A valid seal is S4 only when its token carries accuracy and t plus the
accuracy is before round_time; otherwise S5, whose text gives the reason,
the first that holds: sealed after or too close, no accuracy under the BTSP
policy of ETSI EN 319 421 (0.4.0.2023.1.1), or no accuracy (spec v0.16,
29.7, 29.11). The line of a signer of F6 whose seal does not prove it says
so with the same reason. cms.Token gains HasAccuracy, Policy and BTSP;
Verdicts gain SealReason and SignerLine.Reason; EncryptFiles returns the
verdicts of the area it wrote in Result.Security, so that a writer warns of
a seal without accuracy (rule 19).
security_cms.json is made again: 143 cases, the seals about something else
with an accuracy of a second, and the new cases of 64 with seal_reason.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The check of a minimal INTEGER in the millis of an accuracy was tested only
with 128 and 999, whose low byte has its high bit set: a check that took
every two-byte value under 0x8000 for one that is not minimal left them
all passing. 300, 01 2c, is minimal and must read.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The builder of the tests, cmstest:
- NewCert writes a certificate from the DER of its tbsCertificate, field by
field: names of any string type with any bytes (UTF8String,
PrintableString with an underscore or an at sign, IA5String,
TeletexString, BMPString of odd length or with a surrogate,
VisibleString, NumericString), an attribute twice or none, no version,
times with a fraction, an extension twice, a compressed EC key, an even
modulus, and any signature. A Signer made so serves Signature and Token.
- Options for the version of a SignerInfo, the hashAlgorithm and the
certHash of an ESSCertIDv2, a signatureAlgorithm other than the one of
the key, a certificate twice, two content-type attributes, an attribute
with an arc of 2^31, a SignerInfo twice, BER, signerInfos out of order,
two signature-time-stamp attributes, and edits of the SignedData and of
each SignerInfo.
- Token options for any accuracy, a genTime of free text, ordering FALSE,
a field after the last, an imprint of any length, no message-digest, a
CRL in crls and the certificate of the authority twice.
- Edits of the DER after signing: Edit, Retag, Withdraw (a SignerInfo
removed), WithoutTimeStamp (a CAdES-T removed), Merge (a co-signature)
and Indefinite.
The tests of internal/cms and internal/der fail for each check of cms.go,
cert.go, verify.go and der.go. A mutation run, which replaces each leaf of
each condition by false and by true, one at a time, kills every mutant
that is not equivalent to the code it mutates.
FuzzParseSignature, FuzzParseToken, FuzzParseCert and FuzzDERCheck, seeded
with security_cms.json and with what cmstest builds: no panic, what Check
accepts Split reads, and the parsers fail only with ErrForm or
ErrAlgorithm.
capsule: the case of a seal outside the validity of the certificate gave
an invalid seal; it now tests a certificate that expired before a valid
seal (out of validity) apart from an authority that was not valid at its
time (invalid seal). SIGNERS out of order, empty, too long, with 31 bytes
or with a hash twice are F1 beside a CMS signature that is valid for the
AUTHOR_MESSAGE of those SIGNERS, and the names of certificates show as
spec v0.12 §29.7 says.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Fixes of the review of the session of 1 and 2 October in internal/cms and
internal/der:
- Object identifiers are compared by the bytes of their DER: an arc of 2^31
or more no longer makes an attribute that decides nothing fail the
signature (F1), and an algorithm with one is outside the table (F5, S1),
as spec v0.11 says.
- A SET OF may repeat an element, as X.690 allows: a TSA that sends its
certificate twice no longer gives S2. Two copies of a certificate are one.
- Certificates are read with a profile of their own instead of
encoding/asn1 and crypto/x509, field by field, so that a second
implementation can read them the same: version 3, the fields in order,
names of non-empty SETs, times of validity in DER without a fraction,
extensions without repetition, and the text of a name only from
UTF8String, PrintableString, IA5String, TeletexString in ASCII and
BMPString without surrogates, nothing removed from it. A certificate that
breaks the profile decides nothing unless a SignerInfo names it. The
holder is givenName and surname before commonName, which in the
certificates of the FNMT carries the NIF; the issuer is its commonName or
its organizationName.
- The key: RSA with NULL parameters, exactly a modulus and an exponent, the
modulus odd; EC only uncompressed on P-256, P-384 and P-521.
- A key of another scheme than its algorithm is invalid (F2) and not
outside the table (F5), as step 3 of 29.10 says; a messageImprint of
another length is S3; the crls of a token decide nothing.
- DER: UTCTime and GeneralizedTime in their forms of X.690, a date that
exists, and the millis and micros of accuracy as minimal INTEGERs.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The TSTInfo is read field by field in DER, with accuracy from zero and
millis and micros from 1 to 999, genTime in UTC with Z, no default written
and nothing after the last field. The ContentInfo and the SignerInfo must be
SEQUENCEs, a SignerInfo version must match its sid, an attribute needs a
value and is counted by attribute and not by value, a signing-certificate
beside the v2 decides nothing, PSS parameters come in order without the
trailer, and der.Check refuses the end of contents and the universal tags
the profile does not use.
The writer signs before L is fixed: write asks prepare for the final L, so
the area grows to 64 KiB only when what was signed does not fit and LargeArea
allows it, and nobody signs twice for it. Typed nils are nil, the exclusions
are checked before a file is read, Encrypt refuses the signing options, and
EvaluateSecurityIn gives X if a parser panics. The issuer of a certificate is
filtered like its holder.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
internal/der checks that bytes are one element of DER. internal/cms reads
the detached CMS signature of spec v0.11 29.10 and the RFC 3161 token of
29.11, in the order of the spec, with the closed table of algorithms (RSA
PKCS 1 and PSS of 2048 to 4096 bits, ECDSA on P-256, P-384 and P-521,
SHA-2), with the standard library only. A certificate is read with
encoding/asn1, so that a key of a curve Go lacks makes a signature "not
verifiable" and not malformed. internal/cms/cmstest builds them for tests.
Not wired into capsule yet.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
dev