/* SPDX-License-Identifier: GPL-2.0 */
/*
* Ceph fscrypt functionality
*/
#ifndef _CEPH_CRYPTO_H
#define _CEPH_CRYPTO_H
#include <crypto/sha2.h>
#include <linux/fscrypt.h>
#define CEPH_FSCRYPT_BLOCK_SHIFT 12
#define CEPH_FSCRYPT_BLOCK_SIZE (_AC(1, UL) << CEPH_FSCRYPT_BLOCK_SHIFT)
#define CEPH_FSCRYPT_BLOCK_MASK (~(CEPH_FSCRYPT_BLOCK_SIZE-1))
struct ceph_fs_client;
struct ceph_acl_sec_ctx;
struct ceph_mds_request;
struct ceph_fname {
struct inode *dir;
char *name; // b64 encoded, possibly hashed
unsigned char *ctext; // binary crypttext (if any)
u32 name_len; // length of name buffer
u32 ctext_len; // length of crypttext
bool no_copy;
};
/*
* Header for the crypted file when truncating the size, this
* will be sent to MDS, and the MDS will update the encrypted
* last block and then truncate the size.
*/
struct ceph_fscrypt_truncate_size_header {
__u8 ver;
__u8 compat;
/*
* It will be sizeof(assert_ver + file_offset + block_size)
* if the last block is empty when it's located in a file
* hole. Or the data_len will plus CEPH_FSCRYPT_BLOCK_SIZE.
*/
__le32 data_len;
__le64 change_attr;
__le64 file_offset;
__le32 block_size;
} __packed;
struct ceph_fscrypt_auth {
__le32 cfa_version;
__le32 cfa_blob_len;
u8 cfa_blob[FSCRYPT_SET_CONTEXT_MAX_SIZE];
} __packed;
#define CEPH_FSCRYPT_AUTH_VERSION 1
static inline u32 ceph_fscrypt_auth_len(struct ceph_fscrypt_auth *fa)
{
u32 ctxsize = le32_to_cpu(fa->cfa_blob_len);
return offsetof(struct ceph_fscrypt_auth, cfa_blob) + ctxsize;
}
#ifdef CONFIG_FS_ENCRYPTION
/*
* We want to encrypt filenames when creating them, but the encrypted
* versions of those names may have illegal characters in them. To mitigate
* that, we base64 encode them, but that gives us a result that can exceed
* NAME_MAX.
*
* Follow a similar scheme to fscrypt itself, and cap the filename to a
* smaller size. If the ciphertext name is longer than the value below, then
* sha256 hash the remaining bytes.
*
* For the fscrypt_nokey_name struct the dirhash[2] member is useless in ceph
* so the corresponding struct will be:
*
* struct fscrypt_ceph_nokey_name {
* u8 bytes[157];
* u8 sha256[SHA256_DIGEST_SIZE];
* }; // 180 bytes => 240 bytes base64-encoded, which is <= NAME_MAX (255)
*
* (240 bytes is the maximum size allowed for snapshot names to take into
* account the format: '_<SNAPSHOT-NAME>_<INODE-NUMBER>'.)
*
* Note that for long names that end up having their tail portion hashed, we
* must also store the full encrypted name (in the dentry's alternate_name
* field).
*/
#define CEPH_NOHASH_NAME_MAX (180 - SHA256_DIGEST_SIZE)
#define CEPH_BASE64_CHARS(nbytes) DIV_ROUND_UP((nbytes) * 4, 3)
int ceph_base64_encode(const u8 *src, int srclen, char *dst);
int ceph_base64_decode(const char *src, int srclen, u8 *dst);
void ceph_fscrypt_set_ops(struct super_block *sb);
void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc);
int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
struct ceph_acl_sec_ctx *as);
void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
struct ceph_acl_sec_ctx *as);
int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name,
char *buf);
int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry,
char *buf);
static inline int ceph_fname_alloc_buffer(struct inode *parent,
struct fscrypt_str *fname)
{
if (!IS_ENCRYPTED(parent))
return 0;
return fscrypt_fname_alloc_buffer(NAME_MAX, fname);
}
static inline void ceph_fname_free_buffer(struct inode *parent,
struct fscrypt_str *fname)
{
if (IS_ENCRYPTED(parent))
fscrypt_fname_free_buffer(fname);
}
int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
struct fscrypt_str *oname, bool *is_nokey);
int ceph_fscrypt_prepare_readdir(struct inode *dir);
static inline unsigned int ceph_fscrypt_blocks(u64 off, u64 len)
{
/* crypto blocks cannot span more than one page */
BUILD_BUG_ON(CEPH_FSCRYPT_BLOCK_SHIFT > PAGE_SHIFT);
return ((off+len+CEPH_FSCRYPT_BLOCK_SIZE-1) >> CEPH_FSCRYPT_BLOCK_SHIFT) -
(off >> CEPH_FSCRYPT_BLOCK_SHIFT);
}
/*
* If we have an encrypted inode then we must adjust the offset and
* range of the on-the-wire read to cover an entire encryption block.
* The copy will be done using the original offset and length, after
* we've decrypted the result.
*/
static inline void ceph_fscrypt_adjust_off_and_len(struct inode *inode,
u64 *off, u64 *len)
{
if (IS_ENCRYPTED(inode)) {
*len = ceph_fscrypt_blocks(*off, *len) * CEPH_FSCRYPT_BLOCK_SIZE;
*off &= CEPH_FSCRYPT_BLOCK_MASK;
}
}
int ceph_fscrypt_decrypt_block_inplace(const struct inode *inode,
struct page *page, unsigned int len,
unsigned int offs, u64 lblk_num);
int ceph_fscrypt_encrypt_block_inplace(const struct inode *inode,
struct page *page, unsigned int len,
unsigned int offs, u64 lblk_num,
gfp_t gfp_flags);
int ceph_fscrypt_decrypt_pages(struct inode *inode, struct page **page,
u64 off, int len);
int ceph_fscrypt_decrypt_extents(struct inode *inode, struct page **page,
u64 off, struct ceph_sparse_extent *map,
u32 ext_cnt);
int ceph_fscrypt_encrypt_pages(struct inode *inode, struct page **page, u64 off,
int len, gfp_t gfp);
static inline struct page *ceph_fscrypt_pagecache_page(struct page *page)
{
return fscrypt_is_bounce_page(page) ? fscrypt_pagecache_page(page) : page;
}
#else /* CONFIG_FS_ENCRYPTION */
static inline void ceph_fscrypt_set_ops(struct super_block *sb)
{
}
static inline void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc)
{
}
static inline int ceph_fscrypt_prepare_context(struct inode *dir,
struct inode *inode,
struct ceph_acl_sec_ctx *as)
{
if (IS_ENCRYPTED(dir))
return -EOPNOTSUPP;
return 0;
}
static inline void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
struct ceph_acl_sec_ctx *as_ctx)
{
}
static inline int ceph_encode_encrypted_dname(struct inode *parent,
struct qstr *d_name, char *buf)
{
memcpy(buf, d_name->name, d_name->len);
return d_name->len;
}
static inline int ceph_encode_encrypted_fname(struct inode *parent,
struct dentry *dentry, char *buf)
{
return -EOPNOTSUPP;
}
static inline int ceph_fname_alloc_buffer(struct inode *parent,
struct fscrypt_str *fname)
{
return 0;
}
static inline void ceph_fname_free_buffer(struct inode *parent,
struct fscrypt_str *fname)
{
}
static inline int ceph_fname_to_usr(const struct ceph_fname *fname,
struct fscrypt_str *tname,
struct fscrypt_str *oname, bool *is_nokey)
{
oname->name = fname->name;
oname->len = fname->name_len;
return 0;
}
static inline int ceph_fscrypt_prepare_readdir(struct inode *dir)
{
return 0;
}
static inline void ceph_fscrypt_adjust_off_and_len(struct inode *inode,
u64 *off, u64 *len)
{
}
static inline int ceph_fscrypt_decrypt_block_inplace(const struct inode *inode,
struct page *page, unsigned int len,
unsigned int offs, u64 lblk_num)
{
return 0;
}
static inline int ceph_fscrypt_encrypt_block_inplace(const struct inode *inode,
struct page *page, unsigned int len,
unsigned int offs, u64 lblk_num,
gfp_t gfp_flags)
{
return 0;
}
static inline int ceph_fscrypt_decrypt_pages(struct inode *inode,
struct page **page, u64 off,
int len)
{
return 0;
}
static inline int ceph_fscrypt_decrypt_extents(struct inode *inode,
struct page **page, u64 off,
struct ceph_sparse_extent *map,
u32 ext_cnt)
{
return 0;
}
static inline int ceph_fscrypt_encrypt_pages(struct inode *inode,
struct page **page, u64 off,
int len, gfp_t gfp)
{
return 0;
}
static inline struct page *ceph_fscrypt_pagecache_page(struct page *page)
{
return page;
}
#endif /* CONFIG_FS_ENCRYPTION */
static inline loff_t ceph_fscrypt_page_offset(struct page *page)
{
return page_offset(ceph_fscrypt_pagecache_page(page));
}
#endif /* _CEPH_CRYPTO_H */
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