Hi Michal,
On Tue, Feb 20, 2018 at 11:22 AM, Michal Simek <michal.simek@xxxxxxxxxx> wrote:
> On 20.2.2018 10:40, Geert Uytterhoeven wrote:
>> The cdns_uart_port[] array is indexed using a value derived from the
>> "serialN" alias in DT, which may lead to an out-of-bounds access.
>>
>> Fix this by adding a range check.
>>
>> Fixes: 1f118c02a1819856 ("serial: xuartps: Fix out-of-bounds access through DT alias")
>
> I didn't find this sha1 - patch name is this one.
Bummer, I totally screwed up my scripting...
Fixes: 928e9263492069ee ("tty: xuartps: Initialize ports according to aliases")
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>> ---
>> drivers/tty/serial/xilinx_uartps.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
>> index b9b2bc76bcac606c..abcb4d09a2d866d0 100644
>> --- a/drivers/tty/serial/xilinx_uartps.c
>> +++ b/drivers/tty/serial/xilinx_uartps.c
>> @@ -1110,7 +1110,7 @@ static struct uart_port *cdns_uart_get_port(int id)
>> struct uart_port *port;
>>
>> /* Try the given port id if failed use default method */
>> - if (cdns_uart_port[id].mapbase != 0) {
>> + if (id < CDNS_UART_NR_PORTS && cdns_uart_port[id].mapbase != 0) {
>> /* Find the next unused port */
>> for (id = 0; id < CDNS_UART_NR_PORTS; id++)
>> if (cdns_uart_port[id].mapbase == 0)
>>
>
> Below should be better fix for this driver.
I considered that, too, but...
> --- a/drivers/tty/serial/xilinx_uartps.c
> +++ b/drivers/tty/serial/xilinx_uartps.c
> @@ -1109,6 +1109,9 @@ static struct uart_port *cdns_uart_get_port(int id)
> {
> struct uart_port *port;
>
> + if (id >= CDNS_UART_NR_PORTS)
> + return NULL;
> +
> /* Try the given port id if failed use default method */
> if (cdns_uart_port[id].mapbase != 0) {
> /* Find the next unused port */
> @@ -1117,9 +1120,6 @@ static struct uart_port *cdns_uart_get_port(int id)
> break;
> }
>
> - if (id >= CDNS_UART_NR_PORTS)
> - return NULL;
> -
... the above check cannot be removed, as it is needed to support the loop
above to find an unused port.
> port = &cdns_uart_port[id];
>
> /* At this point, we've got an empty uart_port struct,
> initialize it */
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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