[CI] Upgrade cosign; Wait 30s between signing and verifying signature (#1412)

Author: mickmis

.github/workflows/dss-publish.yml

@@ -25,8 +25,7 @@ jobs:
 
     steps:
       - name: Install Cosign
-        uses: sigstore/cosign-installer@v3.9.1
-
+        uses: sigstore/cosign-installer@cad07c2e89fa2edd6e2d7bab4c1aa38e53f76003  # v4.1.1
       - name: Job information
         run: |
           echo "Job information"

build/build.sh

@@ -56,8 +56,9 @@ else
     echo "Signing docker image ${TAG} (digest: ${DIGEST})..."
     cosign sign --yes "${DIGEST}"
 
-    echo "Verifying signature of docker image ${TAG} (digest: ${DIGEST})..."
-    cosign verify "${DIGEST}" --certificate-identity="${CERT_IDENTITY}" --certificate-oidc-issuer="${CERT_ISSUER}"
+    echo "Verifying signature of docker image ${TAG} (digest: ${DIGEST}) after a 30 seconds wait..."
+    sleep 30 # the signature may not be returned immediately after being published, so as a mitigation we wait for 30 seconds before verifying
+    cosign verify --certificate-identity="${CERT_IDENTITY}" --certificate-oidc-issuer="${CERT_ISSUER}" "${DIGEST}"
 
     echo "Signed and verified signature of docker image ${TAG} (digest: ${DIGEST})..."