;
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}
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static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
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{
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if (str->len == 1 && str->name[0] == '.')
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return true;
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if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
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return true;
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return false;
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}
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static inline struct page *fscrypt_control_page(struct page *page)
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{
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
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#else
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WARN_ON_ONCE(1);
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return ERR_PTR(-EINVAL);
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#endif
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}
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static inline int fscrypt_has_encryption_key(struct inode *inode)
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{
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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return (inode->i_crypt_info != NULL);
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#else
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return 0;
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#endif
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}
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static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry)
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{
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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spin_lock(&dentry->d_lock);
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dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
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spin_unlock(&dentry->d_lock);
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#endif
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}
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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extern const struct dentry_operations fscrypt_d_ops;
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#endif
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static inline void fscrypt_set_d_op(struct dentry *dentry)
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{
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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d_set_d_op(dentry, &fscrypt_d_ops);
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#endif
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}
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#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
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/* crypto.c */
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extern struct kmem_cache *fscrypt_info_cachep;
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int fscrypt_initialize(void);
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extern struct fscrypt_ctx *fscrypt_get_ctx(struct inode *, gfp_t);
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extern void fscrypt_release_ctx(struct fscrypt_ctx *);
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extern struct page *fscrypt_encrypt_page(struct inode *, struct page *, gfp_t);
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extern int fscrypt_decrypt_page(struct page *);
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extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *);
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extern void fscrypt_pullback_bio_page(struct page **, bool);
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extern void fscrypt_restore_control_page(struct page *);
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extern int fscrypt_zeroout_range(struct inode *, pgoff_t, sector_t,
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unsigned int);
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/* policy.c */
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extern int fscrypt_process_policy(struct inode *,
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const struct fscrypt_policy *);
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extern int fscrypt_get_policy(struct inode *, struct fscrypt_policy *);
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extern int fscrypt_has_permitted_context(struct inode *, struct inode *);
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extern int fscrypt_inherit_context(struct inode *, struct inode *,
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void *, bool);
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/* keyinfo.c */
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extern int get_crypt_info(struct inode *);
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extern int fscrypt_get_encryption_info(struct inode *);
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extern void fscrypt_put_encryption_info(struct inode *, struct fscrypt_info *);
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/* fname.c */
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extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
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int lookup, struct fscrypt_name *);
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extern void fscrypt_free_filename(struct fscrypt_name *);
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extern u32 fscrypt_fname_encrypted_size(struct inode *, u32);
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extern int fscrypt_fname_alloc_buffer(struct inode *, u32,
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struct fscrypt_str *);
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extern void fscrypt_fname_free_buffer(struct fscrypt_str *);
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extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32,
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const struct fscrypt_str *, struct fscrypt_str *);
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extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *,
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struct fscrypt_str *);
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#endif
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/* crypto.c */
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static inline struct fscrypt_ctx *fscrypt_notsupp_get_ctx(struct inode *i,
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gfp_t f)
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{
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return ERR_PTR(-EOPNOTSUPP);
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}
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static inline void fscrypt_notsupp_release_ctx(struct fscrypt_ctx *c)
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{
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return;
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}
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static inline struct page *fscrypt_notsupp_encrypt_page(struct inode *i,
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struct page *p, gfp_t f)
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{
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return ERR_PTR(-EOPNOTSUPP);
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}
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static inline int fscrypt_notsupp_decrypt_page(struct page *p)
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{
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return -EOPNOTSUPP;
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}
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static inline void fscrypt_notsupp_decrypt_bio_pages(struct fscrypt_ctx *c,
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struct bio *b)
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{
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return;
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}
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static inline void fscrypt_notsupp_pullback_bio_page(struct page **p, bool b)
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{
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return;
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}
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static inline void fscrypt_notsupp_restore_control_page(struct page *p)
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{
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return;
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}
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static inline int fscrypt_notsupp_zeroout_range(struct inode *i, pgoff_t p,
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sector_t s, unsigned int f)
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{
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return -EOPNOTSUPP;
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}
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/* policy.c */
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static inline int fscrypt_notsupp_process_policy(struct inode *i,
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const struct fscrypt_policy *p)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_notsupp_get_policy(struct inode *i,
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struct fscrypt_policy *p)
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{
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return -EOPNOTSUPP;
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}
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static inline int fscrypt_notsupp_has_permitted_context(struct inode *p,
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struct inode *i)
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{
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return 0;
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}
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static inline int fscrypt_notsupp_inherit_context(struct inode *p,
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struct inode *i, void *v, bool b)
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{
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return -EOPNOTSUPP;
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}
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/* keyinfo.c */
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static inline int fscrypt_notsupp_get_encryption_info(struct inode *i)
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{
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return -EOPNOTSUPP;
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}
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static inline void fscrypt_notsupp_put_encryption_info(struct inode *i,
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struct fscrypt_info *f)
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{
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return;
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}
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/* fname.c */
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static inline int fscrypt_notsupp_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 (dir->i_sb->s_cop->is_encrypted(dir))
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return -EOPNOTSUPP;
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memset(fname, 0, sizeof(struct fscrypt_name));
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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_notsupp_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 u32 fscrypt_notsupp_fname_encrypted_size(struct inode *i, u32 s)
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{
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/* never happens */
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WARN_ON(1);
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return 0;
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}
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static inline int fscrypt_notsupp_fname_alloc_buffer(struct inode *inode,
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u32 ilen, 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_notsupp_fname_free_buffer(struct fscrypt_str *c)
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{
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return;
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}
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static inline int fscrypt_notsupp_fname_disk_to_usr(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 int fscrypt_notsupp_fname_usr_to_disk(struct inode *inode,
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const struct qstr *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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#endif /* _LINUX_FSCRYPTO_H */
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