Clean up tls1_process_ticket().

We only have to find one extension, so do that first then proceed with
processing and decryption. This makes the code more readable and drops
two levels of indent.

ok tb@

1 files changed, 43 insertions, 39 deletions

diff --git a/src/lib/libssl/t1_lib.c b/src/lib/libssl/t1_lib.c
index 2421227c8a..75c936abc7 100644
--- a/src/lib/libssl/t1_lib.c
+++ b/src/lib/libssl/t1_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t1_lib.c,v 1.156 2019/04/21 14:38:32 jsing Exp $ */
+/* $OpenBSD: t1_lib.c,v 1.157 2019/04/21 14:41:30 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -790,7 +790,9 @@ int
 tls1_process_ticket(SSL *s, const unsigned char *session_id, int session_id_len,
     CBS *ext_block, SSL_SESSION **ret)
 {
-        CBS extensions;
+        CBS extensions, ext_data;
+        uint16_t ext_type = 0;
+        int r;
 
         s->internal->tlsext_ticket_expected = 0;
         *ret = NULL;
@@ -813,48 +815,50 @@ tls1_process_ticket(SSL *s, const unsigned char *session_id, int session_id_len,
                 return -1;
 
         while (CBS_len(&extensions) > 0) {
-                uint16_t ext_type;
-                CBS ext_data;
-
                 if (!CBS_get_u16(&extensions, &ext_type) ||
                     !CBS_get_u16_length_prefixed(&extensions, &ext_data))
                         return -1;
 
-                if (ext_type == TLSEXT_TYPE_session_ticket) {
-                        int r;
-                        if (CBS_len(&ext_data) == 0) {
-                                /* The client will accept a ticket but doesn't
-                                 * currently have one. */
-                                s->internal->tlsext_ticket_expected = 1;
-                                return 1;
-                        }
-                        if (s->internal->tls_session_secret_cb != NULL) {
-                                /* Indicate that the ticket couldn't be
-                                 * decrypted rather than generating the session
-                                 * from ticket now, trigger abbreviated
-                                 * handshake based on external mechanism to
-                                 * calculate the master secret later. */
-                                return 2;
-                        }
-
-                        r = tls_decrypt_ticket(s, CBS_data(&ext_data),
-                            CBS_len(&ext_data), session_id, session_id_len, ret);
-
-                        switch (r) {
-                        case 2: /* ticket couldn't be decrypted */
-                                s->internal->tlsext_ticket_expected = 1;
-                                return 2;
-                        case 3: /* ticket was decrypted */
-                                return r;
-                        case 4: /* ticket decrypted but need to renew */
-                                s->internal->tlsext_ticket_expected = 1;
-                                return 3;
-                        default: /* fatal error */
-                                return -1;
-                        }
-                }
+                if (ext_type == TLSEXT_TYPE_session_ticket)
+                        break;
+        }
+
+        if (ext_type != TLSEXT_TYPE_session_ticket)
+                return 0;
+
+        if (CBS_len(&ext_data) == 0) {
+                /*
+                 * The client will accept a ticket but does not currently
+                 * have one.
+                 */
+                s->internal->tlsext_ticket_expected = 1;
+                return 1;
+        }
+
+        if (s->internal->tls_session_secret_cb != NULL) {
+                /*
+                 * Indicate that the ticket could not be decrypted rather than
+                 * generating the session from ticket now, trigger abbreviated
+                 * handshake based on external mechanism to calculate the master
+                 * secret later.
+                 */
+                return 2;
+        }
+
+        r = tls_decrypt_ticket(s, CBS_data(&ext_data), CBS_len(&ext_data),
+            session_id, session_id_len, ret);
+        switch (r) {
+        case 2: /* ticket couldn't be decrypted */
+                s->internal->tlsext_ticket_expected = 1;
+                return 2;
+        case 3: /* ticket was decrypted */
+                return r;
+        case 4: /* ticket decrypted but need to renew */
+                s->internal->tlsext_ticket_expected = 1;
+                return 3;
+        default: /* fatal error */
+                return -1;
         }
-        return 0;
 }
 
 /* tls_decrypt_ticket attempts to decrypt a session ticket.