Re: [PATCH 1/2] ArmPlatformPkg/ArmVExpressFastBootDxe: eliminate deprecated string functions

[Laszlo Ersek <lersek@redhat.com>]

On 10/26/16 12:34, Ard Biesheuvel wrote:
> On 26 October 2016 at 11:32, Laszlo Ersek <lersek@redhat.com> wrote:
>> On 10/25/16 20:17, Ard Biesheuvel wrote:
>>> Get rid of functions that are no longer available when defining
>>> DISABLE_NEW_DEPRECATED_INTERFACES
>>>
>>> Contributed-under: TianoCore Contribution Agreement 1.0
>>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>>> ---
>>>  ArmPlatformPkg/ArmVExpressPkg/ArmVExpressFastBootDxe/ArmVExpressFastBoot.c | 8 ++++----
>>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/ArmPlatformPkg/ArmVExpressPkg/ArmVExpressFastBootDxe/ArmVExpressFastBoot.c b/ArmPlatformPkg/ArmVExpressPkg/ArmVExpressFastBootDxe/ArmVExpressFastBoot.c
>>> index 4d0811cc5eaf..6b39682948aa 100644
>>> --- a/ArmPlatformPkg/ArmVExpressPkg/ArmVExpressFastBootDxe/ArmVExpressFastBoot.c
>>> +++ b/ArmPlatformPkg/ArmVExpressPkg/ArmVExpressFastBootDxe/ArmVExpressFastBoot.c
>>> @@ -269,7 +269,7 @@ ArmFastbootPlatformInit (
>>>
>>>        // Copy handle and partition name
>>>        Entry->PartitionHandle = AllHandles[LoopIndex];
>>> -      StrnCpy (
>>> +      CopyMem (
>>>          Entry->PartitionName,
>>>          PartitionEntries[PartitionNode->PartitionNumber - 1].PartitionName, // Partition numbers start from 1.
>>>          PARTITION_NAME_MAX_LENGTH
>>
>> okay
>>
>>> @@ -320,7 +320,7 @@ ArmFastbootPlatformFlashPartition (
>>>    CHAR16                   PartitionNameUnicode[60];
>>>    BOOLEAN                  PartitionFound;
>>>
>>> -  AsciiStrToUnicodeStr (PartitionName, PartitionNameUnicode);
>>> +  AsciiStrToUnicodeStrS (PartitionName, PartitionNameUnicode, 60);
>>>
>>>    PartitionFound = FALSE;
>>>    Entry = (FASTBOOT_PARTITION_LIST *) GetFirstNode (&(mPartitionListHead));
>>
>> You asked me to introduce a macro for a very similar case in one of my
>> ArmPkg patches...
>>
> 
> You are right, my apologies. In my defense, ArmPkg is something we
> consider maintained, whereas ArmPlatformPkg is a collection of cruft
> which we would like to phase out as soon as we can.

Ah, okay; I didn't realize that. No need to change this hunk then (I
didn't request that anyway). It is correct after all (and beauty we
don't insist upon here, then).

Thanks
Laszlo

> 
>> Anyway, the change is valid.
>>
>>> @@ -396,7 +396,7 @@ ArmFastbootPlatformGetVar (
>>>    )
>>>  {
>>>    if (AsciiStrCmp (Name, "product")) {
>>> -    AsciiStrCpy (Value, FixedPcdGetPtr (PcdFirmwareVendor));
>>> +    AsciiStrCpyS (Value, 60, FixedPcdGetPtr (PcdFirmwareVendor));
>>>    } else {
>>>      *Value = '\0';
>>>    }
>>
>> This is wrong.
>>
>> The signature of this function does not indicate the expected size of
>> the receiving buffer. However, the function is a
>> FASTBOOT_PLATFORM_GETVAR implementation (==
>> FASTBOOT_PLATFORM_PROTOCOL.GetVar() member implementation). The leading
>> comment on that function pointer type says,
>>
>>   Variable names and values may not be larger than 60 bytes, excluding the
>>   terminal null character. This is a limitation of the Fastboot protocol.
>>
>> I.e., 60 non-NUL bytes, plus the terminating NUL, is a valid variable
>> value. Therefore the DestMax parameter should be 61.
>>
>> Just to be sure, I checked the call sites. There is only one call site
>> actually, in
>> "EmbeddedPkg/Application/AndroidFastboot/AndroidFastbootApp.c", function
>> HandleGetVar():
>>
>>   CHAR8      Response[FASTBOOT_COMMAND_MAX_LENGTH + 1] = "OKAY";
>> ...
>>     Status = mPlatform->GetVar (CmdArg, Response + 4);
>>
>> FASTBOOT_COMMAND_MAX_LENGTH is 64 (same file), therefore (Response + 4)
>> points to a (sub-)array of 61 characters. IOW, the call site is
>> consistent with the protocol definition, and the DestMax param should be
>> bumped to 61.
>>
> 
> Thanks for spotting that.
> 
>>> @@ -410,7 +410,7 @@ ArmFastbootPlatformOemCommand (
>>>  {
>>>    CHAR16 CommandUnicode[65];
>>>
>>> -  AsciiStrToUnicodeStr (Command, CommandUnicode);
>>> +  AsciiStrToUnicodeStrS (Command, CommandUnicode, 65);
>>>
>>>    if (AsciiStrCmp (Command, "Demonstrate") == 0) {
>>>      DEBUG ((EFI_D_ERROR, "ARM OEM Fastboot command 'Demonstrate' received.\n"));
>>>
>>
>> This is correct.
>>
> 
> Thanks,
> Ard.
>