crypto/tls: do not drain 0-RTT data on Close

There is no reason a server can't just send a CloseNotify in its first
flight, and then close the connection without reading the 0-RTT data.

Also, it's not expected of Close to block on reading, and interlocking
with a Read can cause a deadlock.

Fixes NCC-2016-001

.travis.yml

@@ -10,10 +10,11 @@ go:
 env:
   - MODE=interop CLIENT=boring
   - MODE=interop CLIENT=bogo
-  - MODE=interop CLIENT=tstclnt ZRTT=1
+  - MODE=interop CLIENT=tstclnt
   - MODE=interop CLIENT=picotls ZRTT=1
   - MODE=interop CLIENT=mint
   - MODE=gotest
+  - MODE=interop CLIENT=tstclnt ZRTT=1
   - MODE=interop CLIENT=boring REVISION=origin/master
   - MODE=interop CLIENT=tstclnt REVISION=default ZRTT=1
 
@@ -22,6 +23,7 @@ matrix:
   allow_failures:
     - env: MODE=interop CLIENT=boring REVISION=origin/master
     - env: MODE=interop CLIENT=tstclnt REVISION=default ZRTT=1
+    - env: MODE=interop CLIENT=tstclnt ZRTT=1 # crashes on close_notify in 0.5RTT
 
 install:
   - if [ "$MODE" = "interop" ]; then ./_dev/tris-localserver/start.sh -d && docker ps -a; fi

_dev/tstclnt/Dockerfile

@@ -18,7 +18,7 @@ ENV USE_64=1 NSS_ENABLE_TLS_1_3=1
 # ARG REVISION=b6dfef6d0ff0
 
 # tstclnt resumption
-ARG REVISION=de6e7c3a39d5
+ARG REVISION=2ed8aef0b360
 
 RUN cd nss && hg pull
 RUN cd nss && hg checkout -C $REVISION

_dev/tstclnt/retransmit.patch

@@ -1,136 +0,0 @@
-diff --git a/cmd/tstclnt/tstclnt.c b/cmd/tstclnt/tstclnt.c
-index eb114e9..419e96f 100644
-+++ b/cmd/tstclnt/tstclnt.c
-@@ -169,19 +169,6 @@ printSecurityInfo(PRFileDesc *fd)
-     }
- }
- 
--void
--handshakeCallback(PRFileDesc *fd, void *client_data)
--{
--    const char *secondHandshakeName = (char *)client_data;
--    if (secondHandshakeName) {
--        SSL_SetURL(fd, secondHandshakeName);
--    }
--    printSecurityInfo(fd);
--    if (renegotiationsDone < renegotiationsToDo) {
--        SSL_ReHandshake(fd, (renegotiationsToDo < 2));
--        ++renegotiationsDone;
--    }
--}
- 
- static void
- PrintUsageHeader(const char *progName)
-@@ -923,13 +910,19 @@ PRUint16 portno = 443;
- int override = 0;
- char *requestString = NULL;
- PRInt32 requestStringLen = 0;
-+PRBool requestSent = PR_FALSE;
- PRBool enableZeroRtt = PR_FALSE;
- 
- static int
--writeBytesToServer(PRFileDesc *s, PRPollDesc *pollset, const char *buf, int nb)
-+writeBytesToServer(PRFileDesc *s, const char *buf, int nb)
- {
-     SECStatus rv;
-     const char *bufp = buf;
-+    PRPollDesc pollset[1];
-+
-+    pollset[SSOCK_FD].in_flags = PR_POLL_WRITE | PR_POLL_EXCEPT;
-+    pollset[SSOCK_FD].out_flags = 0;
-+    pollset[SSOCK_FD].fd = s;
- 
-     FPRINTF(stderr, "%s: Writing %d bytes to server\n",
-             progName, nb);
-@@ -975,6 +968,36 @@ writeBytesToServer(PRFileDesc *s, PRPollDesc *pollset, const char *buf, int nb)
-     return 0;
- }
- 
-+void
-+handshakeCallback(PRFileDesc *fd, void *client_data)
-+{
-+    const char *secondHandshakeName = (char *)client_data;
-+    if (secondHandshakeName) {
-+        SSL_SetURL(fd, secondHandshakeName);
-+    }
-+    printSecurityInfo(fd);
-+    if (renegotiationsDone < renegotiationsToDo) {
-+        SSL_ReHandshake(fd, (renegotiationsToDo < 2));
-+        ++renegotiationsDone;
-+    }
-+    if (requestString && requestSent) {
-+        /* This data was sent in 0-RTT. */
-+        SSLChannelInfo info;
-+        SECStatus rv;
-+
-+        rv = SSL_GetChannelInfo(fd, &info, sizeof(info));
-+        if (rv != SECSuccess)
-+            return;
-+
-+        if (!info.earlyDataAccepted) {
-+            FPRINTF(stderr, "Early data rejected. Re-sending\n");
-+            writeBytesToServer(fd, requestString, requestStringLen);
-+        }
-+    }
-+}
-+
-+#define REQUEST_WAITING (requestString && !requestSent)
-+
- static int
- run_client(void)
- {
-@@ -988,7 +1011,8 @@ run_client(void)
-     PRFileDesc *std_out;
-     PRPollDesc pollset[2];
-     PRBool wrStarted = PR_FALSE;
--    char *requestStringInt = requestString;
-+
-+    requestSent = PR_FALSE;
- 
-     /* Create socket */
-     s = PR_OpenTCPSocket(addr.raw.family);
-@@ -1245,7 +1269,7 @@ run_client(void)
-     pollset[SSOCK_FD].in_flags = PR_POLL_EXCEPT |
-                                  (clientSpeaksFirst ? 0 : PR_POLL_READ);
-     pollset[STDIN_FD].fd = PR_GetSpecialFD(PR_StandardInput);
--    if (!requestStringInt) {
-+    if (!REQUEST_WAITING) {
-         pollset[STDIN_FD].in_flags = PR_POLL_READ;
-         npds = 2;
-     } else {
-@@ -1295,7 +1319,7 @@ run_client(void)
-     */
-     FPRINTF(stderr, "%s: ready...\n", progName);
-     while ((pollset[SSOCK_FD].in_flags | pollset[STDIN_FD].in_flags) ||
--           requestStringInt) {
-+           REQUEST_WAITING) {
-         char buf[4000]; /* buffer for stdin */
-         int nb;         /* num bytes read from stdin. */
- 
-@@ -1333,13 +1357,12 @@ run_client(void)
-                     "%s: PR_Poll returned 0x%02x for socket out_flags.\n",
-                     progName, pollset[SSOCK_FD].out_flags);
-         }
--        if (requestStringInt) {
--            error = writeBytesToServer(s, pollset,
--                                       requestStringInt, requestStringLen);
-+        if (REQUEST_WAITING) {
-+            error = writeBytesToServer(s, requestString, requestStringLen);
-             if (error) {
-                 goto done;
-             }
--            requestStringInt = NULL;
-+            requestSent = PR_TRUE;
-             pollset[SSOCK_FD].in_flags = PR_POLL_READ;
-         }
-         if (pollset[STDIN_FD].out_flags & PR_POLL_READ) {
-@@ -1356,7 +1379,7 @@ run_client(void)
-                 /* EOF on stdin, stop polling stdin for read. */
-                 pollset[STDIN_FD].in_flags = 0;
-             } else {
--                error = writeBytesToServer(s, pollset, buf, nb);
-+                error = writeBytesToServer(s, buf, nb);
-                 if (error) {
-                     goto done;
-                 }

conn.go

@@ -1423,17 +1423,7 @@ func (c *Conn) Close() error {
 	var alertErr error
 
 	c.handshakeMutex.Lock()
-	for c.phase == readingEarlyData {
-		if err := c.readRecord(recordTypeApplicationData); err != nil {
-			alertErr = err
-		}
-	}
-	if alertErr == nil && c.phase == waitingClientFinished {
-		if err := c.hs.readClientFinished13(); err != nil {
-			alertErr = err
-		}
-	}
-	if alertErr == nil && c.phase != handshakeRunning {
+	if c.phase != handshakeRunning {
 		alertErr = c.closeNotify()
 	}
 	c.handshakeMutex.Unlock()