Add checksec to the release process (#476)

A recent [Twitter thread][mudge] suggested that tools like
[`checksec`][checksec] be used to validate release binaries. Checksec
reports whether modern security features like stack canaries are
employed. Proxy builds appear to do pretty well out-of-the-box.

This change introduces a checksec.sh wrapper that is used by the
Makefile during packaging. A new _package_ github action is introduced
to provide `checksec` and `jq` dependencies at runtime. (Note: the
version of checksec provided by debian does not include JSON output, so
it is instead fetched directly from GitHub).

During an automated release, the generated checksec is compared to an
expected set of values and, if a regression is detected, the release
will fail.

[mudge]: https://twitter.com/dotMudge/status/1249359519471341569
[checksec]: https://github.com/slimm609/checksec.sh

.github/actions/package/Dockerfile

@@ -0,0 +1,10 @@
+ARG BASE_IMAGE=rust:1.41.0-buster
+FROM $BASE_IMAGE
+WORKDIR /linkerd
+RUN apt-get update && \
+    apt-get install -y jq && \
+    apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/
+# v2.1.0
+ARG CHECKSEC_SHA=04582bad41589ad479ca8b1f0170ed317475b5a5
+RUN (cd /usr/local/bin && curl -vsLO "https://github.com/slimm609/checksec.sh/blob/$CHECKSEC_SHA/checksec")
+COPY expected-checksec.json validate-checksec.sh /linkerd/

.github/actions/package/expected-checksec.json

@@ -0,0 +1,10 @@
+{
+  "canary": "yes",
+  "fortify_source": "yes",
+  "nx": "yes",
+  "pie": "yes",
+  "relro": "full",
+  "rpath": "no",
+  "runpath": "no",
+  "symbols": "no"
+}

.github/actions/package/validate-checksec.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+set -eu
+
+if [ $# -ne 2 ]; then
+    (
+        echo "usage: $0 EXPECTED RECEIVED"
+        echo
+        echo "Found $# args"
+    ) >&2
+    exit 64
+fi
+
+expected_file="$1"
+received_file="$2"
+if [ ! -f "$expected_file" ]; then
+    echo "JSON output not found: $expected_file" >&2
+    exit 1
+fi
+if [ ! -f "$received_file" ]; then
+    echo "JSON output not found: $received_file" >&2
+    exit 1
+fi
+
+jq -S '.' "$received_file" | diff -u "$expected_file" - >&2

.github/workflows/release.yml

@@ -3,27 +3,37 @@ name: release
 on:
   push:
     tags:
-    - 'release/*'
+      - "release/*"
 
 jobs:
   package:
     runs-on: ubuntu-latest
-    container:
-      image: docker://rust:1.41.0-buster
     steps:
       - name: git co
         uses: actions/checkout@v1
+
       - name: meta
         id: release-tag-meta
         uses: ./.github/actions/release-tag-meta
         with:
           git-ref: ${{ github.ref }}
       #- run: echo "${{ toJSON(steps.release-tag-meta) }}"
-    - name: make package
+
+      - name: package
         env:
           CARGO_RELEASE: "1"
-        PACKAGE_VERSION: ${{ steps.release-tag-meta.outputs.name }}
+          PACKAGE_VERSION: test-0.0.0 # ${{ steps.release-tag-meta.outputs.name }}
-      run: make package
+        uses: ./.github/actions/package
+        with:
+          entrypoint: make
+          args: package
+
+      - name: checksec
+        uses: ./.github/actions/package
+        with:
+          entrypoint: /linkerd/validate-checksec.sh
+          args: /linkerd/expected-checksec.json "target/release/package/linkerd2-proxy-${{ steps.release-tag-meta.outputs.name }}-checksec.json"
+
       - name: release
         uses: softprops/action-gh-release@b21b43d
         env:

Makefile

@@ -14,6 +14,7 @@ TARGET_BIN = $(TARGET)/linkerd2-proxy
 PKG_ROOT = $(TARGET)/package
 PKG_NAME = linkerd2-proxy-$(PACKAGE_VERSION)
 PKG_BASE = $(PKG_ROOT)/$(PKG_NAME)
+PKG_CHECKSEC = $(PKG_BASE)-checksec.json
 PKG = $(PKG_NAME).tar.gz
 
 SHASUM = shasum -a 256
@@ -40,7 +41,7 @@ endif
 $(TARGET_BIN): fetch
 	$(CARGO_BUILD) -p linkerd2-proxy
 
-$(PKG_ROOT)/$(PKG): $(TARGET_BIN)
+$(PKG_ROOT)/$(PKG) $(PKG_CHECKSEC): $(TARGET_BIN)
 	mkdir -p $(PKG_BASE)/bin
 	cp LICENSE $(PKG_BASE)
 	cp $(TARGET_BIN) $(PKG_BASE)/bin/linkerd2-proxy
@@ -51,6 +52,7 @@ ifdef CARGO_DEBUG
 		chmod 644 $(PKG_BASE)/linkerd2-proxy.obj ; \
 	fi
 endif
+	./checksec.sh $(PKG_BASE)/bin/linkerd2-proxy >$(PKG_CHECKSEC) || true
 	cd $(PKG_ROOT) && \
 		tar -czvf $(PKG) $(PKG_NAME) && \
 		($(SHASUM) $(PKG) >$(PKG_NAME).txt) && \

checksec.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+set -eu
+
+require_from() {
+    if ! command -v "$1" >/dev/null 2>/dev/null ; then
+        echo "Please acquire $1 from $2" >&2
+        exit 1
+    fi
+}
+
+require_from readelf     binutils
+require_from checksec    https://github.com/slimm609/checksec.sh
+require_from jq          https://stedolan.github.io/jq/
+
+if [ $# -ne 1 ]; then
+    echo "usage: $0 EXECUTABLE" >&2
+    exit 64
+fi
+
+path="$1"
+if [ ! -x "$path" ]; then
+    echo "Executable not found: $path" >&2
+    exit 1
+fi
+
+out=$(checksec --output=json --file="$path")
+echo "$out" | jq ".[\"$path\"] | del(.\"fortify-able\") | del(.fortified)" 

update-rust-version.sh

@@ -16,5 +16,5 @@ fi
 echo "$VERSION" > rust-toolchain
 sed -i'' -Ee "s/rust:[0-9]+\.[0-9]+\.[0-9]+/rust:$VERSION/" Dockerfile
 
-find .github -name \*.yml \
+find .github -name \*.yml -or -name Dockerfile\* \
-    -exec sed -i'' -Ee "s|docker://rust:[0-9]+\.[0-9]+\.[0-9]+|docker://rust:$VERSION|" '{}' \;
+    -exec sed -i'' -Ee "s|rust:[0-9]+\.[0-9]+\.[0-9]+|rust:$VERSION|" '{}' \;