Verify SEP-10 challenge body integrity after domain signing#237
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Compares the hash of the transaction returned by the configured DomainSigner against the original challenge before signing it with the user's account key. If the body differs, a new DomainSigningModifiedError is thrown and the user-account signature is never applied.
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Pull request overview
This PR strengthens SEP-10 authentication by ensuring that a configured domain signer cannot modify the SEP-10 challenge transaction body before the wallet applies the user-account signature. It does so by comparing the transaction body hash (excluding signatures) before and after domain signing, and rejecting any body changes with a dedicated error.
Changes:
- Added an integrity check in
Sep10.sign()to verify the domain signer returns a transaction with the same envelope body hash as the original challenge. - Introduced
DomainSigningModifiedErrorto clearly signal domain-signer body modification. - Added unit tests covering both the accepted case (signature appended only) and the rejected case (body changed), including assertions that user signing and token POST are not performed on rejection.
Reviewed changes
Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| @stellar/typescript-wallet-sdk/src/walletSdk/Auth/index.ts | Adds post-domain-signing body-hash verification and throws DomainSigningModifiedError on mismatch. |
| @stellar/typescript-wallet-sdk/src/walletSdk/Exceptions/index.ts | Defines the new DomainSigningModifiedError used by SEP-10 signing flow. |
| @stellar/typescript-wallet-sdk/test/auth.test.ts | Adds unit tests for domain signer integrity behavior (accept same body + extra signature; reject modified body). |
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piyalbasu
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May 21, 2026
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This is looking good to me!
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Summary
Sep10.sign()now verifies that the transaction returned by the configuredDomainSignerhas the same body hash as the original challenge before signing it with the user's account key. If the body differs, aDomainSigningModifiedErroris thrown and the user-account signature is not applied.Test plan
DomainSigningModifiedErrorbefore any user-account signing.yarn lintpassesyarn test:cipasses (249 tests, 0 failures)