feat(vex): Add support for CSAF format

docs/docs/supply-chain/vex.md

@@ -5,10 +5,11 @@
 
 Trivy supports filtering detected vulnerabilities using [the Vulnerability Exploitability Exchange (VEX)](https://www.ntia.gov/files/ntia/publications/vex_one-page_summary.pdf), a standardized format for sharing and exchanging information about vulnerabilities.
 By providing VEX alongside the Software Bill of Materials (SBOM) during scanning, it is possible to filter vulnerabilities based on their status.
-Currently, Trivy supports the following two formats:
+Currently, Trivy supports the following three formats:
 
 - [CycloneDX](https://cyclonedx.org/capabilities/vex/)
 - [OpenVEX](https://github.com/openvex/spec)
+- [CSAF](https://oasis-open.github.io/csaf-documentation/specification.html)
 
 This is still an experimental implementation, with only minimal functionality added.
 
@@ -182,4 +183,139 @@ Total: 80 (UNKNOWN: 0, LOW: 58, MEDIUM: 6, HIGH: 16, CRITICAL: 0)
 CVE-2019-8457 is no longer shown as it is filtered out according to the given OpenVEX document.
 
 [openvex]: https://github.com/openvex/spec
-[purl]: https://github.com/package-url/purl-spec
+[purl]: https://github.com/package-url/purl-spec
+
+## CSAF
+Trivy also supports [CSAF][csaf] format for VEX.
+Since CSAF aims to be SBOM format agnostic, both CycloneDX and SPDX formats are available for use as input SBOMs in Trivy.
+
+The following steps are required:
+
+1. Generate a SBOM (CycloneDX or SPDX)
+2. Create a CSAF document based on the SBOM generated in step 1
+3. Provide the CSAF document when scanning the SBOM
+
+### Generating the SBOM
+You can generate a CycloneDX or SPDX SBOM with Trivy as follows:
+
+```shell
+$ trivy image --format spdx-json --output debian11.spdx.json debian:11
+```
+
+### Create the CSAF document
+Create a CSAF document in JSON format as follows:
+
+```
+$ cat <<EOF > debian11.vex.csaf
+{
+  "document": {
+    "category": "csaf_vex",
+    "csaf_version": "2.0",
+    "notes": [
+      {
+        "category": "summary",
+        "text": "Example Company VEX document. Unofficial content for demonstration purposes only.",
+        "title": "Author comment"
+      }
+    ],
+    "publisher": {
+      "category": "vendor",
+      "name": "Example Company ProductCERT",
+      "namespace": "https://psirt.example.com"
+    },
+    "title": "AquaSecurity example VEX document",
+    "tracking": {
+      "current_release_date": "2024-01-01T11:00:00.000Z",
+      "generator": {
+        "date": "2024-01-01T11:00:00.000Z",
+        "engine": {
+          "name": "Secvisogram",
+          "version": "1.11.0"
+        }
+      },
+      "id": "2024-EVD-UC-01-A-001",
+      "initial_release_date": "2024-01-01T11:00:00.000Z",
+      "revision_history": [
+        {
+          "date": "2024-01-01T11:00:00.000Z",
+          "number": "1",
+          "summary": "Initial version."
+        }
+      ],
+      "status": "final",
+      "version": "1"
+    }
+  },
+  "product_tree": {
+    "branches": [
+      {
+        "branches": [
+          {
+            "branches": [
+              {
+                "category": "product_version",
+                "name": "5.3",
+                "product": {
+                  "name": "Database Libraries 5.3",
+                  "product_id": "LIBDB-5328",
+                  "product_identification_helper": {
+                    "purl": "pkg:deb/debian/[email protected]%2Bdfsg1-0.8?arch=amd64\u0026distro=debian-11.8"
+                  }
+                }
+              }
+            ],
+            "category": "product_name",
+            "name": "Database Libraries"
+          }
+        ],
+        "category": "vendor",
+        "name": "Debian"
+      }
+    ]
+  },
+  "vulnerabilities": [
+    {
+      "cve": "CVE-2019-8457",
+      "notes": [
+        {
+          "category": "description",
+          "text": "SQLite3 from 3.6.0 to and including 3.27.2 is vulnerable to heap out-of-bound read in the rtreenode() function when handling invalid rtree tables.",
+          "title": "CVE description"
+        }
+      ],
+      "product_status": {
+        "known_not_affected": [
+          "LIBDB-5328"
+        ]
+      },
+      "threats": [
+        {
+          "category": "impact",
+          "details": "Vulnerable code not in execute path.",
+          "product_ids": [
+            "LIBDB-5328"
+          ]
+        }
+      ]
+    }
+  ]
+}
+EOF
+```
+
+### Scan SBOM with CSAF document
+Provide the CSAF document when scanning the SBOM.
+
+```console
+$ trivy sbom debian11.spdx.json --vex debian11.vex.csaf
+...
+2024-01-02T10:28:26.704+0100	INFO	Filtered out the detected vulnerability	{"VEX format": "CSAF", "vulnerability-id": "CVE-2019-8457", "status": "not_affected"}
+
+debian11.spdx.json (debian 11.6)
+================================
+Total: 80 (UNKNOWN: 0, LOW: 58, MEDIUM: 6, HIGH: 16, CRITICAL: 0)
+```
+
+CVE-2019-8457 is no longer shown as it is filtered out according to the given CSAF document.
+
+[csaf]: https://oasis-open.github.io/csaf-documentation/specification.html

go.mod

@@ -41,6 +41,7 @@ require (
 	github.com/cenkalti/backoff v2.2.1+incompatible
 	github.com/cheggaaa/pb/v3 v3.1.4
 	github.com/containerd/containerd v1.7.11
+	github.com/csaf-poc/csaf_distribution/v3 v3.0.0
 	github.com/docker/docker v24.0.7+incompatible
 	github.com/docker/go-connections v0.4.0
 	github.com/fatih/color v1.15.0
@@ -101,11 +102,11 @@ require (
 	github.com/twitchtv/twirp v8.1.2+incompatible
 	github.com/xeipuuv/gojsonschema v1.2.0
 	github.com/xlab/treeprint v1.2.0
-	go.etcd.io/bbolt v1.3.7
+	go.etcd.io/bbolt v1.3.8
 	go.uber.org/zap v1.26.0
-	golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1
+	golang.org/x/exp v0.0.0-20231110203233-9a3e6036ecaa
 	golang.org/x/mod v0.14.0
-	golang.org/x/sync v0.4.0
+	golang.org/x/sync v0.5.0
 	golang.org/x/term v0.15.0
 	golang.org/x/text v0.14.0
 	golang.org/x/xerrors v0.0.0-20220907171357-04be3eba64a2
@@ -131,11 +132,13 @@ require (
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
 	github.com/Azure/go-autorest v14.2.0+incompatible // indirect
 	github.com/Azure/go-autorest/autorest v0.11.29 // indirect
-	github.com/Azure/go-autorest/autorest/adal v0.9.22 // indirect
+	github.com/Azure/go-autorest/autorest/adal v0.9.23 // indirect
 	github.com/Azure/go-autorest/autorest/date v0.3.0 // indirect
 	github.com/Azure/go-autorest/logger v0.2.1 // indirect
 	github.com/Azure/go-autorest/tracing v0.6.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.1.1 // indirect
+	github.com/Intevation/gval v1.3.0 // indirect
+	github.com/Intevation/jsonpath v0.2.1 // indirect
 	github.com/MakeNowJust/heredoc v1.0.0 // indirect
 	github.com/Masterminds/goutils v1.1.1 // indirect
 	github.com/Masterminds/semver v1.5.0 // indirect
@@ -144,7 +147,7 @@ require (
 	github.com/Microsoft/go-winio v0.6.1 // indirect
 	github.com/Microsoft/hcsshim v0.11.4 // indirect
 	github.com/OneOfOne/xxhash v1.2.8 // indirect
-	github.com/ProtonMail/go-crypto v0.0.0-20230828082145-3c4c8a2d2371 // indirect
+	github.com/ProtonMail/go-crypto v0.0.0-20230923063757-afb1ddc0824c // indirect
 	github.com/VividCortex/ewma v1.2.0 // indirect
 	github.com/agext/levenshtein v1.2.3 // indirect
 	github.com/agnivade/levenshtein v1.1.1 // indirect
@@ -208,7 +211,7 @@ require (
 	github.com/cenkalti/backoff/v4 v4.2.1 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/chai2010/gettext-go v1.0.2 // indirect
-	github.com/cloudflare/circl v1.3.3 // indirect
+	github.com/cloudflare/circl v1.3.6 // indirect
 	github.com/containerd/cgroups v1.1.0 // indirect
 	github.com/containerd/continuity v0.4.2 // indirect
 	github.com/containerd/fifo v1.1.0 // indirect
@@ -252,29 +255,34 @@ require (
 	github.com/go-openapi/spec v0.20.9 // indirect
 	github.com/go-openapi/swag v0.22.4 // indirect
 	github.com/go-openapi/validate v0.22.1 // indirect
+	github.com/go-sql-driver/mysql v1.7.1 // indirect
+	github.com/go-test/deep v1.1.0 // indirect
 	github.com/gobwas/glob v0.2.3 // indirect
-	github.com/goccy/go-yaml v1.8.1 // indirect
+	github.com/goccy/go-yaml v1.9.5 // indirect
 	github.com/gofrs/uuid v4.3.1+incompatible // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang-jwt/jwt/v4 v4.5.0 // indirect
 	github.com/golang-jwt/jwt/v5 v5.0.0 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
 	github.com/google/btree v1.1.2 // indirect
+	github.com/google/flatbuffers v2.0.8+incompatible // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
 	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
+	github.com/google/pprof v0.0.0-20230406165453-00490a63f317 // indirect
 	github.com/google/s2a-go v0.1.5 // indirect
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 // indirect
 	github.com/googleapis/enterprise-certificate-proxy v0.2.5 // indirect
 	github.com/googleapis/gax-go/v2 v2.12.0 // indirect
 	github.com/gorilla/mux v1.8.1 // indirect
 	github.com/gosuri/uitable v0.0.4 // indirect
-	github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7 // indirect
+	github.com/gregjones/httpcache v0.0.0-20190611155906-901d90724c79 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-safetemp v1.0.0 // indirect
 	github.com/hashicorp/go-uuid v1.0.3 // indirect
 	github.com/hashicorp/go-version v1.6.0 // indirect
+	github.com/hashicorp/golang-lru v0.6.0 // indirect
 	github.com/hashicorp/hcl v1.0.0 // indirect
 	github.com/hashicorp/hcl/v2 v2.19.1 // indirect
 	github.com/huandu/xstrings v1.4.0 // indirect
@@ -302,7 +310,7 @@ require (
 	github.com/mattn/go-runewidth v0.0.14 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
 	github.com/microsoft/go-rustaudit v0.0.0-20220808201409-204dfee52032 // indirect
-	github.com/miekg/dns v1.1.50 // indirect
+	github.com/miekg/dns v1.1.53 // indirect
 	github.com/mitchellh/copystructure v1.2.0 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/go-testing-interface v1.14.1 // indirect
@@ -342,6 +350,7 @@ require (
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/rubenv/sql-migrate v1.5.2 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
+	github.com/santhosh-tekuri/jsonschema/v5 v5.3.1 // indirect
 	github.com/sergi/go-diff v1.3.1 // indirect
 	github.com/shibumi/go-pathspec v1.3.0 // indirect
 	github.com/shopspring/decimal v1.3.1 // indirect
@@ -375,7 +384,7 @@ require (
 	golang.org/x/oauth2 v0.13.0 // indirect
 	golang.org/x/sys v0.15.0 // indirect
 	golang.org/x/time v0.5.0 // indirect
-	golang.org/x/tools v0.13.0 // indirect
+	golang.org/x/tools v0.15.0 // indirect
 	google.golang.org/api v0.138.0 // indirect
 	google.golang.org/appengine v1.6.8 // indirect
 	google.golang.org/genproto v0.0.0-20231002182017-d307bd883b97 // indirect
@@ -405,7 +414,7 @@ require (
 	modernc.org/memory v1.7.2 // indirect
 	modernc.org/opt v0.1.3 // indirect
 	modernc.org/strutil v1.1.3 // indirect
-	modernc.org/token v1.0.1 // indirect
+	modernc.org/token v1.1.0 // indirect
 	oras.land/oras-go v1.2.3 // indirect
 	sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd // indirect
 	sigs.k8s.io/kustomize/api v0.13.5-0.20230601165947-6ce0bf390ce3 // indirect