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Update gas metering for calls to empty accounts #1774

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merged 4 commits into from
Aug 25, 2020
Merged

Update gas metering for calls to empty accounts #1774

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6d5b7d7
Update gas metering for calls to empty accounts
wolflo Jul 12, 2020
0e1eee8
Merge branch 'master' into pr/1774
Aug 4, 2020
9cf5973
Add test for call gas costs
wolflo Aug 17, 2020
0096570
Merge branch 'master' into pr/1774
Aug 25, 2020
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2 changes: 1 addition & 1 deletion manticore/platforms/evm.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2144,7 +2144,7 @@ def CALL_gas(self, wanted_gas, address, value, in_offset, in_size, out_offset, o
known_address = False
for address_i in self.world.accounts:
known_address = Operators.OR(known_address, address == address_i)
fee += Operators.ITEBV(512, Operators.AND(known_address, value == 0), 0, GCALLNEW)
fee += Operators.ITEBV(512, Operators.OR(known_address, value == 0), 0, GCALLNEW)
fee += self._get_memfee(in_offset, in_size)

exception = False
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119 changes: 119 additions & 0 deletions tests/ethereum/test_general.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1778,6 +1778,125 @@ def test_selfdestruct(self):
)
self.assertEqual(m.count_ready_states(), 1)

def test_call_gas(self):
GCALLSTATIC = 21721 # 21000 + (3 * 7 push ops) + 700 static cost for call
GCALLVALUE = 9000 # cost added for nonzero callvalue
GCALLNEW = 25000 # cost added for forcing new acct creation
GCALLSTIPEND = 2300 # additional gas sent with a call if value > 0

with disposable_mevm() as m:
# nonempty call target
m.create_account(
address=0x111111111111111111111111111111111111111,
nonce=1 # nonempty account
)

# call(gas, target, value, in_offset, in_size, out_offset, out_size)
# call to empty acct with value = 0
asm_call_empty_no_val = """ PUSH1 0x0
PUSH1 0X0
PUSH1 0x0
PUSH1 0X0
PUSH1 0x0
PUSH20 0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
PUSH1 0x0
CALL
STOP
"""
# call to existing acct with value > 0
asm_call_nonempty_w_val = """ PUSH1 0x0
PUSH1 0X0
PUSH1 0x0
PUSH1 0X0
PUSH1 0x1
PUSH20 0x111111111111111111111111111111111111111
PUSH1 0x0
CALL
STOP
"""
# call to empty acct with value > 0, forcing addition to state trie
asm_call_empty_w_val = """ PUSH1 0x0
PUSH1 0X0
PUSH1 0x0
PUSH1 0X0
PUSH1 0x1
PUSH20 0xbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
PUSH1 0x0
CALL
STOP
"""

call_empty_no_val = m.create_account(
code=EVMAsm.assemble(asm_call_empty_no_val)
)
call_nonempty_w_val = m.create_account(
balance=100,
code=EVMAsm.assemble(asm_call_nonempty_w_val)
)
call_empty_w_val = m.create_account(
balance=100,
code=EVMAsm.assemble(asm_call_empty_w_val)
)

caller = m.create_account(
address=0x222222222222222222222222222222222222222,
balance=1000000000000000000
)

# call to empty acct with value = 0
m.transaction(
caller=caller,
address=call_empty_no_val,
data=b'',
value=0,
gas=50000000
)
self.assertEqual(m.count_ready_states(), 1)
state = next(m.ready_states)
txs = state.platform.transactions
# no value, so no call stipend should be sent
self.assertEqual(txs[-2].gas, 0)
# no value, so only static call cost should be charged
self.assertEqual(txs[-1].used_gas, GCALLSTATIC)

# call to existing acct with value > 0
m.transaction(
caller=caller,
address=call_nonempty_w_val,
data=b'',
value=0,
gas=50000000
)
self.assertEqual(m.count_ready_states(), 1)
state = next(m.ready_states)
txs = state.platform.transactions
# call stipend should be sent with call
self.assertEqual(txs[-2].gas, GCALLSTIPEND)
# cost of call should include value cost, but not new acct cost
self.assertEqual(
txs[-1].used_gas,
GCALLSTATIC + GCALLVALUE - GCALLSTIPEND
)

# call to empty acct with value > 0, forcing addition to state trie
m.transaction(
caller=caller,
address=call_empty_w_val,
data=b'',
value=0,
gas=50000000
)
self.assertEqual(m.count_ready_states(), 1)
state = next(m.ready_states)
txs = state.platform.transactions
# call stipend should be sent with call
self.assertEqual(txs[-2].gas, GCALLSTIPEND)
# cost of call should include value cost and new acct cost
self.assertEqual(
txs[-1].used_gas,
GCALLSTATIC + GCALLVALUE + GCALLNEW - GCALLSTIPEND
)


class EthPluginTests(unittest.TestCase):
def test_FilterFunctions_fallback_function_matching(self):
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