Fixes for CVE-2015-1791.

If a NewSessionTicket is received by a multi-threaded client when
attempting to reuse a previous ticket then a race condition can occur
potentially leading to a double free of the ticket data.

This change cherry-picks the following BoringSSL changes:

b31040d0 – Get rid of CERT_PKEY slots in SESS_CERT.
fd67aa8c – Add SSL_SESSION_from_bytes.
95d31825 – Duplicate SSL_SESSIONs when renewing them.
d65bb78c – Add SSL_initial_handshake_complete.
680ca961 – Preserve session->sess_cert on ticket renewal.

Change-Id: I474065330842e4ab0066b2485c1489a50e4dfd5b

10 files changed, 258 insertions, 131 deletions

diff --git a/src/crypto/err/ssl.errordata b/src/crypto/err/ssl.errordata
index 4ae0a51..9464c3d 100644
--- a/src/crypto/err/ssl.errordata
+++ b/src/crypto/err/ssl.errordata
@@ -20,7 +20,11 @@ SSL,function,112,SSL_CTX_use_certificate_ASN1
 SSL,function,113,SSL_CTX_use_certificate_chain_file
 SSL,function,114,SSL_CTX_use_certificate_file
 SSL,function,115,SSL_CTX_use_psk_identity_hint
+SSL,function,280,SSL_SESSION_from_bytes
 SSL,function,116,SSL_SESSION_new
+SSL,function,281,SSL_SESSION_parse
+SSL,function,150,SSL_SESSION_parse_octet_string
+SSL,function,151,SSL_SESSION_parse_string
 SSL,function,117,SSL_SESSION_print_fp
 SSL,function,118,SSL_SESSION_set1_id_context
 SSL,function,119,SSL_SESSION_to_bytes_full
@@ -58,8 +62,6 @@ SSL,function,146,SSL_use_certificate_file
 SSL,function,147,SSL_use_psk_identity_hint
 SSL,function,148,SSL_write
 SSL,function,149,d2i_SSL_SESSION
-SSL,function,150,d2i_SSL_SESSION_get_octet_string
-SSL,function,151,d2i_SSL_SESSION_get_string
 SSL,function,152,do_ssl3_write
 SSL,function,153,dtls1_accept
 SSL,function,154,dtls1_buffer_record
@@ -82,6 +84,7 @@ SSL,function,166,i2d_SSL_SESSION
 SSL,function,167,ssl3_accept
 SSL,function,169,ssl3_cert_verify_hash
 SSL,function,170,ssl3_check_cert_and_algorithm
+SSL,function,282,ssl3_check_certificate_for_cipher
 SSL,function,171,ssl3_connect
 SSL,function,172,ssl3_ctrl
 SSL,function,173,ssl3_ctx_ctrl
diff --git a/src/include/openssl/ssl.h b/src/include/openssl/ssl.h
index 217dbaf..2735e15 100644
--- a/src/include/openssl/ssl.h
+++ b/src/include/openssl/ssl.h
@@ -517,6 +517,10 @@ OPENSSL_EXPORT uint32_t SSL_get_mode(const SSL *ssl);
 OPENSSL_EXPORT int SSL_get_tls_unique(const SSL *ssl, uint8_t *out,
                                       size_t *out_len, size_t max_out);
 
+/* SSL_initial_handshake_complete returns one if the initial handshake has
+ * completed and zero otherwise. */
+OPENSSL_EXPORT int SSL_initial_handshake_complete(const SSL *ssl);
+
 
 /* Underdocumented functions.
  *
@@ -646,7 +650,12 @@ struct ssl_session_st {
    * disable session caching and tickets. */
   int not_resumable;
 
-  /* The cert is the certificate used to establish this connection */
+  /* The cert is the certificate used to establish this connection
+   *
+   * TODO(davidben): Remove this field. It is not serialized as part of the
+   * session, but some APIs access it. Certificate-related fields, where not
+   * redundant with |peer|, should be added to the session. Others should
+   * probably not be retained across resumptions. */
   struct sess_cert_st /* SESS_CERT */ *sess_cert;
 
   /* This is the cert for the other end. On clients, it will be the same as
@@ -1963,31 +1972,34 @@ OPENSSL_EXPORT int SSL_has_matching_session_id(const SSL *ssl,
 OPENSSL_EXPORT int SSL_SESSION_to_bytes(SSL_SESSION *in, uint8_t **out_data,
                                         size_t *out_len);
 
-/* SSL_SESSION_to_bytes_for_ticket serializes |in|, but excludes the session ID
- * which is not necessary in a session ticket. */
+/* SSL_SESSION_to_bytes_for_ticket serializes |in|, but excludes the session
+ * identification information, namely the session ID and ticket. */
 OPENSSL_EXPORT int SSL_SESSION_to_bytes_for_ticket(SSL_SESSION *in,
                                                    uint8_t **out_data,
                                                    size_t *out_len);
 
+/* SSL_SESSION_from_bytes parses |in_len| bytes from |in| as an SSL_SESSION. It
+ * returns a newly-allocated |SSL_SESSION| on success or NULL on error. */
+OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_from_bytes(const uint8_t *in,
+                                                   size_t in_len);
+
 /* Deprecated: i2d_SSL_SESSION serializes |in| to the bytes pointed to by
  * |*pp|. On success, it returns the number of bytes written and advances |*pp|
  * by that many bytes. On failure, it returns -1. If |pp| is NULL, no bytes are
  * written and only the length is returned.
  *
- * Use SSL_SESSION_to_bytes instead. */
+ * Use |SSL_SESSION_to_bytes| instead. */
 OPENSSL_EXPORT int i2d_SSL_SESSION(SSL_SESSION *in, uint8_t **pp);
 
-/* d2i_SSL_SESSION deserializes a serialized buffer contained in the |length|
- * bytes pointed to by |*pp|. It returns the new SSL_SESSION and advances |*pp|
- * by the number of bytes consumed on success and NULL on failure. If |a| is
- * NULL, the caller takes ownership of the new session and must call
- * |SSL_SESSION_free| when done.
+/* Deprecated: d2i_SSL_SESSION parses a serialized session from the |length|
+ * bytes pointed to by |*pp|. It returns the new |SSL_SESSION| and advances
+ * |*pp| by the number of bytes consumed on success and NULL on failure. The
+ * caller takes ownership of the new session and must call |SSL_SESSION_free|
+ * when done.
  *
- * If |a| and |*a| are not NULL, the SSL_SESSION at |*a| is overridden with the
- * deserialized session rather than allocating a new one. In addition, |a| is
- * not NULL, but |*a| is, |*a| is set to the new SSL_SESSION.
+ * If |a| is non-NULL, |*a| is released and set the new |SSL_SESSION|.
  *
- * Passing a value other than NULL to |a| is deprecated. */
+ * Use |SSL_SESSION_from_bytes| instead. */
 OPENSSL_EXPORT SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp,
                                             long length);
 
@@ -2621,8 +2633,8 @@ OPENSSL_EXPORT const char *SSLeay_version(int unused);
 #define SSL_F_SSL_use_psk_identity_hint 147
 #define SSL_F_SSL_write 148
 #define SSL_F_d2i_SSL_SESSION 149
-#define SSL_F_d2i_SSL_SESSION_get_octet_string 150
-#define SSL_F_d2i_SSL_SESSION_get_string 151
+#define SSL_F_SSL_SESSION_parse_octet_string 150
+#define SSL_F_SSL_SESSION_parse_string 151
 #define SSL_F_do_ssl3_write 152
 #define SSL_F_dtls1_accept 153
 #define SSL_F_dtls1_buffer_record 154
@@ -2747,6 +2759,9 @@ OPENSSL_EXPORT const char *SSLeay_version(int unused);
 #define SSL_F_SSL_AEAD_CTX_open 277
 #define SSL_F_SSL_AEAD_CTX_seal 278
 #define SSL_F_dtls1_seal_record 279
+#define SSL_F_SSL_SESSION_from_bytes 280
+#define SSL_F_SSL_SESSION_parse 281
+#define SSL_F_ssl3_check_certificate_for_cipher 282
 #define SSL_R_APP_DATA_IN_HANDSHAKE 100
 #define SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT 101
 #define SSL_R_BAD_ALERT 102
diff --git a/src/ssl/internal.h b/src/ssl/internal.h
index 7d9a5ad..4d70431 100644
--- a/src/ssl/internal.h
+++ b/src/ssl/internal.h
@@ -581,15 +581,13 @@ typedef struct cert_st {
 } CERT;
 
 typedef struct sess_cert_st {
-  STACK_OF(X509) *cert_chain; /* as received from peer (not for SSL2) */
+  /* cert_chain is the certificate chain sent by the peer. NOTE: for a client,
+   * this does includes the server's leaf certificate, but, for a server, this
+   * does NOT include the client's leaf. */
+  STACK_OF(X509) *cert_chain;
 
-  /* The 'peer_...' members are used only by clients. */
-  int peer_cert_type;
-
-  CERT_PKEY *peer_key; /* points to an element of peer_pkeys (never NULL!) */
-  CERT_PKEY peer_pkeys[SSL_PKEY_NUM];
-  /* Obviously we don't have the private keys of these,
-   * so maybe we shouldn't even use the CERT_PKEY type here. */
+  /* peer_cert, on a client, is the leaf certificate of the peer. */
+  X509 *peer_cert;
 
   DH *peer_dh_tmp;
   EC_KEY *peer_ecdh_tmp;
@@ -799,8 +797,8 @@ CERT *ssl_cert_dup(CERT *cert);
 void ssl_cert_clear_certs(CERT *c);
 void ssl_cert_free(CERT *c);
 SESS_CERT *ssl_sess_cert_new(void);
-void ssl_sess_cert_free(SESS_CERT *sc);
-int ssl_set_peer_cert_type(SESS_CERT *c, int type);
+SESS_CERT *ssl_sess_cert_dup(const SESS_CERT *sess_cert);
+void ssl_sess_cert_free(SESS_CERT *sess_cert);
 int ssl_get_new_session(SSL *s, int session);
 int ssl_get_prev_session(SSL *s, const struct ssl_early_callback_ctx *ctx);
 STACK_OF(SSL_CIPHER) *ssl_bytes_to_cipher_list(SSL *s, const CBS *cbs);
diff --git a/src/ssl/s3_clnt.c b/src/ssl/s3_clnt.c
index 159e2d7..d334e1d 100644
--- a/src/ssl/s3_clnt.c
+++ b/src/ssl/s3_clnt.c
@@ -1028,10 +1028,8 @@ int ssl3_get_server_certificate(SSL *s) {
                       SSL_R_WRONG_CERTIFICATE_TYPE);
     goto f_err;
   }
-  sc->peer_cert_type = i;
-  X509_free(sc->peer_pkeys[i].x509);
-  sc->peer_pkeys[i].x509 = X509_up_ref(x);
-  sc->peer_key = &(sc->peer_pkeys[i]);
+  X509_free(sc->peer_cert);
+  sc->peer_cert = X509_up_ref(x);
 
   X509_free(s->session->peer);
   s->session->peer = X509_up_ref(x);
@@ -1195,8 +1193,7 @@ int ssl3_get_server_key_exchange(SSL *s) {
     }
 
     if (alg_a & SSL_aRSA) {
-      pkey = X509_get_pubkey(
-          s->session->sess_cert->peer_pkeys[SSL_PKEY_RSA_ENC].x509);
+      pkey = X509_get_pubkey(s->session->sess_cert->peer_cert);
     }
     /* else anonymous DH, so no certificate or pkey. */
 
@@ -1258,14 +1255,12 @@ int ssl3_get_server_key_exchange(SSL *s) {
     /* The ECC/TLS specification does not mention the use of DSA to sign
      * ECParameters in the server key exchange message. We do support RSA and
      * ECDSA. */
-    if (alg_a & SSL_aRSA) {
-      pkey = X509_get_pubkey(
-          s->session->sess_cert->peer_pkeys[SSL_PKEY_RSA_ENC].x509);
-    } else if (alg_a & SSL_aECDSA) {
-      pkey =
-          X509_get_pubkey(s->session->sess_cert->peer_pkeys[SSL_PKEY_ECC].x509);
+    if (alg_a & (SSL_aRSA|SSL_aECDSA)) {
+      pkey = X509_get_pubkey(s->session->sess_cert->peer_cert);
+    } else {
+      /* Otherwise this is ECDHE_PSK, so no public key. */
+      assert(alg_a == SSL_aPSK);
     }
-    /* else anonymous ECDH, so no certificate or pkey. */
     EC_KEY_set_public_key(ecdh, srvr_ecpoint);
     s->session->sess_cert->peer_ecdh_tmp = ecdh;
     ecdh = NULL;
@@ -1508,6 +1503,36 @@ int ssl3_get_new_session_ticket(SSL *s) {
     return n;
   }
 
+  if (s->hit) {
+    /* The server is sending a new ticket for an existing session. Sessions are
+     * immutable once established, so duplicate all but the ticket of the
+     * existing session. */
+    uint8_t *bytes;
+    size_t bytes_len;
+    if (!SSL_SESSION_to_bytes_for_ticket(s->session, &bytes, &bytes_len)) {
+      goto err;
+    }
+    SSL_SESSION *new_session = SSL_SESSION_from_bytes(bytes, bytes_len);
+    OPENSSL_free(bytes);
+    if (new_session == NULL) {
+      /* This should never happen. */
+      OPENSSL_PUT_ERROR(SSL, ssl3_get_new_session_ticket, ERR_R_INTERNAL_ERROR);
+      goto err;
+    }
+    if (s->session->sess_cert != NULL) {
+      /* |sess_cert| is not serialized and must be duplicated explicitly. */
+      assert(new_session->sess_cert == NULL);
+      new_session->sess_cert = ssl_sess_cert_dup(s->session->sess_cert);
+      if (new_session->sess_cert == NULL) {
+        SSL_SESSION_free(new_session);
+        goto err;
+      }
+    }
+
+    SSL_SESSION_free(s->session);
+    s->session = new_session;
+  }
+
   CBS_init(&new_session_ticket, s->init_msg, n);
 
   if (!CBS_get_u32(&new_session_ticket,
@@ -1702,8 +1727,7 @@ int ssl3_send_client_key_exchange(SSL *s) {
         goto err;
       }
 
-      pkey = X509_get_pubkey(
-          s->session->sess_cert->peer_pkeys[SSL_PKEY_RSA_ENC].x509);
+      pkey = X509_get_pubkey(s->session->sess_cert->peer_cert);
       if (pkey == NULL ||
           pkey->type != EVP_PKEY_RSA ||
           pkey->pkey.rsa == NULL) {
@@ -2159,9 +2183,7 @@ int ssl3_send_client_certificate(SSL *s) {
 #define has_bits(i, m) (((i) & (m)) == (m))
 
 int ssl3_check_cert_and_algorithm(SSL *s) {
-  int i, idx;
   long alg_k, alg_a;
-  EVP_PKEY *pkey = NULL;
   SESS_CERT *sc;
   DH *dh;
 
@@ -2181,11 +2203,9 @@ int ssl3_check_cert_and_algorithm(SSL *s) {
 
   dh = s->session->sess_cert->peer_dh_tmp;
 
-  /* This is the passed certificate */
-
-  idx = sc->peer_cert_type;
-  if (idx == SSL_PKEY_ECC) {
-    if (ssl_check_srvr_ecc_cert_and_alg(sc->peer_pkeys[idx].x509, s) == 0) {
+  int cert_type = X509_certificate_type(sc->peer_cert, NULL);
+  if (cert_type & EVP_PK_EC) {
+    if (ssl_check_srvr_ecc_cert_and_alg(sc->peer_cert, s) == 0) {
       /* check failed */
       OPENSSL_PUT_ERROR(SSL, ssl3_check_cert_and_algorithm, SSL_R_BAD_ECC_CERT);
       goto f_err;
@@ -2197,25 +2217,21 @@ int ssl3_check_cert_and_algorithm(SSL *s) {
                       SSL_R_MISSING_ECDSA_SIGNING_CERT);
     goto f_err;
   }
-  pkey = X509_get_pubkey(sc->peer_pkeys[idx].x509);
-  i = X509_certificate_type(sc->peer_pkeys[idx].x509, pkey);
-  EVP_PKEY_free(pkey);
 
   /* Check that we have a certificate if we require one */
-  if ((alg_a & SSL_aRSA) && !has_bits(i, EVP_PK_RSA | EVP_PKT_SIGN)) {
+  if ((alg_a & SSL_aRSA) && !has_bits(cert_type, EVP_PK_RSA | EVP_PKT_SIGN)) {
     OPENSSL_PUT_ERROR(SSL, ssl3_check_cert_and_algorithm,
                       SSL_R_MISSING_RSA_SIGNING_CERT);
     goto f_err;
   }
 
-  if ((alg_k & SSL_kRSA) && !has_bits(i, EVP_PK_RSA | EVP_PKT_ENC)) {
+  if ((alg_k & SSL_kRSA) && !has_bits(cert_type, EVP_PK_RSA | EVP_PKT_ENC)) {
     OPENSSL_PUT_ERROR(SSL, ssl3_check_cert_and_algorithm,
                       SSL_R_MISSING_RSA_ENCRYPTING_CERT);
     goto f_err;
   }
 
-  if ((alg_k & SSL_kDHE) &&
-      !(has_bits(i, EVP_PK_DH | EVP_PKT_EXCH) || dh != NULL)) {
+  if ((alg_k & SSL_kDHE) && dh == NULL) {
     OPENSSL_PUT_ERROR(SSL, ssl3_check_cert_and_algorithm, SSL_R_MISSING_DH_KEY);
     goto f_err;
   }
diff --git a/src/ssl/ssl_asn1.c b/src/ssl/ssl_asn1.c
index d1ac1b6..76052df 100644
--- a/src/ssl/ssl_asn1.c
+++ b/src/ssl/ssl_asn1.c
@@ -261,7 +261,7 @@ static int SSL_SESSION_to_bytes_full(SSL_SESSION *in, uint8_t **out_data,
     }
   }
 
-  if (in->tlsext_tick) {
+  if (in->tlsext_tick && !for_ticket) {
     if (!CBB_add_asn1(&session, &child, kTicketTag) ||
         !CBB_add_asn1(&child, &child2, CBS_ASN1_OCTETSTRING) ||
         !CBB_add_bytes(&child2, in->tlsext_tick, in->tlsext_ticklen)) {
@@ -360,26 +360,27 @@ int i2d_SSL_SESSION(SSL_SESSION *in, uint8_t **pp) {
   return len;
 }
 
-/* d2i_SSL_SESSION_get_string gets an optional ASN.1 OCTET STRING
+/* SSL_SESSION_parse_string gets an optional ASN.1 OCTET STRING
  * explicitly tagged with |tag| from |cbs| and saves it in |*out|. On
  * entry, if |*out| is not NULL, it frees the existing contents. If
  * the element was not found, it sets |*out| to NULL. It returns one
  * on success, whether or not the element was found, and zero on
  * decode error. */
-static int d2i_SSL_SESSION_get_string(CBS *cbs, char **out, unsigned tag) {
+static int SSL_SESSION_parse_string(CBS *cbs, char **out, unsigned tag) {
   CBS value;
   int present;
   if (!CBS_get_optional_asn1_octet_string(cbs, &value, &present, tag)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse_string, SSL_R_INVALID_SSL_SESSION);
     return 0;
   }
   if (present) {
     if (CBS_contains_zero_byte(&value)) {
-      OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+      OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse_string,
+                        SSL_R_INVALID_SSL_SESSION);
       return 0;
     }
     if (!CBS_strdup(&value, out)) {
-      OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, ERR_R_MALLOC_FAILURE);
+      OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse_string, ERR_R_MALLOC_FAILURE);
       return 0;
     }
   } else {
@@ -389,45 +390,42 @@ static int d2i_SSL_SESSION_get_string(CBS *cbs, char **out, unsigned tag) {
   return 1;
 }
 
-/* d2i_SSL_SESSION_get_string gets an optional ASN.1 OCTET STRING
+/* SSL_SESSION_parse_string gets an optional ASN.1 OCTET STRING
  * explicitly tagged with |tag| from |cbs| and stows it in |*out_ptr|
  * and |*out_len|. If |*out_ptr| is not NULL, it frees the existing
  * contents. On entry, if the element was not found, it sets
  * |*out_ptr| to NULL. It returns one on success, whether or not the
  * element was found, and zero on decode error. */
-static int d2i_SSL_SESSION_get_octet_string(CBS *cbs, uint8_t **out_ptr,
+static int SSL_SESSION_parse_octet_string(CBS *cbs, uint8_t **out_ptr,
                                             size_t *out_len, unsigned tag) {
   CBS value;
   if (!CBS_get_optional_asn1_octet_string(cbs, &value, NULL, tag)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse_octet_string,
+                      SSL_R_INVALID_SSL_SESSION);
     return 0;
   }
   if (!CBS_stow(&value, out_ptr, out_len)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, ERR_R_MALLOC_FAILURE);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse_octet_string,
+                      ERR_R_MALLOC_FAILURE);
     return 0;
   }
   return 1;
 }
 
-SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
-  SSL_SESSION *ret, *allocated = NULL;
-  CBS cbs, session, cipher, session_id, master_key;
+static SSL_SESSION *SSL_SESSION_parse(CBS *cbs) {
+  SSL_SESSION *ret = NULL;
+  CBS session, cipher, session_id, master_key;
   CBS peer, sid_ctx, peer_sha256, original_handshake_hash;
   int has_peer, has_peer_sha256, extended_master_secret;
   uint64_t version, ssl_version;
   uint64_t session_time, timeout, verify_result, ticket_lifetime_hint;
 
-  if (a && *a) {
-    ret = *a;
-  } else {
-    ret = allocated = SSL_SESSION_new();
-    if (allocated == NULL) {
-      goto err;
-    }
+  ret = SSL_SESSION_new();
+  if (ret == NULL) {
+    goto err;
   }
 
-  CBS_init(&cbs, *pp, length);
-  if (!CBS_get_asn1(&cbs, &session, CBS_ASN1_SEQUENCE) ||
+  if (!CBS_get_asn1(cbs, &session, CBS_ASN1_SEQUENCE) ||
       !CBS_get_asn1_uint64(&session, &version) ||
       !CBS_get_asn1_uint64(&session, &ssl_version) ||
       !CBS_get_asn1(&session, &cipher, CBS_ASN1_OCTETSTRING) ||
@@ -441,21 +439,21 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
                                           kSessionIDContextTag) ||
       !CBS_get_optional_asn1_uint64(&session, &verify_result, kVerifyResultTag,
                                     X509_V_OK)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
-  if (!d2i_SSL_SESSION_get_string(&session, &ret->tlsext_hostname,
-                                  kHostNameTag) ||
-      !d2i_SSL_SESSION_get_string(&session, &ret->psk_identity,
-                                  kPSKIdentityTag)) {
+  if (!SSL_SESSION_parse_string(&session, &ret->tlsext_hostname,
+                                kHostNameTag) ||
+      !SSL_SESSION_parse_string(&session, &ret->psk_identity,
+                                kPSKIdentityTag)) {
     goto err;
   }
   if (!CBS_get_optional_asn1_uint64(&session, &ticket_lifetime_hint,
                                     kTicketLifetimeHintTag, 0)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
-  if (!d2i_SSL_SESSION_get_octet_string(&session, &ret->tlsext_tick,
+  if (!SSL_SESSION_parse_octet_string(&session, &ret->tlsext_tick,
                                         &ret->tlsext_ticklen, kTicketTag)) {
     goto err;
   }
@@ -463,14 +461,14 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
                                           &has_peer_sha256, kPeerSHA256Tag) ||
       !CBS_get_optional_asn1_octet_string(&session, &original_handshake_hash,
                                           NULL, kOriginalHandshakeHashTag)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
-  if (!d2i_SSL_SESSION_get_octet_string(
+  if (!SSL_SESSION_parse_octet_string(
           &session, &ret->tlsext_signed_cert_timestamp_list,
           &ret->tlsext_signed_cert_timestamp_list_length,
           kSignedCertTimestampListTag) ||
-      !d2i_SSL_SESSION_get_octet_string(
+      !SSL_SESSION_parse_octet_string(
           &session, &ret->ocsp_response, &ret->ocsp_response_length,
           kOCSPResponseTag)) {
     goto err;
@@ -479,44 +477,44 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
                                   kExtendedMasterSecretTag,
                                   0 /* default to false */) ||
       CBS_len(&session) != 0) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   ret->extended_master_secret = extended_master_secret;
 
   if (version != SSL_SESSION_ASN1_VERSION) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
 
   /* Only support SSLv3/TLS and DTLS. */
   if ((ssl_version >> 8) != SSL3_VERSION_MAJOR &&
       (ssl_version >> 8) != (DTLS1_VERSION >> 8)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_UNKNOWN_SSL_VERSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_UNKNOWN_SSL_VERSION);
     goto err;
   }
   ret->ssl_version = ssl_version;
 
   uint16_t cipher_value;
   if (!CBS_get_u16(&cipher, &cipher_value) || CBS_len(&cipher) != 0) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_CIPHER_CODE_WRONG_LENGTH);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_CIPHER_CODE_WRONG_LENGTH);
     goto err;
   }
   ret->cipher = SSL_get_cipher_by_value(cipher_value);
   if (ret->cipher == NULL) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_UNSUPPORTED_CIPHER);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_UNSUPPORTED_CIPHER);
     goto err;
   }
 
   if (CBS_len(&session_id) > SSL3_MAX_SSL_SESSION_ID_LENGTH) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   memcpy(ret->session_id, CBS_data(&session_id), CBS_len(&session_id));
   ret->session_id_length = CBS_len(&session_id);
 
   if (CBS_len(&master_key) > SSL_MAX_MASTER_KEY_LENGTH) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   memcpy(ret->master_key, CBS_data(&master_key), CBS_len(&master_key));
@@ -524,7 +522,7 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
 
   if (session_time > LONG_MAX ||
       timeout > LONG_MAX) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   ret->time = session_time;
@@ -540,13 +538,13 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
       goto err;
     }
     if (ptr != CBS_data(&peer) + CBS_len(&peer)) {
-      OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+      OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
       goto err;
     }
   }
 
   if (CBS_len(&sid_ctx) > sizeof(ret->sid_ctx)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   memcpy(ret->sid_ctx, CBS_data(&sid_ctx), CBS_len(&sid_ctx));
@@ -554,7 +552,7 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
 
   if (verify_result > LONG_MAX ||
       ticket_lifetime_hint > 0xffffffff) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   ret->verify_result = verify_result;
@@ -562,7 +560,7 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
 
   if (has_peer_sha256) {
     if (CBS_len(&peer_sha256) != sizeof(ret->peer_sha256)) {
-      OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+      OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
       goto err;
     }
     memcpy(ret->peer_sha256, CBS_data(&peer_sha256), sizeof(ret->peer_sha256));
@@ -573,20 +571,53 @@ SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
 
   if (CBS_len(&original_handshake_hash) >
       sizeof(ret->original_handshake_hash)) {
-    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, SSL_R_INVALID_SSL_SESSION);
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_parse, SSL_R_INVALID_SSL_SESSION);
     goto err;
   }
   memcpy(ret->original_handshake_hash, CBS_data(&original_handshake_hash),
          CBS_len(&original_handshake_hash));
   ret->original_handshake_hash_len = CBS_len(&original_handshake_hash);
 
+  return ret;
+
+err:
+  SSL_SESSION_free(ret);
+  return NULL;
+}
+
+SSL_SESSION *SSL_SESSION_from_bytes(const uint8_t *in, size_t in_len) {
+  CBS cbs;
+  CBS_init(&cbs, in, in_len);
+  SSL_SESSION *ret = SSL_SESSION_parse(&cbs);
+  if (ret == NULL) {
+    return NULL;
+  }
+  if (CBS_len(&cbs) != 0) {
+    OPENSSL_PUT_ERROR(SSL, SSL_SESSION_from_bytes, SSL_R_INVALID_SSL_SESSION);
+    SSL_SESSION_free(ret);
+    return NULL;
+  }
+  return ret;
+}
+
+SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp, long length) {
+  if (length < 0) {
+    OPENSSL_PUT_ERROR(SSL, d2i_SSL_SESSION, ERR_R_INTERNAL_ERROR);
+    return NULL;
+  }
+
+  CBS cbs;
+  CBS_init(&cbs, *pp, length);
+
+  SSL_SESSION *ret = SSL_SESSION_parse(&cbs);
+  if (ret == NULL) {
+    return NULL;
+  }
+
   if (a) {
+    SSL_SESSION_free(*a);
     *a = ret;
   }
   *pp = CBS_data(&cbs);
   return ret;
-
-err:
-  SSL_SESSION_free(allocated);
-  return NULL;
 }
diff --git a/src/ssl/ssl_cert.c b/src/ssl/ssl_cert.c
index f1fd675..85aa079 100644
--- a/src/ssl/ssl_cert.c
+++ b/src/ssl/ssl_cert.c
@@ -119,11 +119,13 @@
 #include <openssl/bio.h>
 #include <openssl/bn.h>
 #include <openssl/buf.h>
+#include <openssl/ec_key.h>
 #include <openssl/dh.h>
 #include <openssl/err.h>
 #include <openssl/mem.h>
 #include <openssl/obj.h>
 #include <openssl/pem.h>
+#include <openssl/x509.h>
 #include <openssl/x509v3.h>
 
 #include "../crypto/dh/internal.h"
@@ -409,33 +411,48 @@ SESS_CERT *ssl_sess_cert_new(void) {
   }
 
   memset(ret, 0, sizeof *ret);
-  ret->peer_key = &(ret->peer_pkeys[SSL_PKEY_RSA_ENC]);
 
   return ret;
 }
 
-void ssl_sess_cert_free(SESS_CERT *sc) {
-  int i;
-
-  if (sc == NULL) {
-    return;
+SESS_CERT *ssl_sess_cert_dup(const SESS_CERT *sess_cert) {
+  SESS_CERT *ret = ssl_sess_cert_new();
+  if (ret == NULL) {
+    return NULL;
   }
 
-  sk_X509_pop_free(sc->cert_chain, X509_free);
-
-  for (i = 0; i < SSL_PKEY_NUM; i++) {
-    X509_free(sc->peer_pkeys[i].x509);
+  if (sess_cert->cert_chain != NULL) {
+    ret->cert_chain = X509_chain_up_ref(sess_cert->cert_chain);
+    if (ret->cert_chain == NULL) {
+      ssl_sess_cert_free(ret);
+      return NULL;
+    }
   }
+  if (sess_cert->peer_cert != NULL) {
+    ret->peer_cert = X509_up_ref(sess_cert->peer_cert);
+  }
+  if (sess_cert->peer_dh_tmp != NULL) {
+    ret->peer_dh_tmp = sess_cert->peer_dh_tmp;
+    DH_up_ref(ret->peer_dh_tmp);
+  }
+  if (sess_cert->peer_ecdh_tmp != NULL) {
+    ret->peer_ecdh_tmp = sess_cert->peer_ecdh_tmp;
+    EC_KEY_up_ref(ret->peer_ecdh_tmp);
+  }
+  return ret;
+}
 
-  DH_free(sc->peer_dh_tmp);
-  EC_KEY_free(sc->peer_ecdh_tmp);
+void ssl_sess_cert_free(SESS_CERT *sess_cert) {
+  if (sess_cert == NULL) {
+    return;
+  }
 
-  OPENSSL_free(sc);
-}
+  sk_X509_pop_free(sess_cert->cert_chain, X509_free);
+  X509_free(sess_cert->peer_cert);
+  DH_free(sess_cert->peer_dh_tmp);
+  EC_KEY_free(sess_cert->peer_ecdh_tmp);
 
-int ssl_set_peer_cert_type(SESS_CERT *sc, int type) {
-  sc->peer_cert_type = type;
-  return 1;
+  OPENSSL_free(sess_cert);
 }
 
 int ssl_verify_cert_chain(SSL *s, STACK_OF(X509) *sk) {
diff --git a/src/ssl/ssl_lib.c b/src/ssl/ssl_lib.c
index e95226f..9e1e308 100644
--- a/src/ssl/ssl_lib.c
+++ b/src/ssl/ssl_lib.c
@@ -1975,8 +1975,16 @@ void ssl_update_cache(SSL *s, int mode) {
     return;
   }
 
+  int has_new_session = !s->hit;
+  if (!s->server && s->tlsext_ticket_expected) {
+    /* A client may see new sessions on abbreviated handshakes if the server
+     * decides to renew the ticket. Once the handshake is completed, it should
+     * be inserted into the cache. */
+    has_new_session = 1;
+  }
+
   SSL_CTX *ctx = s->initial_ctx;
-  if ((ctx->session_cache_mode & mode) == mode && !s->hit &&
+  if ((ctx->session_cache_mode & mode) == mode && has_new_session &&
       ((ctx->session_cache_mode & SSL_SESS_CACHE_NO_INTERNAL_STORE) ||
        SSL_CTX_add_session(ctx, s->session)) &&
       ctx->new_session_cb != NULL) {
@@ -2960,6 +2968,10 @@ err:
   return 0;
 }
 
+int SSL_initial_handshake_complete(const SSL *ssl) {
+  return ssl->s3->initial_handshake_complete;
+}
+
 int SSL_CTX_sess_connect(const SSL_CTX *ctx) { return 0; }
 int SSL_CTX_sess_connect_good(const SSL_CTX *ctx) { return 0; }
 int SSL_CTX_sess_connect_renegotiate(const SSL_CTX *ctx) { return 0; }
diff --git a/src/ssl/ssl_test.cc b/src/ssl/ssl_test.cc
index 1c6e24a..9f2ddb9 100644
--- a/src/ssl/ssl_test.cc
+++ b/src/ssl/ssl_test.cc
@@ -359,6 +359,18 @@ static const char kBadSessionVersion[] =
     "q+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYG"
     "BgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGrgMEAQevAwQBBLADBAEF";
 
+// kBadSessionTrailingData is a custom serialized SSL_SESSION with trailing data
+// appended.
+static const char kBadSessionTrailingData[] =
+    "MIIBdgIBAQICAwMEAsAvBCAG5Q1ndq4Yfmbeo1zwLkNRKmCXGdNgWvGT3cskV0yQ"
+    "kAQwJlrlzkAWBOWiLj/jJ76D7l+UXoizP2KI2C7I2FccqMmIfFmmkUy32nIJ0mZH"
+    "IWoJoQYCBFRDO46iBAICASykAwQBAqUDAgEUphAEDnd3dy5nb29nbGUuY29tqAcE"
+    "BXdvcmxkqQUCAwGJwKqBpwSBpBwUQvoeOk0Kg36SYTcLEkXqKwOBfF9vE4KX0Nxe"
+    "LwjcDTpsuh3qXEaZ992r1N38VDcyS6P7I6HBYN9BsNHM362zZnY27GpTw+Kwd751"
+    "CLoXFPoaMOe57dbBpXoro6Pd3BTbf/Tzr88K06yEOTDKPNj3+inbMaVigtK4PLyP"
+    "q+Topyzvx9USFgRvyuoxn0Hgb+R0A3j6SLRuyOdAi4gv7Y5oliynrSIEIAYGBgYG"
+    "BgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGBgYGrgMEAQevAwQBBLADBAEFAAAA";
+
 static bool DecodeBase64(std::vector<uint8_t> *out, const char *in) {
   size_t len;
   if (!EVP_DecodedLength(&len, strlen(in))) {
@@ -387,10 +399,10 @@ static bool TestSSL_SESSIONEncoding(const char *input_b64) {
   }
 
   // Verify the SSL_SESSION decodes.
-  cptr = bssl::vector_data(&input);
-  ScopedSSL_SESSION session(d2i_SSL_SESSION(NULL, &cptr, input.size()));
-  if (!session || cptr != bssl::vector_data(&input) + input.size()) {
-    fprintf(stderr, "d2i_SSL_SESSION failed\n");
+  ScopedSSL_SESSION session(SSL_SESSION_from_bytes(bssl::vector_data(&input),
+                                                   input.size()));
+  if (!session) {
+    fprintf(stderr, "SSL_SESSION_from_bytes failed\n");
     return false;
   }
 
@@ -409,6 +421,14 @@ static bool TestSSL_SESSIONEncoding(const char *input_b64) {
     return false;
   }
 
+  // Verify the SSL_SESSION also decodes with the legacy API.
+  cptr = bssl::vector_data(&input);
+  session.reset(d2i_SSL_SESSION(NULL, &cptr, input.size()));
+  if (!session || cptr != bssl::vector_data(&input) + input.size()) {
+    fprintf(stderr, "d2i_SSL_SESSION failed\n");
+    return false;
+  }
+
   // Verify the SSL_SESSION encoding round-trips via the legacy API.
   int len = i2d_SSL_SESSION(session.get(), NULL);
   if (len < 0 || (size_t)len != input.size()) {
@@ -447,10 +467,10 @@ static bool TestBadSSL_SESSIONEncoding(const char *input_b64) {
   }
 
   // Verify that the SSL_SESSION fails to decode.
-  const uint8_t *ptr = bssl::vector_data(&input);
-  ScopedSSL_SESSION session(d2i_SSL_SESSION(NULL, &ptr, input.size()));
+  ScopedSSL_SESSION session(SSL_SESSION_from_bytes(bssl::vector_data(&input),
+                                                   input.size()));
   if (session) {
-    fprintf(stderr, "d2i_SSL_SESSION unexpectedly succeeded\n");
+    fprintf(stderr, "SSL_SESSION_from_bytes unexpectedly succeeded\n");
     return false;
   }
   ERR_clear_error();
@@ -537,6 +557,7 @@ int main(void) {
       !TestSSL_SESSIONEncoding(kCustomSession) ||
       !TestBadSSL_SESSIONEncoding(kBadSessionExtraField) ||
       !TestBadSSL_SESSIONEncoding(kBadSessionVersion) ||
+      !TestBadSSL_SESSIONEncoding(kBadSessionTrailingData) ||
       !TestDefaultVersion(0, &TLS_method) ||
       !TestDefaultVersion(SSL3_VERSION, &SSLv3_method) ||
       !TestDefaultVersion(TLS1_VERSION, &TLSv1_method) ||
diff --git a/src/ssl/t1_lib.c b/src/ssl/t1_lib.c
index 9e5c011..213a647 100644
--- a/src/ssl/t1_lib.c
+++ b/src/ssl/t1_lib.c
@@ -2184,7 +2184,7 @@ static int tls_decrypt_ticket(SSL *s, const uint8_t *etick, int eticklen,
   EVP_CIPHER_CTX_cleanup(&ctx);
   p = sdec;
 
-  sess = d2i_SSL_SESSION(NULL, &p, slen);
+  sess = SSL_SESSION_from_bytes(sdec, slen);
   OPENSSL_free(sdec);
   if (sess) {
     /* The session ID, if non-empty, is used by some clients to detect that the
diff --git a/src/ssl/test/bssl_shim.cc b/src/ssl/test/bssl_shim.cc
index 40cb149..3b95d7e 100644
--- a/src/ssl/test/bssl_shim.cc
+++ b/src/ssl/test/bssl_shim.cc
@@ -838,6 +838,20 @@ static bool DoExchange(ScopedSSL_SESSION *out_session, SSL_CTX *ssl_ctx,
         return false;
       }
     }
+
+    if (!config->is_server) {
+      /* Clients should expect a peer certificate chain iff this was not a PSK
+       * cipher suite. */
+      if (config->psk.empty()) {
+        if (SSL_get_peer_cert_chain(ssl.get()) == nullptr) {
+          fprintf(stderr, "Missing peer certificate chain!\n");
+          return false;
+        }
+      } else if (SSL_get_peer_cert_chain(ssl.get()) != nullptr) {
+        fprintf(stderr, "Unexpected peer certificate chain!\n");
+        return false;
+      }
+    }
   }
 
   if (config->export_keying_material > 0) {