Server-side PKCS#7 encode improvements that let downstream EST/SCEP enrollment
code (wolfCert) drive the existing encoder through the public API rather than
hand-rolling DER. Everything is gated under the existing HAVE_PKCS7 — no new
build options and no new public functions; the convenience wrappers live
caller-side.
Allow degenerate (certs-only) SignedData encode
Relax the hashOID != 0 requirement in PKCS7_EncodeSigned() when
sidType == DEGENERATE_SID, so a caller can produce a certs-only bundle (no
signer, attributes, or eContent — the form used by EST /cacerts and SCEP
GetCACert) by selecting DEGENERATE_SID via wc_PKCS7_SetSignerIdentifierType()
and calling wc_PKCS7_EncodeSignedData(). The output round-trips through
wc_PKCS7_VerifySignedData().
Size the signed-attribute array to the actual count
The SignerInfo attribute working array is now sized to the real attribute
count instead of a fixed [7] array. An inline buffer (sized
MAX_SIGNED_ATTRIBS_SZ, the historical footprint) covers the common
allocation-free case; a heap buffer is used only when the count exceeds it.
The default-attribute count comes from a single helper
(wc_PKCS7_GetDefaultSignedAttribCount) so the sizing matches the emission
logic exactly, and the canned-attribute write is bound-checked against the
array capacity. This also fixes a latent overflow where the backing array was
hardcoded [7] while the bound check used MAX_SIGNED_ATTRIBS_SZ. The macro is
retained for source compatibility but no longer caps the count.
Document the decoded-attribute value shape
Documented the stable shape of PKCS7DecodedAttrib.value (the contents of the
SET OF AttributeValue, outer SET tag stripped) so callers can rely on it. No
behavior change.
Fix multi-certificate decode in non-streaming builds
Bound the additional-certificate loop in wc_PKCS7_VerifySignedData against the
absolute end of the certificate set (idx + length) rather than the relative
length. In NO_PKCS7_STREAM builds the old bound dropped trailing certificates
(all but the first when a large eContent preceded the set), failing
verification when the signer cert was among those dropped. Streaming builds
were unaffected.
Tests
Added coverage in pkcs7signed_test: degenerate certs-only encode via the
public API, nine-attribute encode (beyond the inline capacity), decoded
attribute value shape for PrintableString and OCTET STRING, and a
multi-certificate decode regression with large content that triggers the
bound bug under NO_PKCS7_STREAM. Added a signed-attribute selection
round-trip covering a messageDigest-only subset and the no-attributes case
via wc_PKCS7_SetDefaultSignedAttribs/wc_PKCS7_NoDefaultSignedAttribs, a
WOLFSSL_NO_MALLOC over-capacity case that must return BUFFER_E instead of
overrunning the inline buffer, and a malformed certificate-set length that
exercises the certSetEnd clamp in the verifier. Config-sensitive cases are
guarded.
David Garske
HAJA MOHIDEEN M
JacobBarthelmeh
Tobias Frauenschläger
Josh Holtrop
Sean Parkinson
philljj
Aidan Garske
night1rider