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Implement the early data changes required in tls13_change_cipher_state()

Browse source 
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2737)
This commit is contained in:
Matt Caswell 2017-02-21 16:39:43 +00:00
parent 923ac8271b
commit d49e23ec58
4 changed files with 98 additions and 33 deletions
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13
include/openssl/ssl3.h
View file

@ -299,12 +299,13 @@ extern "C" {
# define SSL3_MT_CCS 1
/* These are used when changing over to a new cipher */
# define SSL3_CC_READ 0x01
# define SSL3_CC_WRITE 0x02
# define SSL3_CC_CLIENT 0x10
# define SSL3_CC_SERVER 0x20
# define SSL3_CC_HANDSHAKE 0x40
# define SSL3_CC_APPLICATION 0x80
# define SSL3_CC_READ 0x001
# define SSL3_CC_WRITE 0x002
# define SSL3_CC_CLIENT 0x010
# define SSL3_CC_SERVER 0x020
# define SSL3_CC_EARLY 0x040
# define SSL3_CC_HANDSHAKE 0x080
# define SSL3_CC_APPLICATION 0x100
# define SSL3_CHANGE_CIPHER_CLIENT_WRITE (SSL3_CC_CLIENT|SSL3_CC_WRITE)
# define SSL3_CHANGE_CIPHER_SERVER_READ (SSL3_CC_SERVER|SSL3_CC_READ)
# define SSL3_CHANGE_CIPHER_CLIENT_READ (SSL3_CC_CLIENT|SSL3_CC_READ)

11
ssl/ssl_locl.h
View file

@ -2196,10 +2196,12 @@ __owur int tls13_hkdf_expand(SSL *s, const EVP_MD *md,
const unsigned char *label, size_t labellen,
const unsigned char *hash,
unsigned char *out, size_t outlen);
__owur int tls13_derive_key(SSL *s, const unsigned char *secret,
unsigned char *key, size_t keylen);
__owur int tls13_derive_iv(SSL *s, const unsigned char *secret,
unsigned char *iv, size_t ivlen);
__owur int tls13_derive_key(SSL *s, const EVP_MD *md,
const unsigned char *secret, unsigned char *key,
size_t keylen);
__owur int tls13_derive_iv(SSL *s, const EVP_MD *md,
const unsigned char *secret, unsigned char *iv,
size_t ivlen);
__owur int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
const unsigned char *secret,
unsigned char *fin, size_t finlen);
@ -2352,6 +2354,7 @@ __owur int ssl_log_secret(SSL *ssl, const char *label,
const uint8_t *secret, size_t secret_len);
#define MASTER_SECRET_LABEL "CLIENT_RANDOM"
#define CLIENT_EARLY_LABEL "CLIENT_EARLY_TRAFFIC_SECRET"
#define CLIENT_HANDSHAKE_LABEL "CLIENT_HANDSHAKE_TRAFFIC_SECRET"
#define SERVER_HANDSHAKE_LABEL "SERVER_HANDSHAKE_TRAFFIC_SECRET"
#define CLIENT_APPLICATION_LABEL "CLIENT_TRAFFIC_SECRET_0"

98
ssl/tls13_enc.c
View file

@ -56,6 +56,7 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
|| !WPACKET_sub_memcpy_u8(&pkt, hash, (hash == NULL) ? 0 : hashlen)
|| !WPACKET_get_total_written(&pkt, &hkdflabellen)
|| !WPACKET_finish(&pkt)) {
EVP_PKEY_CTX_free(pctx);
WPACKET_cleanup(&pkt);
return 0;
}
@ -77,26 +78,26 @@ int tls13_hkdf_expand(SSL *s, const EVP_MD *md, const unsigned char *secret,
* Given a |secret| generate a |key| of length |keylen| bytes. Returns 1 on
* success 0 on failure.
*/
int tls13_derive_key(SSL *s, const unsigned char *secret, unsigned char *key,
size_t keylen)
int tls13_derive_key(SSL *s, const EVP_MD *md, const unsigned char *secret,
unsigned char *key, size_t keylen)
{
static const unsigned char keylabel[] = "key";
return tls13_hkdf_expand(s, ssl_handshake_md(s), secret, keylabel,
sizeof(keylabel) - 1, NULL, key, keylen);
return tls13_hkdf_expand(s, md, secret, keylabel, sizeof(keylabel) - 1,
NULL, key, keylen);
}
/*
* Given a |secret| generate an |iv| of length |ivlen| bytes. Returns 1 on
* success 0 on failure.
*/
int tls13_derive_iv(SSL *s, const unsigned char *secret, unsigned char *iv,
size_t ivlen)
int tls13_derive_iv(SSL *s, const EVP_MD *md, const unsigned char *secret,
unsigned char *iv, size_t ivlen)
{
static const unsigned char ivlabel[] = "iv";
return tls13_hkdf_expand(s, ssl_handshake_md(s), secret, ivlabel,
sizeof(ivlabel) - 1, NULL, iv, ivlen);
return tls13_hkdf_expand(s, md, secret, ivlabel, sizeof(ivlabel) - 1,
NULL, iv, ivlen);
}
int tls13_derive_finishedkey(SSL *s, const EVP_MD *md,
@ -242,7 +243,8 @@ int tls13_setup_key_block(SSL *s)
return 1;
}
static int derive_secret_key_and_iv(SSL *s, int send,
static int derive_secret_key_and_iv(SSL *s, int send, const EVP_MD *md,
const EVP_CIPHER *ciph,
const unsigned char *insecret,
const unsigned char *hash,
const unsigned char *label,
@ -251,9 +253,7 @@ static int derive_secret_key_and_iv(SSL *s, int send,
{
unsigned char key[EVP_MAX_KEY_LENGTH];
size_t ivlen, keylen, taglen;
const EVP_MD *md = ssl_handshake_md(s);
size_t hashlen = EVP_MD_size(md);
const EVP_CIPHER *ciph = s->s3->tmp.new_sym_enc;
if (!tls13_hkdf_expand(s, md, insecret, label, labellen, hash, secret,
hashlen)) {
@ -275,8 +275,8 @@ static int derive_secret_key_and_iv(SSL *s, int send,
taglen = 0;
}
if (!tls13_derive_key(s, secret, key, keylen)
|| !tls13_derive_iv(s, secret, iv, ivlen)) {
if (!tls13_derive_key(s, md, secret, key, keylen)
|| !tls13_derive_iv(s, md, secret, iv, ivlen)) {
SSLerr(SSL_F_DERIVE_SECRET_KEY_AND_IV, ERR_R_INTERNAL_ERROR);
goto err;
}
@ -312,6 +312,8 @@ static int derive_secret_key_and_iv(SSL *s, int send,
int tls13_change_cipher_state(SSL *s, int which)
{
static const unsigned char client_early_traffic[] =
"client early traffic secret";
static const unsigned char client_handshake_traffic[] =
"client handshake traffic secret";
static const unsigned char client_application_traffic[] =
@ -334,6 +336,8 @@ int tls13_change_cipher_state(SSL *s, int which)
const unsigned char *label;
size_t labellen, hashlen = 0;
int ret = 0;
const EVP_MD *md;
const EVP_CIPHER *cipher;
if (which & SSL3_CC_READ) {
if (s->enc_read_ctx != NULL) {
@ -367,7 +371,51 @@ int tls13_change_cipher_state(SSL *s, int which)
if (((which & SSL3_CC_CLIENT) && (which & SSL3_CC_WRITE))
|| ((which & SSL3_CC_SERVER) && (which & SSL3_CC_READ))) {
if (which & SSL3_CC_HANDSHAKE) {
if (which & SSL3_CC_EARLY) {
EVP_MD_CTX *mdctx = NULL;
long handlen;
void *hdata;
unsigned int hashlenui;
const SSL_CIPHER *sslcipher = SSL_SESSION_get0_cipher(s->session);
insecret = s->early_secret;
label = client_early_traffic;
labellen = sizeof(client_early_traffic) - 1;
log_label = CLIENT_EARLY_LABEL;
handlen = BIO_get_mem_data(s->s3->handshake_buffer, &hdata);
if (handlen <= 0) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE,
SSL_R_BAD_HANDSHAKE_LENGTH);
goto err;
}
if (sslcipher == NULL) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
goto err;
}
/*
* We need to calculate the handshake digest using the digest from
* the session. We haven't yet selected our ciphersuite so we can't
* use ssl_handshake_md().
*/
mdctx = EVP_MD_CTX_new();
if (mdctx == NULL) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_MALLOC_FAILURE);
goto err;
}
cipher = EVP_get_cipherbynid(SSL_CIPHER_get_cipher_nid(sslcipher));
md = ssl_md(sslcipher->algorithm2);
if (md == NULL || !EVP_DigestInit_ex(mdctx, md, NULL)
|| !EVP_DigestUpdate(mdctx, hdata, handlen)
|| !EVP_DigestFinal_ex(mdctx, hashval, &hashlenui)) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
EVP_MD_CTX_free(mdctx);
goto err;
}
hashlen = hashlenui;
EVP_MD_CTX_free(mdctx);
} else if (which & SSL3_CC_HANDSHAKE) {
insecret = s->handshake_secret;
finsecret = s->client_finished_secret;
finsecretlen = EVP_MD_size(ssl_handshake_md(s));
@ -388,6 +436,7 @@ int tls13_change_cipher_state(SSL *s, int which)
hash = s->server_finished_hash;
}
} else {
/* Early data never applies to client-read/server-write */
if (which & SSL3_CC_HANDSHAKE) {
insecret = s->handshake_secret;
finsecret = s->server_finished_secret;
@ -403,10 +452,14 @@ int tls13_change_cipher_state(SSL *s, int which)
}
}
if (!ssl3_digest_cached_records(s, 1)
|| !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
goto err;
if (!(which & SSL3_CC_EARLY)) {
md = ssl_handshake_md(s);
cipher = s->s3->tmp.new_sym_enc;
if (!ssl3_digest_cached_records(s, 1)
|| !ssl_handshake_hash(s, hashval, sizeof(hashval), &hashlen)) {
SSLerr(SSL_F_TLS13_CHANGE_CIPHER_STATE, ERR_R_INTERNAL_ERROR);
goto err;
}
}
/*
@ -431,8 +484,9 @@ int tls13_change_cipher_state(SSL *s, int which)
s->session->master_key_length = hashlen;
}
if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, insecret, hash,
label, labellen, secret, iv, ciph_ctx)) {
if (!derive_secret_key_and_iv(s, which & SSL3_CC_WRITE, md, cipher,
insecret, hash, label, labellen, secret, iv,
ciph_ctx)) {
goto err;
}
@ -485,7 +539,9 @@ int tls13_update_key(SSL *s, int send)
RECORD_LAYER_reset_read_sequence(&s->rlayer);
}
if (!derive_secret_key_and_iv(s, send, insecret, NULL, application_traffic,
if (!derive_secret_key_and_iv(s, send, ssl_handshake_md(s),
s->s3->tmp.new_sym_enc, insecret, NULL,
application_traffic,
sizeof(application_traffic) - 1, secret, iv,
ciph_ctx))
goto err;

9
test/tls13secretstest.c
View file

@ -192,6 +192,11 @@ int ssl_log_secret(SSL *ssl,
return 1;
}
const EVP_MD *ssl_md(int idx)
{
return EVP_sha256();
}
/* End of mocked out code */
static int test_secret(SSL *s, unsigned char *prk,
@ -222,7 +227,7 @@ static int test_secret(SSL *s, unsigned char *prk,
return 0;
}
if (!tls13_derive_key(s, gensecret, key, KEYLEN)) {
if (!tls13_derive_key(s, md, gensecret, key, KEYLEN)) {
fprintf(stderr, "Key generation failed\n");
return 0;
}
@ -232,7 +237,7 @@ static int test_secret(SSL *s, unsigned char *prk,
return 0;
}
if (!tls13_derive_iv(s, gensecret, iv, IVLEN)) {
if (!tls13_derive_iv(s, md, gensecret, iv, IVLEN)) {
fprintf(stderr, "IV generation failed\n");
return 0;
}