Replace DTLS r_epoch with the read epoch from the TLSv1.2 record layer.

ok inoguchi@ tb@

Author: 4a6f656c

lib/libssl/d1_lib.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_lib.c,v 1.58 2021/07/21 08:42:14 jsing Exp $ */
+/* $OpenBSD: d1_lib.c,v 1.59 2021/08/30 19:12:25 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -191,10 +191,8 @@ dtls1_clear(SSL *s)
 memset(s->d1, 0, sizeof(*s->d1));
 s->d1->internal = internal;
 
-D1I(s)->r_epoch =
- tls12_record_layer_initial_epoch(s->internal->rl);
-
-D1I(s)->unprocessed_rcds.epoch = D1I(s)->r_epoch + 1;
+D1I(s)->unprocessed_rcds.epoch =
+ tls12_record_layer_read_epoch(s->internal->rl) + 1;
 
 if (s->server) {
 D1I(s)->cookie_len = sizeof(D1I(s)->cookie);

lib/libssl/d1_pkt.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_pkt.c,v 1.105 2021/07/31 09:31:04 jsing Exp $ */
+/* $OpenBSD: d1_pkt.c,v 1.106 2021/08/30 19:12:25 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -273,12 +273,14 @@ static int
 dtls1_process_buffered_record(SSL *s)
 {
 /* Check if epoch is current. */
-if (D1I(s)->unprocessed_rcds.epoch != D1I(s)->r_epoch)
+if (D1I(s)->unprocessed_rcds.epoch !=
+ tls12_record_layer_read_epoch(s->internal->rl))
 return (0);
 
 /* Update epoch once all unprocessed records have been processed. */
 if (pqueue_peek(D1I(s)->unprocessed_rcds.q) == NULL) {
-D1I(s)->unprocessed_rcds.epoch = D1I(s)->r_epoch + 1;
+D1I(s)->unprocessed_rcds.epoch =
+ tls12_record_layer_read_epoch(s->internal->rl) + 1;
 return (0);
 }
 
@@ -858,7 +860,7 @@ dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
 /* this may just be a stale retransmit */
 if (!dtls1_get_message_header(rr->data, &msg_hdr))
 return -1;
-if (rr->epoch != D1I(s)->r_epoch) {
+if (rr->epoch != tls12_record_layer_read_epoch(s->internal->rl)) {
 rr->length = 0;
 goto start;
 }
@@ -1136,17 +1138,20 @@ dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap,
 static DTLS1_BITMAP *
 dtls1_get_bitmap(SSL *s, SSL3_RECORD_INTERNAL *rr, unsigned int *is_next_epoch)
 {
-uint16_t next_epoch = D1I(s)->r_epoch + 1;
+uint16_t read_epoch, read_epoch_next;
 
 *is_next_epoch = 0;
 
+read_epoch = tls12_record_layer_read_epoch(s->internal->rl);
+read_epoch_next = read_epoch + 1;
+
 /* In current epoch, accept HM, CCS, DATA, & ALERT */
-if (rr->epoch == D1I(s)->r_epoch)
+if (rr->epoch == read_epoch)
 return &D1I(s)->bitmap;
 
 /* Only HM and ALERT messages can be from the next epoch */
-else if (rr->epoch == next_epoch &&
-(rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) {
+if (rr->epoch == read_epoch_next &&
+ (rr->type == SSL3_RT_HANDSHAKE || rr->type == SSL3_RT_ALERT)) {
 *is_next_epoch = 1;
 return &D1I(s)->next_bitmap;
 }
@@ -1157,7 +1162,6 @@ dtls1_get_bitmap(SSL *s, SSL3_RECORD_INTERNAL *rr, unsigned int *is_next_epoch)
 void
 dtls1_reset_read_seq_numbers(SSL *s)
 {
-D1I(s)->r_epoch++;
 memcpy(&(D1I(s)->bitmap), &(D1I(s)->next_bitmap), sizeof(DTLS1_BITMAP));
 memset(&(D1I(s)->next_bitmap), 0, sizeof(DTLS1_BITMAP));
 }

lib/libssl/dtls_locl.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: dtls_locl.h,v 1.4 2021/07/26 03:17:38 jsing Exp $ */
+/* $OpenBSD: dtls_locl.h,v 1.5 2021/08/30 19:12:25 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -132,13 +132,6 @@ typedef struct dtls1_state_internal_st {
 unsigned char rcvd_cookie[DTLS1_COOKIE_LENGTH];
 unsigned int cookie_len;
 
-/*
- * The current data and handshake epoch. This is initially
- * undefined, and starts at zero once the initial handshake is
- * completed
- */
-unsigned short r_epoch;
-
 /* records being received in the current epoch */
 DTLS1_BITMAP bitmap;
 

lib/libssl/ssl_locl.h

@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.356 2021/07/26 03:17:38 jsing Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.357 2021/08/30 19:12:25 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -641,7 +641,7 @@ void tls12_record_layer_set_version(struct tls12_record_layer *rl,
  uint16_t version);
 void tls12_record_layer_set_initial_epoch(struct tls12_record_layer *rl,
  uint16_t epoch);
-uint16_t tls12_record_layer_initial_epoch(struct tls12_record_layer *rl);
+uint16_t tls12_record_layer_read_epoch(struct tls12_record_layer *rl);
 uint16_t tls12_record_layer_write_epoch(struct tls12_record_layer *rl);
 int tls12_record_layer_use_write_epoch(struct tls12_record_layer *rl,
  uint16_t epoch);

lib/libssl/tls12_record_layer.c

@@ -1,4 +1,4 @@
-/* $OpenBSD: tls12_record_layer.c,v 1.33 2021/08/30 19:00:49 jsing Exp $ */
+/* $OpenBSD: tls12_record_layer.c,v 1.34 2021/08/30 19:12:25 jsing Exp $ */
 /*
  * Copyright (c) 2020 Joel Sing <jsing@openbsd.org>
  *
@@ -296,9 +296,9 @@ tls12_record_layer_set_initial_epoch(struct tls12_record_layer *rl,
 }
 
 uint16_t
-tls12_record_layer_initial_epoch(struct tls12_record_layer *rl)
+tls12_record_layer_read_epoch(struct tls12_record_layer *rl)
 {
-return rl->initial_epoch;
+return rl->read->epoch;
 }
 
 uint16_t
@@ -580,6 +580,10 @@ tls12_record_layer_change_read_cipher_state(struct tls12_record_layer *rl,
 
 /* Read sequence number gets reset to zero. */
 
+/* DTLS epoch is incremented and is permitted to wrap. */
+if (rl->dtls)
+read_new->epoch = rl->read_current->epoch + 1;
+
 if (!tls12_record_layer_change_cipher_state(rl, read_new, 0,
  mac_key, key, iv))
 goto err;