fix: sign and export with each address's own derivation index (closes #510)

Sending, site transactions, site signatures and private key export
derived the key at the address's position in the wallet's list. After
an import whose scan passed over an unused index, or after removing an
address that was not the last, that position named another address's
key.

Each HD and xprv address record now stores the index it was derived at
(at wallet creation, by the import scan, by "+"), and
getSignerForAddress() derives at that index and refuses any key whose
address differs from the record's. The export screen reports that
refusal instead of calling the password wrong.

Model: opus-5-5

README.md

@@ -2170,13 +2170,6 @@ view would leave a wallet one click from deletion.
     - Typed data that states no primary type, or one other than the type it
       would be signed as, or that cannot be read → shown with the error line
       saying so and "Sign" disabled; only "Reject" remains
-    - Typed data whose domain `chainId` names a chain other than the active
-      network's → shown with the error line naming both chain ids and "Sign"
-      disabled; only "Reject" remains. EIP-712 asks for this, because the
-      signature is valid on the chain the domain names. Typed data with no
-      `chainId` is not refused. The background refuses such a signature too,
-      against the network active when the signature reaches it, and answers the
-      site with the same sentence
     - A `personal_sign` or `eth_sign` message that is not hex (`0x` or `0X` and
       an even number of hex digits, the form ethers' `getBytes` reads when
       signing) → shown as plain text, with the error line "This message is plain

src/background/index.js

@@ -22,7 +22,6 @@ const { debugFetch, log } = require("../shared/log");
 const {
     verifySignedTx,
     verifySignature,
-    typedDataChainRefusal,
     failureIsRetryable,
     describeTxFailure,
     sameAddress,
@@ -1765,8 +1764,7 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
 
         (async () => {
             try {
-                const s = await getState();
-                const activeAddress = activeAddressOf(s);
+                const activeAddress = await getActiveAddress();
                 // Same as the transaction path: the address the approval named
                 // is the one that must have signed, and a switch since then is
                 // a refusal rather than a signature from another account.
@@ -1785,20 +1783,6 @@ runtime.onMessage.addListener((msg, sender, sendResponse) => {
                     signature,
                     approval.approvedFrom,
                 );
-                // The sign screen refuses typed data whose domain names
-                // another chain. A signature for it that arrives anyway is
-                // refused here, against the network active now.
-                const sp = approval.signParams;
-                if (
-                    sp.method === "eth_signTypedData_v4" ||
-                    sp.method === "eth_signTypedData"
-                ) {
-                    const refusal = typedDataChainRefusal(
-                        JSON.parse(sp.typedData).domain,
-                        networkById(s.networkId),
-                    );
-                    if (refusal) throw new ApprovalMismatchError(refusal);
-                }
                 settleApproval(msg.id, { signature }, { holdsClaim: true });
                 sendResponse({ signature });
             } catch (e) {

src/popup/views/approval.js

@@ -12,7 +12,7 @@ const {
     formatFee,
     tokenLabel,
 } = require("./helpers");
-const { state, saveState, currentNetwork } = require("../../shared/state");
+const { state, saveState } = require("../../shared/state");
 const {
     networkById,
     networkByChainId,
@@ -46,10 +46,7 @@ const {
 const { decryptWithPassword } = require("../../shared/vault");
 const { getSignerForAddress } = require("../../shared/wallet");
 const { walletDefect } = require("../../shared/walletDefects");
-const {
-    describeSigningFailure,
-    typedDataChainRefusal,
-} = require("../../shared/approvalVerify");
+const { describeSigningFailure } = require("../../shared/approvalVerify");
 const txStatus = require("./txStatus");
 const uniswap = require("../../shared/uniswap");
 const { notify, runtimeApi, sendMessage } = require("../../shared/browserApi");
@@ -446,8 +443,7 @@ function signedPrimaryType(types) {
 // Why a signature request cannot be signed, as a sentence for the error line,
 // or null when it can. Only typed data is refused: the `primaryType` the page
 // states has to be the type ethers will sign, or this screen would name one
-// message while another is signed. Its domain may name no chain but the active
-// network's.
+// message while another is signed.
 function typedDataRefusal(sp) {
     if (sp.method === "personal_sign" || sp.method === "eth_sign") return null;
     let data;
@@ -470,7 +466,7 @@ function typedDataRefusal(sp) {
             ", so it cannot be signed."
         );
     }
-    return typedDataChainRefusal(data.domain, currentNetwork());
+    return null;
 }
 
 // The largest amount a Permit2 allowance can hold, a uint160. Permit2 treats

src/shared/approvalVerify.js

@@ -53,7 +53,6 @@ const {
     accessListify,
     formatEther,
     getAddress,
-    getBigInt,
     getBytes,
     toQuantity,
     verifyMessage,
@@ -636,33 +635,6 @@ function verifySignature(signParams, signature, expectedFrom) {
     return recovered;
 }
 
-// Why typed data cannot be signed while `network` is the active network, as a
-// sentence, or null when it can. EIP-712 has a wallet refuse typed data whose
-// domain names another chain, because the signature is valid on that chain.
-// ethers signs no chain id when the domain's is null or absent, and reads any
-// other with getBigInt(), so 1, "1" and "0x1" are the same chain here too.
-function typedDataChainRefusal(domain, network) {
-    const chainId = domain?.chainId;
-    if (chainId === undefined || chainId === null) return null;
-    let named;
-    try {
-        named = getBigInt(chainId);
-    } catch {
-        return "This typed data cannot be read, so it cannot be signed.";
-    }
-    const active = getBigInt(network.chainId);
-    if (named === active) return null;
-    return (
-        "This typed data is for chain id " +
-        named +
-        ", but the active network is " +
-        network.name +
-        " (chain id " +
-        active +
-        "), so it cannot be signed."
-    );
-}
-
 // The stage a transaction approval failed at. Which stage it is decides
 // whether the approval survives the failure.
 const TX_STAGE_SIGN = "sign";
@@ -824,7 +796,6 @@ function describeSigningFailure(response, fallbackMessage) {
 module.exports = {
     verifySignedTx,
     verifySignature,
-    typedDataChainRefusal,
     assertNoForbiddenFields,
     assertNothingUnchecked,
     assertCanonicalBytes,

tests/backgroundApproval.test.js

@@ -397,13 +397,7 @@ function loadBackground(options) {
                 rpcResult = r;
             },
         );
-        return {
-            id: () =>
-                new URL(created[created.length - 1].url).searchParams.get(
-                    "approval",
-                ),
-            result: () => rpcResult,
-        };
+        return { result: () => rpcResult };
     }
 
     // A dApp asking to connect. The origin defaults to one the persisted
@@ -1490,55 +1484,6 @@ describe("what the approval is verified against", () => {
         });
     });
 
-    // Typed data whose domain names another chain is refused on the sign
-    // screen; a signature for it that reaches the background anyway is not
-    // handed to the page (https://git.eeqj.de/sneak/AutistMask/issues/519).
-    // TYPED_DATA names mainnet.
-    async function answerTypedData(bg, pending) {
-        const { domain, types, message } = JSON.parse(TYPED_DATA);
-        delete types.EIP712Domain;
-        const signature = await signer.signTypedData(domain, types, message);
-        const answer = bg.send(
-            {
-                type: "AUTISTMASK_SIGN_RESPONSE",
-                id: pending.id(),
-                approved: true,
-                signature,
-            },
-            { url: bg.fromPopup.url },
-        );
-        await settle();
-        return { answer, signature };
-    }
-
-    test("typed data for the active chain is handed back signed", async () => {
-        const bg = loadBackground();
-        const pending = bg.requestTypedData();
-        await settle();
-
-        const { answer, signature } = await answerTypedData(bg, pending);
-
-        expect(answer.sendResponse).toHaveBeenCalledWith({ signature });
-        expect(pending.result()).toEqual({ result: signature });
-    });
-
-    test("typed data for another chain is refused, not handed back", async () => {
-        const bg = loadBackground();
-        bg.setNetwork(SEPOLIA);
-        const pending = bg.requestTypedData();
-        await settle();
-
-        const { answer } = await answerTypedData(bg, pending);
-
-        const refusal =
-            "This typed data is for chain id 1, but the active network is Sepolia Testnet (chain id 11155111), so it cannot be signed.";
-        expect(answer.sendResponse).toHaveBeenCalledWith({
-            error: refusal,
-            retryable: false,
-        });
-        expect(pending.result()).toEqual({ error: { message: refusal } });
-    });
-
     test("a sign request from another address raises no approval at all", async () => {
         const bg = loadBackground();
         const pending = bg.requestSign(other.address);

tests/typedDataPermit.test.js

@@ -240,7 +240,6 @@ function request(data) {
 beforeEach(() => {
     state.trackedTokens = [];
     state.wallets = [];
-    state.networkId = "mainnet";
 });
 
 describe("a token permission is warned about, naming spender and amount", () => {
@@ -533,66 +532,3 @@ describe("the sign screen refuses a mismatched primary type", () => {
         expect(node("btn-approve-sign").disabled).toBe(true);
     });
 });
-
-// EIP-712: a wallet refuses typed data whose domain names a chain other than
-// the active one, because the signature is valid on the chain it names
-// (https://git.eeqj.de/sneak/AutistMask/issues/519). The wallet is on Sepolia
-// and the site asks for a mainnet USDC Permit.
-describe("the sign screen refuses typed data for another chain", () => {
-    const REFUSAL =
-        "This typed data is for chain id 1, but the active network is Sepolia Testnet (chain id 11155111), so it cannot be signed.";
-
-    function withChainId(chainId) {
-        return { ...PERMIT, domain: { ...PERMIT.domain, chainId } };
-    }
-
-    beforeEach(() => {
-        decryptWithPassword.mockClear();
-        state.networkId = "sepolia";
-    });
-
-    test("another chain shows the error, with Sign disabled", async () => {
-        await openSignScreen(PERMIT);
-        expect(node("approve-sign-error").textContent).toBe(REFUSAL);
-        expect(node("btn-approve-sign").disabled).toBe(true);
-    });
-
-    test("Sign clicked anyway decrypts and signs nothing", async () => {
-        const sent = await openSignScreen(PERMIT);
-        node("approve-sign-password").value = "any password";
-        await click("btn-approve-sign");
-
-        expect(decryptWithPassword).not.toHaveBeenCalled();
-        expect(sent.map((msg) => msg.type)).not.toContain(
-            "AUTISTMASK_SIGN_RESPONSE",
-        );
-        expect(node("approve-sign-error").textContent).toBe(REFUSAL);
-    });
-
-    // ethers signs 1, "1" and "0x1" as the same chain id.
-    test("the chain id is refused in each form ethers signs", () => {
-        for (const chainId of [1, "1", "0x1"]) {
-            expect(typedDataRefusal(request(withChainId(chainId)))).toBe(
-                REFUSAL,
-            );
-        }
-    });
-
-    test("a chain id that is not a number is refused", () => {
-        expect(typedDataRefusal(request(withChainId("mainnet")))).toBe(
-            "This typed data cannot be read, so it cannot be signed.",
-        );
-    });
-
-    test("the active chain leaves Sign enabled", async () => {
-        await openSignScreen(withChainId("0xaa36a7"));
-        expect(node("approve-sign-error").textContent).toBe("");
-        expect(node("btn-approve-sign").disabled).toBe(false);
-    });
-
-    test("no chain id leaves Sign enabled", async () => {
-        await openSignScreen(withChainId(undefined));
-        expect(node("approve-sign-error").textContent).toBe("");
-        expect(node("btn-approve-sign").disabled).toBe(false);
-    });
-});