krb5 commit [krb5-1.11]: Fix spin loop reading from KDC TCP socket

[Tom Yu]

https://github.com/krb5/krb5/commit/a68c4fb6c498d2507a060db1deb44e0a5a42cd31
commit a68c4fb6c498d2507a060db1deb44e0a5a42cd31
Author: Tom Yu <tlyu at mit.edu>
Date:   Mon Jul 1 15:18:33 2013 -0400

    Fix spin loop reading from KDC TCP socket
    
    In the k5_sendto code for reading from a TCP socket, detect
    end-of-stream when reading the length.  Otherwise we can get stuck in
    an infinite loop of poll() and read().
    
    [ghudson at mit.edu: commit message]
    
    (back ported from commit 53e5c850e05f011e9e7f25c2032aec51d8b352a9)
    
    ticket: 7508
    version_fixed: 1.11.4
    status: resolved

 src/lib/krb5/os/sendto_kdc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib/krb5/os/sendto_kdc.c b/src/lib/krb5/os/sendto_kdc.c
index 96991de..cc7b86f 100644
--- a/src/lib/krb5/os/sendto_kdc.c
+++ b/src/lib/krb5/os/sendto_kdc.c
@@ -1090,9 +1090,9 @@ service_tcp_fd(krb5_context context, struct conn_state *conn,
             nread = SOCKET_READ(conn->fd,
                                 conn->x.in.bufsizebytes + conn->x.in.bufsizebytes_read,
                                 4 - conn->x.in.bufsizebytes_read);
-            if (nread < 0) {
+            if (nread <= 0) {
+                e = nread ? SOCKET_ERRNO : ECONNRESET;
                 TRACE_SENDTO_KDC_TCP_ERROR_RECV_LEN(context, conn, e);
-                e = SOCKET_ERRNO;
                 goto kill_conn;
             }
             conn->x.in.bufsizebytes_read += nread;