1 files changed, 20 insertions, 0 deletions

diff --git a/sys/dev/uart/uart_subr.c b/sys/dev/uart/uart_subr.c
index 4c40a3613ba5..27dfd41b0735 100644
--- a/sys/dev/uart/uart_subr.c
+++ b/sys/dev/uart/uart_subr.c
@@ -242,6 +242,26 @@ uart_getenv(int devtype, struct uart_devinfo *di)
 	 */
 	if (addr == ~0U)
 		return (EINVAL);
+
+	/*
+	 * Accept only the well-known baudrates. Any invalid baudrate
+	 * is silently replaced with a 0-valued baudrate. The 0 baudrate
+	 * has special meaning. It means that we're not supposed to
+	 * program the baudrate and simply communicate with whatever
+	 * speed the hardware is currently programmed for.
+	 */
+	if (di->baudrate >= 19200) {
+		if (di->baudrate % 19200)
+			di->baudrate = 0;
+	} else if (di->baudrate >= 1200) {
+		if (di->baudrate % 1200)
+			di->baudrate = 0;
+	} else if (di->baudrate > 0) {
+		if (di->baudrate % 75)
+			di->baudrate = 0;
+	} else
+		di->baudrate = 0;
+
 	/* XXX the size of the mapping depends on the UART class. */
 	if (bus_space_map(di->bas.bst, addr, 8, 0, &di->bas.bsh) != 0)
 		return (EINVAL);