GHA: Verify toolchain checksum

.github/actions/setup-linux-toolchain/action.yml

@@ -7,17 +7,22 @@ inputs:
 runs:
   using: "composite"
   steps:
-    - name: Set TOOLCHAIN_URL (x86_64)
-      if: inputs.arch == 'x86_64'
+    - name: Set up environment
       shell: bash
       run: |
-        echo "TOOLCHAIN_URL=https://downloads.tuxfamily.org/godotengine/toolchains/linux/2021-02-11/x86_64-godot-linux-gnu_sdk-buildroot.tar.bz2" >> "$GITHUB_ENV"
-
-    - name: Set TOOLCHAIN_URL (x86_32)
-      if: inputs.arch == 'x86_32'
-      shell: bash
-      run: |
-        echo "TOOLCHAIN_URL=https://downloads.tuxfamily.org/godotengine/toolchains/linux/2021-02-11/i686-godot-linux-gnu_sdk-buildroot.tar.bz2" >> "$GITHUB_ENV"
+        # ! Settings:
+        TOOLCHAIN_64_URL=https://downloads.tuxfamily.org/godotengine/toolchains/linux/2021-02-11/x86_64-godot-linux-gnu_sdk-buildroot.tar.bz2
+        TOOLCHAIN_64_SHA=16c8302fcb676c1f0fb9df73d6cff250ba1f4286
+        TOOLCHAIN_32_URL=https://downloads.tuxfamily.org/godotengine/toolchains/linux/2021-02-11/i686-godot-linux-gnu_sdk-buildroot.tar.bz2
+        TOOLCHAIN_32_SHA=6171652abc54ef219e5187bc53660ee4e2f796f4
+        # ! Export variables:
+        if [[ "${{ inputs.arch }}" == "x86_64" ]]; then
+          echo "TOOLCHAIN_URL=${TOOLCHAIN_64_URL}" >> "$GITHUB_ENV"
+          echo "TOOLCHAIN_SHA=${TOOLCHAIN_64_SHA}" >> "$GITHUB_ENV"
+        elif [[ "${{ inputs.arch }}" == "x86_32" ]]; then
+          echo "TOOLCHAIN_URL=${TOOLCHAIN_32_URL}" >> "$GITHUB_ENV"
+          echo "TOOLCHAIN_SHA=${TOOLCHAIN_32_SHA}" >> "$GITHUB_ENV"
+        fi
 
     - name: Cache buildroot
       id: cache-buildroot
@@ -33,6 +38,7 @@ runs:
         mkdir buildroot
         wget ${TOOLCHAIN_URL} -O buildroot/buildroot.tar.bz2
         cd buildroot
+        echo "${TOOLCHAIN_SHA} buildroot.tar.bz2" | shasum --check
         tar -xjf buildroot.tar.bz2
         ls -l
         rm buildroot.tar.bz2