Factor out change cipher spec handing code in the legacy stack.

Factor out the code that handles the processing of a change cipher spec
message that has been read in the legacy stack, deduplicating code in the
DTLS stack.

ok inoguchi@ tb@

1 files changed, 4 insertions, 29 deletions

diff --git a/src/lib/libssl/d1_pkt.c b/src/lib/libssl/d1_pkt.c
index e07fc7e3f9..6ed04395b9 100644
--- a/src/lib/libssl/d1_pkt.c
+++ b/src/lib/libssl/d1_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_pkt.c,v 1.118 2022/02/21 18:22:20 jsing Exp $ */
+/* $OpenBSD: d1_pkt.c,v 1.119 2022/03/12 12:53:03 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -748,33 +748,8 @@ dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
         }
 
         if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC) {
-                /* 'Change Cipher Spec' is just a single byte, so we know
-                 * exactly what the record payload has to look like */
-                /* XDTLS: check that epoch is consistent */
-                if ((rr->length != DTLS1_CCS_HEADER_LENGTH) ||
-                    (rr->off != 0) || (rr->data[0] != SSL3_MT_CCS)) {
-                        al = SSL_AD_DECODE_ERROR;
-                        SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
-                        goto fatal_err;
-                }
-
-                ssl_msg_callback(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1);
-
-                /* We can't process a CCS now, because previous handshake
-                 * messages are still missing, so just drop it.
-                 */
-                if (!s->d1->change_cipher_spec_ok) {
-                        rr->length = 0;
-                        goto start;
-                }
-
-                s->d1->change_cipher_spec_ok = 0;
-
-                s->s3->change_cipher_spec = 1;
-                if (!ssl3_do_change_cipher_spec(s))
-                        goto err;
-
-                rr->length = 0;
+                if ((ret = ssl3_read_change_cipher_spec(s)) <= 0)
+                        return ret;
                 goto start;
         }
 
@@ -872,7 +847,7 @@ dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
 
  fatal_err:
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
- err:
+
         return (-1);
 }