Provide ssl3_packet_read() and ssl3_packet_extend() functions that improve

the awkward API provided by ssl3_read_n(). Call these when we need to
read or extend a packet.

ok beck@

1 files changed, 44 insertions, 14 deletions

diff --git a/src/lib/libssl/s3_pkt.c b/src/lib/libssl/s3_pkt.c
index a9737a7f40..152e384a4b 100644
--- a/src/lib/libssl/s3_pkt.c
+++ b/src/lib/libssl/s3_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_pkt.c,v 1.68 2017/01/23 14:35:42 jsing Exp $ */
+/* $OpenBSD: s3_pkt.c,v 1.69 2017/01/25 06:13:02 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -130,7 +130,7 @@ static int ssl3_get_record(SSL *s);
  * (If s->internal->read_ahead is set, 'max' bytes may be stored in rbuf
  * [plus s->internal->packet_length bytes if extend == 1].)
  */
-int
+static int
 ssl3_read_n(SSL *s, int n, int max, int extend)
 {
         int i, len, left;
@@ -263,9 +263,42 @@ ssl3_read_n(SSL *s, int n, int max, int extend)
         rb->left = left - n;
         s->internal->packet_length += n;
         s->internal->rwstate = SSL_NOTHING;
+
         return (n);
 }
 
+int
+ssl3_packet_read(SSL *s, int plen)
+{
+        int n;
+
+        n = ssl3_read_n(s, plen, s->s3->rbuf.len, 0);
+        if (n <= 0)
+                return n;
+        if (s->internal->packet_length < plen)
+                return s->internal->packet_length;
+
+        return plen;
+}
+
+int
+ssl3_packet_extend(SSL *s, int plen)
+{
+        int rlen, n;
+
+        if (s->internal->packet_length >= plen)
+                return plen;
+        rlen = plen - s->internal->packet_length;
+
+        n = ssl3_read_n(s, rlen, rlen, 1);
+        if (n <= 0)
+                return n;
+        if (s->internal->packet_length < plen)
+                return s->internal->packet_length;
+
+        return plen;
+}
+
 /* Call this to get a new input record.
  * It will return <= 0 if more data is needed, normally due to an error
  * or non-blocking IO.
@@ -296,9 +329,10 @@ again:
                 uint16_t len, ssl_version;
                 uint8_t type;
 
-                n = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
+                n = ssl3_packet_read(s, SSL3_RT_HEADER_LENGTH);
                 if (n <= 0)
-                        return(n); /* error or non-blocking */
+                        return (n);
+
                 s->internal->rstate = SSL_ST_READ_BODY;
 
                 CBS_init(&header, s->internal->packet, n);
@@ -345,17 +379,13 @@ again:
 
         /* s->internal->rstate == SSL_ST_READ_BODY, get and decode the data */
 
-        if (rr->length > s->internal->packet_length - SSL3_RT_HEADER_LENGTH) {
-                /* now s->internal->packet_length == SSL3_RT_HEADER_LENGTH */
-                i = rr->length;
-                n = ssl3_read_n(s, i, i, 1);
-                if (n <= 0)
-                        return(n); /* error or non-blocking io */
-                /* now n == rr->length,
-                 * and s->internal->packet_length == SSL3_RT_HEADER_LENGTH + rr->length */
-        }
+        n = ssl3_packet_extend(s, SSL3_RT_HEADER_LENGTH + rr->length);
+        if (n <= 0)
+                return (n);
+        if (n != SSL3_RT_HEADER_LENGTH + rr->length)
+                return (n);
 
-        s->internal->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
+        s->internal->rstate = SSL_ST_READ_HEADER; /* set state for later operations */
 
         /* At this point, s->internal->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
          * and we have that many bytes in s->internal->packet