ci: fixing AUR deployment

Author: scottc943

.github/workflows/release.yml

@@ -1,4 +1,3 @@
-cat .github/workflows/release.yml
 name: Release
 
 "on":
@@ -108,12 +107,36 @@ jobs:
 
           KEY_PATH="${RUNNER_TEMP}/penguinguide-aur-key"
 
+          NORMALIZED_KEY="$(
+            printf '%s' "${AUR_KEY_B64}" |
+              tr -d '[:space:]'
+          )"
+
+          unset AUR_KEY_B64
+
+          if [[ ! "${NORMALIZED_KEY}" =~ ^[A-Za-z0-9+/]+={0,2}$ ]]; then
+            echo "::error::AUR_KEY_B64 contains characters that are not valid Base64."
+            unset NORMALIZED_KEY
+            exit 1
+          fi
+
+          if (( ${#NORMALIZED_KEY} % 4 != 0 )); then
+            echo "::error::AUR_KEY_B64 has an invalid Base64 length."
+            unset NORMALIZED_KEY
+            exit 1
+          fi
+
           umask 077
 
-          printf '%s' "${AUR_KEY_B64}" |
-            base64 --decode > "${KEY_PATH}"
+          if ! printf '%s' "${NORMALIZED_KEY}" |
+            base64 --decode > "${KEY_PATH}"; then
+            echo "::error::AUR_KEY_B64 could not be decoded."
+            unset NORMALIZED_KEY
+            rm -f "${KEY_PATH}"
+            exit 1
+          fi
 
-          unset AUR_KEY_B64
+          unset NORMALIZED_KEY
 
           chmod 600 "${KEY_PATH}"
 
@@ -129,6 +152,8 @@ jobs:
 
           printf 'AUR_KEY_PATH=%s\n' "${KEY_PATH}" >> "${GITHUB_ENV}"
 
+          echo "AUR deployment key validated successfully."
+
       - name: Run GoReleaser
         shell: bash
         env: