Should adjust some opcode price

[Qiao-Jin]

Summary or problem description

Price of some opcodes should be adjusted to prevent DoS attack as shown below:

(1) EQUAL

Opcode EQUAL can be severely time exhausting for ByteString. Detailed info can be seen in #1855 .

(2) REVERSEN & REVERSEITEMS

Currently price of Opcode.REVERSEN is 400 GasFactor. After testing, it shows running EvaluationStack.Reverse(2048) on a 2048-sized context for 250,000 times (which means 1 GAS) will assume 1 second, which is somehow too long for 1 Gas.

(3) NEWBUFFER

Currently the maximum size of a buffer is defined to be 1Mb. As the MaxStackSize = 2048, that means by NEWBUFFER as much as 2GB's RAM can be exhausted with merely 1.64 GAS.

(4) NEWARRAY & NEWARRAY_T

Similiar with NEWBUFFER, here as much as 2GB's RAM can be exhausted with merely 0.3 GAS.

Neo Version

• Neo 3

Where in the software does this update applies to?

• SDK
• VM

[erikzhang]

We charge for CPU time and storage only. Memory usage is limited, but not charging.

[Qiao-Jin]

Is 1 second per GAS price standard by design? Maybe this is somehow too cheap to prevent attack by malfactors.

[erikzhang]

Is 1 second per GAS price standard by design?

Yes.

[Qiao-Jin]

Closed as these are by design

[roman-khimov]

Is 1 second per GAS price standard by design?

Yes.

Then 1 GAS should cost something close to 0.0000166667 USD?