check for POLLHUP as well as POLLIN, handle transient IO errors as well

as half-close on the output side; ok deraadt millert

diff --git a/usr.bin/ssh/sftp-server.c b/usr.bin/ssh/sftp-server.c
index 6fcb6a1..818b5c6 100644 (file)
--- a/usr.bin/ssh/sftp-server.c
+++ b/usr.bin/ssh/sftp-server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-server.c,v 1.133 2021/11/14 06:15:36 deraadt Exp $ */
+/* $OpenBSD: sftp-server.c,v 1.134 2021/11/18 03:06:03 djm Exp $ */
 /*
  * Copyright (c) 2000-2004 Markus Friedl.  All rights reserved.
  *
@@ -1825,23 +1825,31 @@ sftp_server_main(int argc, char **argv, struct passwd *user_pw)
                }
 
                /* copy stdin to iqueue */
-               if (pfd[0].revents & POLLIN) {
+               if (pfd[0].revents & (POLLIN|POLLHUP)) {
                        len = read(in, buf, sizeof buf);
                        if (len == 0) {
                                debug("read eof");
                                sftp_server_cleanup_exit(0);
                        } else if (len == -1) {
-                               error("read: %s", strerror(errno));
-                               sftp_server_cleanup_exit(1);
+                               if (errno != EAGAIN && errno != EINTR) {
+                                       error("read: %s", strerror(errno));
+                                       sftp_server_cleanup_exit(1);
+                               }
                        } else if ((r = sshbuf_put(iqueue, buf, len)) != 0)
                                fatal_fr(r, "sshbuf_put");
                }
                /* send oqueue to stdout */
-               if (pfd[1].revents & POLLOUT) {
+               if (pfd[1].revents & (POLLOUT|POLLHUP)) {
                        len = write(out, sshbuf_ptr(oqueue), olen);
-                       if (len == -1) {
-                               error("write: %s", strerror(errno));
+                       if (len == 0 || (len == -1 && errno == EPIPE)) {
+                               debug("write eof");
+                               sftp_server_cleanup_exit(0);
+                       } else if (len == -1) {
                                sftp_server_cleanup_exit(1);
+                               if (errno != EAGAIN && errno != EINTR) {
+                                       error("write: %s", strerror(errno));
+                                       sftp_server_cleanup_exit(1);
+                               }
                        } else if ((r = sshbuf_consume(oqueue, len)) != 0)
                                fatal_fr(r, "consume");
                }