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author | Jason Wessel <jason.wessel@windriver.com> | 2009-05-29 13:34:17 -0500 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-06-15 21:44:47 -0700 |
commit | 568d422e9cf52b7b26d2e026ae1617971f62b560 (patch) | |
tree | 4a3ba69a855ca9437995e2a63b0c0174bb542b42 | |
parent | 430eb0d27c1b36c5191c16b2472b26137673a8d4 (diff) | |
download | op-kernel-dev-568d422e9cf52b7b26d2e026ae1617971f62b560.zip op-kernel-dev-568d422e9cf52b7b26d2e026ae1617971f62b560.tar.gz |
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.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c index 9fccc26..8dabac1 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; |