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-rw-r--r--include/linux/fscrypt.h122
1 files changed, 45 insertions, 77 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 1a7bffe78ed5..556f4adf5dc5 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -72,6 +72,21 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode)
return READ_ONCE(inode->i_crypt_info) != NULL;
}
+/**
+ * fscrypt_needs_contents_encryption() - check whether an inode needs
+ * contents encryption
+ *
+ * Return: %true iff the inode is an encrypted regular file and the kernel was
+ * built with fscrypt support.
+ *
+ * If you need to know whether the encrypt bit is set even when the kernel was
+ * built without fscrypt support, you must use IS_ENCRYPTED() directly instead.
+ */
+static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
+{
+ return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
+}
+
static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
{
return inode->i_sb->s_cop->dummy_context &&
@@ -153,82 +168,14 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname)
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 *);
-
-#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->disk_name.name)) {
- const struct fscrypt_digested_name *n =
- (const void *)fname->crypto_buf.name;
- 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->disk_name.name, fname->disk_name.len);
-}
+extern int fscrypt_fname_disk_to_usr(const struct inode *inode,
+ u32 hash, u32 minor_hash,
+ const struct fscrypt_str *iname,
+ struct fscrypt_str *oname);
+extern bool fscrypt_match_name(const struct fscrypt_name *fname,
+ const u8 *de_name, u32 de_name_len);
+extern u64 fscrypt_fname_siphash(const struct inode *dir,
+ const struct qstr *name);
/* bio.c */
extern void fscrypt_decrypt_bio(struct bio *);
@@ -246,6 +193,8 @@ extern int __fscrypt_prepare_rename(struct inode *old_dir,
unsigned int flags);
extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry,
struct fscrypt_name *fname);
+extern int fscrypt_prepare_setflags(struct inode *inode,
+ unsigned int oldflags, unsigned int flags);
extern int __fscrypt_prepare_symlink(struct inode *dir, unsigned int len,
unsigned int max_len,
struct fscrypt_str *disk_link);
@@ -267,6 +216,11 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode)
return false;
}
+static inline bool fscrypt_needs_contents_encryption(const struct inode *inode)
+{
+ return false;
+}
+
static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
{
return false;
@@ -438,7 +392,7 @@ static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)
return;
}
-static inline int fscrypt_fname_disk_to_usr(struct inode *inode,
+static inline int fscrypt_fname_disk_to_usr(const struct inode *inode,
u32 hash, u32 minor_hash,
const struct fscrypt_str *iname,
struct fscrypt_str *oname)
@@ -455,6 +409,13 @@ static inline bool fscrypt_match_name(const struct fscrypt_name *fname,
return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len);
}
+static inline u64 fscrypt_fname_siphash(const struct inode *dir,
+ const struct qstr *name)
+{
+ WARN_ON_ONCE(1);
+ return 0;
+}
+
/* bio.c */
static inline void fscrypt_decrypt_bio(struct bio *bio)
{
@@ -497,6 +458,13 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir,
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,