[cconlon]

This PR makes WolfCryptSignature.engineVerify() throw SignatureException when an RSA or RSA-PSS signature is not exactly the modulus length, as RFC 8017 sections 8.1.2 and 8.2.2 require. Before, the result depended on the native wolfSSL version. Older versions accepted a signature with an extra leading zero byte, while wolfCrypt FIPS v7 rejects it. The new check gives the same result on every native version and matches SunRsaSign.

Changes

• Check the RSA signature length against Rsa.getEncryptSize() in engineVerify(), after the digest is finalized so the hash state still resets.
• Add testRsaVerifyRejectsWrongLengthSignature, which checks that signatures one byte longer or shorter are rejected for both SHA256withRSA and RSASSA-PSS, and that a valid signature still verifies afterward.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #297

Scan targets checked: wolfcrypt-jni-src, wolfcrypt-jni-bugs
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: src/test/java/com/wolfssl/provider/jce/test/WolfCryptSignatureTest.java

Fenrir result: Approved ✅

No new issues found in the changed files.

Advisory only — this automated result does not count as a GitHub approval.

Review tier: Lite

[Copilot]

🟢 Approval recommended

The implementation meets the stated requirement and includes appropriate regression coverage.

0 open findings

What changed in this PR

Enforces consistent RSA signature-length validation in the wolfJCE signature provider.

Changes:

• Rejects RSA and RSA-PSS signatures that differ from the modulus length.
• Tests longer, shorter, and valid signatures while confirming state recovery.

File	Description
WolfCryptSignature.java	Adds RSA signature-length validation.
WolfCryptSignatureTest.java	Tests invalid lengths and subsequent valid verification.

🧠 Review effort: Balanced

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