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Fixing memory calculations overflows

This commit is contained in:
Tomusdrw 2016-01-16 01:24:37 +01:00
parent e0f3f7adcc
commit 24777cc569
2 changed files with 47 additions and 30 deletions
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74
src/evm/interpreter.rs
View File

@ -92,6 +92,13 @@ trait Memory {
fn writeable_slice(&mut self, offset: U256, size: U256) -> &mut[u8];
fn dump(&self);
}
fn is_valid_range(off: usize, size: usize) -> bool {
// When size is zero we haven't actually expanded the memory
let (_a, overflow) = off.overflowing_add(size);
size > 0 && !overflow
}
impl Memory for Vec<u8> {
fn dump(&self) {
println!("MemoryDump:");
@ -106,13 +113,12 @@ impl Memory for Vec<u8> {
}
fn read_slice(&self, init_off_u: U256, init_size_u: U256) -> &[u8] {
let init_off = init_off_u.low_u64() as usize;
let init_size = init_size_u.low_u64() as usize;
// When size is zero we haven't actually expanded the memory
if init_size == 0 {
let off = init_off_u.low_u64() as usize;
let size = init_size_u.low_u64() as usize;
if !is_valid_range(off, size) {
&self[0..0]
} else {
&self[init_off..init_off + init_size]
&self[off..off+size]
}
}
@ -124,8 +130,7 @@ impl Memory for Vec<u8> {
fn writeable_slice(&mut self, offset: U256, size: U256) -> &mut [u8] {
let off = offset.low_u64() as usize;
let s = size.low_u64() as usize;
if s == 0 {
if !is_valid_range(off, s) {
&mut self[0..0]
} else {
&mut self[off..off+s]
@ -323,9 +328,14 @@ impl Interpreter {
InstructionCost::GasMem(default_gas, self.mem_needed(stack.peek(0), stack.peek(1)))
},
instructions::SHA3 => {
let words = add_u256_usize(stack.peek(1), 31) >> 5;
let gas = U256::from(schedule.sha3_gas) + (U256::from(schedule.sha3_word_gas) * words);
InstructionCost::GasMem(gas, self.mem_needed(stack.peek(0), stack.peek(1)))
match add_u256_usize(stack.peek(1), 31) {
(_w, true) => InstructionCost::GasMem(U256::zero(), RequiredMem::OutOfMemory),
(w, false) => {
let words = w >> 5;
let gas = U256::from(schedule.sha3_gas) + (U256::from(schedule.sha3_word_gas) * words);
InstructionCost::GasMem(gas, self.mem_needed(stack.peek(0), stack.peek(1)))
}
}
},
instructions::CALLDATACOPY => {
InstructionCost::GasMemCopy(default_gas, self.mem_needed(stack.peek(0), stack.peek(2)), stack.peek(2).clone())
@ -356,13 +366,16 @@ impl Interpreter {
InstructionCost::GasMem(gas, mem)
},
instructions::DELEGATECALL => {
let gas = add_u256_usize(stack.peek(0), schedule.call_gas);
let mem = self.mem_max(
self.mem_needed(stack.peek(4), stack.peek(5)),
self.mem_needed(stack.peek(2), stack.peek(3))
);
InstructionCost::GasMem(gas, mem)
match add_u256_usize(stack.peek(0), schedule.call_gas) {
(_gas, true) => InstructionCost::GasMem(U256::zero(), RequiredMem::OutOfMemory),
(gas, false) => {
let mem = self.mem_max(
self.mem_needed(stack.peek(4), stack.peek(5)),
self.mem_needed(stack.peek(2), stack.peek(3))
);
InstructionCost::GasMem(gas, mem)
}
}
},
instructions::CREATE => {
let gas = U256::from(schedule.create_gas);
@ -393,9 +406,14 @@ impl Interpreter {
InstructionCost::GasMemCopy(gas, mem_size, copy) => match mem_size {
RequiredMem::Mem(mem_size) => {
let (mem_gas, new_mem_size) = self.mem_gas_cost(schedule, mem.size(), &mem_size);
let copy_gas = U256::from(schedule.copy_gas) * (add_u256_usize(&copy, 31) / U256::from(32));
let gas = try!(self.gas_add(try!(self.gas_add(gas, copy_gas)), mem_gas));
Ok((gas, new_mem_size))
match add_u256_usize(&copy, 31) {
(_c, true) => Err(evm::Error::OutOfGas),
(copy, false) => {
let copy_gas = U256::from(schedule.copy_gas) * (copy / U256::from(32));
let gas = try!(self.gas_add(try!(self.gas_add(gas, copy_gas)), mem_gas));
Ok((gas, new_mem_size))
}
}
},
RequiredMem::OutOfMemory => Err(evm::Error::OutOfGas)
}
@ -415,16 +433,16 @@ impl Interpreter {
s * U256::from(schedule.memory_gas) + s * s / U256::from(schedule.quad_coeff_div)
};
let req_mem_size = mem_size.low_u64() as usize;
let req_mem_size_rounded = (req_mem_size + 31) / 32 * 32;
let current_mem_size = U256::from(current_mem_size);
let req_mem_size_rounded = ((mem_size.clone() + U256::from(31)) >> 5) << 5;
let new_mem_gas = gas_for_mem(U256::from(req_mem_size_rounded));
let current_mem_gas = gas_for_mem(U256::from(current_mem_size));
let current_mem_gas = gas_for_mem(current_mem_size);
(if req_mem_size_rounded > current_mem_size {
new_mem_gas - current_mem_gas
} else {
U256::zero()
}, req_mem_size_rounded)
}, req_mem_size_rounded.low_u64() as usize)
}
@ -452,7 +470,9 @@ impl Interpreter {
} else {
match offset.clone().overflowing_add(size.clone()) {
(_result, true) => RequiredMem::OutOfMemory,
(result, false) => RequiredMem::Mem(result)
(result, false) => {
RequiredMem::Mem(result)
}
}
}
}
@ -1009,8 +1029,8 @@ pub fn set_sign(value: U256, sign: bool) -> U256 {
}
}
fn add_u256_usize(value: &U256, num: usize) -> U256 {
value.clone() + U256::from(num)
fn add_u256_usize(value: &U256, num: usize) -> (U256, bool) {
value.clone().overflowing_add(U256::from(num))
}
fn u256_to_address(value: &U256) -> Address {

3
src/tests/executive.rs
View File

@ -168,9 +168,6 @@ fn do_json_test_for(vm: &VMType, json_data: &[u8]) -> Vec<String> {
let json = Json::from_str(::std::str::from_utf8(json_data).unwrap()).expect("Json is invalid");
let mut failed = Vec::new();
for (name, test) in json.as_object().unwrap() {
// if name != "CallToNameRegistrator0" {
// continue;
// }
println!("name: {:?}", name);
// sync io is usefull when something crashes in jit
// ::std::io::stdout().write(&name.as_bytes());