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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Richard Weinberger <richard@nod.at>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 116/175] um: chan_xterm: Fix fd leak
Date:   Mon, 28 Dec 2020 13:49:29 +0100
Message-Id: <20201228124858.874477091@linuxfoundation.org>
In-Reply-To: <20201228124853.216621466@linuxfoundation.org>
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From: Anton Ivanov <anton.ivanov@cambridgegreys.com>

[ Upstream commit 9431f7c199ab0d02da1482d62255e0b4621cb1b5 ]

xterm serial channel was leaking a fd used in setting up the
port helper

This bug is prehistoric - it predates switching to git. The "fixes"
header here is really just to mark all the versions we would like this to
apply to which is "Anything from the Cretaceous period onwards".

No dinosaurs were harmed in fixing this bug.

Fixes: b40997b872cd ("um: drivers/xterm.c: fix a file descriptor leak")
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/um/drivers/xterm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/um/drivers/xterm.c b/arch/um/drivers/xterm.c
index 20e30be44795b..e3b422ebce09f 100644
--- a/arch/um/drivers/xterm.c
+++ b/arch/um/drivers/xterm.c
@@ -18,6 +18,7 @@
 struct xterm_chan {
 	int pid;
 	int helper_pid;
+	int chan_fd;
 	char *title;
 	int device;
 	int raw;
@@ -33,6 +34,7 @@ static void *xterm_init(char *str, int device, const struct chan_opts *opts)
 		return NULL;
 	*data = ((struct xterm_chan) { .pid 		= -1,
 				       .helper_pid 	= -1,
+				       .chan_fd		= -1,
 				       .device 		= device,
 				       .title 		= opts->xterm_title,
 				       .raw  		= opts->raw } );
@@ -149,6 +151,7 @@ static int xterm_open(int input, int output, int primary, void *d,
 		goto out_kill;
 	}
 
+	data->chan_fd = fd;
 	new = xterm_fd(fd, &data->helper_pid);
 	if (new < 0) {
 		err = new;
@@ -206,6 +209,8 @@ static void xterm_close(int fd, void *d)
 		os_kill_process(data->helper_pid, 0);
 	data->helper_pid = -1;
 
+	if (data->chan_fd != -1)
+		os_close_file(data->chan_fd);
 	os_close_file(fd);
 }
 
-- 
2.27.0