Use the EVM call gas syscall variants (#436)

- Emit the `call_evm` and `delegate_call_evm` syscalls for contract
calls.
- The call gas is no longer ignored.

---------

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>
This commit is contained in:
xermicus
2025-12-18 17:01:24 +01:00
committed by GitHub
parent 25ee4eef5a
commit be6f734cfc
9 changed files with 87 additions and 204 deletions
+2
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@@ -16,10 +16,12 @@ Supported `polkadot-sdk` rev: `unstable2507`
- Standard JSON mode: Don't forward EVM bytecode related output selections to solc.
- The supported `polkadot-sdk` release is `unstable2507`.
- The `INVALID` opcode and OOB memory accesses now consume all remaining gas.
- Emit the `call_evm` and `delegate_call_evm` syscalls for contract calls.
### Fixed:
- The missing `STOP` instruction at the end of `code` blocks.
- The missing bounds check in the internal sbrk implementation.
- The call gas is no longer ignored.
## v0.5.0
+50
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@@ -0,0 +1,50 @@
// SPDX-License-Identifier: MIT
pragma solidity ^0.8;
// Use a non-zero call gas that works with call gas clipping but not with a truncate.
/* runner.json
{
"differential": true,
"actions": [
{
"Upload": {
"code": {
"Solidity": {
"contract": "Other"
}
}
}
},
{
"Instantiate": {
"code": {
"Solidity": {
"contract": "CallGas"
}
},
"data": "1000000000000000000000000000000000000000000000000000000000000001"
}
}
]
}
*/
contract Other {
address public last;
uint public foo;
fallback() external {
last = msg.sender;
foo += 1;
}
}
contract CallGas {
constructor(uint _gas) payable {
Other other = new Other();
address(other).call{ gas: _gas }(hex"");
assert(other.last() == address(this));
}
}
-15
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@@ -23,11 +23,6 @@ pragma solidity ^0.8;
"data": "1c8d16b30000000000000000000000000303030303030303030303030303030303030303000000000000000000000000000000000000000000000000000000000000000a"
}
},
{
"VerifyCall": {
"success": true
}
},
{
"Call": {
"dest": {
@@ -36,11 +31,6 @@ pragma solidity ^0.8;
"data": "fb9e8d050000000000000000000000000000000000000000000000000000000000000001"
}
},
{
"VerifyCall": {
"success": false
}
},
{
"Call": {
"dest": {
@@ -48,11 +38,6 @@ pragma solidity ^0.8;
},
"data": "fb9e8d050000000000000000000000000000000000000000000000000000000000000000"
}
},
{
"VerifyCall": {
"success": false
}
}
]
}
-15
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@@ -23,11 +23,6 @@ pragma solidity ^0.8;
"data": "1c8d16b30000000000000000000000000303030303030303030303030303030303030303000000000000000000000000000000000000000000000000000000000000000a"
}
},
{
"VerifyCall": {
"success": true
}
},
{
"Call": {
"dest": {
@@ -36,11 +31,6 @@ pragma solidity ^0.8;
"data": "fb9e8d050000000000000000000000000000000000000000000000000000000000000001"
}
},
{
"VerifyCall": {
"success": false
}
},
{
"Call": {
"dest": {
@@ -48,11 +38,6 @@ pragma solidity ^0.8;
},
"data": "fb9e8d050000000000000000000000000000000000000000000000000000000000000000"
}
},
{
"VerifyCall": {
"success": false
}
}
]
}
+1 -44
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@@ -66,6 +66,7 @@ test_spec!(add_mod_mul_mod, "AddModMulModTester", "AddModMulMod.sol");
test_spec!(memory_bounds, "MemoryBounds", "MemoryBounds.sol");
test_spec!(selfdestruct, "Selfdestruct", "Selfdestruct.sol");
test_spec!(clz, "CountLeadingZeros", "CountLeadingZeros.sol");
test_spec!(call_gas, "CallGas", "CallGas.sol");
fn instantiate(path: &str, contract: &str) -> Vec<SpecsAction> {
vec![Instantiate {
@@ -451,50 +452,6 @@ fn ext_code_size() {
.run();
}
#[test]
#[should_panic(expected = "ReentranceDenied")]
fn send_denies_reentrancy() {
let value = 1000;
Specs {
actions: vec![
instantiate("contracts/Send.sol", "Send").remove(0),
Call {
origin: TestAddress::Alice,
dest: TestAddress::Instantiated(0),
value,
gas_limit: None,
storage_deposit_limit: None,
data: Contract::send_self(U256::from(value)).calldata,
},
],
differential: false,
..Default::default()
}
.run();
}
#[test]
#[should_panic(expected = "ReentranceDenied")]
fn transfer_denies_reentrancy() {
let value = 1000;
Specs {
actions: vec![
instantiate("contracts/Transfer.sol", "Transfer").remove(0),
Call {
origin: TestAddress::Alice,
dest: TestAddress::Instantiated(0),
value,
gas_limit: None,
storage_deposit_limit: None,
data: Contract::transfer_self(U256::from(value)).calldata,
},
],
differential: false,
..Default::default()
}
.run();
}
#[test]
fn create2_salt() {
let salt = U256::from(777);
+27 -122
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@@ -4,9 +4,8 @@ use inkwell::values::BasicValue;
use crate::polkavm::context::Context;
const STATIC_CALL_FLAG: u32 = 0b0001_0000;
const REENTRANT_CALL_FLAG: u32 = 0b0000_1000;
const SOLIDITY_TRANSFER_GAS_STIPEND_THRESHOLD: u64 = 2300;
const STATIC_CALL_FLAG: u64 = 0b0001_0000;
const REENTRANT_CALL_FLAG: u64 = 0b0000_1000;
/// Translates a contract call.
pub fn call<'ctx>(
@@ -38,33 +37,12 @@ pub fn call<'ctx>(
let output_length_pointer = context.build_alloca_at_entry(context.xlen_type(), "output_length");
context.build_store(output_length_pointer, output_length)?;
let (flags, deposit_limit_value) = if static_call {
let flags = REENTRANT_CALL_FLAG | STATIC_CALL_FLAG;
(
context.xlen_type().const_int(flags as u64, false),
context.word_type().const_zero(),
)
let flags = if static_call {
REENTRANT_CALL_FLAG | STATIC_CALL_FLAG
} else {
call_reentrancy_heuristic(context, gas, input_length, output_length)?
REENTRANT_CALL_FLAG
};
let deposit_pointer = context.build_alloca_at_entry(context.word_type(), "deposit_pointer");
context.build_store(deposit_pointer, deposit_limit_value)?;
let flags_and_callee = revive_runtime_api::calling_convention::pack_hi_lo_reg(
context.builder(),
context.llvm(),
flags,
address_pointer.to_int(context),
"address_and_callee",
)?;
let deposit_and_value = revive_runtime_api::calling_convention::pack_hi_lo_reg(
context.builder(),
context.llvm(),
deposit_pointer.to_int(context),
value_pointer.to_int(context),
"deposit_and_value",
)?;
let input_data = revive_runtime_api::calling_convention::pack_hi_lo_reg(
context.builder(),
context.llvm(),
@@ -85,10 +63,10 @@ pub fn call<'ctx>(
.build_runtime_call(
name,
&[
flags_and_callee.into(),
context.register_type().const_all_ones().into(),
context.register_type().const_all_ones().into(),
deposit_and_value.into(),
context.xlen_type().const_int(flags, false).into(),
address_pointer.to_int(context).into(),
value_pointer.to_int(context).into(),
clip_call_gas(context, gas)?,
input_data.into(),
output_data.into(),
],
@@ -111,7 +89,7 @@ pub fn call<'ctx>(
pub fn delegate_call<'ctx>(
context: &mut Context<'ctx>,
_gas: inkwell::values::IntValue<'ctx>,
gas: inkwell::values::IntValue<'ctx>,
address: inkwell::values::IntValue<'ctx>,
input_offset: inkwell::values::IntValue<'ctx>,
input_length: inkwell::values::IntValue<'ctx>,
@@ -132,18 +110,6 @@ pub fn delegate_call<'ctx>(
let output_length_pointer = context.build_alloca_at_entry(context.xlen_type(), "output_length");
context.build_store(output_length_pointer, output_length)?;
let deposit_pointer = context.build_alloca_at_entry(context.word_type(), "deposit_pointer");
context.build_store(deposit_pointer, context.word_type().const_all_ones())?;
let flags = context.xlen_type().const_int(0u64, false);
let flags_and_callee = revive_runtime_api::calling_convention::pack_hi_lo_reg(
context.builder(),
context.llvm(),
flags,
address_pointer.to_int(context),
"address_and_callee",
)?;
let input_data = revive_runtime_api::calling_convention::pack_hi_lo_reg(
context.builder(),
context.llvm(),
@@ -164,10 +130,9 @@ pub fn delegate_call<'ctx>(
.build_runtime_call(
name,
&[
flags_and_callee.into(),
context.register_type().const_all_ones().into(),
context.register_type().const_all_ones().into(),
deposit_pointer.to_int(context).into(),
context.xlen_type().const_int(0u64, false).into(),
address_pointer.to_int(context).into(),
clip_call_gas(context, gas)?,
input_data.into(),
output_data.into(),
],
@@ -201,82 +166,22 @@ pub fn linker_symbol<'ctx>(
context.build_load_address(context.get_global(path)?.into())
}
/// The Solidity `address.transfer` and `address.send` call detection heuristic.
///
/// # Why
/// This heuristic is an additional security feature to guard against re-entrancy attacks
/// in case contract authors violate Solidity best practices and use `address.transfer` or
/// `address.send`.
/// While contract authors are supposed to never use `address.transfer` or `address.send`,
/// for a small cost we can be extra defensive about it.
///
/// # How
/// The gas stipend emitted by solc for `transfer` and `send` is not static, thus:
/// - Dynamically allow re-entrancy only for calls considered not transfer or send.
/// - Detected balance transfers will supply 0 deposit limit instead of `u256::MAX`.
///
/// Calls are considered transfer or send if:
/// - (Input length | Output lenght) == 0;
/// - Gas <= 2300;
///
/// # Returns
/// The call flags xlen `IntValue` and the deposit limit word `IntValue`.
fn call_reentrancy_heuristic<'ctx>(
context: &mut Context<'ctx>,
/// The runtime implements gas as `u64` so we clip the stipend to `u64::MAX`.
fn clip_call_gas<'ctx>(
context: &Context<'ctx>,
gas: inkwell::values::IntValue<'ctx>,
input_length: inkwell::values::IntValue<'ctx>,
output_length: inkwell::values::IntValue<'ctx>,
) -> anyhow::Result<(
inkwell::values::IntValue<'ctx>,
inkwell::values::IntValue<'ctx>,
)> {
// Branch-free SSA implementation: First derive the heuristic boolean (int1) value.
let input_length_or_output_length =
context
.builder()
.build_or(input_length, output_length, "input_length_or_output_length")?;
let is_no_input_no_output = context.builder().build_int_compare(
inkwell::IntPredicate::EQ,
context.xlen_type().const_zero(),
input_length_or_output_length,
"is_no_input_no_output",
)?;
let gas_stipend = context
.word_type()
.const_int(SOLIDITY_TRANSFER_GAS_STIPEND_THRESHOLD, false);
let is_gas_stipend_for_transfer_or_send = context.builder().build_int_compare(
inkwell::IntPredicate::ULE,
) -> anyhow::Result<inkwell::values::BasicValueEnum<'ctx>> {
let builder = context.builder();
let clipped = context.register_type().const_all_ones();
let is_overflow = builder.build_int_compare(
inkwell::IntPredicate::UGT,
gas,
gas_stipend,
"is_gas_stipend_for_transfer_or_send",
builder.build_int_z_extend(clipped, context.word_type(), "gas_clipped")?,
"is_gas_overflow",
)?;
let is_balance_transfer = context.builder().build_and(
is_no_input_no_output,
is_gas_stipend_for_transfer_or_send,
"is_balance_transfer",
)?;
let is_regular_call = context
.builder()
.build_not(is_balance_transfer, "is_balance_transfer_inverted")?;
let truncated = builder.build_int_truncate(gas, context.register_type(), "gas_truncated")?;
let call_gas = builder.build_select(is_overflow, clipped, truncated, "call_gas")?;
// Call flag: Left shift the heuristic boolean value.
let is_regular_call_xlen = context.builder().build_int_z_extend(
is_regular_call,
context.xlen_type(),
"is_balance_transfer_xlen",
)?;
let call_flags = context.builder().build_left_shift(
is_regular_call_xlen,
context.xlen_type().const_int(3, false),
"flags",
)?;
// Deposit limit value: Sign-extended the heuristic boolean value.
let deposit_limit_value = context.builder().build_int_s_extend(
is_regular_call,
context.word_type(),
"deposit_limit_value",
)?;
Ok((call_flags, deposit_limit_value))
Ok(call_gas)
}
+2 -2
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@@ -53,7 +53,7 @@ POLKAVM_IMPORT(void, block_hash, uint32_t, uint32_t)
POLKAVM_IMPORT(void, block_number, uint32_t)
POLKAVM_IMPORT(uint32_t, call, uint64_t, uint64_t, uint64_t, uint64_t, uint64_t, uint64_t)
POLKAVM_IMPORT(uint32_t, call_evm, uint32_t, uint32_t, uint32_t, uint64_t, uint64_t, uint64_t)
POLKAVM_IMPORT(void, call_data_copy, uint32_t, uint32_t, uint32_t)
@@ -71,7 +71,7 @@ POLKAVM_IMPORT(void, code_hash, uint32_t, uint32_t)
POLKAVM_IMPORT(void, consume_all_gas)
POLKAVM_IMPORT(uint32_t, delegate_call, uint64_t, uint64_t, uint64_t, uint32_t, uint64_t, uint64_t)
POLKAVM_IMPORT(uint32_t, delegate_call_evm, uint32_t, uint32_t, uint64_t, uint64_t, uint64_t)
POLKAVM_IMPORT(void, deposit_event, uint32_t, uint32_t, uint32_t, uint32_t)
+2 -2
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@@ -16,7 +16,7 @@ pub static BLOCK_HASH: &str = "block_hash";
pub static BLOCK_NUMBER: &str = "block_number";
pub static CALL: &str = "call";
pub static CALL: &str = "call_evm";
pub static CALL_DATA_COPY: &str = "call_data_copy";
@@ -32,7 +32,7 @@ pub static CODE_SIZE: &str = "code_size";
pub static CODE_HASH: &str = "code_hash";
pub static DELEGATE_CALL: &str = "delegate_call";
pub static DELEGATE_CALL: &str = "delegate_call_evm";
pub static DEPOSIT_EVENT: &str = "deposit_event";
@@ -113,10 +113,9 @@ impl Error {
let message = r#"
Warning: It looks like you are using '<address payable>.send/transfer(<X>)'.
Using '<address payable>.send/transfer(<X>)' is deprecated and strongly discouraged!
The resolc compiler uses a heuristic to detect '<address payable>.send/transfer(<X>)' calls,
which disables call re-entrancy and supplies all remaining gas instead of the 2300 gas stipend.
However, detection is not guaranteed. You are advised to carefully test this, employ
re-entrancy guards or use the withdrawal pattern instead!
The revive runtime uses a heuristic to detect '<address payable>.send/transfer(<X>)' calls and
the gas stipend used by the runtime is different from the EVM.
You are advised to carefully test this, employ re-entrancy guards or use the withdrawal pattern instead!
Learn more on https://docs.soliditylang.org/en/latest/security-considerations.html#reentrancy
and https://docs.soliditylang.org/en/latest/common-patterns.html#withdrawal-from-contracts
"#