1 files changed, 67 insertions, 35 deletions

diff --git a/src/lib/libssl/ssl_pkt.c b/src/lib/libssl/ssl_pkt.c
index e3b2034eb4..33bb4b659f 100644
--- a/src/lib/libssl/ssl_pkt.c
+++ b/src/lib/libssl/ssl_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_pkt.c,v 1.54 2022/02/21 18:22:20 jsing Exp $ */
+/* $OpenBSD: ssl_pkt.c,v 1.55 2022/03/12 12:53:03 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -752,6 +752,68 @@ ssl3_read_alert(SSL *s)
         return 1;
 }
 
+int
+ssl3_read_change_cipher_spec(SSL *s)
+{
+        SSL3_RECORD_INTERNAL *rr = &s->s3->rrec;
+
+        /*
+         * 'Change Cipher Spec' is just a single byte, so we know exactly what
+         * the record payload has to look like.
+         */
+        if (rr->length != 1 || rr->off != 0) {
+                SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+                return -1;
+        }
+        if (rr->data[0] != SSL3_MT_CCS) {
+                SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER);
+                return -1;
+        }
+
+        /* XDTLS: check that epoch is consistent */
+
+        ssl_msg_callback(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1);
+
+        /* Check that we have a cipher to change to. */
+        if (s->s3->hs.cipher == NULL) {
+                SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
+                ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE);
+                return -1;
+        }
+
+        /* Check that we should be receiving a Change Cipher Spec. */
+        if (SSL_is_dtls(s)) {
+                if (!s->d1->change_cipher_spec_ok) {
+                        /*
+                         * We can't process a CCS now, because previous
+                         * handshake messages are still missing, so just
+                         * drop it.
+                         */
+                        rr->length = 0;
+                        return 1;
+                }
+                s->d1->change_cipher_spec_ok = 0;
+        } else {
+                if ((s->s3->flags & SSL3_FLAGS_CCS_OK) == 0) {
+                        SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
+                        ssl3_send_alert(s, SSL3_AL_FATAL,
+                            SSL_AD_UNEXPECTED_MESSAGE);
+                        return -1;
+                }
+                s->s3->flags &= ~SSL3_FLAGS_CCS_OK;
+        }
+
+        rr->length = 0;
+
+        s->s3->change_cipher_spec = 1;
+        if (!ssl3_do_change_cipher_spec(s))
+                return -1;
+
+        return 1;
+}
+
 /* Return up to 'len' payload bytes received in 'type' records.
  * 'type' is one of the following:
  *
@@ -1044,39 +1106,9 @@ ssl3_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 */
-                if ((rr->length != 1) || (rr->off != 0) ||
-                        (rr->data[0] != SSL3_MT_CCS)) {
-                        al = SSL_AD_ILLEGAL_PARAMETER;
-                        SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC);
-                        goto fatal_err;
-                }
-
-                /* Check we have a cipher to change to */
-                if (s->s3->hs.cipher == NULL) {
-                        al = SSL_AD_UNEXPECTED_MESSAGE;
-                        SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
-                        goto fatal_err;
-                }
-
-                /* Check that we should be receiving a Change Cipher Spec. */
-                if (!(s->s3->flags & SSL3_FLAGS_CCS_OK)) {
-                        al = SSL_AD_UNEXPECTED_MESSAGE;
-                        SSLerror(s, SSL_R_CCS_RECEIVED_EARLY);
-                        goto fatal_err;
-                }
-                s->s3->flags &= ~SSL3_FLAGS_CCS_OK;
-
-                rr->length = 0;
-
-                ssl_msg_callback(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC, rr->data, 1);
-
-                s->s3->change_cipher_spec = 1;
-                if (!ssl3_do_change_cipher_spec(s))
-                        goto err;
-                else
-                        goto start;
+                if ((ret = ssl3_read_change_cipher_spec(s)) <= 0)
+                        return ret;
+                goto start;
         }
 
         /* Unexpected handshake message (Client Hello, or protocol violation) */
@@ -1155,7 +1187,7 @@ ssl3_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);
 }