RustCrypto SM2-PKE has Unchecked AffinePoint Decoding (unwrap) in decrypt()

Summary

RustCrypto: Elliptic Curves is general purpose Elliptic Curve Cryptography (ECC) support, including types and traits for representing various elliptic curve forms, scalars, points, and public/secret keys composed thereof. In versions 0.14.0-pre.0 and 0.14.0-rc.0, a denial-of-service vulnerability exists in the SM2 PKE decryption path where an invalid elliptic-curve point (C1) is decoded and the resulting value is unwrapped without checking. Specifically, AffinePoint::from_encoded_point(&encoded_c1) may return a None/CtOption::None when the supplied coordinates are syntactically valid but do not lie on the SM2 curve. The calling code previously used .unwrap(), causing a panic when presented with such input. This issue has been patched via commit 085b7be.