From efb4e988aa693eb67efaaae82cc4d008facca0f3 Mon Sep 17 00:00:00 2001
From: Rasmus Dahlberg <rasmus@rgdd.se>
Date: Fri, 17 Mar 2023 13:19:13 +0100
Subject: Fork some snippets to get SANs parsing
---
internal/utils/x509.go | 487 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 487 insertions(+)
create mode 100644 internal/utils/x509.go
(limited to 'internal/utils')
diff --git a/internal/utils/x509.go b/internal/utils/x509.go
new file mode 100644
index 0000000..bf99334
--- /dev/null
+++ b/internal/utils/x509.go
@@ -0,0 +1,487 @@
+package utils
+
+import (
+ "fmt"
+
+ ct "github.com/google/certificate-transparency-go"
+ "github.com/google/certificate-transparency-go/asn1"
+ "github.com/google/certificate-transparency-go/x509/pkix"
+)
+
+// Mozilla Public License Version 2.0
+// ==================================
+//
+// 1. Definitions
+// --------------
+//
+// 1.1. "Contributor"
+//
+// means each individual or legal entity that creates, contributes to
+// the creation of, or owns Covered Software.
+//
+// 1.2. "Contributor Version"
+//
+// means the combination of the Contributions of others (if any) used
+// by a Contributor and that particular Contributor's Contribution.
+//
+// 1.3. "Contribution"
+//
+// means Covered Software of a particular Contributor.
+//
+// 1.4. "Covered Software"
+//
+// means Source Code Form to which the initial Contributor has attached
+// the notice in Exhibit A, the Executable Form of such Source Code
+// Form, and Modifications of such Source Code Form, in each case
+// including portions thereof.
+//
+// 1.5. "Incompatible With Secondary Licenses"
+//
+// means
+//
+// (a) that the initial Contributor has attached the notice described
+// in Exhibit B to the Covered Software; or
+//
+// (b) that the Covered Software was made available under the terms of
+// version 1.1 or earlier of the License, but not also under the
+// terms of a Secondary License.
+//
+// 1.6. "Executable Form"
+//
+// means any form of the work other than Source Code Form.
+//
+// 1.7. "Larger Work"
+//
+// means a work that combines Covered Software with other material, in
+// a separate file or files, that is not Covered Software.
+//
+// 1.8. "License"
+//
+// means this document.
+//
+// 1.9. "Licensable"
+//
+// means having the right to grant, to the maximum extent possible,
+// whether at the time of the initial grant or subsequently, any and
+// all of the rights conveyed by this License.
+//
+// 1.10. "Modifications"
+//
+// means any of the following:
+//
+// (a) any file in Source Code Form that results from an addition to,
+// deletion from, or modification of the contents of Covered
+// Software; or
+//
+// (b) any new file in Source Code Form that contains any Covered
+// Software.
+//
+// 1.11. "Patent Claims" of a Contributor
+//
+// means any patent claim(s), including without limitation, method,
+// process, and apparatus claims, in any patent Licensable by such
+// Contributor that would be infringed, but for the grant of the
+// License, by the making, using, selling, offering for sale, having
+// made, import, or transfer of either its Contributions or its
+// Contributor Version.
+//
+// 1.12. "Secondary License"
+//
+// means either the GNU General Public License, Version 2.0, the GNU
+// Lesser General Public License, Version 2.1, the GNU Affero General
+// Public License, Version 3.0, or any later versions of those
+// licenses.
+//
+// 1.13. "Source Code Form"
+//
+// means the form of the work preferred for making modifications.
+//
+// 1.14. "You" (or "Your")
+//
+// means an individual or a legal entity exercising rights under this
+// License. For legal entities, "You" includes any entity that
+// controls, is controlled by, or is under common control with You. For
+// purposes of this definition, "control" means (a) the power, direct
+// or indirect, to cause the direction or management of such entity,
+// whether by contract or otherwise, or (b) ownership of more than
+// fifty percent (50%) of the outstanding shares or beneficial
+// ownership of such entity.
+//
+// 2. License Grants and Conditions
+// --------------------------------
+//
+// 2.1. Grants
+//
+// Each Contributor hereby grants You a world-wide, royalty-free,
+// non-exclusive license:
+//
+// (a) under intellectual property rights (other than patent or trademark)
+//
+// Licensable by such Contributor to use, reproduce, make available,
+// modify, display, perform, distribute, and otherwise exploit its
+// Contributions, either on an unmodified basis, with Modifications, or
+// as part of a Larger Work; and
+//
+// (b) under Patent Claims of such Contributor to make, use, sell, offer
+//
+// for sale, have made, import, and otherwise transfer either its
+// Contributions or its Contributor Version.
+//
+// 2.2. Effective Date
+//
+// The licenses granted in Section 2.1 with respect to any Contribution
+// become effective for each Contribution on the date the Contributor first
+// distributes such Contribution.
+//
+// 2.3. Limitations on Grant Scope
+//
+// The licenses granted in this Section 2 are the only rights granted under
+// this License. No additional rights or licenses will be implied from the
+// distribution or licensing of Covered Software under this License.
+// Notwithstanding Section 2.1(b) above, no patent license is granted by a
+// Contributor:
+//
+// (a) for any code that a Contributor has removed from Covered Software;
+//
+// or
+//
+// (b) for infringements caused by: (i) Your and any other third party's
+//
+// modifications of Covered Software, or (ii) the combination of its
+// Contributions with other software (except as part of its Contributor
+// Version); or
+//
+// (c) under Patent Claims infringed by Covered Software in the absence of
+//
+// its Contributions.
+//
+// This License does not grant any rights in the trademarks, service marks,
+// or logos of any Contributor (except as may be necessary to comply with
+// the notice requirements in Section 3.4).
+//
+// 2.4. Subsequent Licenses
+//
+// No Contributor makes additional grants as a result of Your choice to
+// distribute the Covered Software under a subsequent version of this
+// License (see Section 10.2) or under the terms of a Secondary License (if
+// permitted under the terms of Section 3.3).
+//
+// 2.5. Representation
+//
+// Each Contributor represents that the Contributor believes its
+// Contributions are its original creation(s) or it has sufficient rights
+// to grant the rights to its Contributions conveyed by this License.
+//
+// 2.6. Fair Use
+//
+// This License is not intended to limit any rights You have under
+// applicable copyright doctrines of fair use, fair dealing, or other
+// equivalents.
+//
+// 2.7. Conditions
+//
+// Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+// in Section 2.1.
+//
+// 3. Responsibilities
+// -------------------
+//
+// 3.1. Distribution of Source Form
+//
+// All distribution of Covered Software in Source Code Form, including any
+// Modifications that You create or to which You contribute, must be under
+// the terms of this License. You must inform recipients that the Source
+// Code Form of the Covered Software is governed by the terms of this
+// License, and how they can obtain a copy of this License. You may not
+// attempt to alter or restrict the recipients' rights in the Source Code
+// Form.
+//
+// 3.2. Distribution of Executable Form
+//
+// If You distribute Covered Software in Executable Form then:
+//
+// (a) such Covered Software must also be made available in Source Code
+//
+// Form, as described in Section 3.1, and You must inform recipients of
+// the Executable Form how they can obtain a copy of such Source Code
+// Form by reasonable means in a timely manner, at a charge no more
+// than the cost of distribution to the recipient; and
+//
+// (b) You may distribute such Executable Form under the terms of this
+//
+// License, or sublicense it under different terms, provided that the
+// license for the Executable Form does not attempt to limit or alter
+// the recipients' rights in the Source Code Form under this License.
+//
+// 3.3. Distribution of a Larger Work
+//
+// You may create and distribute a Larger Work under terms of Your choice,
+// provided that You also comply with the requirements of this License for
+// the Covered Software. If the Larger Work is a combination of Covered
+// Software with a work governed by one or more Secondary Licenses, and the
+// Covered Software is not Incompatible With Secondary Licenses, this
+// License permits You to additionally distribute such Covered Software
+// under the terms of such Secondary License(s), so that the recipient of
+// the Larger Work may, at their option, further distribute the Covered
+// Software under the terms of either this License or such Secondary
+// License(s).
+//
+// 3.4. Notices
+//
+// You may not remove or alter the substance of any license notices
+// (including copyright notices, patent notices, disclaimers of warranty,
+// or limitations of liability) contained within the Source Code Form of
+// the Covered Software, except that You may alter any license notices to
+// the extent required to remedy known factual inaccuracies.
+//
+// 3.5. Application of Additional Terms
+//
+// You may choose to offer, and to charge a fee for, warranty, support,
+// indemnity or liability obligations to one or more recipients of Covered
+// Software. However, You may do so only on Your own behalf, and not on
+// behalf of any Contributor. You must make it absolutely clear that any
+// such warranty, support, indemnity, or liability obligation is offered by
+// You alone, and You hereby agree to indemnify every Contributor for any
+// liability incurred by such Contributor as a result of warranty, support,
+// indemnity or liability terms You offer. You may include additional
+// disclaimers of warranty and limitations of liability specific to any
+// jurisdiction.
+//
+// 4. Inability to Comply Due to Statute or Regulation
+// ---------------------------------------------------
+//
+// If it is impossible for You to comply with any of the terms of this
+// License with respect to some or all of the Covered Software due to
+// statute, judicial order, or regulation then You must: (a) comply with
+// the terms of this License to the maximum extent possible; and (b)
+// describe the limitations and the code they affect. Such description must
+// be placed in a text file included with all distributions of the Covered
+// Software under this License. Except to the extent prohibited by statute
+// or regulation, such description must be sufficiently detailed for a
+// recipient of ordinary skill to be able to understand it.
+//
+// 5. Termination
+// --------------
+//
+// 5.1. The rights granted under this License will terminate automatically
+// if You fail to comply with any of its terms. However, if You become
+// compliant, then the rights granted under this License from a particular
+// Contributor are reinstated (a) provisionally, unless and until such
+// Contributor explicitly and finally terminates Your grants, and (b) on an
+// ongoing basis, if such Contributor fails to notify You of the
+// non-compliance by some reasonable means prior to 60 days after You have
+// come back into compliance. Moreover, Your grants from a particular
+// Contributor are reinstated on an ongoing basis if such Contributor
+// notifies You of the non-compliance by some reasonable means, this is the
+// first time You have received notice of non-compliance with this License
+// from such Contributor, and You become compliant prior to 30 days after
+// Your receipt of the notice.
+//
+// 5.2. If You initiate litigation against any entity by asserting a patent
+// infringement claim (excluding declaratory judgment actions,
+// counter-claims, and cross-claims) alleging that a Contributor Version
+// directly or indirectly infringes any patent, then the rights granted to
+// You by any and all Contributors for the Covered Software under Section
+// 2.1 of this License shall terminate.
+//
+// 5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+// end user license agreements (excluding distributors and resellers) which
+// have been validly granted by You or Your distributors under this License
+// prior to termination shall survive termination.
+//
+// ************************************************************************
+// * *
+// * 6. Disclaimer of Warranty *
+// * ------------------------- *
+// * *
+// * Covered Software is provided under this License on an "as is" *
+// * basis, without warranty of any kind, either expressed, implied, or *
+// * statutory, including, without limitation, warranties that the *
+// * Covered Software is free of defects, merchantable, fit for a *
+// * particular purpose or non-infringing. The entire risk as to the *
+// * quality and performance of the Covered Software is with You. *
+// * Should any Covered Software prove defective in any respect, You *
+// * (not any Contributor) assume the cost of any necessary servicing, *
+// * repair, or correction. This disclaimer of warranty constitutes an *
+// * essential part of this License. No use of any Covered Software is *
+// * authorized under this License except under this disclaimer. *
+// * *
+// ************************************************************************
+//
+// ************************************************************************
+// * *
+// * 7. Limitation of Liability *
+// * -------------------------- *
+// * *
+// * Under no circumstances and under no legal theory, whether tort *
+// * (including negligence), contract, or otherwise, shall any *
+// * Contributor, or anyone who distributes Covered Software as *
+// * permitted above, be liable to You for any direct, indirect, *
+// * special, incidental, or consequential damages of any character *
+// * including, without limitation, damages for lost profits, loss of *
+// * goodwill, work stoppage, computer failure or malfunction, or any *
+// * and all other commercial damages or losses, even if such party *
+// * shall have been informed of the possibility of such damages. This *
+// * limitation of liability shall not apply to liability for death or *
+// * personal injury resulting from such party's negligence to the *
+// * extent applicable law prohibits such limitation. Some *
+// * jurisdictions do not allow the exclusion or limitation of *
+// * incidental or consequential damages, so this exclusion and *
+// * limitation may not apply to You. *
+// * *
+// ************************************************************************
+//
+// 8. Litigation
+// -------------
+//
+// Any litigation relating to this License may be brought only in the
+// courts of a jurisdiction where the defendant maintains its principal
+// place of business and such litigation shall be governed by laws of that
+// jurisdiction, without reference to its conflict-of-law provisions.
+// Nothing in this Section shall prevent a party's ability to bring
+// cross-claims or counter-claims.
+//
+// 9. Miscellaneous
+// ----------------
+//
+// This License represents the complete agreement concerning the subject
+// matter hereof. If any provision of this License is held to be
+// unenforceable, such provision shall be reformed only to the extent
+// necessary to make it enforceable. Any law or regulation which provides
+// that the language of a contract shall be construed against the drafter
+// shall not be used to construe this License against a Contributor.
+//
+// 10. Versions of the License
+// ---------------------------
+//
+// 10.1. New Versions
+//
+// Mozilla Foundation is the license steward. Except as provided in Section
+// 10.3, no one other than the license steward has the right to modify or
+// publish new versions of this License. Each version will be given a
+// distinguishing version number.
+//
+// 10.2. Effect of New Versions
+//
+// You may distribute the Covered Software under the terms of the version
+// of the License under which You originally received the Covered Software,
+// or under the terms of any subsequent version published by the license
+// steward.
+//
+// 10.3. Modified Versions
+//
+// If you create software not governed by this License, and you want to
+// create a new license for such software, you may create and use a
+// modified version of this License if you rename the license and remove
+// any references to the name of the license steward (except to note that
+// such modified license differs from this License).
+//
+// 10.4. Distributing Source Code Form that is Incompatible With Secondary
+// Licenses
+//
+// If You choose to distribute Source Code Form that is Incompatible With
+// Secondary Licenses under the terms of this version of the License, the
+// notice described in Exhibit B of this License must be attached.
+//
+// Exhibit A - Source Code Form License Notice
+// -------------------------------------------
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// If it is not possible or desirable to put the notice in a particular
+// file, then You may include the notice in a location (such as a LICENSE
+// file in a relevant directory) where a recipient would be likely to look
+// for such a notice.
+//
+// You may add additional accurate notices of copyright ownership.
+//
+// Exhibit B - "Incompatible With Secondary Licenses" Notice
+// ---------------------------------------------------------
+//
+// This Source Code Form is "Incompatible With Secondary Licenses", as
+// defined by the Mozilla Public License, v. 2.0.
+//
+// From:
+// https://gitlab.torproject.org/tpo/onion-services/sauteed-onions/monitor/-/blob/main/follow-go/main.go#L115-124
+// https://gitlab.torproject.org/tpo/onion-services/sauteed-onions/monitor/-/blob/main/follow-go/x509.go
+// https://github.com/SSLMate/certspotter/blob/54f34077d3bebe8aafce07dcfbffeb928c6e1d04/x509.go#L380
+
+func SANsFromLeafEntries(startIndex int64, leafEntries []ct.LeafEntry) (sans []string, errs []error) {
+ for offset, leafEntry := range leafEntries {
+ leafIndex := startIndex + int64(offset)
+ e, err := ct.LogEntryFromLeaf(leafIndex, &leafEntry)
+ if err != nil {
+ errs = append(errs, fmt.Errorf("leaf at index %d: %v", leafIndex, err))
+ continue
+ }
+ s, err := sansFromLogEntry(e)
+ if err != nil {
+ errs = append(errs, fmt.Errorf("leaf at index %d: %v", leafIndex, err))
+ }
+ sans = append(sans, s...)
+ }
+ return
+}
+
+func sansFromLogEntry(entry *ct.LogEntry) ([]string, error) {
+ if entry.Precert == nil && entry.X509Cert == nil {
+ return nil, fmt.Errorf("no (pre)cert in log entry")
+ }
+ if entry.Precert != nil && entry.X509Cert != nil {
+ return nil, fmt.Errorf("both precert and cert in log entry")
+ }
+
+ var exts []pkix.Extension
+ if entry.Precert != nil {
+ exts = entry.Precert.TBSCertificate.Extensions
+ }
+ if entry.X509Cert != nil {
+ exts = entry.X509Cert.Extensions
+ }
+
+ var sans []string
+ for _, ext := range exts {
+ if ext.Id.Equal(asn1.ObjectIdentifier{2, 5, 29, 17}) {
+ moreSANs, err := extract(ext)
+ if err != nil {
+ return nil, fmt.Errorf("parse: %v", err)
+ }
+
+ sans = append(sans, moreSANs...)
+ }
+ }
+ return sans, nil
+}
+
+func extract(extSAN pkix.Extension) ([]string, error) {
+ var seq asn1.RawValue
+ rest, err := asn1.Unmarshal(extSAN.Value, &seq)
+ if err != nil {
+ return nil, fmt.Errorf("failed to parse subjectAltName extension: %v", err)
+ }
+ if len(rest) != 0 {
+ // Don't complain if the SAN is followed by exactly one zero byte, which is a common error.
+ if !(len(rest) == 1 && rest[0] == 0) {
+ return nil, fmt.Errorf("trailing data in subjectAltName extension: %v", rest)
+ }
+ }
+ if !seq.IsCompound || seq.Tag != 16 || seq.Class != 0 {
+ return nil, fmt.Errorf("failed to parse subjectAltName extension: bad SAN sequence")
+ }
+
+ sans := []string{}
+ buf := seq.Bytes
+ for len(buf) > 0 {
+ var val asn1.RawValue
+ var err error
+ buf, err = asn1.Unmarshal(buf, &val)
+ if err != nil {
+ return nil, fmt.Errorf("failed to parse subjectAltName extension item: %v", err)
+ }
+
+ sans = append(sans, string(val.Bytes))
+ }
+ return sans, nil
+}
--
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