Description

The verify method of the SwapClaim proof ensures certain conditions with expect statements instead of returning an error. Many of these conditions are checks on user-provided input.

These expects are user-reachable; as such, a user could cause a panic and crash a node.

pub fn verify(
	&self,
	vk: &PreparedVerifyingKey<Bls12_377>,
	public: SwapClaimProofPublic,
) -> anyhow::Result<()> {
	let proof =
		Proof::deserialize_compressed_unchecked(&self.0[..]).map_err(|e| anyhow::anyhow!(e))?;

	let mut public_inputs = Vec::new();
	public_inputs.extend(
		Fq::from(public.anchor.0)
			.to_field_elements()
			.expect("Fq types are Bls12-377 field members"),
	);
	...
}

Impact

Malicious attackers could supply inputs that could crash the node and cause a chain halt.

Recommendations

Change the expects to return Results instead to avoid these panics.

Remediation

This issue has been acknowledged by Penumbra Labs, and a fix was implemented in commit fc9fbec7↗.