pkcs7: add RSA-PSS support for SignedData by sameehj · Pull Request #9742 · wolfSSL/wolfssl

sameehj · 2026-02-05T10:14:30Z

Add full RSA-PSS (RSASSA-PSS) support to PKCS#7 SignedData encoding and verification.

This change enables SignerInfo.signatureAlgorithm to use id-RSASSA-PSS with explicit RSASSA-PSS-params (hash, MGF1, salt length), as required by RFC 4055 and CMS profiles.

Key changes:

Add RSA-PSS encode and verify paths for PKCS7 SignedData
Encode full RSASSA-PSS AlgorithmIdentifier parameters
Decode RSA-PSS parameters from SignerInfo for verification
Treat RSA-PSS like ECDSA (sign raw digest, not DigestInfo)
Fix certificate signatureAlgorithm parameter length handling
Add API test coverage for RSA-PSS SignedData

This resolves failures when using RSA-PSS signer certificates (e.g. -173 invalid signature algorithm) and maintains backward compatibility with RSA PKCS#1 v1.5 and ECDSA.

Testing

API: New test test_wc_PKCS7_EncodeSignedData_RSA_PSS (guarded by HAVE_PKCS7, WC_RSA_PSS, RSA, filesystem, SHA-256). Uses certs/rsapss/client-rsapss.der and client-rsapss-priv.der; encodes SignedData and optionally round-trip verifies.
CI: os-check.yml updated with build --enable-pkcs7 CPPFLAGS=-DWC_RSA_PSS.
Manual: Encode/verify with RSA-PSS signer cert; existing RSA and ECDSA SignedData tests unchanged.

Checklist

added tests
updated/added doxygen (PKCS7_RSA_PSS page; cryptocb RSA-PSS notes; pkcs7.h EncodeSignedData \ref)
updated appropriate READMEs (examples/configs/README.md; user_settings_pkcs7.h with WC_RSA_PSS)
Updated manual and documentation (doxygen; main README/ChangeLog at merge time)

sameehj · 2026-02-06T10:47:02Z

retest this please

sameehj · 2026-02-11T10:50:08Z

retest this please

sameehj · 2026-02-12T13:44:37Z

retest this please

Copilot

Pull request overview

This PR adds CMS/PKCS#7 SignedData support for RSA-PSS (id-RSASSA-PSS) by encoding/decoding RSASSA-PSS-params and adding RSA-PSS sign/verify paths alongside existing RSA PKCS#1 v1.5 and ECDSA handling.

Changes:

Add RSA-PSS signing and verification support in PKCS7 SignedData, including RSASSA-PSS parameter parsing/encoding.
Fix/adjust ASN.1 helpers to support decoding RSA-PSS parameters in template/non-template builds and improve RSA public-key decode behavior.
Add RSA-PSS API test coverage, documentation updates, and CI build coverage for WC_RSA_PSS.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
wolfssl/wolfcrypt/pkcs7.h	Adds fields to store decoded RSA-PSS params for verification.
wolfssl/wolfcrypt/asn.h	Declares internal helpers to encode/decode RSASSA-PSS params.
wolfcrypt/src/pkcs7.c	Implements RSA-PSS sign/verify paths and parses/encodes RSASSA-PSS AlgorithmIdentifier parameters.
wolfcrypt/src/asn.c	Implements manual RSASSA-PSS params parsing and adds RSASSA-PSS AlgorithmIdentifier encoding helper; adjusts ASN helpers/length handling.
wolfcrypt/src/aes.c	Adds Clang diagnostic push/pop around the file.
tests/api/test_pkcs7.h	Registers the new RSA-PSS SignedData API test behind feature guards.
tests/api/test_pkcs7.c	Adds `test_wc_PKCS7_EncodeSignedData_RSA_PSS` with encode + round-trip verify.
examples/configs/user_settings_pkcs7.h	Enables `WC_RSA_PSS` in the PKCS#7 config template.
examples/configs/README.md	Documents enabling RSA-PSS SignedData via `WC_RSA_PSS`.
doc/dox_comments/header_files/pkcs7.h	Adds doxygen reference for RSA-PSS usage.
doc/dox_comments/header_files/doxygen_pages.h	Adds a new doxygen page `PKCS7_RSA_PSS`.
doc/dox_comments/header_files/cryptocb.h	Documents crypto-callback behavior for RSA-PSS operations.
.wolfssl_known_macro_extras	Minor macro list adjustment.
.github/workflows/os-check.yml	Adds CI build variant enabling PKCS7 + `WC_RSA_PSS`.

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wolfcrypt/src/pkcs7.c

dgarske

Also needs conflict resolved with rebase. Thanks

doc/dox_comments/header_files/cryptocb.h

dgarske · 2026-02-17T20:57:53Z

wolfcrypt/src/asn.c

Can you use a macro or enum that already exists for the 128? Also if its really that big you should have a WOLFSSL_SMALL_STACK option. We do have some helper macros for that... see WC_ALLOC_VAR_EX

Defined RSA_PSS_ALGOID_TMPBUF_SZ macro for the 128-byte buffer size. Added WOLFSSL_SMALL_STACK support using XMALLOC/XFREE for heap allocation of the temp buffer.

dgarske · 2026-02-17T21:01:08Z

wolfcrypt/src/pkcs7.c

Why -1 for the defaults on these?

AI, dropped!

wolfcrypt/src/pkcs7.c

dgarske · 2026-02-17T21:03:29Z

wolfcrypt/src/pkcs7.c

Can't you just use DecodedCert dCert[1];?

dgarske · 2026-02-17T21:04:58Z

wolfcrypt/src/asn.c

@SparkiDev please review these changes specifically. Thanks

tests/api/test_pkcs7.c

dgarske · 2026-02-17T21:06:14Z

tests/api/test_pkcs7.c

wc_PKCS7_New already calls wc_PKCS7_Init internally, so this zeroes the struct again, discarding testDevId and replacing it with INVALID_DEVID.

Fixed. Removed the redundant wc_PKCS7_Init after wc_PKCS7_New; testDevId is now preserved.

wolfcrypt/src/asn.c

dgarske · 2026-02-17T21:09:36Z

doc/dox_comments/header_files/cryptocb.h

wc_RsaFunction is the raw RSA private key operation (no PSS padding applied). A developer reading this as example code for WC_PK_TYPE_RSA_PSS would implement a callback that performs a raw unpadded RSA operation, producing a cryptographically invalid signature. The example should use wc_RsaPSS_Sign_ex (or at minimum include a prominent comment that PSS padding must be applied before/after the raw operation).

Fixed. Example now uses wc_RsaPSS_Sign_ex (with PSS padding) instead of raw wc_RsaFunction.

wolfcrypt/src/pkcs7.c

SparkiDev · 2026-02-17T23:35:23Z

wolfcrypt/src/asn.c

Make it work then.
The code was there and it needs to be made to work.

It didn't at some point, now it works

dgarske · 2026-02-18T18:58:41Z

wolfcrypt/src/aes.c

@douzzer thoughts on this? I am not sure I like adding a pragma here. Since you are working in aes.c right now curious your thoughts.

I tried to drop, this is usually triggered with -pedantic, let's see if the CI complains.

dgarske · 2026-02-18T18:59:37Z

wolfcrypt/src/asn.c

Do we need to loose the original comments and formatting?

Add full RSA-PSS (RSASSA-PSS) support to PKCS#7 SignedData encoding and verification. This change enables SignerInfo.signatureAlgorithm to use id-RSASSA-PSS with explicit RSASSA-PSS-params (hash, MGF1, salt length), as required by RFC 4055 and CMS profiles. Key changes: - Add RSA-PSS encode and verify paths for PKCS7 SignedData - Encode full RSASSA-PSS AlgorithmIdentifier parameters - Decode RSA-PSS parameters from SignerInfo for verification - Treat RSA-PSS like ECDSA (sign raw digest, not DigestInfo) - Fix certificate signatureAlgorithm parameter length handling - Add API test coverage for RSA-PSS SignedData This resolves failures when using RSA-PSS signer certificates (e.g. -173 invalid signature algorithm) and maintains backward compatibility with RSA PKCS#1 v1.5 and ECDSA. Signed-off-by: Sameeh Jubran <sameeh@wolfssl.com>

sameehj force-pushed the pkcs7-rsa-pss branch 6 times, most recently from c4749c5 to 38bcb07 Compare February 6, 2026 10:15

sameehj force-pushed the pkcs7-rsa-pss branch 16 times, most recently from a4ff167 to 2f8e307 Compare February 10, 2026 17:55

sameehj force-pushed the pkcs7-rsa-pss branch from 2f8e307 to 1185846 Compare February 12, 2026 12:15

sameehj requested review from SparkiDev and dgarske February 12, 2026 13:50

sameehj force-pushed the pkcs7-rsa-pss branch 2 times, most recently from cb9f6e4 to d4d412b Compare February 13, 2026 06:40

LinuxJedi requested a review from Copilot February 13, 2026 11:00

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sameehj force-pushed the pkcs7-rsa-pss branch 3 times, most recently from a0edf71 to e29ff91 Compare February 16, 2026 10:21

sameehj requested review from dgarske and removed request for douzzer February 17, 2026 20:47

sameehj assigned sameehj and wolfSSL-Bot and unassigned sameehj Feb 17, 2026

sameehj removed request for dgarske and wolfSSL-Bot February 17, 2026 20:50

dgarske reviewed Feb 17, 2026

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dgarske requested a review from SparkiDev February 17, 2026 21:04

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@SparkiDev please review these changes specifically. Thanks

dgarske requested changes Feb 17, 2026

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sameehj force-pushed the pkcs7-rsa-pss branch 2 times, most recently from db85770 to 1289ea8 Compare February 18, 2026 13:20

dgarske requested review from SparkiDev and dgarske February 18, 2026 18:57

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Do we need to loose the original comments and formatting?

sameehj force-pushed the pkcs7-rsa-pss branch 3 times, most recently from 9845a05 to dd416f8 Compare February 19, 2026 11:48

sameehj force-pushed the pkcs7-rsa-pss branch from dd416f8 to 2379563 Compare February 19, 2026 13:15

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sameehj commented Feb 11, 2026

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sameehj commented Feb 5, 2026 •

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