|
| 1 | +--- |
| 2 | +id: verifying-signed-images |
| 3 | +title: Verifying Signed Images |
| 4 | +sidebar_label: Verify Signed Images |
| 5 | +description: Learn how to verify Seerr's signed container images and SBOM attestations using Cosign, Docker, Podman, or Skopeo. |
| 6 | +--- |
| 7 | + |
| 8 | +import Tabs from '@theme/Tabs'; |
| 9 | +import TabItem from '@theme/TabItem'; |
| 10 | + |
| 11 | +# Verifying Signed Images |
| 12 | + |
| 13 | +All Seerr container images published to GitHub Container Registry (GHCR) are cryptographically signed using [Sigstore Cosign](https://docs.sigstore.dev/quickstart/quickstart-cosign/). |
| 14 | +This ensures that the images you pull are authentic, tamper-proof, and built by the official Seerr release pipeline. |
| 15 | + |
| 16 | +Each image also includes a CycloneDX SBOM (Software Bill of Materials) attestation, generated with [Trivy](https://aquasecurity.github.io/trivy/), providing transparency about all dependencies included in the image. |
| 17 | + |
| 18 | +--- |
| 19 | + |
| 20 | +## Prerequisites |
| 21 | + |
| 22 | +You will need the following tools installed: |
| 23 | + |
| 24 | +- [Cosign](https://docs.sigstore.dev/cosign/system_config/installation/) |
| 25 | +- [Docker](https://docs.docker.com/get-docker/) **or** |
| 26 | +- [Podman](https://podman.io/getting-started/installation) (including [Skopeo](https://github.com/containers/skopeo/blob/main/install.md)) |
| 27 | + |
| 28 | +```bash |
| 29 | +cosign version |
| 30 | +``` |
| 31 | + |
| 32 | +If using **Podman**, ensure `skopeo` is available: |
| 33 | + |
| 34 | +```bash |
| 35 | +skopeo --version |
| 36 | +``` |
| 37 | + |
| 38 | +--- |
| 39 | + |
| 40 | +## Image Locations |
| 41 | + |
| 42 | +Official Seerr images are available from: |
| 43 | + |
| 44 | +- GitHub Container Registry (GHCR): `ghcr.io/seerr-team/seerr:<tag>` |
| 45 | + |
| 46 | +You can view all available tags on the [Seerr Releases page](https://github.com/seerr-team/seerr/releases). |
| 47 | + |
| 48 | +--- |
| 49 | + |
| 50 | +## Verifying a Specific Release Tag |
| 51 | + |
| 52 | +Each tagged release (for example `v2.7.4`) is immutable and cryptographically signed. |
| 53 | +Verification should always be performed using the image digest (SHA256). |
| 54 | + |
| 55 | +### Retrieve the Image Digest |
| 56 | + |
| 57 | +<Tabs groupId="verify-methods"> |
| 58 | + <TabItem value="docker" label="Docker"> |
| 59 | + |
| 60 | +```bash |
| 61 | +docker buildx imagetools inspect docker.io/seerr-team/seerr:v2.7.4 --format '{{json .Manifest.Digest}}' | tr -d '"' |
| 62 | +``` |
| 63 | + </TabItem> |
| 64 | + |
| 65 | + <TabItem value="podman" label="Podman / Skopeo"> |
| 66 | + |
| 67 | +```bash |
| 68 | +skopeo inspect docker://ghcr.io/seerr-team/seerr:v2.7.4 --format '{{.Digest}}' |
| 69 | +``` |
| 70 | + </TabItem> |
| 71 | +</Tabs> |
| 72 | + |
| 73 | +Example output: |
| 74 | + |
| 75 | +``` |
| 76 | +sha256:abcd1234... |
| 77 | +``` |
| 78 | + |
| 79 | +--- |
| 80 | + |
| 81 | +### Verify the Image Signature |
| 82 | + |
| 83 | +<Tabs groupId="registry-methods"> |
| 84 | + <TabItem value="ghcr" label="GitHub Container Registry (GHCR)"> |
| 85 | + |
| 86 | +```bash |
| 87 | +cosign verify ghcr.io/seerr-team/seerr@sha256:abcd1234... \ |
| 88 | + --certificate-identity "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v2.7.4" \ |
| 89 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 90 | +``` |
| 91 | + </TabItem> |
| 92 | + |
| 93 | + <TabItem value="dockerhub" label="Docker Hub"> |
| 94 | + |
| 95 | +```bash |
| 96 | +cosign verify seerr/seerr@sha256:abcd1234... \ |
| 97 | + --certificate-identity "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v2.7.4" \ |
| 98 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 99 | +``` |
| 100 | + </TabItem> |
| 101 | +</Tabs> |
| 102 | + |
| 103 | +:::info Successful Verification Example |
| 104 | +Verification for `ghcr.io/seerr-team/seerr@sha256:abcd1234...` |
| 105 | + |
| 106 | +The following checks were performed: |
| 107 | + |
| 108 | +- Cosign claims validated |
| 109 | +- Signatures verified against the transparency log |
| 110 | +- Certificate issued by Fulcio to the expected workflow identity |
| 111 | +::: |
| 112 | + |
| 113 | +--- |
| 114 | + |
| 115 | +## Verifying the `latest` Tag |
| 116 | + |
| 117 | +:::warning Latest Tag Warning |
| 118 | +The `latest` tag is **mutable**, meaning it will change with each new release. |
| 119 | +Always verify the digest that `latest` currently points to. |
| 120 | +::: |
| 121 | + |
| 122 | +### Retrieve the Digest for `latest` |
| 123 | + |
| 124 | +<Tabs groupId="verify-methods"> |
| 125 | + <TabItem value="docker" label="Docker"> |
| 126 | + |
| 127 | +```bash |
| 128 | +docker buildx imagetools inspect ghcr.io/seerr-team/seerr:latest --format '{{json .Manifest.Digest}}' | tr -d '"' |
| 129 | +``` |
| 130 | + </TabItem> |
| 131 | + |
| 132 | + <TabItem value="podman" label="Podman / Skopeo"> |
| 133 | + |
| 134 | +```bash |
| 135 | +skopeo inspect docker://ghcr.io/seerr-team/seerr:latest --format '{{.Digest}}' |
| 136 | +``` |
| 137 | + </TabItem> |
| 138 | +</Tabs> |
| 139 | + |
| 140 | +Example output: |
| 141 | + |
| 142 | +``` |
| 143 | +sha256:abcd1234... |
| 144 | +``` |
| 145 | + |
| 146 | +### Verify the Signature |
| 147 | + |
| 148 | +<Tabs groupId="registry-methods"> |
| 149 | + <TabItem value="ghcr" label="GHCR"> |
| 150 | + |
| 151 | +```bash |
| 152 | +cosign verify ghcr.io/seerr-team/seerr@sha256:abcd1234... \ |
| 153 | + --certificate-identity-regexp "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v.*" \ |
| 154 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 155 | +``` |
| 156 | + </TabItem> |
| 157 | + |
| 158 | + <TabItem value="dockerhub" label="Docker Hub"> |
| 159 | + |
| 160 | +```bash |
| 161 | +cosign verify seerr/seerr@sha256:abcd1234... \ |
| 162 | + --certificate-identity-regexp "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v.*" \ |
| 163 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 164 | +``` |
| 165 | + </TabItem> |
| 166 | +</Tabs> |
| 167 | + |
| 168 | +:::tip |
| 169 | +The wildcard `v.*` ensures verification works for any versioned release that `latest` represents. |
| 170 | +::: |
| 171 | + |
| 172 | +--- |
| 173 | + |
| 174 | +## Verifying SBOM Attestations |
| 175 | + |
| 176 | +Each image includes a CycloneDX SBOM attestation. |
| 177 | + |
| 178 | +### Verify the Attestation |
| 179 | + |
| 180 | +```bash |
| 181 | +cosign verify-attestation ghcr.io/seerr-team/seerr@sha256:abcd1234... \ |
| 182 | + --type cyclonedx \ |
| 183 | + --certificate-identity "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v2.7.4" \ |
| 184 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 185 | +``` |
| 186 | +:::info Successful Verification Example |
| 187 | +Verification for `ghcr.io/seerr-team/seerr@sha256:abcd1234...` |
| 188 | + |
| 189 | +The following checks were performed: |
| 190 | + |
| 191 | +- Cosign claims validated |
| 192 | +- Signatures verified against the transparency log |
| 193 | +- Certificate issued by Fulcio to the expected workflow identity |
| 194 | +::: |
| 195 | + |
| 196 | +### Extract the SBOM for Inspection |
| 197 | + |
| 198 | +```bash |
| 199 | +cosign verify-attestation ghcr.io/seerr-team/seerr@sha256:abcd1234... \ |
| 200 | + --type cyclonedx \ |
| 201 | + --certificate-identity "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v2.7.4" \ |
| 202 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" | jq -r '.payload | @base64d' > sbom.json |
| 203 | +``` |
| 204 | + |
| 205 | +You can open `sbom.json` in a CycloneDX viewer or analyse it with [Trivy](https://aquasecurity.github.io/trivy/) or [Dependency-Track](https://dependencytrack.org/). |
| 206 | + |
| 207 | +--- |
| 208 | + |
| 209 | +## Expected Certificate Identity |
| 210 | + |
| 211 | +The expected certificate identity for all signed Seerr images is: |
| 212 | + |
| 213 | +``` |
| 214 | +https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v* |
| 215 | +``` |
| 216 | + |
| 217 | +This confirms that the image was: |
| 218 | + |
| 219 | +- Built by the official Seerr Release workflow |
| 220 | +- Produced from the seerr-team/seerr repository |
| 221 | +- Signed using GitHub’s OIDC identity via Sigstore Fulcio |
| 222 | + |
| 223 | +--- |
| 224 | + |
| 225 | +## Troubleshooting |
| 226 | + |
| 227 | +| Issue | Likely Cause | Suggested Fix | |
| 228 | +|-------|---------------|----------------| |
| 229 | +| `no matching signatures` | Incorrect digest or tag | Retrieve the digest again using Docker or Skopeo | |
| 230 | +| `certificate identity does not match expected` | Workflow reference changed | Ensure your `--certificate-identity` matches this documentation | |
| 231 | +| `cosign: command not found` | Cosign not installed | Install Cosign from the official release | |
| 232 | +| `certificate expired` | Old release | Verify a newer tag or digest | |
| 233 | + |
| 234 | +--- |
| 235 | + |
| 236 | +## Example: Full Verification Flow |
| 237 | + |
| 238 | +<Tabs groupId="verify-examples"> |
| 239 | + <TabItem value="docker" label="Docker"> |
| 240 | + |
| 241 | +```bash |
| 242 | +DIGEST=$(docker buildx imagetools inspect ghcr.io/seerr-team/seerr:latest --format '{{json .Manifest.Digest}}' | tr -d '"') |
| 243 | + |
| 244 | +cosign verify ghcr.io/seerr-team/seerr@"$DIGEST" \ |
| 245 | + --certificate-identity-regexp "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v.*" \ |
| 246 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 247 | + |
| 248 | +cosign verify-attestation ghcr.io/seerr-team/seerr@"$DIGEST" \ |
| 249 | + --type cyclonedx \ |
| 250 | + --certificate-identity-regexp "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v.*" \ |
| 251 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 252 | +``` |
| 253 | + </TabItem> |
| 254 | + |
| 255 | + <TabItem value="podman" label="Podman / Skopeo"> |
| 256 | + |
| 257 | +```bash |
| 258 | +DIGEST=$(skopeo inspect docker://ghcr.io/seerr-team/seerr:latest --format '{{.Digest}}') |
| 259 | + |
| 260 | +cosign verify ghcr.io/seerr-team/seerr@"$DIGEST" \ |
| 261 | + --certificate-identity-regexp "https://github.com/seerr-team/seerr/.github/workflows/release.yml@refs/tags/v.*" \ |
| 262 | + --certificate-oidc-issuer "https://token.actions.githubusercontent.com" |
| 263 | +``` |
| 264 | + </TabItem> |
| 265 | +</Tabs> |
| 266 | + |
| 267 | +--- |
| 268 | + |
| 269 | +## Further Reading |
| 270 | + |
| 271 | +- [Sigstore Documentation](https://docs.sigstore.dev) |
| 272 | +- [Cosign Verification Guide](https://docs.sigstore.dev/cosign/verifying/verify/) |
| 273 | +- [CycloneDX Specification](https://cyclonedx.org/specification/overview/) |
| 274 | +- [Trivy Documentation](https://trivy.dev/latest/docs/) |
| 275 | +- [Skopeo Documentation](https://github.com/containers/skopeo) |
| 276 | +- [Podman Documentation](https://podman.io/get-started/) |
| 277 | +- [Docker Documentation](https://docs.docker.com/) |
| 278 | +- [Seerr GitHub Repository](https://github.com/seerr-team/seerr) |
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