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Implement the batch verification host functions (#920)
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* Implement the batch verification host functions

* PR link

* Tweak debug assert

* Oops, the batch must be initialized
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@tomaka
tomaka committed Jul 16, 2023
1 parent 265d6e0 commit de93ea3
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Showing 2 changed files with 94 additions and 20 deletions.
113 changes: 93 additions & 20 deletions lib/src/executor/host.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -533,6 +533,7 @@ impl HostVmPrototype {
common: self.common,
vm,
storage_transaction_depth: 0,
signatures_batch_verification: None,
allocator,
}),
})
Expand Down Expand Up @@ -1372,7 +1373,20 @@ impl ReadyToRun {
HostFunction::ext_crypto_ed25519_public_keys_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ed25519_generate_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ed25519_sign_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ed25519_verify_version_1 => {
HostFunction::ext_crypto_ed25519_verify_version_1
| HostFunction::ext_crypto_ed25519_batch_verify_version_1 => {
let is_batch_verification = matches!(
host_fn,
HostFunction::ext_crypto_ed25519_batch_verify_version_1
);

if is_batch_verification && self.inner.signatures_batch_verification.is_none() {
return HostVm::Error {
error: Error::BatchVerifyWithoutStarting,
prototype: self.inner.into_prototype(),
};
}

let (message_ptr, message_size) = expect_pointer_size_raw!(1);
HostVm::SignatureVerification(SignatureVerification {
algorithm: SignatureVerificationAlgorithm::Ed25519,
Expand All @@ -1381,13 +1395,26 @@ impl ReadyToRun {
message_ptr,
message_size,
inner: self.inner,
is_batch_verification,
})
}
HostFunction::ext_crypto_ed25519_batch_verify_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_sr25519_public_keys_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_sr25519_generate_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_sr25519_sign_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_sr25519_verify_version_1 => {
HostFunction::ext_crypto_sr25519_verify_version_1
| HostFunction::ext_crypto_sr25519_batch_verify_version_1 => {
let is_batch_verification = matches!(
host_fn,
HostFunction::ext_crypto_sr25519_batch_verify_version_1
);

if is_batch_verification && self.inner.signatures_batch_verification.is_none() {
return HostVm::Error {
error: Error::BatchVerifyWithoutStarting,
prototype: self.inner.into_prototype(),
};
}

let (message_ptr, message_size) = expect_pointer_size_raw!(1);
HostVm::SignatureVerification(SignatureVerification {
algorithm: SignatureVerificationAlgorithm::Sr25519V1,
Expand All @@ -1396,6 +1423,7 @@ impl ReadyToRun {
message_ptr,
message_size,
inner: self.inner,
is_batch_verification,
})
}
HostFunction::ext_crypto_sr25519_verify_version_2 => {
Expand All @@ -1407,9 +1435,9 @@ impl ReadyToRun {
message_ptr,
message_size,
inner: self.inner,
is_batch_verification: false,
})
}
HostFunction::ext_crypto_sr25519_batch_verify_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ecdsa_generate_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ecdsa_sign_version_1 => {
// NOTE: safe to unwrap here because we supply the nn to blake2b fn
Expand Down Expand Up @@ -1438,7 +1466,20 @@ impl ReadyToRun {
}
}
HostFunction::ext_crypto_ecdsa_public_keys_version_1 => host_fn_not_implemented!(),
HostFunction::ext_crypto_ecdsa_verify_version_1 => {
HostFunction::ext_crypto_ecdsa_verify_version_1
| HostFunction::ext_crypto_ecdsa_batch_verify_version_1 => {
let is_batch_verification = matches!(
host_fn,
HostFunction::ext_crypto_ecdsa_batch_verify_version_1
);

if is_batch_verification && self.inner.signatures_batch_verification.is_none() {
return HostVm::Error {
error: Error::BatchVerifyWithoutStarting,
prototype: self.inner.into_prototype(),
};
}

let (message_ptr, message_size) = expect_pointer_size_raw!(1);
HostVm::SignatureVerification(SignatureVerification {
algorithm: SignatureVerificationAlgorithm::Ecdsa,
Expand All @@ -1447,6 +1488,7 @@ impl ReadyToRun {
message_ptr,
message_size,
inner: self.inner,
is_batch_verification,
})
}
HostFunction::ext_crypto_ecdsa_verify_version_2 => host_fn_not_implemented!(),
Expand Down Expand Up @@ -1479,9 +1521,9 @@ impl ReadyToRun {
message_ptr: expect_pointer_constant_size_raw!(1, 32),
message_size: 32,
inner: self.inner,
is_batch_verification: false,
})
}
HostFunction::ext_crypto_ecdsa_batch_verify_version_1 => host_fn_not_implemented!(),

HostFunction::ext_crypto_secp256k1_ecdsa_recover_version_1
| HostFunction::ext_crypto_secp256k1_ecdsa_recover_version_2 => {
Expand Down Expand Up @@ -1582,26 +1624,31 @@ impl ReadyToRun {
.alloc_write_and_return_pointer_size(host_fn.name(), iter::once(&result))
}
HostFunction::ext_crypto_start_batch_verify_version_1 => {
if self.inner.signatures_batch_verification.is_some() {
return HostVm::Error {
error: Error::AlreadyBatchVerify,
prototype: self.inner.into_prototype(),
};
}

self.inner.signatures_batch_verification = Some(true);

HostVm::ReadyToRun(ReadyToRun {
resume_value: None,
inner: self.inner,
})
}
HostFunction::ext_crypto_finish_batch_verify_version_1 => {
// This function is a dummy implementation. After `ext_crypto_start_batch_verify`
// has been called, the runtime is supposed to call
// `ext_crypto_ed25519_batch_verify`, `ext_crypto_sr25519_batch_verify`, or
// `ext_crypto_ecdsa_batch_verify`, then retrieve the result using
// `ext_crypto_finish_batch_verify`. However, none of the three
// `<algo>_batch_verify` functions is supported by smoldot at the moment.
// Thus, if the runtime calls `ext_crypto_finish_batch_verify`, then it
// necessarily means that the batch is empty, and thus we always return success.
// At the moment, batch signatures verification isn't enabled on any production
// chain.
// Once support for any of the `<algo>_batch_verify` function is added, this
// implementation should of course change.
let Some(outcome) = self.inner.signatures_batch_verification.take()
else {
return HostVm::Error {
error: Error::NoBatchVerify,
prototype: self.inner.into_prototype(),
}
};

HostVm::ReadyToRun(ReadyToRun {
resume_value: Some(vm::WasmValue::I32(1)),
resume_value: Some(vm::WasmValue::I32(if outcome { 1 } else { 0 })),
inner: self.inner,
})
}
Expand Down Expand Up @@ -2760,6 +2807,8 @@ pub struct SignatureVerification {
message_ptr: u32,
/// Size of the message. Guaranteed to be in range.
message_size: u32,
/// `true` if the host function is a batch verification function.
is_batch_verification: bool,
}

enum SignatureVerificationAlgorithm {
Expand Down Expand Up @@ -2926,7 +2975,14 @@ impl SignatureVerification {
self.resume(false)
}

fn resume(self, success: bool) -> HostVm {
fn resume(mut self, success: bool) -> HostVm {
debug_assert!(
!self.is_batch_verification || self.inner.signatures_batch_verification.is_some()
);
if self.is_batch_verification && !success {
self.inner.signatures_batch_verification = Some(false);
}

// All signature-related host functions work the same way in terms of return value.
HostVm::ReadyToRun(ReadyToRun {
resume_value: Some(vm::WasmValue::I32(if success { 1 } else { 0 })),
Expand Down Expand Up @@ -3430,6 +3486,15 @@ struct Inner {
/// The depth of storage transaction started with `ext_storage_start_transaction_version_1`.
storage_transaction_depth: u32,

/// The host provides a "batch signature verification" mechanism, where the runtime can start
/// verifying multiple signatures at once. This mechanism is deprecated, but is emulated
/// through a simple field.
///
/// Contains `Some` if and only if the runtime is currently within a batch signatures
/// verification. If `Some`, contains `true` if all the signatures have been verified
/// successfully so far.
signatures_batch_verification: Option<bool>,

/// Memory allocator in order to answer the calls to `malloc` and `free`.
allocator: allocator::FreeingBumpHeapAllocator,

Expand Down Expand Up @@ -3746,6 +3811,14 @@ pub enum Error {
#[display(fmt = "Called `ext_default_child_storage_root_version_1` or
`ext_default_child_storage_root_version_2` on a child trie that doesn't exist.")]
ChildStorageRootTrieDoesntExist,
/// Runtime has tried to perform a signature batch verification before initiating a batch
/// verification.
BatchVerifyWithoutStarting,
/// Runtime has tried to initiate a batch signatures verification while there was already one
/// in progress.
AlreadyBatchVerify,
/// Runtime has tried to finish a batch signatures verification while none is in progress.
NoBatchVerify,
/// The host function isn't implemented.
// TODO: this variant should eventually disappear as all functions are implemented
#[display(fmt = "Host function not implemented: {function}")]
Expand Down
1 change: 1 addition & 0 deletions wasm-node/CHANGELOG.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
### Added

- Add support for the `ext_trie_keccak_256_root_version_1`, `ext_trie_keccak_256_root_version_2`, `ext_trie_keccak_256_ordered_root_version_1`, and `ext_trie_keccak_256_ordered_root_version_2` host functions. ([#906](https://github.com/smol-dot/smoldot/pull/906))
- Add support for the `ext_crypto_ed25519_batch_verify_version_1`, `ext_crypto_sr25519_batch_verify_version_1`, `ext_crypto_ecdsa_batch_verify_version_1`, `ext_crypto_start_batch_verify_version_1`, and `ext_crypto_finish_batch_verify_version_1` host functions. ([#920](https://github.com/smol-dot/smoldot/pull/920))

### Changed

Expand Down

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