[PATCH 1/1] cmd: fdt: check fdt address

[Heinrich Schuchardt]

On 12/31/23 15:22, Simon Glass wrote:
> Hi Heinrich,
> 
> On Wed, Dec 20, 2023 at 5:00 PM Heinrich Schuchardt
> <heinrich.schuchardt at canonical.com> wrote:
>>
>> Trying to read a device-tree from an illegal address leads to a crash.
>>
>> Check that the parameter passed to 'fdt addr' is within the RAM area and
>> non-zero.
> 
> What is the motivation for this patch? Is something crashing? We don't
> do this with the 'md' command, for example.

QEMU with too little memory was crashing. But maybe we should write an 
explicit warning about too little memory instead.

Best regards

Heinrich

> 
> Regards,
> Simon
> 
> 
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>> ---
>>   cmd/fdt.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/cmd/fdt.c b/cmd/fdt.c
>> index 331564c13b..dc954ea7d5 100644
>> --- a/cmd/fdt.c
>> +++ b/cmd/fdt.c
>> @@ -193,6 +193,11 @@ static int do_fdt(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
>>                  }
>>
>>                  addr = hextoul(argv[0], NULL);
>> +               if (!addr || addr < gd->ram_base || addr >= gd->ram_top) {
>> +                       printf("Invalid address\n");
>> +                       return CMD_RET_FAILURE;
>> +               }
>> +
>>                  blob = map_sysmem(addr, 0);
>>                  if ((quiet && fdt_check_header(blob)) ||
>>                      (!quiet && !fdt_valid(&blob)))
>> --
>> 2.40.1
>>