diff options
| author |   Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2022-06-06 13:04:21 +0300 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-10 13:49:57 +0200 |
| commit | 51ad36baacb3b2fd1bd980138a937d30d6c84cdf (patch) | |
| tree | 8eabb46704586aeb0f9d9855fb0f2171289b170d | |
| parent | serial: Clear rs485 struct when non-RS485 mode is set (diff) | |
| download | linux-rng-51ad36baacb3b2fd1bd980138a937d30d6c84cdf.tar.xz linux-rng-51ad36baacb3b2fd1bd980138a937d30d6c84cdf.zip | |
serial: return -EINVAL for non-legacy RS485 flags
In order to be add new flags more cleanly and safely, return -EINVAL
from TIOCSRS485 ioctl for the flags bits which are not among the
current legacy ones.
This might cause a regression for userspace as those non-flag bits do
not currently trigger -EINVAL. However, it would only occur if the
userspace is sending garbage bits so perhaps we'll get away with this
change.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-25-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 6be538720564..621fc15e2e54 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1276,6 +1276,27 @@ static int uart_get_icount(struct tty_struct *tty, return 0; } +#define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \ + SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \ + SER_RS485_TERMINATE_BUS) + +static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485) +{ + u32 flags = rs485->flags; + + /* Don't return -EINVAL for unsupported legacy flags */ + flags &= ~SER_RS485_LEGACY_FLAGS; + + /* + * For any bit outside of the legacy ones that is not supported by + * the driver, return -EINVAL. + */ + if (flags & ~port->rs485_supported->flags) + return -EINVAL; + + return 0; +} + static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485) { u32 supported_flags = port->rs485_supported->flags; @@ -1375,6 +1396,9 @@ static int uart_set_rs485_config(struct uart_port *port, if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user))) return -EFAULT; + ret = uart_check_rs485_flags(port, &rs485); + if (ret) + return ret; uart_sanitize_serial_rs485(port, &rs485); spin_lock_irqsave(&port->lock, flags); |