| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 129/210] watchdog: rc32434_wdt: fix ioctl error handling | Date | Sun, 10 Apr 2016 11:35:50 -0700 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Michael S. Tsirkin <mst@redhat.com>
commit 10e7ac22cdd4d211cef99afcb9371b70cb175be6 upstream.
Calling return copy_to_user(...) in an ioctl will not do the right thing if there's a pagefault: copy_to_user returns the number of bytes not copied in this case.
Fix up watchdog/rc32434_wdt to do return copy_to_user(...)) ? -EFAULT : 0;
instead.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/watchdog/rc32434_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/watchdog/rc32434_wdt.c +++ b/drivers/watchdog/rc32434_wdt.c @@ -237,7 +237,7 @@ static long rc32434_wdt_ioctl(struct fil return -EINVAL; /* Fall through */ case WDIOC_GETTIMEOUT: - return copy_to_user(argp, &timeout, sizeof(int)); + return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0; default: return -ENOTTY; }
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