On 20.2.2018 11:38, Geert Uytterhoeven wrote:
> 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.
You are right.
I have checked 4 patches I have sent in past which didn't reach mainline
(probably because of RFC)
Take a look at
https://www.spinics.net/lists/linux-serial/msg27106.html
I have removed cdns_uart_port array completely there.
Thanks,
Michal
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