webpki/error.rs
1// Copyright 2015 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
10// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
12// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
13// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15#[cfg(feature = "alloc")]
16use alloc::string::String;
17#[cfg(feature = "alloc")]
18use alloc::vec::Vec;
19use core::fmt;
20use core::ops::ControlFlow;
21
22use pki_types::UnixTime;
23#[cfg(feature = "alloc")]
24use pki_types::{AlgorithmIdentifier, ServerName};
25
26use crate::verify_cert::RequiredEkuNotFoundContext;
27
28/// An error that occurs during certificate validation or name validation.
29#[derive(Clone, Debug, PartialEq, Eq)]
30#[non_exhaustive]
31pub enum Error {
32 /// The encoding of some ASN.1 DER-encoded item is invalid.
33 BadDer,
34
35 /// The encoding of an ASN.1 DER-encoded time is invalid.
36 BadDerTime,
37
38 /// A CA certificate is being used as an end-entity certificate.
39 CaUsedAsEndEntity,
40
41 /// The certificate is expired; i.e. the time it is being validated for is
42 /// later than the certificate's notAfter time.
43 CertExpired {
44 /// The validation time.
45 time: UnixTime,
46 /// The notAfter time of the certificate.
47 not_after: UnixTime,
48 },
49
50 /// The certificate is not valid for the name it is being validated for.
51 CertNotValidForName(InvalidNameContext),
52
53 /// The certificate is not valid yet; i.e. the time it is being validated
54 /// for is earlier than the certificate's notBefore time.
55 CertNotValidYet {
56 /// The validation time.
57 time: UnixTime,
58 /// The notBefore time of the certificate.
59 not_before: UnixTime,
60 },
61
62 /// The certificate, or one of its issuers, has been revoked.
63 CertRevoked,
64
65 /// The CRL is expired; i.e. the verification time is not before the time
66 /// in the CRL nextUpdate field.
67 CrlExpired {
68 /// The validation time.
69 time: UnixTime,
70 /// The nextUpdate time of the CRL.
71 next_update: UnixTime,
72 },
73
74 /// An end-entity certificate is being used as a CA certificate.
75 EndEntityUsedAsCa,
76
77 /// An X.509 extension is invalid.
78 ExtensionValueInvalid,
79
80 /// The certificate validity period (notBefore, notAfter) is invalid; e.g.
81 /// the notAfter time is earlier than the notBefore time.
82 InvalidCertValidity,
83
84 /// A CRL number extension was invalid:
85 /// - it was mis-encoded
86 /// - it was negative
87 /// - it was too long
88 InvalidCrlNumber,
89
90 /// A iPAddress name constraint was invalid:
91 /// - it had a sparse network mask (ie, cannot be written in CIDR form).
92 /// - it was too long or short
93 InvalidNetworkMaskConstraint,
94
95 /// A serial number was invalid:
96 /// - it was misencoded
97 /// - it was negative
98 /// - it was too long
99 InvalidSerialNumber,
100
101 /// The CRL signature is invalid for the issuer's public key.
102 InvalidCrlSignatureForPublicKey,
103
104 /// The signature is invalid for the given public key.
105 InvalidSignatureForPublicKey,
106
107 /// A CRL was signed by an issuer that has a KeyUsage bitstring that does not include
108 /// the cRLSign key usage bit.
109 IssuerNotCrlSigner,
110
111 /// A presented or reference DNS identifier was malformed, potentially
112 /// containing invalid characters or invalid labels.
113 MalformedDnsIdentifier,
114
115 /// The certificate extensions are malformed.
116 ///
117 /// In particular, webpki requires the DNS name(s) be in the subjectAltName
118 /// extension as required by the CA/Browser Forum Baseline Requirements
119 /// and as recommended by RFC6125.
120 MalformedExtensions,
121
122 /// A name constraint was malformed, potentially containing invalid characters or
123 /// invalid labels.
124 MalformedNameConstraint,
125
126 /// The maximum number of name constraint comparisons has been reached.
127 MaximumNameConstraintComparisonsExceeded,
128
129 /// The maximum number of internal path building calls has been reached. Path complexity is too great.
130 MaximumPathBuildCallsExceeded,
131
132 /// The path search was terminated because it became too deep.
133 MaximumPathDepthExceeded,
134
135 /// The maximum number of signature checks has been reached. Path complexity is too great.
136 MaximumSignatureChecksExceeded,
137
138 /// The certificate violates one or more name constraints.
139 NameConstraintViolation,
140
141 /// The certificate violates one or more path length constraints.
142 PathLenConstraintViolated,
143
144 /// The certificate is not valid for the Extended Key Usage for which it is
145 /// being validated.
146 #[deprecated(since = "0.103.2", note = "use RequiredEkuNotFoundContext instead")]
147 RequiredEkuNotFound,
148
149 /// The certificate is not valid for the Extended Key Usage for which it is
150 /// being validated.
151 RequiredEkuNotFoundContext(RequiredEkuNotFoundContext),
152
153 /// The algorithm in the TBSCertificate "signature" field of a certificate
154 /// does not match the algorithm in the signature of the certificate.
155 SignatureAlgorithmMismatch,
156
157 /// Trailing data was found while parsing DER-encoded input for the named type.
158 TrailingData(DerTypeId),
159
160 /// A valid issuer for the certificate could not be found.
161 UnknownIssuer,
162
163 /// The certificate's revocation status could not be determined.
164 UnknownRevocationStatus,
165
166 /// The certificate is not a v3 X.509 certificate.
167 ///
168 /// This error may be also reported if the certificate version field
169 /// is malformed.
170 UnsupportedCertVersion,
171
172 /// The certificate contains an unsupported critical extension.
173 UnsupportedCriticalExtension,
174
175 /// The CRL contains an issuing distribution point with no distribution point name,
176 /// or a distribution point name relative to an issuer.
177 UnsupportedCrlIssuingDistributionPoint,
178
179 /// The CRL is not a v2 X.509 CRL.
180 ///
181 /// The RFC 5280 web PKI profile mandates only version 2 be used. See section
182 /// 5.1.2.1 for more information.
183 ///
184 /// This error may also be reported if the CRL version field is malformed.
185 UnsupportedCrlVersion,
186
187 /// The CRL is an unsupported "delta" CRL.
188 UnsupportedDeltaCrl,
189
190 /// The CRL contains unsupported "indirect" entries.
191 UnsupportedIndirectCrl,
192
193 /// The `ServerName` contained an unsupported type of value.
194 UnsupportedNameType,
195
196 /// The revocation reason is not in the set of supported revocation reasons.
197 UnsupportedRevocationReason,
198
199 /// The CRL is partitioned by revocation reasons.
200 UnsupportedRevocationReasonsPartitioning,
201
202 /// The signature algorithm for a signature over a CRL is not in the set of supported
203 /// signature algorithms given.
204 #[deprecated(
205 since = "0.103.4",
206 note = "use UnsupportedCrlSignatureAlgorithmContext instead"
207 )]
208 UnsupportedCrlSignatureAlgorithm,
209
210 /// The signature algorithm for a signature is not in the set of supported
211 /// signature algorithms given.
212 UnsupportedCrlSignatureAlgorithmContext(UnsupportedSignatureAlgorithmContext),
213
214 /// The signature algorithm for a signature is not in the set of supported
215 /// signature algorithms given.
216 #[deprecated(
217 since = "0.103.4",
218 note = "use UnsupportedSignatureAlgorithmContext instead"
219 )]
220 UnsupportedSignatureAlgorithm,
221
222 /// The signature algorithm for a signature is not in the set of supported
223 /// signature algorithms given.
224 UnsupportedSignatureAlgorithmContext(UnsupportedSignatureAlgorithmContext),
225
226 /// The CRL signature's algorithm does not match the algorithm of the issuer
227 /// public key it is being validated for. This may be because the public key
228 /// algorithm's OID isn't recognized (e.g. DSA), or the public key
229 /// algorithm's parameters don't match the supported parameters for that
230 /// algorithm (e.g. ECC keys for unsupported curves), or the public key
231 /// algorithm and the signature algorithm simply don't match (e.g.
232 /// verifying an RSA signature with an ECC public key).
233 #[deprecated(
234 since = "0.103.4",
235 note = "use UnsupportedCrlSignatureAlgorithmForPublicKeyContext instead"
236 )]
237 UnsupportedCrlSignatureAlgorithmForPublicKey,
238
239 /// The signature's algorithm does not match the algorithm of the public
240 /// key it is being validated for. This may be because the public key
241 /// algorithm's OID isn't recognized (e.g. DSA), or the public key
242 /// algorithm's parameters don't match the supported parameters for that
243 /// algorithm (e.g. ECC keys for unsupported curves), or the public key
244 /// algorithm and the signature algorithm simply don't match (e.g.
245 /// verifying an RSA signature with an ECC public key).
246 UnsupportedCrlSignatureAlgorithmForPublicKeyContext(
247 UnsupportedSignatureAlgorithmForPublicKeyContext,
248 ),
249
250 /// The signature's algorithm does not match the algorithm of the public
251 /// key it is being validated for. This may be because the public key
252 /// algorithm's OID isn't recognized (e.g. DSA), or the public key
253 /// algorithm's parameters don't match the supported parameters for that
254 /// algorithm (e.g. ECC keys for unsupported curves), or the public key
255 /// algorithm and the signature algorithm simply don't match (e.g.
256 /// verifying an RSA signature with an ECC public key).
257 #[deprecated(
258 since = "0.103.4",
259 note = "use UnsupportedSignatureAlgorithmForPublicKeyContext instead"
260 )]
261 UnsupportedSignatureAlgorithmForPublicKey,
262
263 /// The signature's algorithm does not match the algorithm of the public
264 /// key it is being validated for. This may be because the public key
265 /// algorithm's OID isn't recognized (e.g. DSA), or the public key
266 /// algorithm's parameters don't match the supported parameters for that
267 /// algorithm (e.g. ECC keys for unsupported curves), or the public key
268 /// algorithm and the signature algorithm simply don't match (e.g.
269 /// verifying an RSA signature with an ECC public key).
270 UnsupportedSignatureAlgorithmForPublicKeyContext(
271 UnsupportedSignatureAlgorithmForPublicKeyContext,
272 ),
273}
274
275impl Error {
276 // Compare the Error with the new error by rank, returning the higher rank of the two as
277 // the most specific error.
278 pub(crate) fn most_specific(self, new: Self) -> Self {
279 // Assign an error a numeric value ranking it by specificity.
280 if self.rank() >= new.rank() { self } else { new }
281 }
282
283 // Return a numeric indication of how specific the error is, where an error with a higher rank
284 // is considered more useful to an end user than an error with a lower rank. This is used by
285 // Error::most_specific to compare two errors in order to return which is more specific.
286 #[allow(clippy::as_conversions)] // We won't exceed u32 errors.
287 pub(crate) fn rank(&self) -> u32 {
288 match &self {
289 // Errors related to certificate validity
290 Self::CertNotValidYet { .. } | Self::CertExpired { .. } => 290,
291 Self::CertNotValidForName(_) => 280,
292 Self::CertRevoked | Self::UnknownRevocationStatus | Self::CrlExpired { .. } => 270,
293 Self::InvalidCrlSignatureForPublicKey | Self::InvalidSignatureForPublicKey => 260,
294 Self::SignatureAlgorithmMismatch => 250,
295 #[allow(deprecated)]
296 Self::RequiredEkuNotFound | Self::RequiredEkuNotFoundContext(_) => 240,
297 Self::NameConstraintViolation => 230,
298 Self::PathLenConstraintViolated => 220,
299 Self::CaUsedAsEndEntity | Self::EndEntityUsedAsCa => 210,
300 Self::IssuerNotCrlSigner => 200,
301
302 // Errors related to supported features used in an invalid way.
303 Self::InvalidCertValidity => 190,
304 Self::InvalidNetworkMaskConstraint => 180,
305 Self::InvalidSerialNumber => 170,
306 Self::InvalidCrlNumber => 160,
307
308 // Errors related to unsupported features.
309 #[allow(deprecated)]
310 Self::UnsupportedCrlSignatureAlgorithmForPublicKey
311 | Self::UnsupportedCrlSignatureAlgorithmForPublicKeyContext(_)
312 | Self::UnsupportedSignatureAlgorithmForPublicKey
313 | Self::UnsupportedSignatureAlgorithmForPublicKeyContext(_) => 150,
314 #[allow(deprecated)]
315 Self::UnsupportedCrlSignatureAlgorithm
316 | Self::UnsupportedCrlSignatureAlgorithmContext(_)
317 | Self::UnsupportedSignatureAlgorithm
318 | Self::UnsupportedSignatureAlgorithmContext(_) => 140,
319 Self::UnsupportedCriticalExtension => 130,
320 Self::UnsupportedCertVersion => 130,
321 Self::UnsupportedCrlVersion => 120,
322 Self::UnsupportedDeltaCrl => 110,
323 Self::UnsupportedIndirectCrl => 100,
324 Self::UnsupportedNameType => 95,
325 Self::UnsupportedRevocationReason => 90,
326 Self::UnsupportedRevocationReasonsPartitioning => 80,
327 Self::UnsupportedCrlIssuingDistributionPoint => 70,
328 Self::MaximumPathDepthExceeded => 61,
329
330 // Errors related to malformed data.
331 Self::MalformedDnsIdentifier => 60,
332 Self::MalformedNameConstraint => 50,
333 Self::MalformedExtensions | Self::TrailingData(_) => 40,
334 Self::ExtensionValueInvalid => 30,
335
336 // Generic DER errors.
337 Self::BadDerTime => 20,
338 Self::BadDer => 10,
339
340 // Special case errors - not subject to ranking.
341 Self::MaximumSignatureChecksExceeded => 0,
342 Self::MaximumPathBuildCallsExceeded => 0,
343 Self::MaximumNameConstraintComparisonsExceeded => 0,
344
345 // Default catch all error - should be renamed in the future.
346 Self::UnknownIssuer => 0,
347 }
348 }
349
350 /// Returns true for errors that should be considered fatal during path building. Errors of
351 /// this class should halt any further path building and be returned immediately.
352 #[inline]
353 pub(crate) fn is_fatal(&self) -> bool {
354 matches!(
355 self,
356 Self::MaximumSignatureChecksExceeded
357 | Self::MaximumPathBuildCallsExceeded
358 | Self::MaximumNameConstraintComparisonsExceeded
359 )
360 }
361}
362
363impl From<Error> for ControlFlow<Error, Error> {
364 fn from(value: Error) -> Self {
365 match value {
366 // If an error is fatal, we've exhausted the potential for continued search.
367 err if err.is_fatal() => Self::Break(err),
368 // Otherwise we've rejected one candidate chain, but may continue to search for others.
369 err => Self::Continue(err),
370 }
371 }
372}
373
374impl fmt::Display for Error {
375 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
376 write!(f, "{self:?}")
377 }
378}
379
380#[cfg(feature = "std")]
381impl ::std::error::Error for Error {}
382
383/// Additional context for the `CertNotValidForName` error variant.
384///
385/// The contents of this type depend on whether the `alloc` feature is enabled.
386#[derive(Clone, Debug, PartialEq, Eq)]
387pub struct InvalidNameContext {
388 /// Expected server name.
389 #[cfg(feature = "alloc")]
390 pub expected: ServerName<'static>,
391 /// The names presented in the end entity certificate.
392 ///
393 /// These are the subject names as present in the leaf certificate and may contain DNS names
394 /// with or without a wildcard label as well as IP address names.
395 #[cfg(feature = "alloc")]
396 pub presented: Vec<String>,
397}
398
399/// Additional context for the `UnsupportedSignatureAlgorithmForPublicKey` error variant.
400///
401/// The contents of this type depend on whether the `alloc` feature is enabled.
402#[derive(Clone, Debug, PartialEq, Eq)]
403pub struct UnsupportedSignatureAlgorithmForPublicKeyContext {
404 /// The signature algorithm OID.
405 #[cfg(feature = "alloc")]
406 pub signature_algorithm_id: Vec<u8>,
407 /// The public key algorithm OID.
408 #[cfg(feature = "alloc")]
409 pub public_key_algorithm_id: Vec<u8>,
410}
411
412/// Additional context for the `UnsupportedSignatureAlgorithm` error variant.
413///
414/// The contents of this type depend on whether the `alloc` feature is enabled.
415#[derive(Clone, Debug, PartialEq, Eq)]
416pub struct UnsupportedSignatureAlgorithmContext {
417 /// The signature algorithm OID that was unsupported.
418 #[cfg(feature = "alloc")]
419 pub signature_algorithm_id: Vec<u8>,
420 /// Supported algorithms that were available for signature verification.
421 #[cfg(feature = "alloc")]
422 pub supported_algorithms: Vec<AlgorithmIdentifier>,
423}
424
425/// Trailing data was found while parsing DER-encoded input for the named type.
426#[allow(missing_docs)]
427#[non_exhaustive]
428#[derive(Clone, Copy, Debug, Eq, PartialEq)]
429pub enum DerTypeId {
430 BitString,
431 Bool,
432 Certificate,
433 CertificateExtensions,
434 CertificateTbsCertificate,
435 CertRevocationList,
436 CertRevocationListExtension,
437 CrlDistributionPoint,
438 CommonNameInner,
439 CommonNameOuter,
440 DistributionPointName,
441 Extension,
442 GeneralName,
443 RevocationReason,
444 Signature,
445 SignatureAlgorithm,
446 SignedData,
447 SubjectPublicKeyInfo,
448 Time,
449 TrustAnchorV1,
450 TrustAnchorV1TbsCertificate,
451 U8,
452 RevokedCertificate,
453 RevokedCertificateExtension,
454 RevokedCertEntry,
455 IssuingDistributionPoint,
456}