diff options
| author | Chris Leech <cleech@redhat.com> | 2025-08-21 13:48:15 -0700 |
|---|---|---|
| committer | Keith Busch <kbusch@kernel.org> | 2025-09-15 16:42:07 -0700 |
| commit | 1cab50da62aa810e532396fcaeb96cf9c3fdf87a (patch) | |
| tree | d4d2acfd60189c7a6ba7166513390c218d997cd7 | |
| parent | df4666a4908a6d883f628f93a3e6c80981332035 (diff) | |
nvme-auth: add hkdf_expand_label()
Provide an implementation of RFC 8446 (TLS 1.3) HKDF-Expand-Label
Signed-off-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Hannes Reinecke <hare@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
| -rw-r--r-- | drivers/nvme/common/auth.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/drivers/nvme/common/auth.c b/drivers/nvme/common/auth.c index 91e273b89fea..c6eae8e6b6f9 100644 --- a/drivers/nvme/common/auth.c +++ b/drivers/nvme/common/auth.c @@ -684,6 +684,59 @@ out_free_enc: EXPORT_SYMBOL_GPL(nvme_auth_generate_digest); /** + * hkdf_expand_label - HKDF-Expand-Label (RFC 8846 section 7.1) + * @hmac_tfm: hash context keyed with pseudorandom key + * @label: ASCII label without "tls13 " prefix + * @labellen: length of @label + * @context: context bytes + * @contextlen: length of @context + * @okm: output keying material + * @okmlen: length of @okm + * + * Build the TLS 1.3 HkdfLabel structure and invoke hkdf_expand(). + * + * Returns 0 on success with output keying material stored in @okm, + * or a negative errno value otherwise. + */ +static int hkdf_expand_label(struct crypto_shash *hmac_tfm, + const u8 *label, unsigned int labellen, + const u8 *context, unsigned int contextlen, + u8 *okm, unsigned int okmlen) +{ + int err; + u8 *info; + unsigned int infolen; + const char *tls13_prefix = "tls13 "; + unsigned int prefixlen = strlen(tls13_prefix); + + if (WARN_ON(labellen > (255 - prefixlen))) + return -EINVAL; + if (WARN_ON(contextlen > 255)) + return -EINVAL; + + infolen = 2 + (1 + prefixlen + labellen) + (1 + contextlen); + info = kzalloc(infolen, GFP_KERNEL); + if (!info) + return -ENOMEM; + + /* HkdfLabel.Length */ + put_unaligned_be16(okmlen, info); + + /* HkdfLabel.Label */ + info[2] = prefixlen + labellen; + memcpy(info + 3, tls13_prefix, prefixlen); + memcpy(info + 3 + prefixlen, label, labellen); + + /* HkdfLabel.Context */ + info[3 + prefixlen + labellen] = contextlen; + memcpy(info + 4 + prefixlen + labellen, context, contextlen); + + err = hkdf_expand(hmac_tfm, info, infolen, okm, okmlen); + kfree_sensitive(info); + return err; +} + +/** * nvme_auth_derive_tls_psk - Derive TLS PSK * @hmac_id: Hash function identifier * @psk: generated input PSK |