On Sun, Jan 24, 2021 at 03:04:31PM +0100, Stephan Müller wrote: > @@ -74,16 +57,14 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, > return PTR_ERR(hmac_tfm); > } > > - if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != sizeof(prk))) { > + if (WARN_ON(crypto_shash_digestsize(hmac_tfm) != HKDF_HASHLEN)) { > err = -EINVAL; > goto err_free_tfm; > } > > - err = hkdf_extract(hmac_tfm, master_key, master_key_size, prk); > - if (err) > - goto err_free_tfm; > - > - err = crypto_shash_setkey(hmac_tfm, prk, sizeof(prk)); > + /* HKDF-Extract (RFC 5869 section 2.2), unsalted */ > + err = crypto_hkdf_extract(hmac_tfm, NULL, 0, > + master_key, master_key_size); > if (err) > goto err_free_tfm; > > @@ -93,7 +74,6 @@ int fscrypt_init_hkdf(struct fscrypt_hkdf *hkdf, const u8 *master_key, > err_free_tfm: > crypto_free_shash(hmac_tfm); > out: > - memzero_explicit(prk, sizeof(prk)); > return err; > } The 'out' label isn't needed anymore. 'goto out' should be replaced with 'return 0'. - Eric