wbrawner/openssl
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Parse large GOST ClientKeyExchange messages

Browse source 
Large GOST ClientKeyExchange messages are sent by VipNet CSP, one of
Russian certified products implementing GOST TLS, when a server
certificate contains 512-bit keys.

This behaviour was present in 1.0.2 branch and needs to be restored.
Backport of #10376

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10376)
This commit is contained in:
Dmitry Belyavskiy 2019-11-07 17:35:13 +03:00
parent 5fe8210085
commit fa2f67f707
1 changed files with 41 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

75
ssl/statem/statem_srvr.c
View file

@ -23,9 +23,24 @@
#include <openssl/dh.h>
#include <openssl/bn.h>
#include <openssl/md5.h>
#include <openssl/asn1t.h>
#define TICKET_NONCE_SIZE 8
typedef struct {
ASN1_TYPE *kxBlob;
ASN1_TYPE *opaqueBlob;
} GOST_KX_MESSAGE;
DECLARE_ASN1_FUNCTIONS(GOST_KX_MESSAGE)
ASN1_SEQUENCE(GOST_KX_MESSAGE) = {
ASN1_SIMPLE(GOST_KX_MESSAGE, kxBlob, ASN1_ANY),
ASN1_OPT(GOST_KX_MESSAGE, opaqueBlob, ASN1_ANY),
} ASN1_SEQUENCE_END(GOST_KX_MESSAGE)
IMPLEMENT_ASN1_FUNCTIONS(GOST_KX_MESSAGE)
static int tls_construct_encrypted_extensions(SSL *s, WPACKET *pkt);
/*
@ -3320,9 +3335,9 @@ static int tls_process_cke_gost(SSL *s, PACKET *pkt)
const unsigned char *start;
size_t outlen = 32, inlen;
unsigned long alg_a;
unsigned int asn1id, asn1len;
GOST_KX_MESSAGE *pKX = NULL;
const unsigned char *ptr;
int ret = 0;
PACKET encdata;
/* Get our certificate private key */
alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@ -3363,42 +3378,33 @@ static int tls_process_cke_gost(SSL *s, PACKET *pkt)
if (EVP_PKEY_derive_set_peer(pkey_ctx, client_pub_pkey) <= 0)
ERR_clear_error();
}
/* Decrypt session key */
if (!PACKET_get_1(pkt, &asn1id)
|| asn1id != (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)
|| !PACKET_peek_1(pkt, &asn1len)) {
SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
}
if (asn1len == 0x81) {
/*
* Long form length. Should only be one byte of length. Anything else
* isn't supported.
* We did a successful peek before so this shouldn't fail
*/
if (!PACKET_forward(pkt, 1)) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
}
} else if (asn1len >= 0x80) {
/*
* Indefinite length, or more than one long form length bytes. We don't
* support it
*/
SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
} /* else short form length */
if (!PACKET_as_length_prefixed_1(pkt, &encdata)) {
SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
ptr = PACKET_data(pkt);
/* Some implementations provide extra data in the opaqueBlob
* We have nothing to do with this blob so we just skip it */
pKX = d2i_GOST_KX_MESSAGE(NULL, &ptr, PACKET_remaining(pkt));
if (pKX == NULL
|| pKX->kxBlob == NULL
|| ASN1_TYPE_get(pKX->kxBlob) != V_ASN1_SEQUENCE) {
SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
}
if (!PACKET_forward(pkt, ptr - PACKET_data(pkt))) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
}
inlen = PACKET_remaining(&encdata);
start = PACKET_data(&encdata);
if (PACKET_remaining(pkt) != 0) {
SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PROCESS_CKE_GOST,
SSL_R_DECRYPTION_FAILED);
goto err;
}
inlen = pKX->kxBlob->value.sequence->length;
start = pKX->kxBlob->value.sequence->data;
if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen, start,
inlen) <= 0) {
@ -3420,6 +3426,7 @@ static int tls_process_cke_gost(SSL *s, PACKET *pkt)
ret = 1;
err:
EVP_PKEY_CTX_free(pkey_ctx);
GOST_KX_MESSAGE_free(pKX);
return ret;
#else
/* Should never happen */