Clean up read sequence handling in DTLS.

Pass the explicit DTLS read sequence number to dtls1_record_bitmap_update()
and dtls1_record_replay_check(), rather than expecting it to be in
S3I(s)->read_sequence. Also, store the read sequence number into
S3I(s)->rrec.seq_num when we're processing the record header, rather than
having dtls1_record_replay_check() be responsible for copying it.

ok inoguchi@ tb@

1 files changed, 21 insertions, 19 deletions

diff --git a/src/lib/libssl/d1_pkt.c b/src/lib/libssl/d1_pkt.c
index 4c450d2cb9..18d0ec5a3f 100644
--- a/src/lib/libssl/d1_pkt.c
+++ b/src/lib/libssl/d1_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: d1_pkt.c,v 1.86 2021/01/13 18:20:54 jsing Exp $ */
+/* $OpenBSD: d1_pkt.c,v 1.87 2021/01/13 18:32:00 jsing Exp $ */
 /*
  * DTLS implementation written by Nagendra Modadugu
  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
@@ -184,8 +184,10 @@ satsub64be(const unsigned char *v1, const unsigned char *v2)
 
 static int have_handshake_fragment(SSL *s, int type, unsigned char *buf,
     int len, int peek);
-static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap);
-static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap);
+static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap,
+    const unsigned char *seq);
+static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap,
+    const unsigned char *seq);
 static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD_INTERNAL *rr,
     unsigned int *is_next_epoch);
 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
@@ -414,10 +416,15 @@ again:
                     !CBS_get_bytes(&header, &seq_no, 6))
                         goto again;
 
+                if (!CBS_get_u16(&header, &len))
+                        goto again;
+
                 if (!CBS_write_bytes(&seq_no, &(S3I(s)->read_sequence[2]),
                     sizeof(S3I(s)->read_sequence) - 2, NULL))
                         goto again;
-                if (!CBS_get_u16(&header, &len))
+
+                if (!CBS_write_bytes(&seq_no, &rr->seq_num[2],
+                    sizeof(rr->seq_num) - 2, NULL))
                         goto again;
 
                 rr->type = type;
@@ -466,7 +473,7 @@ again:
          */
         if (!(D1I(s)->listen && rr->type == SSL3_RT_HANDSHAKE &&
             p != NULL && *p == SSL3_MT_CLIENT_HELLO) &&
-            !dtls1_record_replay_check(s, bitmap))
+            !dtls1_record_replay_check(s, bitmap, rr->seq_num))
                 goto again;
 
         /* just read a 0 length packet */
@@ -484,7 +491,7 @@ again:
                             rr->seq_num) < 0)
                                 return (-1);
                         /* Mark receipt of record. */
-                        dtls1_record_bitmap_update(s, bitmap);
+                        dtls1_record_bitmap_update(s, bitmap, rr->seq_num);
                 }
                 goto again;
         }
@@ -493,7 +500,7 @@ again:
                 goto again;
 
         /* Mark receipt of record. */
-        dtls1_record_bitmap_update(s, bitmap);
+        dtls1_record_bitmap_update(s, bitmap, rr->seq_num);
 
         return (1);
 }
@@ -1128,34 +1135,30 @@ do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
 }
 
 static int
-dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
+dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap,
+    const unsigned char *seq)
 {
-        int cmp;
         unsigned int shift;
-        const unsigned char *seq = S3I(s)->read_sequence;
+        int cmp;
 
         cmp = satsub64be(seq, bitmap->max_seq_num);
-        if (cmp > 0) {
-                memcpy (S3I(s)->rrec.seq_num, seq, 8);
+        if (cmp > 0)
                 return 1; /* this record in new */
-        }
         shift = -cmp;
         if (shift >= sizeof(bitmap->map)*8)
                 return 0; /* stale, outside the window */
         else if (bitmap->map & (1UL << shift))
                 return 0; /* record previously received */
 
-        memcpy(S3I(s)->rrec.seq_num, seq, 8);
         return 1;
 }
 
-
 static void
-dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
+dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap,
+    const unsigned char *seq)
 {
-        int cmp;
         unsigned int shift;
-        const unsigned char *seq = S3I(s)->read_sequence;
+        int cmp;
 
         cmp = satsub64be(seq, bitmap->max_seq_num);
         if (cmp > 0) {
@@ -1172,7 +1175,6 @@ dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
         }
 }
 
-
 int
 dtls1_dispatch_alert(SSL *s)
 {