From 183d400c72ab3f234b648c7ee346df0de9420212 Mon Sep 17 00:00:00 2001 From: jsing Date: Sun, 19 Aug 2018 15:29:26 +0000 Subject: [PATCH] Convert ssl3_send_newsession_ticket() to CBB. This removes a memorable BUF_MEM_grow() and associated comment. ok inoguchi@ tb@ --- lib/libssl/ssl_srvr.c | 119 +++++++++++++++++++++++------------------- 1 file changed, 64 insertions(+), 55 deletions(-) diff --git a/lib/libssl/ssl_srvr.c b/lib/libssl/ssl_srvr.c index 2fde588cb92..80c7208c138 100644 --- a/lib/libssl/ssl_srvr.c +++ b/lib/libssl/ssl_srvr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssl_srvr.c,v 1.39 2018/08/16 18:13:15 jsing Exp $ */ +/* $OpenBSD: ssl_srvr.c,v 1.40 2018/08/19 15:29:26 jsing Exp $ */ /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * @@ -2527,10 +2527,14 @@ ssl3_send_server_certificate(SSL *s) int ssl3_send_newsession_ticket(SSL *s) { - unsigned char *d, *p, *macstart; + CBB cbb, session_ticket, ticket; + unsigned char *enc_ticket = NULL; unsigned char *senc = NULL; const unsigned char *const_p; - int len, slen_full, slen; + unsigned char *p, *hmac; + size_t hmac_len; + int enc_ticket_len, slen; + int slen_full = 0; SSL_SESSION *sess; unsigned int hlen; EVP_CIPHER_CTX ctx; @@ -2539,7 +2543,16 @@ ssl3_send_newsession_ticket(SSL *s) unsigned char iv[EVP_MAX_IV_LENGTH]; unsigned char key_name[16]; + EVP_CIPHER_CTX_init(&ctx); + HMAC_CTX_init(&hctx); + + memset(&cbb, 0, sizeof(cbb)); + if (S3I(s)->hs.state == SSL3_ST_SW_SESSION_TICKET_A) { + if (!ssl3_handshake_msg_start_cbb(s, &cbb, &session_ticket, + SSL3_MT_NEWSESSION_TICKET)) + goto err; + /* get session encoding length */ slen_full = i2d_SSL_SESSION(s->session, NULL); /* @@ -2575,24 +2588,6 @@ ssl3_send_newsession_ticket(SSL *s) i2d_SSL_SESSION(sess, &p); SSL_SESSION_free(sess); - /* - * Grow buffer if need be: the length calculation is as - * follows 1 (size of message name) + 3 (message length - * bytes) + 4 (ticket lifetime hint) + 2 (ticket length) + - * 16 (key name) + max_iv_len (iv length) + - * session_length + max_enc_block_size (max encrypted session - * length) + max_md_size (HMAC). - */ - if (!BUF_MEM_grow(s->internal->init_buf, ssl3_handshake_msg_hdr_len(s) + - 22 + EVP_MAX_IV_LENGTH + EVP_MAX_BLOCK_LENGTH + - EVP_MAX_MD_SIZE + slen)) - goto err; - - d = p = ssl3_handshake_msg_start(s, SSL3_MT_NEWSESSION_TICKET); - - EVP_CIPHER_CTX_init(&ctx); - HMAC_CTX_init(&hctx); - /* * Initialize HMAC and cipher contexts. If callback present * it does all the work otherwise use generated values @@ -2613,55 +2608,69 @@ ssl3_send_newsession_ticket(SSL *s) memcpy(key_name, tctx->internal->tlsext_tick_key_name, 16); } + /* Encrypt the session ticket. */ + if ((enc_ticket = calloc(1, slen + EVP_MAX_BLOCK_LENGTH)) == NULL) + goto err; + if (!EVP_EncryptUpdate(&ctx, enc_ticket, &enc_ticket_len, senc, slen)) + goto err; + if (!EVP_EncryptFinal_ex(&ctx, enc_ticket, &enc_ticket_len)) + goto err; + + /* Generate the HMAC. */ + if (!HMAC_Update(&hctx, key_name, sizeof(key_name))) + goto err; + if (!HMAC_Update(&hctx, iv, EVP_CIPHER_CTX_iv_length(&ctx))) + goto err; + if (!HMAC_Update(&hctx, enc_ticket, enc_ticket_len)) + goto err; + + if ((hmac_len = HMAC_size(&hctx)) <= 0) + goto err; + /* * Ticket lifetime hint (advisory only): * We leave this unspecified for resumed session * (for simplicity), and guess that tickets for new * sessions will live as long as their sessions. */ - l2n(s->internal->hit ? 0 : s->session->timeout, p); - - /* Skip ticket length for now */ - p += 2; - /* Output key name */ - macstart = p; - memcpy(p, key_name, 16); - p += 16; - /* output IV */ - memcpy(p, iv, EVP_CIPHER_CTX_iv_length(&ctx)); - p += EVP_CIPHER_CTX_iv_length(&ctx); - /* Encrypt session data */ - EVP_EncryptUpdate(&ctx, p, &len, senc, slen); - p += len; - EVP_EncryptFinal_ex(&ctx, p, &len); - p += len; - EVP_CIPHER_CTX_cleanup(&ctx); - - HMAC_Update(&hctx, macstart, p - macstart); - HMAC_Final(&hctx, p, &hlen); - HMAC_CTX_cleanup(&hctx); - p += hlen; - - /* Now write out lengths: p points to end of data written */ - /* Total length */ - len = p - d; - - /* Skip ticket lifetime hint. */ - p = d + 4; - s2n(len - 6, p); /* Message length */ - - ssl3_handshake_msg_finish(s, len); + if (!CBB_add_u32(&session_ticket, + s->internal->hit ? 0 : s->session->timeout)) + goto err; - S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_B; + if (!CBB_add_u16_length_prefixed(&session_ticket, &ticket)) + goto err; + if (!CBB_add_bytes(&ticket, key_name, sizeof(key_name))) + goto err; + if (!CBB_add_bytes(&ticket, iv, EVP_CIPHER_CTX_iv_length(&ctx))) + goto err; + if (!CBB_add_bytes(&ticket, enc_ticket, enc_ticket_len)) + goto err; + if (!CBB_add_space(&ticket, &hmac, hmac_len)) + goto err; - freezero(senc, slen_full); + if (!HMAC_Final(&hctx, hmac, &hlen)) + goto err; + + if (!ssl3_handshake_msg_finish_cbb(s, &cbb)) + goto err; + + S3I(s)->hs.state = SSL3_ST_SW_SESSION_TICKET_B; } + EVP_CIPHER_CTX_cleanup(&ctx); + HMAC_CTX_cleanup(&hctx); + freezero(senc, slen_full); + free(enc_ticket); + /* SSL3_ST_SW_SESSION_TICKET_B */ return (ssl3_handshake_write(s)); err: + CBB_cleanup(&cbb); + EVP_CIPHER_CTX_cleanup(&ctx); + HMAC_CTX_cleanup(&hctx); freezero(senc, slen_full); + free(enc_ticket); return (-1); } -- 2.20.1