add readme and workflow

Signed-off-by: linus-sun <[email protected]>

.github/workflows/ct_reusable_monitoring.yml

@@ -0,0 +1,83 @@
+# Copyright 2024 The Sigstore Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: Certificate Transparency Monitoring Template
+
+on:
+  workflow_call:
+    inputs:
+      once:
+        description: 'whether to run the identity monitor once or periodically'
+        default: true
+        required: false
+        type: boolean
+      config:
+        description: 'multiline yaml of configuration settings for identity monitor run'
+        required: true
+        type: string
+
+permissions:
+  contents: read
+
+env:
+  UPLOADED_LOG_NAME: checkpoint
+  LOG_FILE: checkpoint_log.txt
+
+jobs:
+  detect-workflow:
+    runs-on: ubuntu-latest
+    permissions:
+      id-token: write # Needed to detect the current reusable repository and ref.
+    outputs:
+      repository: ${{ steps.detect.outputs.repository }}
+      ref: ${{ steps.detect.outputs.ref }}
+    steps:
+      - name: Detect the repository and ref
+        id: detect
+        uses: slsa-framework/slsa-github-generator/.github/actions/detect-workflow-js@5a775b367a56d5bd118a224a811bba288150a563 # v2.0.0
+    # NOTE: This GHA should not be run concurrently.
+    concurrency:
+      group: certificate-transparency-monitor
+      cancel-in-progress: true
+
+  monitor:
+    runs-on: ubuntu-latest
+    needs: [detect-workflow]
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          repository: ${{ needs.detect-workflow.outputs.repository }}
+          ref: "${{ needs.detect-workflow.outputs.ref }}"
+      - uses: actions/setup-go@41dfa10bad2bb2ae585af6ee5bb4d7d973ad74ed # v5.1.0
+        with:
+          go-version: '1.23'
+      - name: Download artifact
+        uses: dawidd6/action-download-artifact@bf251b5aa9c2f7eeb574a96ee720e24f801b7c11 # v6
+        with:
+          name: ${{ env.UPLOADED_LOG_NAME }}
+        # Skip on first run since there will be no checkpoint
+        continue-on-error: true
+      - name: Log current checkpoints
+        run: cat ${{ env.LOG_FILE }}
+        # Skip on first run
+        continue-on-error: true
+      - run: go run ./cmd/ct_monitor --config ${{ inputs.config }} --file ${{ env.LOG_FILE }} --once=${{ inputs.once }}"
+      - name: Upload checkpoint
+        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
+        with:
+          name: ${{ env.UPLOADED_LOG_NAME }}
+          path: ${{ env.LOG_FILE }}
+          retention-days: ${{ inputs.artifact_retention_days }}
+      - name: Log new checkpoints
+        run: cat ${{ env.LOG_FILE }}

README.md

@@ -120,6 +120,54 @@ Upcoming features:
 * Support for other identities
    * CI identity values in Fulcio certificates
 
+## Certificate transparency log monitoring
+
+Certificate transparency log instances can also be monitored. To run, create a GitHub Actions workflow that uses the
+[reusable certificate transparency log monitoring workflow](https://github.com/sigstore/rekor-monitor/blob/main/.github/workflows/ct_reusable_monitoring.yml).
+It is recommended to run the log monitor every hour for optimal performance.
+
+Example workflow below:
+
+```
+name: Fulcio log and identity monitor
+on:
+  schedule:
+    - cron: '0 * * * *' # every hour
+
+permissions: read-all
+
+jobs:
+  run_consistency_proof:
+    permissions:
+      contents: read # Needed to checkout repositories
+      issues: write # Needed if you set "file_issue: true"
+      id-token: write # Needed to detect the current reusable repository and ref
+    uses: sigstore/rekor-monitor/.github/workflows/reusable_monitoring.yaml@main
+    with:
+      file_issue: true # Strongly recommended: Files an issue on monitoring failure
+      artifact_retention_days: 14 # Optional, default is 14: Must be longer than the cron job frequency
+      identities: |
+        certIdentities:
+          - certSubject: user@domain\.com
+          - certSubject: otheruser@domain\.com
+            issuers:
+              - https://accounts\.google\.com
+              - https://github\.com/login
+          - certSubject: https://github\.com/actions/starter-workflows/blob/main/\.github/workflows/lint\.yaml@.*
+            issuers:
+              - https://token\.actions\.githubusercontent\.com
+        subjects:
+          - subject@domain\.com
+        fingerprints:
+          - A0B1C2D3E4F5
+        fulcioExtensions:
+          build-config-uri:
+            - https://example.com/owner/repository/build-config.yml
+        customExtensions:
+          - objectIdentifier: 1.3.6.1.4.1.57264.1.9
+            extensionValues: https://github.com/slsa-framework/slsa-github-generator/.github/workflows/[email protected]
+```
+
 ## Security
 
 Please report any vulnerabilities following Sigstore's [security process](https://github.com/sigstore/.github/blob/main/SECURITY.md).

cmd/ct_monitor/main.go

@@ -138,11 +138,19 @@ func main() {
 		}
 
 		if identity.MonitoredValuesExist(monitoredValues) {
-			_, err = ct.IdentitySearch(fulcioClient, *config.StartIndex, *config.EndIndex, monitoredValues)
+			foundEntries, err := ct.IdentitySearch(fulcioClient, *config.StartIndex, *config.EndIndex, monitoredValues)
 			if err != nil {
 				fmt.Fprintf(os.Stderr, "failed to successfully complete identity search: %v", err)
 				return
 			}
+
+			notificationPool := notifications.CreateNotificationPool(config)
+
+			err = notifications.TriggerNotifications(notificationPool, foundEntries)
+			if err != nil {
+				// continue running consistency check if notifications fail to trigger
+				fmt.Fprintf(os.Stderr, "failed to trigger notifications: %v", err)
+			}
 		}
 
 		if *once || inputEndIndex != nil {
@@ -152,5 +160,4 @@ func main() {
 		config.StartIndex = config.EndIndex
 		config.EndIndex = nil
 	}
-
 }

pkg/ct/monitor.go

@@ -87,7 +87,7 @@ func MatchedIndices(logEntries []ct.LogEntry, mvs identity.MonitoredValues) ([]i
 	return matchedEntries, nil
 }
 
-func IdentitySearch(client *ctclient.LogClient, startIndex int, endIndex int, mvs identity.MonitoredValues) ([]identity.LogEntry, error) {
+func IdentitySearch(client *ctclient.LogClient, startIndex int, endIndex int, mvs identity.MonitoredValues) ([]identity.MonitoredIdentity, error) {
 	retrievedEntries, err := GetCTLogEntries(client, startIndex, endIndex)
 	if err != nil {
 		return nil, err
@@ -96,5 +96,7 @@ func IdentitySearch(client *ctclient.LogClient, startIndex int, endIndex int, mv
 	if err != nil {
 		return nil, err
 	}
-	return matchedEntries, nil
+	identities := identity.CreateIdentitiesList(mvs)
+	monitoredIdentities := identity.CreateMonitoredIdentities(matchedEntries, identities)
+	return monitoredIdentities, nil
 }