feat: add cosign signing for docker images in release pipeline

.github/workflows/release.yml

@@ -9,6 +9,7 @@ on:
 permissions:
   contents: write   # Required for creating releases
   packages: write   # Required for pushing to GHCR
+  id-token: write   # Required for cosign keyless signing
 
 jobs:
   build-and-release:
@@ -55,7 +56,11 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
+      - name: Install cosign
+        uses: sigstore/cosign-installer@59acb6260d9c0ba8f4a2f9d9b48431a222b68e20 # v3.5.0
+
       - name: Build and push Squid image
+        id: build_squid
         uses: docker/build-push-action@v5
         with:
           context: ./containers/squid
@@ -66,7 +71,27 @@ jobs:
           cache-from: type=gha
           cache-to: type=gha,mode=max
 
+      - name: Sign Squid image with cosign
+        run: |
+          cosign sign --yes \
+            ghcr.io/${{ github.repository }}/squid@${{ steps.build_squid.outputs.digest }}
+
+      - name: Generate SBOM for Squid image
+        uses: anchore/sbom-action@d94f46e13c6c62f59525ac9a1e147a99dc0b9bf5 # v0.17.0
+        with:
+          image: ghcr.io/${{ github.repository }}/squid@${{ steps.build_squid.outputs.digest }}
+          format: spdx-json
+          output-file: squid-sbom.spdx.json
+
+      - name: Attest SBOM for Squid image
+        run: |
+          cosign attest --yes \
+            --predicate squid-sbom.spdx.json \
+            --type spdxjson \
+            ghcr.io/${{ github.repository }}/squid@${{ steps.build_squid.outputs.digest }}
+
       - name: Build and push Agent image
+        id: build_agent
         uses: docker/build-push-action@v5
         with:
           context: ./containers/agent
@@ -77,6 +102,25 @@ jobs:
           cache-from: type=gha
           cache-to: type=gha,mode=max
 
+      - name: Sign Agent image with cosign
+        run: |
+          cosign sign --yes \
+            ghcr.io/${{ github.repository }}/agent@${{ steps.build_agent.outputs.digest }}
+
+      - name: Generate SBOM for Agent image
+        uses: anchore/sbom-action@d94f46e13c6c62f59525ac9a1e147a99dc0b9bf5 # v0.17.0
+        with:
+          image: ghcr.io/${{ github.repository }}/agent@${{ steps.build_agent.outputs.digest }}
+          format: spdx-json
+          output-file: agent-sbom.spdx.json
+
+      - name: Attest SBOM for Agent image
+        run: |
+          cosign attest --yes \
+            --predicate agent-sbom.spdx.json \
+            --type spdxjson \
+            ghcr.io/${{ github.repository }}/agent@${{ steps.build_agent.outputs.digest }}
+
       - name: Install pkg for binary creation
         run: npm install -g pkg
 

README.md

@@ -31,6 +31,47 @@ sudo awf --help
 
 **Note:** Verify checksums after download by downloading `checksums.txt` from the release page.
 
+### Docker Image Verification
+
+All published Docker images are signed with [cosign](https://github.com/sigstore/cosign) using keyless signing. You can verify the signatures to ensure image authenticity and integrity:
+
+```bash
+# Install cosign (recommended: use package manager)
+# See https://docs.sigstore.dev/cosign/installation/ for all installation options
+
+# Homebrew (macOS/Linux)
+# brew install cosign
+
+# Debian/Ubuntu (via official package repository)
+# sudo apt update && sudo apt install -y cosign
+
+# Quick install for testing (verify checksums from GitHub release page for production)
+curl -sSfL https://github.com/sigstore/cosign/releases/latest/download/cosign-linux-amd64 -o cosign
+chmod +x cosign
+sudo mv cosign /usr/local/bin/
+
+# Verify Squid image signature
+cosign verify \
+  --certificate-identity-regexp 'https://github.com/githubnext/gh-aw-firewall/.*' \
+  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
+  ghcr.io/githubnext/gh-aw-firewall/squid:latest
+
+# Verify Agent image signature
+cosign verify \
+  --certificate-identity-regexp 'https://github.com/githubnext/gh-aw-firewall/.*' \
+  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
+  ghcr.io/githubnext/gh-aw-firewall/agent:latest
+
+# Verify SBOM attestation
+cosign verify-attestation \
+  --certificate-identity-regexp 'https://github.com/githubnext/gh-aw-firewall/.*' \
+  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
+  --type spdxjson \
+  ghcr.io/githubnext/gh-aw-firewall/squid:latest
+```
+
+The images are signed during the release process using GitHub Actions OIDC tokens, ensuring they come from the official repository.
+
 ### Basic Usage
 
 ```bash

docs/RELEASE_TEMPLATE.md

@@ -83,3 +83,35 @@ Published to GitHub Container Registry:
 - `ghcr.io/{{REPOSITORY}}/agent:{{VERSION_NUMBER}}`
 - `ghcr.io/{{REPOSITORY}}/squid:latest`
 - `ghcr.io/{{REPOSITORY}}/agent:latest`
+
+### Image Verification
+
+All container images are signed with [cosign](https://github.com/sigstore/cosign) for authenticity and integrity verification:
+
+```bash
+# Install cosign (recommended: use package manager)
+# See https://docs.sigstore.dev/cosign/installation/
+
+# Homebrew: brew install cosign
+# Debian/Ubuntu: sudo apt install cosign
+# For other options, see the official documentation
+
+# Direct download (⚠️ Verify checksums from GitHub release page for production use)
+curl -sSfL https://github.com/sigstore/cosign/releases/latest/download/cosign-linux-amd64 -o cosign
+chmod +x cosign && sudo mv cosign /usr/local/bin/
+
+# Verify image signature (example for squid image)
+cosign verify \
+  --certificate-identity-regexp 'https://github.com/{{REPOSITORY}}/.*' \
+  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
+  ghcr.io/{{REPOSITORY}}/squid:{{VERSION_NUMBER}}
+
+# Verify SBOM attestation
+cosign verify-attestation \
+  --certificate-identity-regexp 'https://github.com/{{REPOSITORY}}/.*' \
+  --certificate-oidc-issuer 'https://token.actions.githubusercontent.com' \
+  --type spdxjson \
+  ghcr.io/{{REPOSITORY}}/squid:{{VERSION_NUMBER}}
+```
+
+Images are signed using keyless signing with GitHub Actions OIDC tokens, ensuring they come from the official repository.