Plumb decode errors through key share parsing code.

Distinguish between decode errors and other errors, so that we can send
a SSL_AD_DECODE_ERROR alert when appropriate.

Fixes a tlsfuzzer failure, due to it expecting a decode error alert and
not receiving one.

Prompted by anton@

ok tb@

diff --git a/lib/libssl/ssl_clnt.c b/lib/libssl/ssl_clnt.c
index 19d8365..9811612 100644 (file)
--- a/lib/libssl/ssl_clnt.c
+++ b/lib/libssl/ssl_clnt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_clnt.c,v 1.134 2022/01/09 15:55:37 jsing Exp $ */
+/* $OpenBSD: ssl_clnt.c,v 1.135 2022/01/11 18:28:41 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1214,7 +1214,7 @@ ssl3_get_server_certificate(SSL *s)
 static int
 ssl3_get_server_kex_dhe(SSL *s, CBS *cbs)
 {
-       int invalid_params, invalid_key;
+       int decode_error, invalid_params, invalid_key;
        int nid = NID_dhKeyAgreement;
 
        tls_key_share_free(S3I(s)->hs.key_share);
@@ -1222,29 +1222,35 @@ ssl3_get_server_kex_dhe(SSL *s, CBS *cbs)
                goto err;
 
        if (!tls_key_share_peer_params(S3I(s)->hs.key_share, cbs,
-           &invalid_params))
-               goto decode_err;
+           &decode_error, &invalid_params)) {
+               if (decode_error) {
+                       SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+                       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+               }
+               goto err;
+       }
        if (!tls_key_share_peer_public(S3I(s)->hs.key_share, cbs,
-           &invalid_key))
-               goto decode_err;
+           &decode_error, &invalid_key)) {
+               if (decode_error) {
+                       SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+                       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+               }
+               goto err;
+       }
 
        if (invalid_params) {
-               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                SSLerror(s, SSL_R_BAD_DH_P_LENGTH);
+               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                goto err;
        }
        if (invalid_key) {
-               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                SSLerror(s, SSL_R_BAD_DH_PUB_KEY_LENGTH);
+               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                goto err;
        }
 
        return 1;
 
- decode_err:
-       SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
-       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
-
  err:
        return 0;
 }
@@ -1254,6 +1260,7 @@ ssl3_get_server_kex_ecdhe(SSL *s, CBS *cbs)
 {
        uint8_t curve_type;
        uint16_t curve_id;
+       int decode_error;
        CBS public;
 
        if (!CBS_get_u8(cbs, &curve_type))
@@ -1285,14 +1292,18 @@ ssl3_get_server_kex_ecdhe(SSL *s, CBS *cbs)
        if ((S3I(s)->hs.key_share = tls_key_share_new(curve_id)) == NULL)
                goto err;
 
-       if (!tls_key_share_peer_public(S3I(s)->hs.key_share, &public, NULL))
+       if (!tls_key_share_peer_public(S3I(s)->hs.key_share, &public,
+           &decode_error, NULL)) {
+               if (decode_error)
+                       goto decode_err;
                goto err;
+       }
 
        return 1;
 
  decode_err:
-       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
        SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
  err:
        return 0;
 }

diff --git a/lib/libssl/ssl_kex.c b/lib/libssl/ssl_kex.c
index 78b528b..cd6713b 100644 (file)
--- a/lib/libssl/ssl_kex.c
+++ b/lib/libssl/ssl_kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_kex.c,v 1.8 2021/12/04 14:03:22 jsing Exp $ */
+/* $OpenBSD: ssl_kex.c,v 1.9 2022/01/11 18:28:41 jsing Exp $ */
 /*
  * Copyright (c) 2020, 2021 Joel Sing <jsing@openbsd.org>
  *
@@ -156,18 +156,24 @@ ssl_kex_public_dhe(DH *dh, CBB *cbb)
 }
 
 int
-ssl_kex_peer_params_dhe(DH *dh, CBS *cbs, int *invalid_params)
+ssl_kex_peer_params_dhe(DH *dh, CBS *cbs, int *decode_error,
+    int *invalid_params)
 {
        BIGNUM *p = NULL, *g = NULL;
        CBS dh_p, dh_g;
        int ret = 0;
 
+       *decode_error = 0;
        *invalid_params = 0;
 
-       if (!CBS_get_u16_length_prefixed(cbs, &dh_p))
+       if (!CBS_get_u16_length_prefixed(cbs, &dh_p)) {
+               *decode_error = 1;
                goto err;
-       if (!CBS_get_u16_length_prefixed(cbs, &dh_g))
+       }
+       if (!CBS_get_u16_length_prefixed(cbs, &dh_g)) {
+               *decode_error = 1;
                goto err;
+       }
 
        if ((p = BN_bin2bn(CBS_data(&dh_p), CBS_len(&dh_p), NULL)) == NULL)
                goto err;
@@ -194,17 +200,21 @@ ssl_kex_peer_params_dhe(DH *dh, CBS *cbs, int *invalid_params)
 }
 
 int
-ssl_kex_peer_public_dhe(DH *dh, CBS *cbs, int *invalid_key)
+ssl_kex_peer_public_dhe(DH *dh, CBS *cbs, int *decode_error,
+    int *invalid_key)
 {
        BIGNUM *pub_key = NULL;
        int check_flags;
        CBS dh_y;
        int ret = 0;
 
+       *decode_error = 0;
        *invalid_key = 0;
 
-       if (!CBS_get_u16_length_prefixed(cbs, &dh_y))
+       if (!CBS_get_u16_length_prefixed(cbs, &dh_y)) {
+               *decode_error = 1;
                goto err;
+       }
 
        if ((pub_key = BN_bin2bn(CBS_data(&dh_y), CBS_len(&dh_y),
            NULL)) == NULL)

diff --git a/lib/libssl/ssl_locl.h b/lib/libssl/ssl_locl.h
index fcb3694..0eca4e6 100644 (file)
--- a/lib/libssl/ssl_locl.h
+++ b/lib/libssl/ssl_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.380 2022/01/09 15:53:52 jsing Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.381 2022/01/11 18:28:41 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1424,8 +1424,10 @@ int ssl_kex_generate_dhe(DH *dh, DH *dh_params);
 int ssl_kex_generate_dhe_params_auto(DH *dh, size_t key_len);
 int ssl_kex_params_dhe(DH *dh, CBB *cbb);
 int ssl_kex_public_dhe(DH *dh, CBB *cbb);
-int ssl_kex_peer_params_dhe(DH *dh, CBS *cbs, int *invalid_params);
-int ssl_kex_peer_public_dhe(DH *dh, CBS *cbs, int *invalid_key);
+int ssl_kex_peer_params_dhe(DH *dh, CBS *cbs, int *decode_error,
+    int *invalid_params);
+int ssl_kex_peer_public_dhe(DH *dh, CBS *cbs, int *decode_error,
+    int *invalid_key);
 int ssl_kex_derive_dhe(DH *dh, DH *dh_peer,
     uint8_t **shared_key, size_t *shared_key_len);
 

diff --git a/lib/libssl/ssl_srvr.c b/lib/libssl/ssl_srvr.c
index 0979750..dd622c2 100644 (file)
--- a/lib/libssl/ssl_srvr.c
+++ b/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.137 2022/01/09 15:40:13 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.138 2022/01/11 18:28:41 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1701,21 +1701,26 @@ ssl3_get_client_kex_dhe(SSL *s, CBS *cbs)
 {
        uint8_t *key = NULL;
        size_t key_len = 0;
-       int invalid_key;
+       int decode_error, invalid_key;
        int ret = 0;
 
        if (S3I(s)->hs.key_share == NULL) {
-               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
                SSLerror(s, SSL_R_MISSING_TMP_DH_KEY);
+               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_HANDSHAKE_FAILURE);
                goto err;
        }
 
        if (!tls_key_share_peer_public(S3I(s)->hs.key_share, cbs,
-           &invalid_key))
+           &decode_error, &invalid_key)) {
+               if (decode_error) {
+                       SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+                       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+               }
                goto err;
+       }
        if (invalid_key) {
-               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                SSLerror(s, SSL_R_BAD_DH_PUB_KEY_LENGTH);
+               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
                goto err;
        }
 
@@ -1738,6 +1743,7 @@ ssl3_get_client_kex_ecdhe(SSL *s, CBS *cbs)
 {
        uint8_t *key = NULL;
        size_t key_len = 0;
+       int decode_error;
        CBS public;
        int ret = 0;
 
@@ -1747,10 +1753,19 @@ ssl3_get_client_kex_ecdhe(SSL *s, CBS *cbs)
                goto err;
        }
 
-       if (!CBS_get_u8_length_prefixed(cbs, &public))
+       if (!CBS_get_u8_length_prefixed(cbs, &public)) {
+               SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+               ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
                goto err;
-       if (!tls_key_share_peer_public(S3I(s)->hs.key_share, &public, NULL))
+       }
+       if (!tls_key_share_peer_public(S3I(s)->hs.key_share, &public,
+           &decode_error, NULL)) {
+               if (decode_error) {
+                       SSLerror(s, SSL_R_BAD_PACKET_LENGTH);
+                       ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+               }
                goto err;
+       }
 
        if (!tls_key_share_derive(S3I(s)->hs.key_share, &key, &key_len))
                goto err;

diff --git a/lib/libssl/ssl_tlsext.c b/lib/libssl/ssl_tlsext.c
index 7538efd..69f8ddb 100644 (file)
--- a/lib/libssl/ssl_tlsext.c
+++ b/lib/libssl/ssl_tlsext.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_tlsext.c,v 1.107 2022/01/11 18:24:03 jsing Exp $ */
+/* $OpenBSD: ssl_tlsext.c,v 1.108 2022/01/11 18:28:41 jsing Exp $ */
 /*
  * Copyright (c) 2016, 2017, 2019 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2017 Doug Hogan <doug@openbsd.org>
@@ -1478,6 +1478,7 @@ int
 tlsext_keyshare_server_parse(SSL *s, uint16_t msg_type, CBS *cbs, int *alert)
 {
        CBS client_shares, key_exchange;
+       int decode_error;
        uint16_t group;
 
        if (!CBS_get_u16_length_prefixed(cbs, &client_shares))
@@ -1515,8 +1516,11 @@ tlsext_keyshare_server_parse(SSL *s, uint16_t msg_type, CBS *cbs, int *alert)
                        return 0;
                }
                if (!tls_key_share_peer_public(S3I(s)->hs.key_share,
-                   &key_exchange, NULL))
+                   &key_exchange, &decode_error, NULL)) {
+                       if (!decode_error)
+                               *alert = SSL_AD_INTERNAL_ERROR;
                        return 0;
+               }
        }
 
        return 1;
@@ -1561,6 +1565,7 @@ int
 tlsext_keyshare_client_parse(SSL *s, uint16_t msg_type, CBS *cbs, int *alert)
 {
        CBS key_exchange;
+       int decode_error;
        uint16_t group;
 
        /* Unpack server share. */
@@ -1588,8 +1593,11 @@ tlsext_keyshare_client_parse(SSL *s, uint16_t msg_type, CBS *cbs, int *alert)
                return 0;
        }
        if (!tls_key_share_peer_public(S3I(s)->hs.key_share,
-           &key_exchange, NULL))
+           &key_exchange, &decode_error, NULL)) {
+               if (!decode_error)
+                       *alert = SSL_AD_INTERNAL_ERROR;
                return 0;
+       }
 
        return 1;
 }

diff --git a/lib/libssl/tls_internal.h b/lib/libssl/tls_internal.h
index f7f9392..a009635 100644 (file)
--- a/lib/libssl/tls_internal.h
+++ b/lib/libssl/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.4 2022/01/07 15:46:30 jsing Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.5 2022/01/11 18:28:41 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019, 2021 Joel Sing <jsing@openbsd.org>
  *
@@ -72,9 +72,9 @@ int tls_key_share_generate(struct tls_key_share *ks);
 int tls_key_share_params(struct tls_key_share *ks, CBB *cbb);
 int tls_key_share_public(struct tls_key_share *ks, CBB *cbb);
 int tls_key_share_peer_params(struct tls_key_share *ks, CBS *cbs,
-    int *invalid_params);
+    int *decode_error, int *invalid_params);
 int tls_key_share_peer_public(struct tls_key_share *ks, CBS *cbs,
-    int *invalid_key);
+    int *decode_error, int *invalid_key);
 int tls_key_share_derive(struct tls_key_share *ks, uint8_t **shared_key,
     size_t *shared_key_len);
 

diff --git a/lib/libssl/tls_key_share.c b/lib/libssl/tls_key_share.c
index eb30a0e..e5e6c30 100644 (file)
--- a/lib/libssl/tls_key_share.c
+++ b/lib/libssl/tls_key_share.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_key_share.c,v 1.3 2022/01/07 15:46:30 jsing Exp $ */
+/* $OpenBSD: tls_key_share.c,v 1.4 2022/01/11 18:28:41 jsing Exp $ */
 /*
  * Copyright (c) 2020, 2021 Joel Sing <jsing@openbsd.org>
  *
@@ -301,14 +301,15 @@ tls_key_share_public(struct tls_key_share *ks, CBB *cbb)
 
 static int
 tls_key_share_peer_params_dhe(struct tls_key_share *ks, CBS *cbs,
-    int *invalid_params)
+    int *decode_error, int *invalid_params)
 {
        if (ks->dhe != NULL || ks->dhe_peer != NULL)
                return 0;
 
        if ((ks->dhe_peer = DH_new()) == NULL)
                return 0;
-       if (!ssl_kex_peer_params_dhe(ks->dhe_peer, cbs, invalid_params))
+       if (!ssl_kex_peer_params_dhe(ks->dhe_peer, cbs, decode_error,
+           invalid_params))
                return 0;
        if ((ks->dhe = DHparams_dup(ks->dhe_peer)) == NULL)
                return 0;
@@ -318,22 +319,24 @@ tls_key_share_peer_params_dhe(struct tls_key_share *ks, CBS *cbs,
 
 int
 tls_key_share_peer_params(struct tls_key_share *ks, CBS *cbs,
-    int *invalid_params)
+    int *decode_error, int *invalid_params)
 {
        if (ks->nid != NID_dhKeyAgreement)
                return 0;
 
-       return tls_key_share_peer_params_dhe(ks, cbs, invalid_params);
+       return tls_key_share_peer_params_dhe(ks, cbs, decode_error,
+            invalid_params);
 }
 
 static int
 tls_key_share_peer_public_dhe(struct tls_key_share *ks, CBS *cbs,
-    int *invalid_key)
+    int *decode_error, int *invalid_key)
 {
        if (ks->dhe_peer == NULL)
                return 0;
 
-       return ssl_kex_peer_public_dhe(ks->dhe_peer, cbs, invalid_key);
+       return ssl_kex_peer_public_dhe(ks->dhe_peer, cbs, decode_error,
+           invalid_key);
 }
 
 static int
@@ -362,30 +365,39 @@ tls_key_share_peer_public_ecdhe_ecp(struct tls_key_share *ks, CBS *cbs)
 }
 
 static int
-tls_key_share_peer_public_x25519(struct tls_key_share *ks, CBS *cbs)
+tls_key_share_peer_public_x25519(struct tls_key_share *ks, CBS *cbs,
+    int *decode_error)
 {
        size_t out_len;
 
+       *decode_error = 0;
+
        if (ks->x25519_peer_public != NULL)
                return 0;
 
-       if (CBS_len(cbs) != X25519_KEY_LENGTH)
+       if (CBS_len(cbs) != X25519_KEY_LENGTH) {
+               *decode_error = 1;
                return 0;
+       }
 
        return CBS_stow(cbs, &ks->x25519_peer_public, &out_len);
 }
 
 int
-tls_key_share_peer_public(struct tls_key_share *ks, CBS *cbs, int *invalid_key)
+tls_key_share_peer_public(struct tls_key_share *ks, CBS *cbs, int *decode_error,
+    int *invalid_key)
 {
+       *decode_error = 0;
+
        if (invalid_key != NULL)
                *invalid_key = 0;
 
        if (ks->nid == NID_dhKeyAgreement)
-               return tls_key_share_peer_public_dhe(ks, cbs, invalid_key);
+               return tls_key_share_peer_public_dhe(ks, cbs, decode_error,
+                   invalid_key);
 
        if (ks->nid == NID_X25519)
-               return tls_key_share_peer_public_x25519(ks, cbs);
+               return tls_key_share_peer_public_x25519(ks, cbs, decode_error);
 
        return tls_key_share_peer_public_ecdhe_ecp(ks, cbs);
 }