Hi, We upgraded a code base from openssl 1.0.2 to openssl1.1.1b. The upgrade was straightforward and we manage to activate and use TLS1.3. OpenSSL is used to implement multi-threaded HTTPS server.
While using TLS1.3 as the minimum version with option SSL_OP_NO_TICKET the app crash randomly due to a race condition in openssl, exactly when 2 threads use the same SSL_SESSION*. Some t We don't install any session management callback and we keep session caching mode to 2 ( SSL_SESS_CACHE_SERVER). I made some debugging/tracing and I found that SSL_OP_NO_TICKET force openssl to call lookup_sess_in_cache() function ( file ssl_sess.c ) CRYPTO_THREAD_read_lock(s->session_ctx->lock); ret = lh_SSL_SESSION_retrieve(s->session_ctx->sessions, &data); if (ret != NULL) { /* don't allow other threads to steal it: */ SSL_SESSION_up_ref(ret); } CRYPTO_THREAD_unlock(s->session_ctx->lock); lh_SSL_SESSION_retriev() doesn't make any lock check in retrieved session and lookup_sess_in_cache don't lock the session avec SSL_SESSION have a CRYPT_RWLOCK member. I can't provide a sample to reproduce the crash, it's totaly random. Here example of thread call stack: Thread1: libssl-1_1-x64.dll!tls_parse_ctos_supported_groups(ssl_st * s, PACKET * pkt, unsigned int context, x509_st * x, unsigned __int64 chainidx) Ligne 966 C libssl-1_1-x64.dll!tls_parse_extension(ssl_st * s, tlsext_index_en idx, int context, raw_extension_st * exts, x509_st * x, unsigned __int64 chainidx) Ligne 715 C libssl-1_1-x64.dll!tls_parse_all_extensions(ssl_st * s, int context, raw_extension_st * exts, x509_st * x, unsigned __int64 chainidx, int fin) Ligne 748 C libssl-1_1-x64.dll!tls_early_post_process_client_hello(ssl_st * s) Ligne 1883 C libssl-1_1-x64.dll!tls_post_process_client_hello(ssl_st * s, WORK_STATE wst) Ligne 2222 C libssl-1_1-x64.dll!ossl_statem_server_post_process_message(ssl_st * s, WORK_STATE wst) Ligne 1220 C libssl-1_1-x64.dll!read_state_machine(ssl_st * s) Ligne 664 C libssl-1_1-x64.dll!state_machine(ssl_st * s, int server) Ligne 434 C libssl-1_1-x64.dll!ossl_statem_accept(ssl_st * s) Ligne 256 C libssl-1_1-x64.dll!ssl3_read_bytes(ssl_st * s, int type, int * recvd_type, unsigned char * buf, unsigned __int64 len, int peek, unsigned __int64 * readbytes) Ligne 1270 C libssl-1_1-x64.dll!ssl3_read_internal(ssl_st * s, void * buf, unsigned __int64 len, int peek, unsigned __int64 * readbytes) Ligne 4473 C libssl-1_1-x64.dll!ssl3_read(ssl_st * s, void * buf, unsigned __int64 len, unsigned __int64 * readbytes) Ligne 4498 C libssl-1_1-x64.dll!ssl_read_internal(ssl_st * s, void * buf, unsigned __int64 num, unsigned __int64 * readbytes) Ligne 1754 C libssl-1_1-x64.dll!SSL_read(ssl_st * s, void * buf, int num) Ligne 1766 C Thread2: libcrypto-1_1-x64.dll!CRYPTO_malloc(unsigned __int64 num, const char * file, int line) Ligne 222 C libssl-1_1-x64.dll!tls1_save_u16(PACKET * pkt, wchar_t * * pdest, unsigned __int64 * pdestlen) Ligne 1779 C libssl-1_1-x64.dll!tls_parse_ctos_supported_groups(ssl_st * s, PACKET * pkt, unsigned int context, x509_st * x, unsigned __int64 chainidx) Ligne 968 C libssl-1_1-x64.dll!tls_parse_extension(ssl_st * s, tlsext_index_en idx, int context, raw_extension_st * exts, x509_st * x, unsigned __int64 chainidx) Ligne 715 C libssl-1_1-x64.dll!tls_parse_all_extensions(ssl_st * s, int context, raw_extension_st * exts, x509_st * x, unsigned __int64 chainidx, int fin) Ligne 748 C libssl-1_1-x64.dll!tls_early_post_process_client_hello(ssl_st * s) Ligne 1883 C libssl-1_1-x64.dll!tls_post_process_client_hello(ssl_st * s, WORK_STATE wst) Ligne 2222 C libssl-1_1-x64.dll!ossl_statem_server_post_process_message(ssl_st * s, WORK_STATE wst) Ligne 1220 C libssl-1_1-x64.dll!read_state_machine(ssl_st * s) Ligne 664 C libssl-1_1-x64.dll!state_machine(ssl_st * s, int server) Ligne 434 C libssl-1_1-x64.dll!ossl_statem_accept(ssl_st * s) Ligne 256 C libssl-1_1-x64.dll!ssl3_read_bytes(ssl_st * s, int type, int * recvd_type, unsigned char * buf, unsigned __int64 len, int peek, unsigned __int64 * readbytes) Ligne 1270 C libssl-1_1-x64.dll!ssl3_read_internal(ssl_st * s, void * buf, unsigned __int64 len, int peek, unsigned __int64 * readbytes) Ligne 4473 C libssl-1_1-x64.dll!ssl3_read(ssl_st * s, void * buf, unsigned __int64 len, unsigned __int64 * readbytes) Ligne 4498 C libssl-1_1-x64.dll!ssl_read_internal(ssl_st * s, void * buf, unsigned __int64 num, unsigned __int64 * readbytes) Ligne 1754 C libssl-1_1-x64.dll!SSL_read(ssl_st * s, void * buf, int num) Ligne 1766 C