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-rw-r--r--fs/ceph/crypto.h288
1 files changed, 288 insertions, 0 deletions
diff --git a/fs/ceph/crypto.h b/fs/ceph/crypto.h
new file mode 100644
index 000000000000..47e0c319fc68
--- /dev/null
+++ b/fs/ceph/crypto.h
@@ -0,0 +1,288 @@
+/* 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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