sanity check

PR: 1679

ssl/s3_pkt.c

@@ -1302,6 +1302,13 @@ int ssl3_do_change_cipher_spec(SSL *s)
 
 	if (s->s3->tmp.key_block == NULL)
 		{
+		if (s->session == NULL) 
+			{
+			/* might happen if dtls1_read_bytes() calls this */
+			SSLerr(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC,SSL_R_CCS_RECEIVED_EARLY);
+			return (0);
+			}
+
 		s->session->cipher=s->s3->tmp.new_cipher;
 		if (!s->method->ssl3_enc->setup_key_block(s)) return(0);
 		}

ssl/ssl.h

@@ -1822,6 +1822,7 @@ void ERR_load_SSL_strings(void);
 #define SSL_F_SSL3_CONNECT				 132
 #define SSL_F_SSL3_CTRL					 213
 #define SSL_F_SSL3_CTX_CTRL				 133
+#define SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC		 292
 #define SSL_F_SSL3_ENC					 134
 #define SSL_F_SSL3_GENERATE_KEY_BLOCK			 238
 #define SSL_F_SSL3_GET_CERTIFICATE_REQUEST		 135

ssl/ssl_err.c

@@ -138,6 +138,7 @@ static ERR_STRING_DATA SSL_str_functs[]=
 {ERR_FUNC(SSL_F_SSL3_CONNECT),	"SSL3_CONNECT"},
 {ERR_FUNC(SSL_F_SSL3_CTRL),	"SSL3_CTRL"},
 {ERR_FUNC(SSL_F_SSL3_CTX_CTRL),	"SSL3_CTX_CTRL"},
+{ERR_FUNC(SSL_F_SSL3_DO_CHANGE_CIPHER_SPEC),	"SSL3_DO_CHANGE_CIPHER_SPEC"},
 {ERR_FUNC(SSL_F_SSL3_ENC),	"SSL3_ENC"},
 {ERR_FUNC(SSL_F_SSL3_GENERATE_KEY_BLOCK),	"SSL3_GENERATE_KEY_BLOCK"},
 {ERR_FUNC(SSL_F_SSL3_GET_CERTIFICATE_REQUEST),	"SSL3_GET_CERTIFICATE_REQUEST"},