sharpetronics/strongswan
1
0
Fork 0
mirror of https://github.com/strongswan/strongswan.git synced 2025-10-08 00:02:03 -04:00
Code Issues Projects Releases Wiki Activity

tls-hkdf: Handle label expansion inside expand_label()

Browse Source 
We have to expand arbitrary external labels the same way when exporting
key material.
This commit is contained in:
Tobias Brunner 2020-09-01 18:48:41 +02:00
parent 3e89d26e1c
commit 86cda1a3c0
1 changed files with 22 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
src/libtls/tls_hkdf.c
View File

@ -75,16 +75,16 @@ struct private_tls_hkdf_t {
}; };
static char *hkdf_labels[] = { static char *hkdf_labels[] = {
"tls13 ext binder", "ext binder",
"tls13 res binder", "res binder",
"tls13 c e traffic", "c e traffic",
"tls13 e exp master", "e exp master",
"tls13 c hs traffic", "c hs traffic",
"tls13 s hs traffic", "s hs traffic",
"tls13 c ap traffic", "c ap traffic",
"tls13 s ap traffic", "s ap traffic",
"tls13 exp master", "exp master",
"tls13 res master", "res master",
}; };
/** /**
@ -149,7 +149,7 @@ static bool expand_label(private_tls_hkdf_t *this, chunk_t secret,
{ {
bool success; bool success;
if (label.len < 7 || label.len > 255 || context.len > 255) if (!label.len || label.len > 249 || context.len > 255)
{ {
return FALSE; return FALSE;
} }
@ -157,6 +157,7 @@ static bool expand_label(private_tls_hkdf_t *this, chunk_t secret,
/* HKDFLabel as defined in RFC 8446, section 7.1 */ /* HKDFLabel as defined in RFC 8446, section 7.1 */
bio_writer_t *writer = bio_writer_create(0); bio_writer_t *writer = bio_writer_create(0);
writer->write_uint16(writer, length); writer->write_uint16(writer, length);
label = chunk_cata("cc", chunk_from_str("tls13 "), label);
writer->write_data8(writer, label); writer->write_data8(writer, label);
writer->write_data8(writer, context); writer->write_data8(writer, context);
@ -251,7 +252,7 @@ static bool move_to_phase_1(private_tls_hkdf_t *this)
*/ */
static bool move_to_phase_2(private_tls_hkdf_t *this) static bool move_to_phase_2(private_tls_hkdf_t *this)
{ {
chunk_t derived, okm; chunk_t okm;
switch (this->phase) switch (this->phase)
{ {
@ -263,8 +264,8 @@ static bool move_to_phase_2(private_tls_hkdf_t *this)
} }
/* fall-through */ /* fall-through */
case HKDF_PHASE_1: case HKDF_PHASE_1:
derived = chunk_from_str("tls13 derived"); if (!derive_secret(this, this->prk, chunk_from_str("derived"),
if (!derive_secret(this, this->prk, derived, chunk_empty, &okm)) chunk_empty, &okm))
{ {
DBG1(DBG_TLS, "unable to derive secret"); DBG1(DBG_TLS, "unable to derive secret");
return FALSE; return FALSE;
@ -320,7 +321,7 @@ static bool move_to_phase_2(private_tls_hkdf_t *this)
*/ */
static bool move_to_phase_3(private_tls_hkdf_t *this) static bool move_to_phase_3(private_tls_hkdf_t *this)
{ {
chunk_t derived, okm, ikm_zero; chunk_t okm, ikm_zero;
switch (this->phase) switch (this->phase)
{ {
@ -334,8 +335,8 @@ static bool move_to_phase_3(private_tls_hkdf_t *this)
/* fall-through */ /* fall-through */
case HKDF_PHASE_2: case HKDF_PHASE_2:
/* prepare okm for next extract */ /* prepare okm for next extract */
derived = chunk_from_str("tls13 derived"); if (!derive_secret(this, this->prk, chunk_from_str("derived"),
if (!derive_secret(this, this->prk, derived, chunk_empty, &okm)) chunk_empty, &okm))
{ {
DBG1(DBG_TLS, "unable to derive secret"); DBG1(DBG_TLS, "unable to derive secret");
return FALSE; return FALSE;
@ -424,7 +425,7 @@ METHOD(tls_hkdf_t, generate_secret, bool,
previous = this->server_traffic_secret; previous = this->server_traffic_secret;
} }
if (!expand_label(this, previous, chunk_from_str("tls13 traffic upd"), if (!expand_label(this, previous, chunk_from_str("traffic upd"),
chunk_empty, this->hasher->get_hash_size(this->hasher), chunk_empty, this->hasher->get_hash_size(this->hasher),
&okm)) &okm))
{ {
@ -503,21 +504,21 @@ static bool get_shared_label_keys(private_tls_hkdf_t *this, chunk_t label,
METHOD(tls_hkdf_t, derive_key, bool, METHOD(tls_hkdf_t, derive_key, bool,
private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *key) private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *key)
{ {
return get_shared_label_keys(this, chunk_from_str("tls13 key"), is_server, return get_shared_label_keys(this, chunk_from_str("key"), is_server,
length, key); length, key);
} }
METHOD(tls_hkdf_t, derive_iv, bool, METHOD(tls_hkdf_t, derive_iv, bool,
private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *iv) private_tls_hkdf_t *this, bool is_server, size_t length, chunk_t *iv)
{ {
return get_shared_label_keys(this, chunk_from_str("tls13 iv"), is_server, return get_shared_label_keys(this, chunk_from_str("iv"), is_server,
length, iv); length, iv);
} }
METHOD(tls_hkdf_t, derive_finished, bool, METHOD(tls_hkdf_t, derive_finished, bool,
private_tls_hkdf_t *this, bool is_server, chunk_t *finished) private_tls_hkdf_t *this, bool is_server, chunk_t *finished)
{ {
return get_shared_label_keys(this, chunk_from_str("tls13 finished"), return get_shared_label_keys(this, chunk_from_str("finished"),
is_server, is_server,
this->hasher->get_hash_size(this->hasher), this->hasher->get_hash_size(this->hasher),
finished); finished);