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Release 4.12 include/linux/fscrypt_supp.h

Directory: include/linux
 * fscrypt_supp.h
 * This is included by filesystems configured with encryption support.



#include <linux/fscrypt_common.h>

/* crypto.c */
extern struct kmem_cache *fscrypt_info_cachep;
extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
extern void fscrypt_release_ctx(struct fscrypt_ctx *);
extern struct page *fscrypt_encrypt_page(const struct inode *, struct page *,
						unsigned int, unsigned int,
						u64, gfp_t);
extern int fscrypt_decrypt_page(const struct inode *, struct page *, unsigned int,
				unsigned int, u64);
extern void fscrypt_restore_control_page(struct page *);

extern const struct dentry_operations fscrypt_d_ops;

static inline void fscrypt_set_d_op(struct dentry *dentry) { d_set_d_op(dentry, &fscrypt_d_ops); }


Eric Biggers20100.00%1100.00%

static inline void fscrypt_set_encrypted_dentry(struct dentry *dentry) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY; spin_unlock(&dentry->d_lock); }


Eric Biggers34100.00%1100.00%

/* policy.c */ extern int fscrypt_ioctl_set_policy(struct file *, const void __user *); extern int fscrypt_ioctl_get_policy(struct file *, void __user *); extern int fscrypt_has_permitted_context(struct inode *, struct inode *); extern int fscrypt_inherit_context(struct inode *, struct inode *, void *, bool); /* keyinfo.c */ extern int fscrypt_get_encryption_info(struct inode *); extern void fscrypt_put_encryption_info(struct inode *, struct fscrypt_info *); /* fname.c */ extern int fscrypt_setup_filename(struct inode *, const struct qstr *, int lookup, struct fscrypt_name *); extern void fscrypt_free_filename(struct fscrypt_name *); extern u32 fscrypt_fname_encrypted_size(const struct inode *, u32); extern int fscrypt_fname_alloc_buffer(const struct inode *, u32, struct fscrypt_str *); extern void fscrypt_fname_free_buffer(struct fscrypt_str *); extern int fscrypt_fname_disk_to_usr(struct inode *, u32, u32, const struct fscrypt_str *, struct fscrypt_str *); extern int fscrypt_fname_usr_to_disk(struct inode *, const struct qstr *, struct fscrypt_str *); #define FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE 32 /* Extracts the second-to-last ciphertext block; see explanation below */ #define FSCRYPT_FNAME_DIGEST(name, len) \ ((name) + round_down((len) - FS_CRYPTO_BLOCK_SIZE - 1, \ FS_CRYPTO_BLOCK_SIZE)) #define FSCRYPT_FNAME_DIGEST_SIZE FS_CRYPTO_BLOCK_SIZE /** * fscrypt_digested_name - alternate identifier for an on-disk filename * * When userspace lists an encrypted directory without access to the key, * filenames whose ciphertext is longer than FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE * bytes are shown in this abbreviated form (base64-encoded) rather than as the * full ciphertext (base64-encoded). This is necessary to allow supporting * filenames up to NAME_MAX bytes, since base64 encoding expands the length. * * To make it possible for filesystems to still find the correct directory entry * despite not knowing the full on-disk name, we encode any filesystem-specific * 'hash' and/or 'minor_hash' which the filesystem may need for its lookups, * followed by the second-to-last ciphertext block of the filename. Due to the * use of the CBC-CTS encryption mode, the second-to-last ciphertext block * depends on the full plaintext. (Note that ciphertext stealing causes the * last two blocks to appear "flipped".) This makes accidental collisions very * unlikely: just a 1 in 2^128 chance for two filenames to collide even if they * share the same filesystem-specific hashes. * * However, this scheme isn't immune to intentional collisions, which can be * created by anyone able to create arbitrary plaintext filenames and view them * without the key. Making the "digest" be a real cryptographic hash like * SHA-256 over the full ciphertext would prevent this, although it would be * less efficient and harder to implement, especially since the filesystem would * need to calculate it for each directory entry examined during a search. */ struct fscrypt_digested_name { u32 hash; u32 minor_hash; u8 digest[FSCRYPT_FNAME_DIGEST_SIZE]; }; /** * fscrypt_match_name() - test whether the given name matches a directory entry * @fname: the name being searched for * @de_name: the name from the directory entry * @de_name_len: the length of @de_name in bytes * * Normally @fname->disk_name will be set, and in that case we simply compare * that to the name stored in the directory entry. The only exception is that * if we don't have the key for an encrypted directory and a filename in it is * very long, then we won't have the full disk_name and we'll instead need to * match against the fscrypt_digested_name. * * Return: %true if the name matches, otherwise %false. */
static inline bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len) { if (unlikely(!fname-> { const struct fscrypt_digested_name *n = (const void *)fname->; if (WARN_ON_ONCE(fname->usr_fname->name[0] != '_')) return false; if (de_name_len <= FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE) return false; return !memcmp(FSCRYPT_FNAME_DIGEST(de_name, de_name_len), n->digest, FSCRYPT_FNAME_DIGEST_SIZE); } if (de_name_len != fname->disk_name.len) return false; return !memcmp(de_name, fname->, fname->disk_name.len); }


Eric Biggers130100.00%1100.00%

/* bio.c */ extern void fscrypt_decrypt_bio_pages(struct fscrypt_ctx *, struct bio *); extern void fscrypt_pullback_bio_page(struct page **, bool); extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t, unsigned int); #endif /* _LINUX_FSCRYPT_SUPP_H */

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Directory: include/linux
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