Re: [PATCH v4] hw/gpio/aspeed: Add reg_table_count to AspeedGPIOClass

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 20/6/24 16:20, Philippe Mathieu-Daudé wrote:
> On 20/6/24 16:02, Zheyu Ma wrote:
>> ASan detected a global-buffer-overflow error in the aspeed_gpio_read()
>> function. This issue occurred when reading beyond the bounds of the
>> reg_table.
>>
>> To enhance the safety and maintainability of the Aspeed GPIO code, 
>> this commit
>> introduces a reg_table_count member to the AspeedGPIOClass structure. 
>> This
>> change ensures that the size of the GPIO register table is explicitly 
>> tracked
>> and initialized, reducing the risk of errors if new register tables are
>> introduced in the future.
>>
>> Reproducer:
>> cat << EOF | qemu-system-aarch64 -display none \
>> -machine accel=qtest, -m 512M -machine ast1030-evb -qtest stdio
>> readq 0x7e780272
>> EOF
>>
>> ASAN log indicating the issue:
>> ==2602930==ERROR: AddressSanitizer: global-buffer-overflow on address 
>> 0x55a5da29e128 at pc 0x55a5d700dc62 bp 0x7fff096c4e90 sp 0x7fff096c4e88
>> READ of size 2 at 0x55a5da29e128 thread T0
>>      #0 0x55a5d700dc61 in aspeed_gpio_read hw/gpio/aspeed_gpio.c:564:14
>>      #1 0x55a5d933f3ab in memory_region_read_accessor 
>> system/memory.c:445:11
>>      #2 0x55a5d92fba40 in access_with_adjusted_size 
>> system/memory.c:573:18
>>      #3 0x55a5d92f842c in memory_region_dispatch_read1 
>> system/memory.c:1426:16
>>      #4 0x55a5d92f7b68 in memory_region_dispatch_read 
>> system/memory.c:1459:9
>>      #5 0x55a5d9376ad1 in flatview_read_continue_step 
>> system/physmem.c:2836:18
>>      #6 0x55a5d9376399 in flatview_read_continue system/physmem.c:2877:19
>>      #7 0x55a5d93775b8 in flatview_read system/physmem.c:2907:12
>>

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2355

>> Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
>> ---
>> Changes in v4:
>> - Change the variable name to 'reg_table_count'
>> - Change the 'reg_table_count' type to unsigned
> 
> Thanks,
> 
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> 
>> Changes in v3:
>> - Add the reproducer
>> ---
>>   hw/gpio/aspeed_gpio.c         | 17 +++++++++++++++++
>>   include/hw/gpio/aspeed_gpio.h |  1 +
>>   2 files changed, 18 insertions(+)
>