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| author | Peter Hurley <peter@hurleysoftware.com> | 2016-01-12 15:14:46 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-02-06 23:04:51 -0800 |
| commit | 308bbc9ab838d0ace0298268c7970ba9513e2c65 (patch) | |
| tree | d9f36e4b088a95cfffd280cda838ff4a3f5cbcc9 /drivers | |
| parent | d56edd7ed0ed46a8043ee3040ededbd190818ccf (diff) | |
| download | linux-stable-308bbc9ab838d0ace0298268c7970ba9513e2c65.tar.gz linux-stable-308bbc9ab838d0ace0298268c7970ba9513e2c65.tar.bz2 linux-stable-308bbc9ab838d0ace0298268c7970ba9513e2c65.zip | |
serial: omap: Prevent DoS using unprivileged ioctl(TIOCSRS485)
The omap-serial driver emulates RS485 delays using software timers,
but neglects to clamp the input values from the unprivileged
ioctl(TIOCSRS485). Because the software implementation busy-waits,
malicious userspace could stall the cpu for ~49 days.
Clamp the input values to < 100ms.
Fixes: 4a0ac0f55b18 ("OMAP: add RS485 support")
Cc: <stable@vger.kernel.org> # 3.12+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/serial/omap-serial.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index b645f9228ed7..27d3b978f16e 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1343,7 +1343,7 @@ static inline void serial_omap_add_console_port(struct uart_omap_port *up) /* Enable or disable the rs485 support */ static int -serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) +serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485) { struct uart_omap_port *up = to_uart_omap_port(port); unsigned int mode; @@ -1356,8 +1356,12 @@ serial_omap_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf) up->ier = 0; serial_out(up, UART_IER, 0); + /* Clamp the delays to [0, 100ms] */ + rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U); + rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U); + /* store new config */ - port->rs485 = *rs485conf; + port->rs485 = *rs485; /* * Just as a precaution, only allow rs485 |