From: Gen Zhang <blackgod016574@gmail.com>
To: jslaby@suse.com
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] tty_io: Fix a missing-check bug in drivers/tty/tty_io.c
Date: Wed, 22 May 2019 09:40:06 +0800 [thread overview]
Message-ID: <20190522014006.GB4093@zhanggen-UX430UQ> (raw)
In alloc_tty_struct(), tty->dev is assigned by tty_get_device(). And it
calls class_find_device(). And class_find_device() may return NULL.
And tty->dev is dereferenced in the following codes. When
tty_get_device() returns NULL, dereferencing this tty->dev null pointer
may cause the kernel go wrong. Thus we should check tty->dev.
Further, if tty_get_device() returns NULL, we should free tty and
return NULL.
Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
---
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 033ac7e..1444b59 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3008,6 +3008,10 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
tty->index = idx;
tty_line_name(driver, idx, tty->name);
tty->dev = tty_get_device(tty);
+ if (!tty->dev) {
+ kfree(tty);
+ return NULL;
+ }
return tty;
}
next reply other threads:[~2019-05-22 1:40 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 1:40 Gen Zhang [this message]
2019-05-22 4:25 ` [PATCH] tty_io: Fix a missing-check bug in drivers/tty/tty_io.c Jiri Slaby
2019-05-22 8:06 ` Gen Zhang
2019-05-22 8:15 ` Jiri Slaby
2019-05-22 10:29 ` Johan Hovold
2019-05-22 10:32 ` Jiri Slaby
2019-05-22 11:13 ` Gen Zhang
2019-05-22 11:19 ` Johan Hovold
2019-05-22 11:24 ` Gen Zhang
2019-05-22 11:18 ` Gen Zhang
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