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Harden privileged filesystem deletion against TOCTOU attacks #1

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28 changes: 28 additions & 0 deletions .github/workflows/build.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -30,3 +30,31 @@ jobs:
CODE_SIGN_IDENTITY="" \
CODE_SIGNING_REQUIRED=NO \
CODE_SIGNING_ALLOWED=NO

- name: Verify privileged helper packaging
run: |
set -euo pipefail
APP="build/Build/Products/Release/PureMac.app"
HELPER="${APP}/Contents/Library/LaunchServices/com.puremac.privileged-helper"
PLIST="${APP}/Contents/Library/LaunchDaemons/com.puremac.privileged-cleaning.plist"
test -x "${HELPER}"
test -f "${PLIST}"
plutil -lint "${PLIST}"
test "$(/usr/libexec/PlistBuddy -c 'Print :Label' "${PLIST}")" = "com.puremac.privileged-cleaning"
test "$(/usr/libexec/PlistBuddy -c 'Print :BundleProgram' "${PLIST}")" = "Contents/Library/LaunchServices/com.puremac.privileged-helper"
test "$(/usr/libexec/PlistBuddy -c 'Print :AssociatedBundleIdentifiers:0' "${PLIST}")" = "com.puremac.app"
test "$(/usr/libexec/PlistBuddy -c 'Print :MachServices:com.puremac.privileged-cleaning' "${PLIST}")" = "true"
lipo -archs "${HELPER}" | grep -q "arm64"
lipo -archs "${HELPER}" | grep -q "x86_64"

- name: Test
run: |
xcodebuild -project PureMac.xcodeproj \
-scheme PureMac \
-configuration Debug \
-destination 'platform=macOS' \
-derivedDataPath build-tests \
test \
CODE_SIGN_IDENTITY="" \
CODE_SIGNING_REQUIRED=NO \
CODE_SIGNING_ALLOWED=NO
23 changes: 23 additions & 0 deletions .github/workflows/release.yml
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Expand Up @@ -129,12 +129,35 @@ jobs:
run: |
set -euo pipefail
APP="build/export/PureMac.app"
HELPER="${APP}/Contents/Library/LaunchServices/com.puremac.privileged-helper"
DAEMON_PLIST="${APP}/Contents/Library/LaunchDaemons/com.puremac.privileged-cleaning.plist"
APP_REQUIREMENT='anchor apple generic and identifier "com.puremac.app" and certificate leaf[subject.OU] = "H3WXHVTP97"'
HELPER_REQUIREMENT='anchor apple generic and identifier "com.puremac.privileged-helper" and certificate leaf[subject.OU] = "H3WXHVTP97"'
test -x "${HELPER}"
test -f "${DAEMON_PLIST}"
plutil -lint "${DAEMON_PLIST}"
test "$(/usr/libexec/PlistBuddy -c 'Print :Label' "${DAEMON_PLIST}")" = "com.puremac.privileged-cleaning"
test "$(/usr/libexec/PlistBuddy -c 'Print :BundleProgram' "${DAEMON_PLIST}")" = "Contents/Library/LaunchServices/com.puremac.privileged-helper"
test "$(/usr/libexec/PlistBuddy -c 'Print :AssociatedBundleIdentifiers:0' "${DAEMON_PLIST}")" = "com.puremac.app"
test "$(/usr/libexec/PlistBuddy -c 'Print :MachServices:com.puremac.privileged-cleaning' "${DAEMON_PLIST}")" = "true"
codesign --verify --deep --strict --verbose=2 "${APP}"
codesign --verify --strict --verbose=2 "${HELPER}"
codesign --verify --strict --verbose=2 -R="${APP_REQUIREMENT}" "${APP}"
codesign --verify --strict --verbose=2 -R="${HELPER_REQUIREMENT}" "${HELPER}"
codesign -dvv "${APP}" 2>&1 | tee /tmp/cs-info.txt
codesign -dvv "${HELPER}" 2>&1 | tee /tmp/helper-cs-info.txt
codesign -d --entitlements :- "${APP}" > /tmp/app-entitlements.plist
codesign -d --entitlements :- "${HELPER}" > /tmp/helper-entitlements.plist
! plutil -p /tmp/app-entitlements.plist | grep -E 'get-task-allow|disable-library-validation|allow-dyld-environment-variables'
! plutil -p /tmp/helper-entitlements.plist | grep -E 'get-task-allow|disable-library-validation|allow-dyld-environment-variables'
grep -q "flags=0x10000(runtime)" /tmp/cs-info.txt || { echo "::error::Hardened runtime missing"; exit 1; }
grep -q "Identifier=com.puremac.privileged-helper" /tmp/helper-cs-info.txt || { echo "::error::Unexpected privileged helper identifier"; exit 1; }
grep -q "TeamIdentifier=${TEAM_ID}" /tmp/helper-cs-info.txt || { echo "::error::Unexpected privileged helper team"; exit 1; }
grep -q "flags=0x10000(runtime)" /tmp/helper-cs-info.txt || { echo "::error::Privileged helper hardened runtime missing"; exit 1; }
spctl --assess --type execute --verbose=4 "${APP}" || true
# Universal arch check
lipo -archs "${APP}/Contents/MacOS/PureMac" | grep -q "x86_64" && lipo -archs "${APP}/Contents/MacOS/PureMac" | grep -q "arm64"
lipo -archs "${HELPER}" | grep -q "x86_64" && lipo -archs "${HELPER}" | grep -q "arm64"

- name: Build DMG
env:
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