Re: [PATCH v2 6/7] fs: use HKDF implementation from kernel crypto API
From: Eric Biggers <ebiggers@kernel.org>
Date: 2021-01-28 20:20:02
Also in:
keyrings, linux-fscrypt, lkml
On Sun, Jan 24, 2021 at 03:04:31PM +0100, Stephan Müller wrote:
quoted hunk ↗ jump to hunk
@@ -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