Promote max_cert_list and max_send_fragment to functions.

Also size them based on the limits in the quantities they control (after
checking bounds at the API boundary).

BUG=404754

Change-Id: Id56ba45465a473a1a793244904310ef747f29b63
Reviewed-on: https://boringssl-review.googlesource.com/4559
Reviewed-by: Adam Langley <agl@google.com>

include/openssl/ssl.h

@@ -877,7 +877,7 @@ struct ssl_ctx_st {
 
   uint32_t options;
   uint32_t mode;
-  long max_cert_list;
+  uint32_t max_cert_list;
 
   struct cert_st /* CERT */ *cert;
   int read_ahead;
@@ -917,7 +917,7 @@ struct ssl_ctx_st {
 
   /* Maximum amount of data to send in one fragment. actual record size can be
    * more than this due to padding and MAC overheads. */
-  unsigned int max_send_fragment;
+  uint16_t max_send_fragment;
 
   /* TLS extensions servername callback */
   int (*tlsext_servername_callback)(SSL *, int *, void *);
@@ -1360,10 +1360,10 @@ struct ssl_st {
 
   uint32_t options; /* protocol behaviour */
   uint32_t mode;    /* API behaviour */
-  long max_cert_list;
+  uint32_t max_cert_list;
   int client_version; /* what was passed, used for
                        * SSLv3/TLS rollback check */
-  unsigned int max_send_fragment;
+  uint16_t max_send_fragment;
   char *tlsext_hostname;
   /* should_ack_sni is true if the SNI extension should be acked. This is
    * only used by a server. */
@@ -1605,11 +1605,6 @@ DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
 #define SSL_CTRL_SET_SESS_CACHE_MODE 44
 #define SSL_CTRL_GET_SESS_CACHE_MODE 45
 
-#define SSL_CTRL_GET_MAX_CERT_LIST 50
-#define SSL_CTRL_SET_MAX_CERT_LIST 51
-
-#define SSL_CTRL_SET_MAX_SEND_FRAGMENT 52
-
 /* see tls1.h for macros based on these */
 #define SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG 54
 #define SSL_CTRL_SET_TLSEXT_HOSTNAME 55
@@ -2158,19 +2153,37 @@ OPENSSL_EXPORT int SSL_get_ex_data_X509_STORE_CTX_idx(void);
  * is resolved. */
 OPENSSL_EXPORT int SSL_CTX_get_read_ahead(const SSL_CTX *ctx);
 OPENSSL_EXPORT void SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes);
-#define SSL_CTX_get_max_cert_list(ctx) \
-  SSL_CTX_ctrl(ctx, SSL_CTRL_GET_MAX_CERT_LIST, 0, NULL)
-#define SSL_CTX_set_max_cert_list(ctx, m) \
-  SSL_CTX_ctrl(ctx, SSL_CTRL_SET_MAX_CERT_LIST, m, NULL)
-#define SSL_get_max_cert_list(ssl) \
-  SSL_ctrl(ssl, SSL_CTRL_GET_MAX_CERT_LIST, 0, NULL)
-#define SSL_set_max_cert_list(ssl, m) \
-  SSL_ctrl(ssl, SSL_CTRL_SET_MAX_CERT_LIST, m, NULL)
-
-#define SSL_CTX_set_max_send_fragment(ctx, m) \
-  SSL_CTX_ctrl(ctx, SSL_CTRL_SET_MAX_SEND_FRAGMENT, m, NULL)
-#define SSL_set_max_send_fragment(ssl, m) \
-  SSL_ctrl(ssl, SSL_CTRL_SET_MAX_SEND_FRAGMENT, m, NULL)
+
+/* SSL_CTX_get_max_cert_list returns the maximum length, in bytes, of a peer
+ * certificate chain accepted by |ctx|. */
+OPENSSL_EXPORT size_t SSL_CTX_get_max_cert_list(const SSL_CTX *ctx);
+
+/* SSL_CTX_set_max_cert_list sets the maximum length, in bytes, of a peer
+ * certificate chain to |max_cert_list|. This affects how much memory may be
+ * consumed during the handshake. */
+OPENSSL_EXPORT void SSL_CTX_set_max_cert_list(SSL_CTX *ctx,
+                                              size_t max_cert_list);
+
+/* SSL_get_max_cert_list returns the maximum length, in bytes, of a peer
+ * certificate chain accepted by |ssl|. */
+OPENSSL_EXPORT size_t SSL_get_max_cert_list(const SSL *ssl);
+
+/* SSL_set_max_cert_list sets the maximum length, in bytes, of a peer
+ * certificate chain to |max_cert_list|. This affects how much memory may be
+ * consumed during the handshake. */
+OPENSSL_EXPORT void SSL_set_max_cert_list(SSL *ssl, size_t max_cert_list);
+
+/* SSL_CTX_set_max_send_fragment sets the maximum length, in bytes, of records
+ * sent by |ctx|. Beyond this length, handshake messages and application data
+ * will be split into multiple records. */
+OPENSSL_EXPORT void SSL_CTX_set_max_send_fragment(SSL_CTX *ctx,
+                                                  size_t max_send_fragment);
+
+/* SSL_set_max_send_fragment sets the maximum length, in bytes, of records
+ * sent by |ssl|. Beyond this length, handshake messages and application data
+ * will be split into multiple records. */
+OPENSSL_EXPORT void SSL_set_max_send_fragment(SSL *ssl,
+                                              size_t max_send_fragment);
 
 /* SSL_CTX_set_tmp_dh_callback configures |ctx| to use |callback| to determine
  * the group for DHE ciphers. |callback| should ignore |is_export| and
@@ -2387,6 +2400,9 @@ OPENSSL_EXPORT const char *SSLeay_version(int unused);
 #define SSL_CTRL_MODE doesnt_exist
 #define SSL_CTRL_GET_READ_AHEAD doesnt_exist
 #define SSL_CTRL_SET_READ_AHEAD doesnt_exist
+#define SSL_CTRL_GET_MAX_CERT_LIST doesnt_exist
+#define SSL_CTRL_SET_MAX_CERT_LIST doesnt_exist
+#define SSL_CTRL_SET_MAX_SEND_FRAGMENT doesnt_exist
 #define SSL_CTRL_SET_TLSEXT_SERVERNAME_CB doesnt_exist
 #define SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB doesnt_exist
 #define DTLS_CTRL_GET_TIMEOUT doesnt_exist
@@ -2406,6 +2422,12 @@ OPENSSL_EXPORT const char *SSLeay_version(int unused);
 #define SSL_set_mode SSL_set_mode
 #define SSL_CTX_get_read_ahead SSL_CTX_get_read_ahead
 #define SSL_CTX_set_read_ahead SSL_CTX_set_read_ahead
+#define SSL_CTX_get_max_cert_list SSL_CTX_get_max_cert_list
+#define SSL_get_max_cert_list SSL_get_max_cert_list
+#define SSL_CTX_set_max_cert_list SSL_CTX_set_max_cert_list
+#define SSL_set_max_cert_list SSL_set_max_cert_list
+#define SSL_CTX_set_max_send_fragment SSL_CTX_set_max_send_fragment
+#define SSL_set_max_send_fragment SSL_set_max_send_fragment
 #define SSL_CTX_set_tlsext_servername_callback \
     SSL_CTX_set_tlsext_servername_callback
 #define SSL_CTX_set_tlsext_ticket_key_cb SSL_CTX_set_tlsext_ticket_key_cb

ssl/d1_both.c

@@ -470,8 +470,8 @@ static hm_fragment *dtls1_get_buffered_message(
  * be greater if the maximum certificate list size requires it. */
 static size_t dtls1_max_handshake_message_len(const SSL *s) {
   size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
-  if (max_len < (size_t)s->max_cert_list) {
-    return (size_t)s->max_cert_list;
+  if (max_len < s->max_cert_list) {
+    return s->max_cert_list;
   }
   return max_len;
 }

ssl/s3_clnt.c

@@ -925,7 +925,7 @@ int ssl3_get_server_certificate(SSL *s) {
   const uint8_t *data;
 
   n = s->method->ssl_get_message(s, SSL3_ST_CR_CERT_A, SSL3_ST_CR_CERT_B,
-                                 SSL3_MT_CERTIFICATE, s->max_cert_list,
+                                 SSL3_MT_CERTIFICATE, (long)s->max_cert_list,
                                  ssl_hash_message, &ok);
 
   if (!ok) {

ssl/s3_srvr.c

@@ -2220,7 +2220,7 @@ int ssl3_get_client_certificate(SSL *s) {
   int is_first_certificate = 1;
 
   n = s->method->ssl_get_message(s, SSL3_ST_SR_CERT_A, SSL3_ST_SR_CERT_B, -1,
-                                 s->max_cert_list, ssl_hash_message, &ok);
+                                 (long)s->max_cert_list, ssl_hash_message, &ok);
 
   if (!ok) {
     return n;

ssl/ssl_lib.c

@@ -161,6 +161,9 @@ OPENSSL_COMPILE_ASSERT(SSL_R_TLSV1_ALERT_NO_RENEGOTIATION ==
                            SSL_AD_NO_RENEGOTIATION + SSL_AD_REASON_OFFSET,
                        ssl_alert_reason_code_mismatch);
 
+/* kMaxHandshakeSize is the maximum size, in bytes, of a handshake message. */
+static const size_t kMaxHandshakeSize = (1u << 24) - 1;
+
 static CRYPTO_EX_DATA_CLASS g_ex_data_class_ssl = CRYPTO_EX_DATA_CLASS_INIT;
 static CRYPTO_EX_DATA_CLASS g_ex_data_class_ssl_ctx = CRYPTO_EX_DATA_CLASS_INIT;
 
@@ -1009,18 +1012,50 @@ uint32_t SSL_CTX_get_mode(const SSL_CTX *ctx) { return ctx->mode; }
 
 uint32_t SSL_get_mode(const SSL *ssl) { return ssl->mode; }
 
-long SSL_ctrl(SSL *s, int cmd, long larg, void *parg) {
-  long l;
+size_t SSL_CTX_get_max_cert_list(const SSL_CTX *ctx) {
+  return ctx->max_cert_list;
+}
 
-  switch (cmd) {
-    case SSL_CTRL_GET_MAX_CERT_LIST:
-      return s->max_cert_list;
+void SSL_CTX_set_max_cert_list(SSL_CTX *ctx, size_t max_cert_list) {
+  if (max_cert_list > kMaxHandshakeSize) {
+    max_cert_list = kMaxHandshakeSize;
+  }
+  ctx->max_cert_list = (uint32_t)max_cert_list;
+}
 
-    case SSL_CTRL_SET_MAX_CERT_LIST:
-      l = s->max_cert_list;
-      s->max_cert_list = larg;
-      return l;
+size_t SSL_get_max_cert_list(const SSL *ssl) {
+  return ssl->max_cert_list;
+}
+
+void SSL_set_max_cert_list(SSL *ssl, size_t max_cert_list) {
+  if (max_cert_list > kMaxHandshakeSize) {
+    max_cert_list = kMaxHandshakeSize;
+  }
+  ssl->max_cert_list = (uint32_t)max_cert_list;
+}
+
+void SSL_CTX_set_max_send_fragment(SSL_CTX *ctx, size_t max_send_fragment) {
+  if (max_send_fragment < 512) {
+    max_send_fragment = 512;
+  }
+  if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
+    max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;
+  }
+  ctx->max_send_fragment = (uint16_t)max_send_fragment;
+}
 
+void SSL_set_max_send_fragment(SSL *ssl, size_t max_send_fragment) {
+  if (max_send_fragment < 512) {
+    max_send_fragment = 512;
+  }
+  if (max_send_fragment > SSL3_RT_MAX_PLAIN_LENGTH) {
+    max_send_fragment = SSL3_RT_MAX_PLAIN_LENGTH;
+  }
+  ssl->max_send_fragment = (uint16_t)max_send_fragment;
+}
+
+long SSL_ctrl(SSL *s, int cmd, long larg, void *parg) {
+  switch (cmd) {
     case SSL_CTRL_SET_MTU:
       if (larg < (long)dtls1_min_mtu()) {
         return 0;
@@ -1031,13 +1066,6 @@ long SSL_ctrl(SSL *s, int cmd, long larg, void *parg) {
       }
       return 0;
 
-    case SSL_CTRL_SET_MAX_SEND_FRAGMENT:
-      if (larg < 512 || larg > SSL3_RT_MAX_PLAIN_LENGTH) {
-        return 0;
-      }
-      s->max_send_fragment = larg;
-      return 1;
-
     case SSL_CTRL_GET_RI_SUPPORT:
       if (s->s3) {
         return s->s3->send_connection_binding;
@@ -1068,14 +1096,6 @@ long SSL_CTX_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg) {
   long l;
 
   switch (cmd) {
-    case SSL_CTRL_GET_MAX_CERT_LIST:
-      return ctx->max_cert_list;
-
-    case SSL_CTRL_SET_MAX_CERT_LIST:
-      l = ctx->max_cert_list;
-      ctx->max_cert_list = larg;
-      return l;
-
     case SSL_CTRL_SET_SESS_CACHE_SIZE:
       l = ctx->session_cache_size;
       ctx->session_cache_size = larg;
@@ -1095,13 +1115,6 @@ long SSL_CTX_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg) {
     case SSL_CTRL_SESS_NUMBER:
       return lh_SSL_SESSION_num_items(ctx->sessions);
 
-    case SSL_CTRL_SET_MAX_SEND_FRAGMENT:
-      if (larg < 512 || larg > SSL3_RT_MAX_PLAIN_LENGTH) {
-        return 0;
-      }
-      ctx->max_send_fragment = larg;
-      return 1;
-
     default:
       return ctx->method->ssl_ctx_ctrl(ctx, cmd, larg, parg);
   }