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// Copyright 2018-2020 Parity Technologies (UK) Ltd. // This file is part of Substrate. // Substrate is free software: you can redistribute it and/or modify // it under the terms of the GNU General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // Substrate is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // You should have received a copy of the GNU General Public License // along with Substrate. If not, see <http://www.gnu.org/licenses/>. //! Environment definition of the wasm smart-contract runtime. use crate::{Schedule, Trait, CodeHash, BalanceOf, Error}; use crate::exec::{ Ext, ExecResult, ExecReturnValue, StorageKey, TopicOf, ReturnFlags, ExecError }; use crate::gas::{Gas, GasMeter, Token, GasMeterResult}; use crate::wasm::env_def::ConvertibleToWasm; use sp_sandbox; use parity_wasm::elements::ValueType; use frame_system; use frame_support::dispatch::DispatchError; use sp_std::prelude::*; use codec::{Decode, Encode}; use sp_runtime::traits::{Bounded, SaturatedConversion}; use sp_io::hashing::{ keccak_256, blake2_256, blake2_128, sha2_256, }; /// Every error that can be returned to a contract when it calls any of the host functions. #[repr(u32)] pub enum ReturnCode { /// API call successful. Success = 0, /// The called function trapped and has its state changes reverted. /// In this case no output buffer is returned. CalleeTrapped = 1, /// The called function ran to completion but decided to revert its state. /// An output buffer is returned when one was supplied. CalleeReverted = 2, /// The passed key does not exist in storage. KeyNotFound = 3, /// Transfer failed because it would have brought the sender's total balance below the /// subsistence threshold. BelowSubsistenceThreshold = 4, /// Transfer failed for other reasons. Most probably reserved or locked balance of the /// sender prevents the transfer. TransferFailed = 5, /// The newly created contract is below the subsistence threshold after executing /// its constructor. NewContractNotFunded = 6, /// No code could be found at the supplied code hash. CodeNotFound = 7, /// The contract that was called is either no contract at all (a plain account) /// or is a tombstone. NotCallable = 8, } impl ConvertibleToWasm for ReturnCode { type NativeType = Self; const VALUE_TYPE: ValueType = ValueType::I32; fn to_typed_value(self) -> sp_sandbox::Value { sp_sandbox::Value::I32(self as i32) } fn from_typed_value(_: sp_sandbox::Value) -> Option<Self> { debug_assert!(false, "We will never receive a ReturnCode but only send it to wasm."); None } } impl From<ExecReturnValue> for ReturnCode { fn from(from: ExecReturnValue) -> Self { if from.flags.contains(ReturnFlags::REVERT) { Self::CalleeReverted } else { Self::Success } } } /// The data passed through when a contract uses `seal_return`. struct ReturnData { /// The flags as passed through by the contract. They are still unchecked and /// will later be parsed into a `ReturnFlags` bitflags struct. flags: u32, /// The output buffer passed by the contract as return data. data: Vec<u8>, } /// Enumerates all possible reasons why a trap was generated. /// /// This is either used to supply the caller with more information about why an error /// occurred (the SupervisorError variant). /// The other case is where the trap does not constitute an error but rather was invoked /// as a quick way to terminate the application (all other variants). enum TrapReason { /// The supervisor trapped the contract because of an error condition occurred during /// execution in privileged code. SupervisorError(DispatchError), /// Signals that trap was generated in response to call `seal_return` host function. Return(ReturnData), /// Signals that a trap was generated in response to a successful call to the /// `seal_terminate` host function. Termination, /// Signals that a trap was generated because of a successful restoration. Restoration, } /// Can only be used for one call. pub(crate) struct Runtime<'a, E: Ext + 'a> { ext: &'a mut E, input_data: Option<Vec<u8>>, schedule: &'a Schedule, memory: sp_sandbox::Memory, gas_meter: &'a mut GasMeter<E::T>, trap_reason: Option<TrapReason>, } impl<'a, E: Ext + 'a> Runtime<'a, E> { pub(crate) fn new( ext: &'a mut E, input_data: Vec<u8>, schedule: &'a Schedule, memory: sp_sandbox::Memory, gas_meter: &'a mut GasMeter<E::T>, ) -> Self { Runtime { ext, input_data: Some(input_data), schedule, memory, gas_meter, trap_reason: None, } } } /// Converts the sandbox result and the runtime state into the execution outcome. /// /// It evaluates information stored in the `trap_reason` variable of the runtime and /// bases the outcome on the value if this variable. Only if `trap_reason` is `None` /// the result of the sandbox is evaluated. pub(crate) fn to_execution_result<E: Ext>( runtime: Runtime<E>, sandbox_result: Result<sp_sandbox::ReturnValue, sp_sandbox::Error>, ) -> ExecResult { // If a trap reason is set we base our decision solely on that. if let Some(trap_reason) = runtime.trap_reason { return match trap_reason { // The trap was the result of the execution `return` host function. TrapReason::Return(ReturnData{ flags, data }) => { let flags = ReturnFlags::from_bits(flags).ok_or_else(|| "used reserved bit in return flags" )?; Ok(ExecReturnValue { flags, data, }) }, TrapReason::Termination => { Ok(ExecReturnValue { flags: ReturnFlags::empty(), data: Vec::new(), }) }, TrapReason::Restoration => { Ok(ExecReturnValue { flags: ReturnFlags::empty(), data: Vec::new(), }) }, TrapReason::SupervisorError(error) => Err(error)?, } } // Check the exact type of the error. match sandbox_result { // No traps were generated. Proceed normally. Ok(_) => { Ok(ExecReturnValue { flags: ReturnFlags::empty(), data: Vec::new() }) } // `Error::Module` is returned only if instantiation or linking failed (i.e. // wasm binary tried to import a function that is not provided by the host). // This shouldn't happen because validation process ought to reject such binaries. // // Because panics are really undesirable in the runtime code, we treat this as // a trap for now. Eventually, we might want to revisit this. Err(sp_sandbox::Error::Module) => Err("validation error")?, // Any other kind of a trap should result in a failure. Err(sp_sandbox::Error::Execution) | Err(sp_sandbox::Error::OutOfBounds) => Err(Error::<E::T>::ContractTrapped)? } } #[cfg_attr(test, derive(Debug, PartialEq, Eq))] #[derive(Copy, Clone)] pub enum RuntimeToken { /// Explicit call to the `gas` function. Charge the gas meter /// with the value provided. Explicit(u32), /// The given number of bytes is read from the sandbox memory. ReadMemory(u32), /// The given number of bytes is written to the sandbox memory. WriteMemory(u32), /// The given number of bytes is read from the sandbox memory and /// is returned as the return data buffer of the call. ReturnData(u32), /// (topic_count, data_bytes): A buffer of the given size is posted as an event indexed with the /// given number of topics. DepositEvent(u32, u32), } impl<T: Trait> Token<T> for RuntimeToken { type Metadata = Schedule; fn calculate_amount(&self, metadata: &Schedule) -> Gas { use self::RuntimeToken::*; let value = match *self { Explicit(amount) => Some(amount.into()), ReadMemory(byte_count) => metadata .sandbox_data_read_cost .checked_mul(byte_count.into()), WriteMemory(byte_count) => metadata .sandbox_data_write_cost .checked_mul(byte_count.into()), ReturnData(byte_count) => metadata .return_data_per_byte_cost .checked_mul(byte_count.into()), DepositEvent(topic_count, data_byte_count) => { let data_cost = metadata .event_data_per_byte_cost .checked_mul(data_byte_count.into()); let topics_cost = metadata .event_per_topic_cost .checked_mul(topic_count.into()); data_cost .and_then(|data_cost| { topics_cost.and_then(|topics_cost| { data_cost.checked_add(topics_cost) }) }) .and_then(|data_and_topics_cost| data_and_topics_cost.checked_add(metadata.event_base_cost) ) }, }; value.unwrap_or_else(|| Bounded::max_value()) } } /// Charge the gas meter with the specified token. /// /// Returns `Err(HostError)` if there is not enough gas. fn charge_gas<T: Trait, Tok: Token<T>>( gas_meter: &mut GasMeter<T>, metadata: &Tok::Metadata, trap_reason: &mut Option<TrapReason>, token: Tok, ) -> Result<(), sp_sandbox::HostError> { match gas_meter.charge(metadata, token) { GasMeterResult::Proceed => Ok(()), GasMeterResult::OutOfGas => { *trap_reason = Some(TrapReason::SupervisorError(Error::<T>::OutOfGas.into())); Err(sp_sandbox::HostError) }, } } /// Read designated chunk from the sandbox memory, consuming an appropriate amount of /// gas. /// /// Returns `Err` if one of the following conditions occurs: /// /// - calculating the gas cost resulted in overflow. /// - out of gas /// - requested buffer is not within the bounds of the sandbox memory. fn read_sandbox_memory<E: Ext>( ctx: &mut Runtime<E>, ptr: u32, len: u32, ) -> Result<Vec<u8>, sp_sandbox::HostError> { charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::ReadMemory(len), )?; let mut buf = vec![0u8; len as usize]; ctx.memory.get(ptr, buf.as_mut_slice()) .map_err(|_| store_err(ctx, Error::<E::T>::OutOfBounds))?; Ok(buf) } /// Read designated chunk from the sandbox memory into the supplied buffer, consuming /// an appropriate amount of gas. /// /// Returns `Err` if one of the following conditions occurs: /// /// - calculating the gas cost resulted in overflow. /// - out of gas /// - requested buffer is not within the bounds of the sandbox memory. fn read_sandbox_memory_into_buf<E: Ext>( ctx: &mut Runtime<E>, ptr: u32, buf: &mut [u8], ) -> Result<(), sp_sandbox::HostError> { charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::ReadMemory(buf.len() as u32), )?; ctx.memory.get(ptr, buf).map_err(|_| store_err(ctx, Error::<E::T>::OutOfBounds)) } /// Read designated chunk from the sandbox memory, consuming an appropriate amount of /// gas, and attempt to decode into the specified type. /// /// Returns `Err` if one of the following conditions occurs: /// /// - calculating the gas cost resulted in overflow. /// - out of gas /// - requested buffer is not within the bounds of the sandbox memory. /// - the buffer contents cannot be decoded as the required type. fn read_sandbox_memory_as<E: Ext, D: Decode>( ctx: &mut Runtime<E>, ptr: u32, len: u32, ) -> Result<D, sp_sandbox::HostError> { let buf = read_sandbox_memory(ctx, ptr, len)?; D::decode(&mut &buf[..]).map_err(|_| store_err(ctx, Error::<E::T>::DecodingFailed)) } /// Write the given buffer to the designated location in the sandbox memory, consuming /// an appropriate amount of gas. /// /// Returns `Err` if one of the following conditions occurs: /// /// - calculating the gas cost resulted in overflow. /// - out of gas /// - designated area is not within the bounds of the sandbox memory. fn write_sandbox_memory<E: Ext>( ctx: &mut Runtime<E>, ptr: u32, buf: &[u8], ) -> Result<(), sp_sandbox::HostError> { charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::WriteMemory(buf.len() as u32), )?; ctx.memory.set(ptr, buf) .map_err(|_| store_err(ctx, Error::<E::T>::OutOfBounds)) } /// Write the given buffer and its length to the designated locations in sandbox memory. // /// `out_ptr` is the location in sandbox memory where `buf` should be written to. /// `out_len_ptr` is an in-out location in sandbox memory. It is read to determine the /// lenght of the buffer located at `out_ptr`. If that buffer is large enough the actual /// `buf.len()` is written to this location. /// /// If `out_ptr` is set to the sentinel value of `u32::max_value()` and `allow_skip` is true the /// operation is skipped and `Ok` is returned. This is supposed to help callers to make copying /// output optional. For example to skip copying back the output buffer of an `seal_call` /// when the caller is not interested in the result. /// /// In addition to the error conditions of `write_sandbox_memory` this functions returns /// `Err` if the size of the buffer located at `out_ptr` is too small to fit `buf`. fn write_sandbox_output<E: Ext>( ctx: &mut Runtime<E>, out_ptr: u32, out_len_ptr: u32, buf: &[u8], allow_skip: bool, ) -> Result<(), sp_sandbox::HostError> { if allow_skip && out_ptr == u32::max_value() { return Ok(()); } let buf_len = buf.len() as u32; let len: u32 = read_sandbox_memory_as(ctx, out_len_ptr, 4)?; if len < buf_len { Err(store_err(ctx, Error::<E::T>::OutputBufferTooSmall))? } charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::WriteMemory(buf_len.saturating_add(4)), )?; ctx.memory.set(out_ptr, buf)?; ctx.memory.set(out_len_ptr, &buf_len.encode())?; Ok(()) } /// Stores a DispatchError returned from an Ext function into the trap_reason. /// /// This allows through supervisor generated errors to the caller. fn store_err<E, Error>(ctx: &mut Runtime<E>, err: Error) -> sp_sandbox::HostError where E: Ext, Error: Into<DispatchError>, { ctx.trap_reason = Some(TrapReason::SupervisorError(err.into())); sp_sandbox::HostError } /// Fallible conversion of `DispatchError` to `ReturnCode`. fn err_into_return_code<T: Trait>(from: DispatchError) -> Result<ReturnCode, DispatchError> { use ReturnCode::*; let below_sub = Error::<T>::BelowSubsistenceThreshold.into(); let transfer_failed = Error::<T>::TransferFailed.into(); let not_funded = Error::<T>::NewContractNotFunded.into(); let no_code = Error::<T>::CodeNotFound.into(); let invalid_contract = Error::<T>::NotCallable.into(); match from { x if x == below_sub => Ok(BelowSubsistenceThreshold), x if x == transfer_failed => Ok(TransferFailed), x if x == not_funded => Ok(NewContractNotFunded), x if x == no_code => Ok(CodeNotFound), x if x == invalid_contract => Ok(NotCallable), err => Err(err) } } /// Fallible conversion of a `ExecResult` to `ReturnCode`. fn exec_into_return_code<T: Trait>(from: ExecResult) -> Result<ReturnCode, DispatchError> { use crate::exec::ErrorOrigin::Callee; let ExecError { error, origin } = match from { Ok(retval) => return Ok(retval.into()), Err(err) => err, }; match (error, origin) { (_, Callee) => Ok(ReturnCode::CalleeTrapped), (err, _) => err_into_return_code::<T>(err) } } /// Used by Runtime API that calls into other contracts. /// /// Those need to transform the the `ExecResult` returned from the execution into /// a `ReturnCode`. If this conversion fails because the `ExecResult` constitutes a /// a fatal error then this error is stored in the `ExecutionContext` so it can be /// extracted for display in the UI. fn map_exec_result<E: Ext>(ctx: &mut Runtime<E>, result: ExecResult) -> Result<ReturnCode, sp_sandbox::HostError> { match exec_into_return_code::<E::T>(result) { Ok(code) => Ok(code), Err(err) => Err(store_err(ctx, err)), } } /// Try to convert an error into a `ReturnCode`. /// /// Used to decide between fatal and non-fatal errors. fn map_dispatch_result<T, E: Ext>(ctx: &mut Runtime<E>, result: Result<T, DispatchError>) -> Result<ReturnCode, sp_sandbox::HostError> { let err = if let Err(err) = result { err } else { return Ok(ReturnCode::Success) }; match err_into_return_code::<E::T>(err) { Ok(code) => Ok(code), Err(err) => Err(store_err(ctx, err)), } } // *********************************************************** // * AFTER MAKING A CHANGE MAKE SURE TO UPDATE COMPLEXITY.MD * // *********************************************************** // Define a function `fn init_env<E: Ext>() -> HostFunctionSet<E>` that returns // a function set which can be imported by an executed contract. // // # Note // // Any input that leads to a out of bound error (reading or writing) or failing to decode // data passed to the supervisor will lead to a trap. This is not documented explicitly // for every function. define_env!(Env, <E: Ext>, // Account for used gas. Traps if gas used is greater than gas limit. // // NOTE: This is a implementation defined call and is NOT a part of the public API. // This call is supposed to be called only by instrumentation injected code. // // - amount: How much gas is used. gas(ctx, amount: u32) => { charge_gas( &mut ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::Explicit(amount) )?; Ok(()) }, // Set the value at the given key in the contract storage. // // The value length must not exceed the maximum defined by the contracts module parameters. // Storing an empty value is disallowed. // // # Parameters // // - `key_ptr`: pointer into the linear memory where the location to store the value is placed. // - `value_ptr`: pointer into the linear memory where the value to set is placed. // - `value_len`: the length of the value in bytes. // // # Traps // // - If value length exceeds the configured maximum value length of a storage entry. // - Upon trying to set an empty storage entry (value length is 0). seal_set_storage(ctx, key_ptr: u32, value_ptr: u32, value_len: u32) => { if value_len > ctx.ext.max_value_size() { // Bail out if value length exceeds the set maximum value size. return Err(sp_sandbox::HostError); } let mut key: StorageKey = [0; 32]; read_sandbox_memory_into_buf(ctx, key_ptr, &mut key)?; let value = Some(read_sandbox_memory(ctx, value_ptr, value_len)?); ctx.ext.set_storage(key, value); Ok(()) }, // Clear the value at the given key in the contract storage. // // # Parameters // // - `key_ptr`: pointer into the linear memory where the location to clear the value is placed. seal_clear_storage(ctx, key_ptr: u32) => { let mut key: StorageKey = [0; 32]; read_sandbox_memory_into_buf(ctx, key_ptr, &mut key)?; ctx.ext.set_storage(key, None); Ok(()) }, // Retrieve the value under the given key from storage. // // # Parameters // // - `key_ptr`: pointer into the linear memory where the key of the requested value is placed. // - `out_ptr`: pointer to the linear memory where the value is written to. // - `out_len_ptr`: in-out pointer into linear memory where the buffer length // is read from and the value length is written to. // // # Errors // // `ReturnCode::KeyNotFound` seal_get_storage(ctx, key_ptr: u32, out_ptr: u32, out_len_ptr: u32) -> ReturnCode => { let mut key: StorageKey = [0; 32]; read_sandbox_memory_into_buf(ctx, key_ptr, &mut key)?; if let Some(value) = ctx.ext.get_storage(&key) { write_sandbox_output(ctx, out_ptr, out_len_ptr, &value, false)?; Ok(ReturnCode::Success) } else { Ok(ReturnCode::KeyNotFound) } }, // Transfer some value to another account. // // # Parameters // // - account_ptr: a pointer to the address of the beneficiary account // Should be decodable as an `T::AccountId`. Traps otherwise. // - account_len: length of the address buffer. // - value_ptr: a pointer to the buffer with value, how much value to send. // Should be decodable as a `T::Balance`. Traps otherwise. // - value_len: length of the value buffer. // // # Errors // // `ReturnCode::BelowSubsistenceThreshold` // `ReturnCode::TransferFailed` seal_transfer( ctx, account_ptr: u32, account_len: u32, value_ptr: u32, value_len: u32 ) -> ReturnCode => { let callee: <<E as Ext>::T as frame_system::Trait>::AccountId = read_sandbox_memory_as(ctx, account_ptr, account_len)?; let value: BalanceOf<<E as Ext>::T> = read_sandbox_memory_as(ctx, value_ptr, value_len)?; let result = ctx.ext.transfer(&callee, value, ctx.gas_meter); map_dispatch_result(ctx, result) }, // Make a call to another contract. // // The callees output buffer is copied to `output_ptr` and its length to `output_len_ptr`. // The copy of the output buffer can be skipped by supplying the sentinel value // of `u32::max_value()` to `output_ptr`. // // # Parameters // // - callee_ptr: a pointer to the address of the callee contract. // Should be decodable as an `T::AccountId`. Traps otherwise. // - callee_len: length of the address buffer. // - gas: how much gas to devote to the execution. // - value_ptr: a pointer to the buffer with value, how much value to send. // Should be decodable as a `T::Balance`. Traps otherwise. // - value_len: length of the value buffer. // - input_data_ptr: a pointer to a buffer to be used as input data to the callee. // - input_data_len: length of the input data buffer. // - output_ptr: a pointer where the output buffer is copied to. // - output_len_ptr: in-out pointer to where the length of the buffer is read from // and the actual length is written to. // // # Errors // // An error means that the call wasn't successful output buffer is returned unless // stated otherwise. // // `ReturnCode::CalleeReverted`: Output buffer is returned. // `ReturnCode::CalleeTrapped` // `ReturnCode::BelowSubsistenceThreshold` // `ReturnCode::TransferFailed` // `ReturnCode::NotCallable` seal_call( ctx, callee_ptr: u32, callee_len: u32, gas: u64, value_ptr: u32, value_len: u32, input_data_ptr: u32, input_data_len: u32, output_ptr: u32, output_len_ptr: u32 ) -> ReturnCode => { let callee: <<E as Ext>::T as frame_system::Trait>::AccountId = read_sandbox_memory_as(ctx, callee_ptr, callee_len)?; let value: BalanceOf<<E as Ext>::T> = read_sandbox_memory_as(ctx, value_ptr, value_len)?; let input_data = read_sandbox_memory(ctx, input_data_ptr, input_data_len)?; let nested_gas_limit = if gas == 0 { ctx.gas_meter.gas_left() } else { gas.saturated_into() }; let ext = &mut ctx.ext; let call_outcome = ctx.gas_meter.with_nested(nested_gas_limit, |nested_meter| { match nested_meter { Some(nested_meter) => { ext.call( &callee, value, nested_meter, input_data, ) } // there is not enough gas to allocate for the nested call. None => Err(Error::<<E as Ext>::T>::OutOfGas.into()), } }); if let Ok(output) = &call_outcome { write_sandbox_output(ctx, output_ptr, output_len_ptr, &output.data, true)?; } map_exec_result(ctx, call_outcome) }, // Instantiate a contract with the specified code hash. // // This function creates an account and executes the constructor defined in the code specified // by the code hash. The address of this new account is copied to `address_ptr` and its length // to `address_len_ptr`. The constructors output buffer is copied to `output_ptr` and its // length to `output_len_ptr`. The copy of the output buffer and address can be skipped by // supplying the sentinel value of `u32::max_value()` to `output_ptr` or `address_ptr`. // // After running the constructor it is verfied that the contract account holds at // least the subsistence threshold. If that is not the case the instantion fails and // the contract is not created. // // # Parameters // // - code_hash_ptr: a pointer to the buffer that contains the initializer code. // - code_hash_len: length of the initializer code buffer. // - gas: how much gas to devote to the execution of the initializer code. // - value_ptr: a pointer to the buffer with value, how much value to send. // Should be decodable as a `T::Balance`. Traps otherwise. // - value_len: length of the value buffer. // - input_data_ptr: a pointer to a buffer to be used as input data to the initializer code. // - input_data_len: length of the input data buffer. // - address_ptr: a pointer where the new account's address is copied to. // - address_len_ptr: in-out pointer to where the length of the buffer is read from // and the actual length is written to. // - output_ptr: a pointer where the output buffer is copied to. // - output_len_ptr: in-out pointer to where the length of the buffer is read from // and the actual length is written to. // // # Errors // // Please consult the `ReturnCode` enum declaration for more information on those // errors. Here we only note things specific to this function. // // An error means that the account wasn't created and no address or output buffer // is returned unless stated otherwise. // // `ReturnCode::CalleeReverted`: Output buffer is returned. // `ReturnCode::CalleeTrapped` // `ReturnCode::BelowSubsistenceThreshold` // `ReturnCode::TransferFailed` // `ReturnCode::NewContractNotFunded` // `ReturnCode::CodeNotFound` seal_instantiate( ctx, code_hash_ptr: u32, code_hash_len: u32, gas: u64, value_ptr: u32, value_len: u32, input_data_ptr: u32, input_data_len: u32, address_ptr: u32, address_len_ptr: u32, output_ptr: u32, output_len_ptr: u32 ) -> ReturnCode => { let code_hash: CodeHash<<E as Ext>::T> = read_sandbox_memory_as(ctx, code_hash_ptr, code_hash_len)?; let value: BalanceOf<<E as Ext>::T> = read_sandbox_memory_as(ctx, value_ptr, value_len)?; let input_data = read_sandbox_memory(ctx, input_data_ptr, input_data_len)?; let nested_gas_limit = if gas == 0 { ctx.gas_meter.gas_left() } else { gas.saturated_into() }; let ext = &mut ctx.ext; let instantiate_outcome = ctx.gas_meter.with_nested(nested_gas_limit, |nested_meter| { match nested_meter { Some(nested_meter) => { ext.instantiate( &code_hash, value, nested_meter, input_data ) } // there is not enough gas to allocate for the nested call. None => Err(Error::<<E as Ext>::T>::OutOfGas.into()), } }); if let Ok((address, output)) = &instantiate_outcome { if !output.flags.contains(ReturnFlags::REVERT) { write_sandbox_output( ctx, address_ptr, address_len_ptr, &address.encode(), true )?; } write_sandbox_output(ctx, output_ptr, output_len_ptr, &output.data, true)?; } map_exec_result(ctx, instantiate_outcome.map(|(_id, retval)| retval)) }, // Remove the calling account and transfer remaining balance. // // This function never returns. Either the termination was successful and the // execution of the destroyed contract is halted. Or it failed during the termination // which is considered fatal and results in a trap + rollback. // // - beneficiary_ptr: a pointer to the address of the beneficiary account where all // where all remaining funds of the caller are transfered. // Should be decodable as an `T::AccountId`. Traps otherwise. // - beneficiary_len: length of the address buffer. // // # Traps // // - The contract is live i.e is already on the call stack. seal_terminate( ctx, beneficiary_ptr: u32, beneficiary_len: u32 ) => { let beneficiary: <<E as Ext>::T as frame_system::Trait>::AccountId = read_sandbox_memory_as(ctx, beneficiary_ptr, beneficiary_len)?; if let Ok(_) = ctx.ext.terminate(&beneficiary, ctx.gas_meter) { ctx.trap_reason = Some(TrapReason::Termination); } Err(sp_sandbox::HostError) }, seal_input(ctx, buf_ptr: u32, buf_len_ptr: u32) => { if let Some(input) = ctx.input_data.take() { write_sandbox_output(ctx, buf_ptr, buf_len_ptr, &input, false) } else { Err(sp_sandbox::HostError) } }, // Cease contract execution and save a data buffer as a result of the execution. // // This function never retuns as it stops execution of the caller. // This is the only way to return a data buffer to the caller. Returning from // execution without calling this function is equivalent to calling: // ``` // seal_return(0, 0, 0); // ``` // // The flags argument is a bitfield that can be used to signal special return // conditions to the supervisor: // --- lsb --- // bit 0 : REVERT - Revert all storage changes made by the caller. // bit [1, 31]: Reserved for future use. // --- msb --- // // Using a reserved bit triggers a trap. seal_return(ctx, flags: u32, data_ptr: u32, data_len: u32) => { charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::ReturnData(data_len) )?; ctx.trap_reason = Some(TrapReason::Return(ReturnData { flags, data: read_sandbox_memory(ctx, data_ptr, data_len)?, })); // The trap mechanism is used to immediately terminate the execution. // This trap should be handled appropriately before returning the result // to the user of this crate. Err(sp_sandbox::HostError) }, // Stores the address of the caller into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // If this is a top-level call (i.e. initiated by an extrinsic) the origin address of the // extrinsic will be returned. Otherwise, if this call is initiated by another contract then the // address of the contract will be returned. The value is encoded as T::AccountId. seal_caller(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.caller().encode(), false) }, // Stores the address of the current contract into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. seal_address(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.address().encode(), false) }, // Stores the price for the specified amount of gas into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Balance. // // # Note // // It is recommended to avoid specifying very small values for `gas` as the prices for a single // gas can be smaller than one. seal_weight_to_fee(ctx, gas: u64, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output( ctx, out_ptr, out_len_ptr, &ctx.ext.get_weight_price(gas).encode(), false ) }, // Stores the amount of gas left into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as Gas. seal_gas_left(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.gas_meter.gas_left().encode(), false) }, // Stores the balance of the current account into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Balance. seal_balance(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.balance().encode(), false) }, // Stores the value transferred along with this call or as endowment into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Balance. seal_value_transferred(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output( ctx, out_ptr, out_len_ptr, &ctx.ext.value_transferred().encode(), false ) }, // Stores a random number for the current block and the given subject into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Hash. seal_random(ctx, subject_ptr: u32, subject_len: u32, out_ptr: u32, out_len_ptr: u32) => { // The length of a subject can't exceed `max_subject_len`. if subject_len > ctx.schedule.max_subject_len { return Err(sp_sandbox::HostError); } let subject_buf = read_sandbox_memory(ctx, subject_ptr, subject_len)?; write_sandbox_output( ctx, out_ptr, out_len_ptr, &ctx.ext.random(&subject_buf).encode(), false ) }, // Load the latest block timestamp into the supplied buffer // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. seal_now(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.now().encode(), false) }, // Stores the minimum balance (a.k.a. existential deposit) into the supplied buffer. // // The data is encoded as T::Balance. seal_minimum_balance(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.minimum_balance().encode(), false) }, // Stores the tombstone deposit into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Balance. // // # Note // // The tombstone deposit is on top of the existential deposit. So in order for // a contract to leave a tombstone the balance of the contract must not go // below the sum of existential deposit and the tombstone deposit. The sum // is commonly referred as subsistence threshold in code. seal_tombstone_deposit(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output( ctx, out_ptr, out_len_ptr, &ctx.ext.tombstone_deposit().encode(), false ) }, // Try to restore the given destination contract sacrificing the caller. // // This function will compute a tombstone hash from the caller's storage and the given code hash // and if the hash matches the hash found in the tombstone at the specified address - kill // the caller contract and restore the destination contract and set the specified `rent_allowance`. // All caller's funds are transfered to the destination. // // If there is no tombstone at the destination address, the hashes don't match or this contract // instance is already present on the contract call stack, a trap is generated. // // Otherwise, the destination contract is restored. This function is diverging and stops execution // even on success. // // `dest_ptr`, `dest_len` - the pointer and the length of a buffer that encodes `T::AccountId` // with the address of the to be restored contract. // `code_hash_ptr`, `code_hash_len` - the pointer and the length of a buffer that encodes // a code hash of the to be restored contract. // `rent_allowance_ptr`, `rent_allowance_len` - the pointer and the length of a buffer that // encodes the rent allowance that must be set in the case of successful restoration. // `delta_ptr` is the pointer to the start of a buffer that has `delta_count` storage keys // laid out sequentially. // // # Traps // // - Tombstone hashes do not match // - Calling cantract is live i.e is already on the call stack. seal_restore_to( ctx, dest_ptr: u32, dest_len: u32, code_hash_ptr: u32, code_hash_len: u32, rent_allowance_ptr: u32, rent_allowance_len: u32, delta_ptr: u32, delta_count: u32 ) => { let dest: <<E as Ext>::T as frame_system::Trait>::AccountId = read_sandbox_memory_as(ctx, dest_ptr, dest_len)?; let code_hash: CodeHash<<E as Ext>::T> = read_sandbox_memory_as(ctx, code_hash_ptr, code_hash_len)?; let rent_allowance: BalanceOf<<E as Ext>::T> = read_sandbox_memory_as(ctx, rent_allowance_ptr, rent_allowance_len)?; let delta = { // We don't use `with_capacity` here to not eagerly allocate the user specified amount // of memory. let mut delta = Vec::new(); let mut key_ptr = delta_ptr; for _ in 0..delta_count { const KEY_SIZE: usize = 32; // Read the delta into the provided buffer and collect it into the buffer. let mut delta_key: StorageKey = [0; KEY_SIZE]; read_sandbox_memory_into_buf(ctx, key_ptr, &mut delta_key)?; delta.push(delta_key); // Offset key_ptr to the next element. key_ptr = key_ptr.checked_add(KEY_SIZE as u32).ok_or_else(|| sp_sandbox::HostError)?; } delta }; if let Ok(()) = ctx.ext.restore_to( dest, code_hash, rent_allowance, delta, ) { ctx.trap_reason = Some(TrapReason::Restoration); } Err(sp_sandbox::HostError) }, // Deposit a contract event with the data buffer and optional list of topics. There is a limit // on the maximum number of topics specified by `max_event_topics`. // // - topics_ptr - a pointer to the buffer of topics encoded as `Vec<T::Hash>`. The value of this // is ignored if `topics_len` is set to 0. The topics list can't contain duplicates. // - topics_len - the length of the topics buffer. Pass 0 if you want to pass an empty vector. // - data_ptr - a pointer to a raw data buffer which will saved along the event. // - data_len - the length of the data buffer. seal_deposit_event(ctx, topics_ptr: u32, topics_len: u32, data_ptr: u32, data_len: u32) => { let mut topics: Vec::<TopicOf<<E as Ext>::T>> = match topics_len { 0 => Vec::new(), _ => read_sandbox_memory_as(ctx, topics_ptr, topics_len)?, }; // If there are more than `max_event_topics`, then trap. if topics.len() > ctx.schedule.max_event_topics as usize { return Err(sp_sandbox::HostError); } // Check for duplicate topics. If there are any, then trap. if has_duplicates(&mut topics) { return Err(sp_sandbox::HostError); } let event_data = read_sandbox_memory(ctx, data_ptr, data_len)?; charge_gas( ctx.gas_meter, ctx.schedule, &mut ctx.trap_reason, RuntimeToken::DepositEvent(topics.len() as u32, data_len) )?; ctx.ext.deposit_event(topics, event_data); Ok(()) }, // Set rent allowance of the contract // // - value_ptr: a pointer to the buffer with value, how much to allow for rent // Should be decodable as a `T::Balance`. Traps otherwise. // - value_len: length of the value buffer. seal_set_rent_allowance(ctx, value_ptr: u32, value_len: u32) => { let value: BalanceOf<<E as Ext>::T> = read_sandbox_memory_as(ctx, value_ptr, value_len)?; ctx.ext.set_rent_allowance(value); Ok(()) }, // Stores the rent allowance into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. // // The data is encoded as T::Balance. seal_rent_allowance(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.rent_allowance().encode(), false) }, // Prints utf8 encoded string from the data buffer. // Only available on `--dev` chains. // This function may be removed at any time, superseded by a more general contract debugging feature. seal_println(ctx, str_ptr: u32, str_len: u32) => { let data = read_sandbox_memory(ctx, str_ptr, str_len)?; if let Ok(utf8) = core::str::from_utf8(&data) { sp_runtime::print(utf8); } Ok(()) }, // Stores the current block number of the current contract into the supplied buffer. // // The value is stored to linear memory at the address pointed to by `out_ptr`. // `out_len_ptr` must point to a u32 value that describes the available space at // `out_ptr`. This call overwrites it with the size of the value. If the available // space at `out_ptr` is less than the size of the value a trap is triggered. seal_block_number(ctx, out_ptr: u32, out_len_ptr: u32) => { write_sandbox_output(ctx, out_ptr, out_len_ptr, &ctx.ext.block_number().encode(), false) }, // Computes the SHA2 256-bit hash on the given input buffer. // // Returns the result directly into the given output buffer. // // # Note // // - The `input` and `output` buffer may overlap. // - The output buffer is expected to hold at least 32 bytes (256 bits). // - It is the callers responsibility to provide an output buffer that // is large enough to hold the expected amount of bytes returned by the // chosen hash function. // // # Parameters // // - `input_ptr`: the pointer into the linear memory where the input // data is placed. // - `input_len`: the length of the input data in bytes. // - `output_ptr`: the pointer into the linear memory where the output // data is placed. The function will write the result // directly into this buffer. seal_hash_sha2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => { compute_hash_on_intermediate_buffer(ctx, sha2_256, input_ptr, input_len, output_ptr) }, // Computes the KECCAK 256-bit hash on the given input buffer. // // Returns the result directly into the given output buffer. // // # Note // // - The `input` and `output` buffer may overlap. // - The output buffer is expected to hold at least 32 bytes (256 bits). // - It is the callers responsibility to provide an output buffer that // is large enough to hold the expected amount of bytes returned by the // chosen hash function. // // # Parameters // // - `input_ptr`: the pointer into the linear memory where the input // data is placed. // - `input_len`: the length of the input data in bytes. // - `output_ptr`: the pointer into the linear memory where the output // data is placed. The function will write the result // directly into this buffer. seal_hash_keccak_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => { compute_hash_on_intermediate_buffer(ctx, keccak_256, input_ptr, input_len, output_ptr) }, // Computes the BLAKE2 256-bit hash on the given input buffer. // // Returns the result directly into the given output buffer. // // # Note // // - The `input` and `output` buffer may overlap. // - The output buffer is expected to hold at least 32 bytes (256 bits). // - It is the callers responsibility to provide an output buffer that // is large enough to hold the expected amount of bytes returned by the // chosen hash function. // // # Parameters // // - `input_ptr`: the pointer into the linear memory where the input // data is placed. // - `input_len`: the length of the input data in bytes. // - `output_ptr`: the pointer into the linear memory where the output // data is placed. The function will write the result // directly into this buffer. seal_hash_blake2_256(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => { compute_hash_on_intermediate_buffer(ctx, blake2_256, input_ptr, input_len, output_ptr) }, // Computes the BLAKE2 128-bit hash on the given input buffer. // // Returns the result directly into the given output buffer. // // # Note // // - The `input` and `output` buffer may overlap. // - The output buffer is expected to hold at least 16 bytes (128 bits). // - It is the callers responsibility to provide an output buffer that // is large enough to hold the expected amount of bytes returned by the // chosen hash function. // // # Parameters // // - `input_ptr`: the pointer into the linear memory where the input // data is placed. // - `input_len`: the length of the input data in bytes. // - `output_ptr`: the pointer into the linear memory where the output // data is placed. The function will write the result // directly into this buffer. seal_hash_blake2_128(ctx, input_ptr: u32, input_len: u32, output_ptr: u32) => { compute_hash_on_intermediate_buffer(ctx, blake2_128, input_ptr, input_len, output_ptr) }, ); /// Computes the given hash function on the supplied input. /// /// Reads from the sandboxed input buffer into an intermediate buffer. /// Returns the result directly to the output buffer of the sandboxed memory. /// /// It is the callers responsibility to provide an output buffer that /// is large enough to hold the expected amount of bytes returned by the /// chosen hash function. /// /// # Note /// /// The `input` and `output` buffers may overlap. fn compute_hash_on_intermediate_buffer<E, F, R>( ctx: &mut Runtime<E>, hash_fn: F, input_ptr: u32, input_len: u32, output_ptr: u32, ) -> Result<(), sp_sandbox::HostError> where E: Ext, F: FnOnce(&[u8]) -> R, R: AsRef<[u8]>, { // Copy input into supervisor memory. let input = read_sandbox_memory(ctx, input_ptr, input_len)?; // Compute the hash on the input buffer using the given hash function. let hash = hash_fn(&input); // Write the resulting hash back into the sandboxed output buffer. write_sandbox_memory( ctx, output_ptr, hash.as_ref(), )?; Ok(()) } /// Finds duplicates in a given vector. /// /// This function has complexity of O(n log n) and no additional memory is required, although /// the order of items is not preserved. fn has_duplicates<T: PartialEq + AsRef<[u8]>>(items: &mut Vec<T>) -> bool { // Sort the vector items.sort_by(|a, b| { Ord::cmp(a.as_ref(), b.as_ref()) }); // And then find any two consecutive equal elements. items.windows(2).any(|w| { match w { &[ref a, ref b] => a == b, _ => false, } }) }