From: Christian Brauner <christian.brauner@ubuntu.com>
Date: Fri, 16 Feb 2018 23:04:30 +0000 (+0100)
Subject: console: ensure that fd is marked EBADF
X-Git-Tag: lxc-2.0.10~325
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=84bdd46000f8452857efc6acd1af4a512f122b7c;p=thirdparty%2Flxc.git

console: ensure that fd is marked EBADF

If the handler closes the file descriptor for the peer or master fd it is
crucial that we mark it as -EBADF. This will prevent lxc_console_delete()
from calling close() on an already closed file descriptor again. I've
observed the double close in the attach code.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---

diff --git a/src/lxc/console.c b/src/lxc/console.c
index c233d9bd8..d928122fd 100644
--- a/src/lxc/console.c
+++ b/src/lxc/console.c
@@ -215,16 +215,20 @@ int lxc_console_cb_con(int fd, uint32_t events, void *data,
 	if (r <= 0) {
 		INFO("Console client on fd %d has exited", fd);
 		lxc_mainloop_del_handler(descr, fd);
-		if (fd == console->peer) {
+
+		if (fd == console->master) {
+			console->master = -EBADF;
+		} else if (fd == console->peer) {
 			if (console->tty_state) {
 				lxc_console_signal_fini(console->tty_state);
 				console->tty_state = NULL;
 			}
-			console->peer = -1;
-			close(fd);
-			return 0;
+			console->peer = -EBADF;
+		} else {
+			ERROR("Handler received unexpected file descriptor");
 		}
 		close(fd);
+
 		return LXC_MAINLOOP_CLOSE;
 	}