Add checksum validation to hawkeye installation (#785)

Related to https://github.com/apple/container/pull/1869

Signed-off-by: Kathryn Baldauf <k_baldauf@apple.com>

scripts/install-hawkeye.sh

@@ -13,10 +13,38 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+set -euo pipefail
+
 if command -v .local/bin/hawkeye >/dev/null 2>&1; then
     echo "hawkeye already installed"
-else
-    echo "Installing hawkeye"
-    export VERSION=v6.5.1
-    curl --proto '=https' --tlsv1.2 -LsSf https://github.com/korandoru/hawkeye/releases/download/${VERSION}/hawkeye-installer.sh | CARGO_HOME=.local sh -s -- --no-modify-path
+    exit 0
 fi
+
+# This installer supports Apple silicon (arm64 macOS) only.
+if [ "$(uname -s)" != "Darwin" ] || [ "$(uname -m)" != "arm64" ]; then
+    echo "error: install-hawkeye.sh supports Apple silicon (arm64 macOS) only" >&2
+    exit 1
+fi
+
+VERSION=v6.5.1
+ARTIFACT="hawkeye-aarch64-apple-darwin.tar.xz"
+ARTIFACT_URL="https://github.com/korandoru/hawkeye/releases/download/${VERSION}/${ARTIFACT}"
+# Pinned SHA-256 of ${ARTIFACT} for ${VERSION}; update when bumping VERSION.
+EXPECTED_SHA256="99777f21e4e56c9946ed93621885532c6a0476377f497565c583f5911f2cbb1f"
+
+echo "Installing hawkeye ${VERSION}"
+workdir="$(mktemp -d)"
+trap 'rm -rf "${workdir}"' EXIT
+tarball="${workdir}/${ARTIFACT}"
+
+# Download the tarball, verify it against the pinned checksum (aborts on
+# mismatch), then extract just the hawkeye binary into .local/bin.
+curl --proto '=https' --tlsv1.2 -LsSf "${ARTIFACT_URL}" -o "${tarball}"
+echo "${EXPECTED_SHA256}  ${tarball}" | shasum -a 256 -c -
+
+tar -xf "${tarball}" --strip-components 1 -C "${workdir}"
+mkdir -p .local/bin
+mv "${workdir}/hawkeye" .local/bin/hawkeye
+chmod +x .local/bin/hawkeye
+
+echo "hawkeye ${VERSION} installed to .local/bin/hawkeye"