Thread: [Firebird-devel] getInfo() result format

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   Hello All.

   isc_info_truncated is a terminal item which is NOT followed by two bytes 
length, right?

-- 
   WBR, SD.

On 9/7/22 19:18, Dimitry Sibiryakov wrote:
> Hello All.
>
>   isc_info_truncated is a terminal item which is NOT followed by two 
> bytes length, right?
>

Not sure what you mean by 'terminal item', but it may be followed by 
isc_info_end if that fits into buffer.
What about two bytes length - it's single-byte item not followed by 
anything.

see how it's added:

bool Service::ck_space_for_numeric(UCHAR*& info, const UCHAR* const end)
{
     if ((info + 1 + sizeof(ULONG)) > end)
     {
         if (info < end)
             *info++ = isc_info_truncated;
         if (info < end)
             *info++ = isc_info_end;
         return false;
     }
     return true;
}

Alex Peshkoff via Firebird-devel wrote 07.09.2022 18:26:
> Not sure what you mean by 'terminal item', but it may be followed by 
> isc_info_end if that fits into buffer.
> What about two bytes length - it's single-byte item not followed by anything.
> 
> see how it's added:

   Ok, now see how it is handled:

while (!redo && *p != isc_info_end && p < buf + buf_len)
{
	const UCHAR item = *p++;
	const USHORT len = static_cast<USHORT>(gds__vax_integer(p, 2));

	p += 2;

	switch (item)
	{
	.......
	case isc_info_truncated:
		redo = true;
		break;

	default:
		(Arg::Gds(isc_random) << "Invalid info item").raise();
	}

	p += len;
}

   At fourth line you can get read-past-buffer and may be crash. And this code 
is copy-pasted everywhere in Firebird source.

-- 
   WBR, SD.

On 9/7/22 19:33, Dimitry Sibiryakov wrote:

>   At fourth line you can get read-past-buffer and may be crash. And 
> this code is copy-pasted everywhere in Firebird source.
>

Do not remember - does ClumpletReader already supports getInfo() result 
format?

Alex Peshkoff via Firebird-devel wrote 07.09.2022 18:40:
> Do not remember - does ClumpletReader already supports getInfo() result format?

   Sorry, can't remember.

-- 
   WBR, SD.

On 9/8/22 12:49, Dimitry Sibiryakov wrote:
> Alex Peshkoff via Firebird-devel wrote 07.09.2022 18:40:
>> Do not remember - does ClumpletReader already supports getInfo() 
>> result format?
>
>   Sorry, can't remember.
>

Supports, down to FB3. I.e. looks like we need an src review. Add a 
ticket please.

Thread: [Firebird-devel] getInfo() result format

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