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authorJason Wessel <jason.wessel@windriver.com>2009-05-29 13:34:17 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-06-15 21:44:47 -0700
commit568d422e9cf52b7b26d2e026ae1617971f62b560 (patch)
tree4a3ba69a855ca9437995e2a63b0c0174bb542b42
parent430eb0d27c1b36c5191c16b2472b26137673a8d4 (diff)
USB: usb_serial: only allow sysrq on a console port
The only time a sysrq should get processed is if the attached device is a console. This is intended to protect sysrq execution on a host connected with a terminal program. Here is the problem scenario: host A <-- rs232 link --> host B Host A is using mincom and a usb pl2303 device to connect to host b which is a linux system with a usb pl2303 device acting as the serial console. When host B is rebooted the pl2303 emits random junk characters on reset. These character sequences contain serial break signals most of the time and when translated to a sysrq have caused host A to get random processes killed, reboots or power down. It is true that in this setup with this patch host B might still have the same problem as host A if you reboot host A. In most cases host A is a development host which seldom gets rebooted, and you could turn off sysrq temporarily on host B if you need to reboot host A. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/usb/serial/generic.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 9fccc26235a..8dabac1929b 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -528,7 +528,7 @@ void usb_serial_generic_unthrottle(struct tty_struct *tty)
int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
{
- if (port->sysrq) {
+ if (port->sysrq && port->console) {
if (ch && time_before(jiffies, port->sysrq)) {
handle_sysrq(ch, tty_port_tty_get(&port->port));
port->sysrq = 0;