From 8ccbd216c61539e4d2d7add7be5efd78fb9a9864 Mon Sep 17 00:00:00 2001 From: Matt Johnston Date: Tue, 29 Sep 2015 21:53:27 +0800 Subject: [PATCH] make sure that the test for queued packets to write occurs after those packets might have been enqueued by set_connect_fds() --- common-session.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/common-session.c b/common-session.c index 2485cd8..96d747d 100644 --- a/common-session.c +++ b/common-session.c @@ -159,6 +159,16 @@ void session_loop(void(*loophandler)()) { FD_ZERO(&readfd); dropbear_assert(ses.payload == NULL); + /* We get woken up when signal handlers write to this pipe. + SIGCHLD in svr-chansession is the only one currently. */ + FD_SET(ses.signal_pipe[0], &readfd); + + /* set up for channels which can be read/written */ + setchannelfds(&readfd, &writefd, writequeue_has_space); + + /* Pending connections to test */ + set_connect_fds(&writefd); + /* We delay reading from the input socket during initial setup until after we have written out our initial KEXINIT packet (empty writequeue). This means our initial packet can be in-flight while we're doing a blocking @@ -170,19 +180,12 @@ void session_loop(void(*loophandler)()) { && writequeue_has_space) { FD_SET(ses.sock_in, &readfd); } + + /* Ordering is important, this test must occur after any other function + might have queued packets (such as connection handlers) */ if (ses.sock_out != -1 && !isempty(&ses.writequeue)) { FD_SET(ses.sock_out, &writefd); } - - /* We get woken up when signal handlers write to this pipe. - SIGCHLD in svr-chansession is the only one currently. */ - FD_SET(ses.signal_pipe[0], &readfd); - - /* set up for channels which can be read/written */ - setchannelfds(&readfd, &writefd, writequeue_has_space); - - /* Pending connections to test */ - set_connect_fds(&writefd); val = select(ses.maxfd+1, &readfd, &writefd, NULL, &timeout);