Commit a58e2035 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt 

Pull fscrypt updates from Eric Biggers:
 "A couple bug fixes for fs/crypto/:

   - Fix handling of major dirhash values that happen to be 0.

   - Fix cases where keys were derived differently on big endian systems
     than on little endian systems (affecting some newer features only)"

* tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/fscrypt:
  fscrypt: fix derivation of SipHash keys on big endian CPUs
  fscrypt: don't ignore minor_hash when hash is 0
parents a60c538e 2fc2b430

fs/crypto/fname.c

+3 −7
Original line number Diff line number Diff line
@@ -344,13 +344,9 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, 
		     offsetof(struct fscrypt_nokey_name, sha256));

	BUILD_BUG_ON(BASE64_CHARS(FSCRYPT_NOKEY_NAME_MAX) > NAME_MAX);



	if (hash) {

	nokey_name.dirhash[0] = hash;

	nokey_name.dirhash[1] = minor_hash;

	} else {

		nokey_name.dirhash[0] = 0;

		nokey_name.dirhash[1] = 0;

	}



	if (iname->len <= sizeof(nokey_name.bytes)) {

		memcpy(nokey_name.bytes, iname->name, iname->len);

		size = offsetof(struct fscrypt_nokey_name, bytes[iname->len]);

fs/crypto/keysetup.c

+32 −8
Original line number Diff line number Diff line
@@ -210,15 +210,40 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci, 
	return err;

}



/*

 * Derive a SipHash key from the given fscrypt master key and the given

 * application-specific information string.

 *

 * Note that the KDF produces a byte array, but the SipHash APIs expect the key

 * as a pair of 64-bit words.  Therefore, on big endian CPUs we have to do an

 * endianness swap in order to get the same results as on little endian CPUs.

 */

static int fscrypt_derive_siphash_key(const struct fscrypt_master_key *mk,

				      u8 context, const u8 *info,

				      unsigned int infolen, siphash_key_t *key)

{

	int err;



	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, context, info, infolen,

				  (u8 *)key, sizeof(*key));

	if (err)

		return err;



	BUILD_BUG_ON(sizeof(*key) != 16);

	BUILD_BUG_ON(ARRAY_SIZE(key->key) != 2);

	le64_to_cpus(&key->key[0]);

	le64_to_cpus(&key->key[1]);

	return 0;

}



int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,

			       const struct fscrypt_master_key *mk)

{

	int err;



	err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf, HKDF_CONTEXT_DIRHASH_KEY,

	err = fscrypt_derive_siphash_key(mk, HKDF_CONTEXT_DIRHASH_KEY,

					 ci->ci_nonce, FSCRYPT_FILE_NONCE_SIZE,

				  (u8 *)&ci->ci_dirhash_key,

				  sizeof(ci->ci_dirhash_key));

					 &ci->ci_dirhash_key);

	if (err)

		return err;

	ci->ci_dirhash_key_initialized = true;
@@ -253,10 +278,9 @@ static int fscrypt_setup_iv_ino_lblk_32_key(struct fscrypt_info *ci, 
		if (mk->mk_ino_hash_key_initialized)

			goto unlock;



		err = fscrypt_hkdf_expand(&mk->mk_secret.hkdf,

					  HKDF_CONTEXT_INODE_HASH_KEY, NULL, 0,

					  (u8 *)&mk->mk_ino_hash_key,

					  sizeof(mk->mk_ino_hash_key));

		err = fscrypt_derive_siphash_key(mk,

						 HKDF_CONTEXT_INODE_HASH_KEY,

						 NULL, 0, &mk->mk_ino_hash_key);

		if (err)

			goto unlock;

		/* pairs with smp_load_acquire() above */