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wiggle: copy guest strings from shared memory (#5475)

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* wiggle: copy guest strings from shared memory

Along the same lines as #5471, this change adds a new smart pointer,
`GuestStrCow`, to copy the string bytes over from Wasm memory to the
host when the string is found in shared memory. This is necessary to
maintain Rust guarantees: with shared memory, the bytes backing a
`GuestStr` could be altered by another thread and this would invalidate
the assumption that we can dereference at any point to `&str`.
`GuestStrCow` is essentially a wrapper around `GuestStr` when the memory
is not shared but copies the memory region into a `String` when the
memory is shared.

This change updates the uses of Wiggle strings in both wasi-common and
wasi-crypto.

* review: perform UTF-8 check on `GuestStr` construction
This commit is contained in:
Andrew Brown
2023-01-04 08:10:00 -08:00
committed by GitHub
parent 52ba72f341
commit 7c67378ab6
6 changed files with 96 additions and 54 deletions
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10
crates/wasi-crypto/src/wiggle_interfaces/asymmetric_common.rs
View File

@@ -17,7 +17,7 @@ impl super::wasi_ephemeral_crypto_asymmetric_common::WasiEphemeralCryptoAsymmetr
alg_str: &wiggle::GuestPtr<'_, str>,
options_handle: &guest_types::OptOptions,
) -> Result<guest_types::Keypair, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let options_handle = match *options_handle {
guest_types::OptOptions::Some(options_handle) => Some(options_handle),
guest_types::OptOptions::None => None,
@@ -89,7 +89,7 @@ impl super::wasi_ephemeral_crypto_asymmetric_common::WasiEphemeralCryptoAsymmetr
alg_str: &wiggle::GuestPtr<'_, str>,
options_handle: &guest_types::OptOptions,
) -> Result<guest_types::Keypair, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let options_handle = match *options_handle {
guest_types::OptOptions::Some(options_handle) => Some(options_handle),
guest_types::OptOptions::None => None,
@@ -107,7 +107,7 @@ impl super::wasi_ephemeral_crypto_asymmetric_common::WasiEphemeralCryptoAsymmetr
encoded_len: guest_types::Size,
encoding: guest_types::KeypairEncoding,
) -> Result<guest_types::Keypair, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let encoded = &*encoded_ptr
.as_array(encoded_len)
.as_slice()?
@@ -167,7 +167,7 @@ impl super::wasi_ephemeral_crypto_asymmetric_common::WasiEphemeralCryptoAsymmetr
encoded_len: guest_types::Size,
encoding: guest_types::PublickeyEncoding,
) -> Result<guest_types::Publickey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let encoded = &*encoded_ptr
.as_array(encoded_len)
.as_slice()?
@@ -218,7 +218,7 @@ impl super::wasi_ephemeral_crypto_asymmetric_common::WasiEphemeralCryptoAsymmetr
encoded_len: guest_types::Size,
encoding: guest_types::SecretkeyEncoding,
) -> Result<guest_types::Secretkey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let encoded = &*encoded_ptr
.as_array(encoded_len)
.as_slice()?

6
crates/wasi-crypto/src/wiggle_interfaces/common.rs
View File

@@ -27,7 +27,7 @@ impl super::wasi_ephemeral_crypto_common::WasiEphemeralCryptoCommon for WasiCryp
value_ptr: &wiggle::GuestPtr<'_, u8>,
value_len: guest_types::Size,
) -> Result<(), guest_types::CryptoErrno> {
let name_str: &str = &*name_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let name_str: &str = &*name_str.as_cow()?;
let value: &[u8] = {
&*value_ptr
.as_array(value_len)
@@ -44,7 +44,7 @@ impl super::wasi_ephemeral_crypto_common::WasiEphemeralCryptoCommon for WasiCryp
buffer_ptr: &wiggle::GuestPtr<'_, u8>,
buffer_len: guest_types::Size,
) -> Result<(), guest_types::CryptoErrno> {
let name_str: &str = &*name_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let name_str: &str = &*name_str.as_cow()?;
let buffer: &'static mut [u8] = unsafe {
std::mem::transmute(
&mut *buffer_ptr
@@ -62,7 +62,7 @@ impl super::wasi_ephemeral_crypto_common::WasiEphemeralCryptoCommon for WasiCryp
name_str: &wiggle::GuestPtr<'_, str>,
value: u64,
) -> Result<(), guest_types::CryptoErrno> {
let name_str: &str = &*name_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let name_str: &str = &*name_str.as_cow()?;
Ok((&*self).options_set_u64(options_handle.into(), name_str, value)?)
}

2
crates/wasi-crypto/src/wiggle_interfaces/signatures.rs
View File

@@ -22,7 +22,7 @@ impl super::wasi_ephemeral_crypto_signatures::WasiEphemeralCryptoSignatures for
encoded_len: guest_types::Size,
encoding: guest_types::SignatureEncoding,
) -> Result<guest_types::Signature, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let encoded = &*encoded_ptr
.as_array(encoded_len)
.as_slice()?

14
crates/wasi-crypto/src/wiggle_interfaces/symmetric.rs
View File

@@ -12,7 +12,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
alg_str: &wiggle::GuestPtr<'_, str>,
options_handle: &guest_types::OptOptions,
) -> Result<guest_types::SymmetricKey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let options_handle = match *options_handle {
guest_types::OptOptions::Some(options_handle) => Some(options_handle),
guest_types::OptOptions::None => None,
@@ -86,7 +86,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
alg_str: &wiggle::GuestPtr<'_, str>,
options_handle: &guest_types::OptOptions,
) -> Result<guest_types::SymmetricKey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let options_handle = match *options_handle {
guest_types::OptOptions::Some(options_handle) => Some(options_handle),
guest_types::OptOptions::None => None,
@@ -102,7 +102,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
raw_ptr: &wiggle::GuestPtr<'_, u8>,
raw_len: guest_types::Size,
) -> Result<guest_types::SymmetricKey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let raw = &*raw_ptr
.as_array(raw_len)
.as_slice()?
@@ -153,7 +153,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
key_handle: &guest_types::OptSymmetricKey,
options_handle: &guest_types::OptOptions,
) -> Result<guest_types::SymmetricState, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
let key_handle = match *key_handle {
guest_types::OptSymmetricKey::Some(key_handle) => Some(key_handle),
guest_types::OptSymmetricKey::None => None,
@@ -178,7 +178,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
value_ptr: &wiggle::GuestPtr<'_, u8>,
value_max_len: guest_types::Size,
) -> Result<guest_types::Size, guest_types::CryptoErrno> {
let name_str: &str = &*name_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let name_str: &str = &*name_str.as_cow()?;
let value = &mut *value_ptr
.as_array(value_max_len)
.as_slice_mut()?
@@ -193,7 +193,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
symmetric_state_handle: guest_types::SymmetricState,
name_str: &wiggle::GuestPtr<'_, str>,
) -> Result<u64, guest_types::CryptoErrno> {
let name_str: &str = &*name_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let name_str: &str = &*name_str.as_cow()?;
Ok((&*self).options_get_u64(symmetric_state_handle.into(), name_str)?)
}
@@ -244,7 +244,7 @@ impl super::wasi_ephemeral_crypto_symmetric::WasiEphemeralCryptoSymmetric for Wa
symmetric_state_handle: guest_types::SymmetricState,
alg_str: &wiggle::GuestPtr<'_, str>,
) -> Result<guest_types::SymmetricKey, guest_types::CryptoErrno> {
let alg_str = &*alg_str.as_str()?.expect("cannot use with shared memories; see https://github.com/bytecodealliance/wasmtime/issues/5235 (TODO)");
let alg_str = &*alg_str.as_cow()?;
Ok((&*self)
.symmetric_state_squeeze_key(symmetric_state_handle.into(), alg_str)?
.into())