Element R: error message panicked at src/encryption.rs:118

[andybalaam]

Using Element R today I see this in the log:

panicked at src/encryption.rs:118:18:
internal error: entered unreachable code: Unknown variant

Stack:

1391/</module.exports.__wbg_new_abda76e883ba8a5f@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js:7169:17
@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js line 7924 > WebAssembly.instantiate:wasm-function[10344]:0x3b0c4a
@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js line 7924 > WebAssembly.instantiate:wasm-function[1849]:0x26338c
@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js line 7924 > WebAssembly.instantiate:wasm-function[5745]:0x32e2db
@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js line 7924 > WebAssembly.instantiate:wasm-function[4244]:0x2fc1be
@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js line 7924 > WebAssembly.instantiate:wasm-function[4085]:0x2f57eb
get algorithms@https://develop.element.io/bundles/79181f06fa91b4cfd025/37.js:1608:26
rustDeviceToJsDevice@https://develop.element.io/bundles/79181f06fa91b4cfd025/34.js:2147:26
1540/</getUserDevices/<@https://develop.element.io/bundles/79181f06fa91b4cfd025/34.js:573:166
getUserDevices@https://develop.element.io/bundles/79181f06fa91b4cfd025/34.js:573:36

and just before that:

Uncaught (in promise) Error: recursive use of an object detected which would lead to unsafe aliasing in rust
    __wbindgen_throw matrix_sdk_crypto_wasm.js:7830
    free matrix_sdk_crypto_wasm.js:1436
    getUserDevices rust-crypto.ts:515
    getUserDevices rust-crypto.ts:515
    getUserDeviceInfo rust-crypto.ts:471
    shieldStatusForRoom ShieldUtils.ts:59
    updateE2EStatus RoomView.tsx:1525
    RoomView_RoomView RoomView.tsx:1506
    emit events.js:158
    emit typed-event-emitter.ts:89
    forSource ReEmitter.ts:55
    emit events.js:153
    emit typed-event-emitter.ts:89
    onUserIdentityUpdated rust-crypto.ts:1391
    initRustCrypto index.ts:75
    __wbg_call_9495de66fdbe016b matrix_sdk_crypto_wasm.js:7611
    handleError matrix_sdk_crypto_wasm.js:328
    __wbg_call_9495de66fdbe016b matrix_sdk_crypto_wasm.js:7610
    __wbg_adapter_59 matrix_sdk_crypto_wasm.js:274
    real matrix_sdk_crypto_wasm.js:216
    promise callback*1391/</module.exports.__wbg_then_ec5db6d509eb475f matrix_sdk_crypto_wasm.js:7716
    __wbg_adapter_59 matrix_sdk_crypto_wasm.js:274
    real matrix_sdk_crypto_wasm.js:216
    promise callback*1391/</module.exports.__wbg_then_ec5db6d509eb475f matrix_sdk_crypto_wasm.js:7716
    __wbg_adapter_53 matrix_sdk_crypto_wasm.js:266
    real matrix_sdk_crypto_wasm.js:252
    __wbg_setonsuccess_925a7718d3f62bc1 matrix_sdk_crypto_wasm.js:7408

[richvdh]

The panic comes from this code:

impl From<matrix_sdk_crypto::types::EventEncryptionAlgorithm> for EncryptionAlgorithm {
    fn from(value: matrix_sdk_crypto::types::EventEncryptionAlgorithm) -> Self {
        use matrix_sdk_crypto::types::EventEncryptionAlgorithm::*;

        match value {
            OlmV1Curve25519AesSha2 => Self::OlmV1Curve25519AesSha2,
            MegolmV1AesSha2 => Self::MegolmV1AesSha2,
            _ => unreachable!("Unknown variant"),
        }
    }
}

... which rather suggests there is a device somewhere that claims to support an algorithm other than m.olm.v1.curve25519-aes-sha2 or m.megolm.v1.aes-sha2. That is of course legitimate and should not cause our application to panic.

The "recursive use of object" error is probably a separate problem

[uhoreg]

AFAICT, since TypeScript doesn't do enums the same way that Rust does, the only way to fix this is to pass around strings on the JS side instead of enums. Is that right?

(I suspect that this bug was triggered by someone trying the MLS POC on their account.)

[richvdh]

AFAICT, since TypeScript doesn't do enums the same way that Rust does, the only way to fix this is to pass around strings on the JS side instead of enums. Is that right?

I'm not sure it is. We could add an entry in matrix-sdk-crypto-wasm::encryption::EncryptionAlgorithm for "unrecognised"?

[uhoreg]

I'm not sure it is. We could add an entry in matrix-sdk-crypto-wasm::encryption::EncryptionAlgorithm for "unrecognised"?

I suppose. I guess the JavaScript doesn't care whether devices support algorithms that it doesn't know about.

[BillCarsonFr]

Waiting for a new bindings version

[uhoreg]

js-sdk depends on the version of the bindings that has this fixed