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linux: update TLS version 1 PSK derivation
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The original implementation for handling 'version 1' TLS PSK derivation
was incomplete as the 'label' argument for the HKDF-Expand-Label
functionality was not according to the spec.
Update the implementation to match the spec.

Signed-off-by: Hannes Reinecke <hare@suse.de>
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@hreinecke @igaw
hreinecke authored and igaw committed Aug 1, 2024
1 parent 12346ad commit 854a6dc
Showing 1 changed file with 90 additions and 62 deletions.
152 changes: 90 additions & 62 deletions src/nvme/linux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -551,22 +551,18 @@ static int derive_retained_key(int hmac, const char *hostnqn,
return -1;
}

static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
int version, int hmac, char *identity,
unsigned char *retained, size_t key_len)
static int derive_psk_digest(const char *hostnqn, const char *subsysnqn,
int version, int hmac,
unsigned char *retained, size_t key_len,
char *digest, size_t digest_len)
{
if (version != 0) {
nvme_msg(NULL, LOG_ERR, "NVMe TLS 2.0 is not supported; "
"recompile with OpenSSL support.\n");
errno = ENOTSUP;
return -1;
}
sprintf(identity, "NVMe0R%02d %s %s",
hmac, hostnqn, subsysnqn);
return strlen(identity);
nvme_msg(NULL, LOG_ERR, "NVMe TLS 2.0 is not supported; "
"recompile with OpenSSL support.\n");
errno = ENOTSUP;
return -1;
}

static int derive_tls_key(int hmac, const char *identity,
static int derive_tls_key(int version, int hmac, const char *context,
unsigned char *retained,
unsigned char *psk, size_t key_len)
{
Expand Down Expand Up @@ -662,7 +658,7 @@ static int derive_retained_key(int hmac, const char *hostnqn,
return key_len;
}

static int derive_tls_key(int hmac, const char *identity,
static int derive_tls_key(int version, int hmac, const char *context,
unsigned char *retained,
unsigned char *psk, size_t key_len)
{
Expand Down Expand Up @@ -710,9 +706,20 @@ static int derive_tls_key(int hmac, const char *identity,
errno = ENOKEY;
return -1;
}
if (version == 1) {
char hash_str[4];

sprintf(hash_str, "%02d ", hmac);
if (EVP_PKEY_CTX_add1_hkdf_info(ctx,
(const unsigned char *)hash_str,
strlen(hash_str)) <= 0) {
errno = ENOKEY;
return -1;
}
}
if (EVP_PKEY_CTX_add1_hkdf_info(ctx,
(const unsigned char *)identity,
strlen(identity)) <= 0) {
(const unsigned char *)context,
strlen(context)) <= 0) {
errno = ENOKEY;
return -1;
}
Expand Down Expand Up @@ -792,28 +799,18 @@ int nvme_gen_dhchap_key(char *hostnqn, enum nvme_hmac_alg hmac,
return 0;
}

static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
int version, int hmac, char *identity,
unsigned char *retained, size_t key_len)
static int derive_psk_digest(const char *hostnqn, const char *subsysnqn,
int version, int hmac,
unsigned char *retained, size_t key_len,
char *digest, size_t digest_len)
{
static const char hmac_seed[] = "NVMe-over-Fabrics";
size_t hmac_len;
const EVP_MD *md = select_hmac(hmac, &hmac_len);
_cleanup_hmac_ctx_ HMAC_CTX *hmac_ctx = NULL;
_cleanup_free_ unsigned char *psk_ctx = NULL;
_cleanup_free_ char *enc_ctx = NULL;
size_t len;

if (version == 0) {
sprintf(identity, "NVMe%01dR%02d %s %s",
version, hmac, hostnqn, subsysnqn);
return strlen(identity);
}
if (version > 1) {
errno = EINVAL;
return -1;
}

hmac_ctx = HMAC_CTX_new();
if (!hmac_ctx) {
errno = ENOMEM;
Expand Down Expand Up @@ -860,17 +857,19 @@ static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
errno = ENOKEY;
return -1;
}
enc_ctx = malloc(key_len * 2);
memset(enc_ctx, 0, key_len * 2);
len = base64_encode(psk_ctx, key_len, enc_ctx);
if (key_len * 2 > digest_len) {
errno = EINVAL;
return -1;
}
memset(digest, 0, digest_len);
len = base64_encode(psk_ctx, key_len, digest);
if (len < 0) {
errno = ENOKEY;
return len;
}
sprintf(identity, "NVMe%01dR%02d %s %s %s",
version, hmac, hostnqn, subsysnqn, enc_ctx);
return strlen(identity);
return strlen(digest);
}

#endif /* !CONFIG_OPENSSL_1 */

#ifdef CONFIG_OPENSSL_3
Expand Down Expand Up @@ -965,9 +964,10 @@ int nvme_gen_dhchap_key(char *hostnqn, enum nvme_hmac_alg hmac,
return 0;
}

static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
int version, int hmac, char *identity,
unsigned char *retained, size_t key_len)
static int derive_psk_digest(const char *hostnqn, const char *subsysnqn,
int version, int hmac,
unsigned char *retained, size_t key_len,
char *digest, size_t digest_len)
{
static const char hmac_seed[] = "NVMe-over-Fabrics";
size_t hmac_len;
Expand All @@ -976,21 +976,10 @@ static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
_cleanup_evp_mac_ctx_ EVP_MAC_CTX *mac_ctx = NULL;
_cleanup_evp_mac_ EVP_MAC *mac = NULL;
char *progq = NULL;
char *digest = NULL;
char *dig = NULL;
_cleanup_free_ unsigned char *psk_ctx = NULL;
_cleanup_free_ char *enc_ctx = NULL;
size_t len;

if (version == 0) {
sprintf(identity, "NVMe%01dR%02d %s %s",
version, hmac, hostnqn, subsysnqn);
return strlen(identity);
}
if (version > 1) {
errno = EINVAL;
return -1;
}

lib_ctx = OSSL_LIB_CTX_new();
if (!lib_ctx) {
errno = ENOMEM;
Expand All @@ -1009,19 +998,19 @@ static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
}
switch (hmac) {
case NVME_HMAC_ALG_SHA2_256:
digest = OSSL_DIGEST_NAME_SHA2_256;
dig = OSSL_DIGEST_NAME_SHA2_256;
break;
case NVME_HMAC_ALG_SHA2_384:
digest = OSSL_DIGEST_NAME_SHA2_384;
dig = OSSL_DIGEST_NAME_SHA2_384;
break;
default:
errno = EINVAL;
break;
}
if (!digest)
if (!dig)
return -1;
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST,
digest, 0);
dig, 0);
*p = OSSL_PARAM_construct_end();

psk_ctx = malloc(key_len);
Expand Down Expand Up @@ -1065,25 +1054,47 @@ static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
errno = EMSGSIZE;
return -1;
}
enc_ctx = malloc(hmac_len * 2);
memset(enc_ctx, 0, hmac_len * 2);
len = base64_encode(psk_ctx, hmac_len, enc_ctx);
if (hmac_len * 2 > digest_len) {
errno = EINVAL;
return -1;
}
memset(digest, 0, digest_len);
len = base64_encode(psk_ctx, hmac_len, digest);
if (len < 0) {
errno = ENOKEY;
return len;
}
return strlen(digest);
}
#endif /* !CONFIG_OPENSSL_3 */

static int gen_tls_identity(const char *hostnqn, const char *subsysnqn,
int version, int hmac, char *digest,
char *identity)
{
if (version == 0) {
sprintf(identity, "NVMe%01dR%02d %s %s",
version, hmac, hostnqn, subsysnqn);
return strlen(identity);
}
if (version > 1) {
errno = EINVAL;
return -1;
}

sprintf(identity, "NVMe%01dR%02d %s %s %s",
version, hmac, hostnqn, subsysnqn, enc_ctx);
version, hmac, hostnqn, subsysnqn, digest);
return strlen(identity);
}
#endif /* !CONFIG_OPENSSL_3 */

static int derive_nvme_keys(const char *hostnqn, const char *subsysnqn,
char *identity, int version,
int hmac, unsigned char *configured,
unsigned char *psk, int key_len)
{
_cleanup_free_ unsigned char *retained = NULL;
_cleanup_free_ char *digest = NULL;
char *context = identity;
int ret = -1;

if (!hostnqn || !subsysnqn || !identity || !psk) {
Expand All @@ -1099,11 +1110,28 @@ static int derive_nvme_keys(const char *hostnqn, const char *subsysnqn,
ret = derive_retained_key(hmac, hostnqn, configured, retained, key_len);
if (ret < 0)
return ret;

if (version == 1) {
size_t digest_len = 2 * key_len;

digest = malloc(digest_len);
if (!digest) {
errno = ENOMEM;
return -1;
}
ret = derive_psk_digest(hostnqn, subsysnqn, version, hmac,
retained, key_len,
digest, digest_len);
if (ret)
return ret;
context = digest;
}
ret = gen_tls_identity(hostnqn, subsysnqn, version, hmac,
identity, retained, key_len);
digest, identity);
if (ret < 0)
return ret;
return derive_tls_key(hmac, identity, retained, psk, key_len);
return derive_tls_key(version, hmac, context, retained,
psk, key_len);
}

static size_t nvme_identity_len(int hmac, int version, const char *hostnqn,
Expand Down

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