[night1rider]

Legacy PKCS#7 ANY-typed eContent (a non-OCTET STRING element, e.g. a SEQUENCE as RFC 2315 permits) must be a single DER element spanning the whole content. Before this change, a message with extra bytes appended after that element could verify and return the appended bytes as content, even though the messageDigest only covers the first element's value.

This change adds a span check in the signed-attributes verification path: the ANY element must be a single DER element covering the whole eContent, otherwise verification fails with ASN_PARSE_E. Rejected forms are trailing bytes after the element, an indefinite length, and a high-tag-number identifier. The check runs before the precomputed-hash branch, so it applies to both wc_PKCS7_VerifySignedData and wc_PKCS7_VerifySignedData_ex.

pkcs7->content for an ANY-typed eContent reports the whole DER element (contentSz includes the tag and length octets); the CMS OCTET STRING case is unchanged and reports the value only. contentIsPkcs7Type is reset per verify so a reused object parses each message afresh.

Documentation for wc_PKCS7_VerifySignedData is updated to describe the reported content form, the scope of the rejection, and the content lifetime. Tests cover value extraction, trailing-data rejection on both entry points, long-form and non-minimal lengths, streaming input, and the minimal 2-byte element.

How to run the new test:

./configure --enable-all
make -j"$(nproc)"
./tests/unit.test --group pkcs7_sd

[Copilot]

🟡 Changes recommended

Critical ASN.1 ANY parsing flaws can allow verification to succeed while returning bytes not covered by the verified digest.

2 open issues

• Reject ANY payloads missing a length byte · New
• Parse or reject high-tag-number ANY identifiers · New

What changed in this PR

This PR tightens wolfCrypt’s PKCS#7 signed-attribute verification so legacy ANY-typed eContent returns only the element value covered by the messageDigest.

Changes:

• Adds a whole-content span check to reject trailing bytes, including when a precomputed hash is supplied.
• Strips the ANY element’s tag and length after successful verification.
• Adds regression cases for value extraction and trailing-data rejection, including streaming input.

File	Description
wolfcrypt/​src/​pkcs7.c	Validates ANY content spans and returns the element value.
tests/​api/​test_pkcs7.h	Registers the new regression test in pkcs7_sd.
tests/​api/​test_pkcs7.c	Tests ordinary, precomputed-hash, and streaming verification paths.

_{Review effort: Balanced}

[github-actions]

MemBrowse Memory Report · Explore what changed →

gcc-arm-cortex-m4-pkcs7

• FLASH: .text +128 B (+0.1%, 222,868 B / 262,144 B, total: 85% used)

zephyr-frdm_rw612

• FLASH: log_const_area -8 B, rodata -8 B, text +1,544 B (+0.5%, 283,992 B / 67,108,864 B, total: 0% used)

No memory changes detected for:

• gcc-arm-cortex-m0plus
• gcc-arm-cortex-m3
• gcc-arm-cortex-m4
• gcc-arm-cortex-m4-baremetal
• gcc-arm-cortex-m4-crypto-only
• gcc-arm-cortex-m4-dtls13
• gcc-arm-cortex-m4-min-ecc
• gcc-arm-cortex-m4-openssl-compat
• gcc-arm-cortex-m4-pq
• gcc-arm-cortex-m4-rsa-only
• gcc-arm-cortex-m4-sp-math
• gcc-arm-cortex-m4-tls12
• gcc-arm-cortex-m4-tls13
• gcc-arm-cortex-m7
• gcc-arm-cortex-m7-pq
• gcc-arm-cortex-m7-tls13
• stm32-sim-stm32h753

---

_{Catch memory regressions in CI with MemBrowse. Free for open source.}

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-bugs
Not reviewed (no scan target covers them): tests/api/test_pkcs7.h
Coverage: 2 of 2 in-scope changed file(s) opened by the reviewer

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

[Copilot]

🟡 Changes recommended

The ANY payload check accepts an unterminated indefinite-length SEQUENCE as empty content, allowing verification to succeed for an invalid DER element.

1 open issue

• Reject unterminated indefinite-length ASN.1 elements · New

2 resolved since last review

• Parse or reject high-tag-number ANY identifiers
• Reject ANY payloads missing a length byte

_{Review effort: Balanced}

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-bugs
Not reviewed (no scan target covers them): tests/api/test_pkcs7.h
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: tests/api/test_pkcs7.c

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

Fenrir's latest completed scan found no issues; clearing the prior automated change request.

[Copilot]

🟡 Changes recommended

Successful ANY verification still exposes tag-and-length bytes instead of value-only content, and the documentation omits the input-buffer lifetime requirement for aliased content.

2 open issues

• Document input-buffer lifetime for aliased content · New
• ANY verification exposes the full element instead of only its value · New

1 resolved since last review

• Reject unterminated indefinite-length ASN.1 elements

_{Review effort: Balanced}

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-bugs
Not reviewed (no scan target covers them): doc/dox_comments/header_files/pkcs7.h, tests/api/test_pkcs7.h
Coverage: 1 of 2 in-scope changed file(s) opened by the reviewer; not opened: tests/api/test_pkcs7.c

Findings: 1
1 finding(s) posted as inline comments (see file-level comments below)

This review was generated automatically by Fenrir. Reported findings require changes before merge.

Review tier: Lite

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfssl-bugs
Unchanged since last review (not re-run): wolfcrypt-src, wolfcrypt-bugs
Not reviewed (no scan target covers them): doc/dox_comments/header_files/pkcs7.h, tests/api/test_pkcs7.h
Coverage: 0 of 1 in-scope changed file(s) opened by the reviewer; not opened: tests/api/test_pkcs7.c

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

Fenrir's latest completed scan found no issues; clearing the prior automated change request.

[Copilot]

🟡 Changes recommended

Split header/footer verification can accept a shortened ANY element with a matching digest without validating its declared span, leaving a critical verification bypass.

1 open issue

• Validate split-input ANY element spans before accepting supplied digests · New

2 resolved since last review

• ANY verification exposes the full element instead of only its value
• Document input-buffer lifetime for aliased content

_{Review effort: Balanced}

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota. Try requesting a review at a lower effort level.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-bugs
Not reviewed (no scan target covers them): doc/dox_comments/header_files/pkcs7.h, tests/api/test_pkcs7.h, tests/api/test_tsp.h
Coverage: 3 of 4 in-scope changed file(s) opened by the reviewer; not opened: tests/api/test_pkcs7.c

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]

Copilot was unable to review this pull request because the user who requested the review has insufficient remaining quota. Try requesting a review at a lower effort level.

[wolfSSL-Fenrir-bot]

Fenrir Automated Review — PR #11963

Scan targets checked: wolfcrypt-src, wolfcrypt-bugs, wolfssl-bugs
Not reviewed (no scan target covers them): doc/dox_comments/header_files/pkcs7.h, doc/dox_comments/header_files/tsp.h, tests/api/test_pkcs7.h, tests/api/test_tsp.h
Coverage: 2 of 6 in-scope changed file(s) opened by the reviewer; not opened: tests/api/test_pkcs7.c, tests/unit-mcdc/test_pkcs7_arg_whitebox.c, tests/unit-mcdc/test_pkcs7_whitebox.c, wolfcrypt/src/tsp.c

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