In ssl3_get_client_key_exchange() parsing a GOST session key, invoke the

regular ASN.1 parser rather than trying to handroll one and potentially
misbehave; OpenSSL PR #3335 via OpenSSL trunk.

2 files changed, 16 insertions, 26 deletions

diff --git a/src/lib/libssl/s3_srvr.c b/src/lib/libssl/s3_srvr.c
index c31ac39fe1..b0bfe493e8 100644
--- a/src/lib/libssl/s3_srvr.c
+++ b/src/lib/libssl/s3_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_srvr.c,v 1.72 2014/07/11 09:24:44 beck Exp $ */
+/* $OpenBSD: s3_srvr.c,v 1.73 2014/07/11 12:24:51 miod Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -2181,6 +2181,8 @@ ssl3_get_client_key_exchange(SSL *s)
                 unsigned char premaster_secret[32], *start;
                 size_t outlen = 32, inlen;
                 unsigned long alg_a;
+                int Ttag, Tclass;
+                long Tlen;
 
                 /* Get our certificate private key*/
                 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@@ -2205,22 +2207,15 @@ ssl3_get_client_key_exchange(SSL *s)
                                 ERR_clear_error();
                 }
                 /* Decrypt session key */
-                if ((*p != ( V_ASN1_SEQUENCE| V_ASN1_CONSTRUCTED))) {
-                        SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
-                            SSL_R_DECRYPTION_FAILED);
-                        goto gerr;
-                }
-                if (p[1] == 0x81) {
-                        start = p + 3;
-                        inlen = p[2];
-                } else if (p[1] < 0x80) {
-                        start = p + 2;
-                        inlen = p[1];
-                } else {
+                if (ASN1_get_object((const unsigned char **)&p, &Tlen, &Ttag,
+                    &Tclass, n) != V_ASN1_CONSTRUCTED ||
+                    Ttag != V_ASN1_SEQUENCE || Tclass != V_ASN1_UNIVERSAL) {
                         SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                             SSL_R_DECRYPTION_FAILED);
                         goto gerr;
                 }
+                start = p;
+                inlen = Tlen;
                 if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen,
                     start, inlen) <=0) {
                         SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
diff --git a/src/lib/libssl/src/ssl/s3_srvr.c b/src/lib/libssl/src/ssl/s3_srvr.c
index c31ac39fe1..b0bfe493e8 100644
--- a/src/lib/libssl/src/ssl/s3_srvr.c
+++ b/src/lib/libssl/src/ssl/s3_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_srvr.c,v 1.72 2014/07/11 09:24:44 beck Exp $ */
+/* $OpenBSD: s3_srvr.c,v 1.73 2014/07/11 12:24:51 miod Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -2181,6 +2181,8 @@ ssl3_get_client_key_exchange(SSL *s)
                 unsigned char premaster_secret[32], *start;
                 size_t outlen = 32, inlen;
                 unsigned long alg_a;
+                int Ttag, Tclass;
+                long Tlen;
 
                 /* Get our certificate private key*/
                 alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@@ -2205,22 +2207,15 @@ ssl3_get_client_key_exchange(SSL *s)
                                 ERR_clear_error();
                 }
                 /* Decrypt session key */
-                if ((*p != ( V_ASN1_SEQUENCE| V_ASN1_CONSTRUCTED))) {
-                        SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
-                            SSL_R_DECRYPTION_FAILED);
-                        goto gerr;
-                }
-                if (p[1] == 0x81) {
-                        start = p + 3;
-                        inlen = p[2];
-                } else if (p[1] < 0x80) {
-                        start = p + 2;
-                        inlen = p[1];
-                } else {
+                if (ASN1_get_object((const unsigned char **)&p, &Tlen, &Ttag,
+                    &Tclass, n) != V_ASN1_CONSTRUCTED ||
+                    Ttag != V_ASN1_SEQUENCE || Tclass != V_ASN1_UNIVERSAL) {
                         SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,
                             SSL_R_DECRYPTION_FAILED);
                         goto gerr;
                 }
+                start = p;
+                inlen = Tlen;
                 if (EVP_PKEY_decrypt(pkey_ctx, premaster_secret, &outlen,
                     start, inlen) <=0) {
                         SSLerr(SSL_F_SSL3_GET_CLIENT_KEY_EXCHANGE,