ES256: return errors instead of panicking on invalid byte conversions#3722
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ES256: return errors instead of panicking on invalid byte conversions#3722
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Replace the `From<[u8; N]>` / `From<&[u8; N]>` impls on `ES256PublicKey` and `ES256Signature` with `TryFrom`, matching the existing `Commitment` precedent in the multisig module. The previous impls called `from_bytes(...).expect(...)`, which panics on inputs that `p256` rejects (invalid SEC1 tag byte for the public key; zero or out-of-range `r`/`s` scalars for the signature). No current call site feeds untrusted bytes through these impls, but the `TryFrom` form removes the footgun. Also remove the `Default` impl on `ES256Signature`: it attempted to construct a signature from all-zero bytes, which `p256` rejects (panicking with a misleading "Invalid slice length" message). The impl had no callers.
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Replace the
From<[u8; N]>/From<&[u8; N]>impls onES256PublicKeyandES256SignaturewithTryFrom, matching the existingCommitmentprecedent in the multisig module. The previous impls calledfrom_bytes(...).expect(...), which panics on inputs thatp256rejects (invalid SEC1 tag byte for the public key; zero or out-of-ranger/sscalars for the signature). No current call site feeds untrusted bytes through these impls, but theTryFromform removes the footgun.Also remove the
Defaultimpl onES256Signature: it attempted to construct a signature from all-zero bytes, whichp256rejects (panicking with a misleading "Invalid slice length" message). The impl had no callers.Pull request checklist
clippyandrustfmtwarnings.