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Add GPG signature verification to install script (#7944)

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* Add GPG signature verification to install script

The script fetches the KEYS file from GitHub, as well
as the .asc files on the release and verifies the
release artifacts are signed by a valid key.

Added new boolean config options in the install script
which allow for fine-grained control over verification
and output:

- DEBUG: sets -x in the bash script (default: false)
- VERIFY_CHECKSUM: verifies checksum (default: true)
- VERIFY_SIGNATURE: verifies signature (default: true)

Also reduced check for curl/wget to only one time.

Resolves #7943.
Resolves #7838.

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* disable signature verification by default

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* remove repeated line

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* fix typo

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* do not auto-import GPG keys

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* silence errors about missing commands

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* use a temporary gpg keyring

Signed-off-by: Josh Dolitsky <393494+jdolitsky@users.noreply.github.com>

* Fix wget commands for VERIFY_SIGNATURES=true

Signed-off-by: jdolitsky <393494+jdolitsky@users.noreply.github.com>
pull/8077/merge
Josh Dolitsky 4 years ago committed by GitHub
parent 64d4399f06
commit 6898ad1457
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 110 additions and 18 deletions
Show Stats Download Patch File Download Diff File

128
scripts/get-helm-3
Unescape View File

@ -19,8 +19,16 @@
: ${BINARY_NAME:="helm"}
: ${USE_SUDO:="true"}
: ${DEBUG:="false"}
: ${VERIFY_CHECKSUM:="true"}
: ${VERIFY_SIGNATURES:="false"}
: ${HELM_INSTALL_DIR:="/usr/local/bin"}
HAS_CURL="$(type "curl" &> /dev/null && echo true || echo false)"
HAS_WGET="$(type "wget" &> /dev/null && echo true || echo false)"
HAS_OPENSSL="$(type "openssl" &> /dev/null && echo true || echo false)"
HAS_GPG="$(type "gpg" &> /dev/null && echo true || echo false)"
# initArch discovers the architecture for this system.
initArch() {
ARCH=$(uname -m)
@ -58,7 +66,7 @@ runAsRoot() {
}
# verifySupported checks that the os/arch combination is supported for
# binary builds.
# binary builds, as well whether or not necessary tools are present.
verifySupported() {
local supported="darwin-amd64\nlinux-386\nlinux-amd64\nlinux-arm\nlinux-arm64\nlinux-ppc64le\nlinux-s390x\nwindows-amd64"
if ! echo "${supported}" | grep -q "${OS}-${ARCH}"; then
@ -67,10 +75,29 @@ verifySupported() {
exit 1
fi
if ! type "curl" > /dev/null && ! type "wget" > /dev/null; then
if [ "${HAS_CURL}" != "true" ] && [ "${HAS_WGET}" != "true" ]; then
echo "Either curl or wget is required"
exit 1
fi
if [ "${VERIFY_CHECKSUM}" == "true" ] && [ "${HAS_OPENSSL}" != "true" ]; then
echo "In order to verify checksum, openssl must first be installed."
echo "Please install openssl or set VERIFY_CHECKSUM=false in your environment."
exit 1
fi
if [ "${VERIFY_SIGNATURES}" == "true" ]; then
if [ "${HAS_GPG}" != "true" ]; then
echo "In order to verify signatures, gpg must first be installed."
echo "Please install gpg or set VERIFY_SIGNATURES=false in your environment."
exit 1
fi
if [ "${OS}" != "linux" ]; then
echo "Signature verification is currently only supported on Linux."
echo "Please set VERIFY_SIGNATURES=false or verify the signatures manually."
exit 1
fi
fi
}
# checkDesiredVersion checks if the desired version is available.
@ -78,9 +105,9 @@ checkDesiredVersion() {
if [ "x$DESIRED_VERSION" == "x" ]; then
# Get tag from release URL
local latest_release_url="https://github.com/helm/helm/releases"
if type "curl" > /dev/null; then
if [ "${HAS_CURL}" == "true" ]; then
TAG=$(curl -Ls $latest_release_url | grep 'href="/helm/helm/releases/tag/v3.[0-9]*.[0-9]*\"' | grep -v no-underline | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
elif type "wget" > /dev/null; then
elif [ "${HAS_WGET}" == "true" ]; then
TAG=$(wget $latest_release_url -O - 2>&1 | grep 'href="/helm/helm/releases/tag/v3.[0-9]*.[0-9]*\"' | grep -v no-underline | head -n 1 | cut -d '"' -f 2 | awk '{n=split($NF,a,"/");print a[n]}' | awk 'a !~ $0{print}; {a=$0}')
fi
else
@ -115,35 +142,94 @@ downloadFile() {
HELM_TMP_FILE="$HELM_TMP_ROOT/$HELM_DIST"
HELM_SUM_FILE="$HELM_TMP_ROOT/$HELM_DIST.sha256"
echo "Downloading $DOWNLOAD_URL"
if type "curl" > /dev/null; then
if [ "${HAS_CURL}" == "true" ]; then
curl -SsL "$CHECKSUM_URL" -o "$HELM_SUM_FILE"
elif type "wget" > /dev/null; then
wget -q -O "$HELM_SUM_FILE" "$CHECKSUM_URL"
fi
if type "curl" > /dev/null; then
curl -SsL "$DOWNLOAD_URL" -o "$HELM_TMP_FILE"
elif type "wget" > /dev/null; then
elif [ "${HAS_WGET}" == "true" ]; then
wget -q -O "$HELM_SUM_FILE" "$CHECKSUM_URL"
wget -q -O "$HELM_TMP_FILE" "$DOWNLOAD_URL"
fi
}
# installFile verifies the SHA256 for the file, then unpacks and
# installs it.
# verifyFile verifies the SHA256 checksum of the binary package
# and the GPG signatures for both the package and checksum file
# (depending on settings in environment).
verifyFile() {
if [ "${VERIFY_CHECKSUM}" == "true" ]; then
verifyChecksum
fi
if [ "${VERIFY_SIGNATURES}" == "true" ]; then
verifySignatures
fi
}
# installFile installs the Helm binary.
installFile() {
HELM_TMP="$HELM_TMP_ROOT/$BINARY_NAME"
mkdir -p "$HELM_TMP"
tar xf "$HELM_TMP_FILE" -C "$HELM_TMP"
HELM_TMP_BIN="$HELM_TMP/$OS-$ARCH/helm"
echo "Preparing to install $BINARY_NAME into ${HELM_INSTALL_DIR}"
runAsRoot cp "$HELM_TMP_BIN" "$HELM_INSTALL_DIR/$BINARY_NAME"
echo "$BINARY_NAME installed into $HELM_INSTALL_DIR/$BINARY_NAME"
}
# verifyChecksum verifies the SHA256 checksum of the binary package.
verifyChecksum() {
printf "Verifying checksum... "
local sum=$(openssl sha1 -sha256 ${HELM_TMP_FILE} | awk '{print $2}')
local expected_sum=$(cat ${HELM_SUM_FILE})
if [ "$sum" != "$expected_sum" ]; then
echo "SHA sum of ${HELM_TMP_FILE} does not match. Aborting."
exit 1
fi
echo "Done."
}
mkdir -p "$HELM_TMP"
tar xf "$HELM_TMP_FILE" -C "$HELM_TMP"
HELM_TMP_BIN="$HELM_TMP/$OS-$ARCH/helm"
echo "Preparing to install $BINARY_NAME into ${HELM_INSTALL_DIR}"
runAsRoot cp "$HELM_TMP_BIN" "$HELM_INSTALL_DIR/$BINARY_NAME"
echo "$BINARY_NAME installed into $HELM_INSTALL_DIR/$BINARY_NAME"
# verifySignatures obtains the latest KEYS file from GitHub master branch
# as well as the signature .asc files from the specific GitHub release,
# then verifies that the release artifacts were signed by a maintainer's key.
verifySignatures() {
printf "Verifying signatures... "
local keys_filename="KEYS"
local github_keys_url="https://raw.githubusercontent.com/helm/helm/master/${keys_filename}"
if [ "${HAS_CURL}" == "true" ]; then
curl -SsL "${github_keys_url}" -o "${HELM_TMP_ROOT}/${keys_filename}"
elif [ "${HAS_WGET}" == "true" ]; then
wget -q -O "${HELM_TMP_ROOT}/${keys_filename}" "${github_keys_url}"
fi
local gpg_keyring="${HELM_TMP_ROOT}/keyring.gpg"
local gpg_homedir="${HELM_TMP_ROOT}/gnupg"
mkdir -p -m 0700 "${gpg_homedir}"
local gpg_stderr_device="/dev/null"
if [ "${DEBUG}" == "true" ]; then
gpg_stderr_device="/dev/stderr"
fi
gpg --batch --quiet --homedir="${gpg_homedir}" --import "${HELM_TMP_ROOT}/${keys_filename}" 2> "${gpg_stderr_device}"
gpg --batch --no-default-keyring --keyring "${gpg_homedir}/pubring.kbx" --export > "${gpg_keyring}"
local github_release_url="https://github.com/helm/helm/releases/download/${TAG}"
if [ "${HAS_CURL}" == "true" ]; then
curl -SsL "${github_release_url}/helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256.asc" -o "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256.asc"
curl -SsL "${github_release_url}/helm-${TAG}-${OS}-${ARCH}.tar.gz.asc" -o "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.asc"
elif [ "${HAS_WGET}" == "true" ]; then
wget -q -O "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256.asc" "${github_release_url}/helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256.asc"
wget -q -O "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.asc" "${github_release_url}/helm-${TAG}-${OS}-${ARCH}.tar.gz.asc"
fi
local error_text="If you think this might be a potential security issue,"
error_text="${error_text}\nplease see here: https://github.com/helm/community/blob/master/SECURITY.md"
local num_goodlines_sha=$(gpg --verify --keyring="${gpg_keyring}" --status-fd=1 "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256.asc" 2> "${gpg_stderr_device}" | grep -c -E '^\[GNUPG:\] (GOODSIG|VALIDSIG)')
if [[ ${num_goodlines_sha} -lt 2 ]]; then
echo "Unable to verify the signature of helm-${TAG}-${OS}-${ARCH}.tar.gz.sha256!"
echo -e "${error_text}"
exit 1
fi
local num_goodlines_tar=$(gpg --verify --keyring="${gpg_keyring}" --status-fd=1 "${HELM_TMP_ROOT}/helm-${TAG}-${OS}-${ARCH}.tar.gz.asc" 2> "${gpg_stderr_device}" | grep -c -E '^\[GNUPG:\] (GOODSIG|VALIDSIG)')
if [[ ${num_goodlines_tar} -lt 2 ]]; then
echo "Unable to verify the signature of helm-${TAG}-${OS}-${ARCH}.tar.gz!"
echo -e "${error_text}"
exit 1
fi
echo "Done."
}
# fail_trap is executed if an error occurs.
@ -195,6 +281,11 @@ cleanup() {
trap "fail_trap" EXIT
set -e
# Set debug if desired
if [ "${DEBUG}" == "true" ]; then
set -x
fi
# Parsing input arguments (if any)
export INPUT_ARGUMENTS="${@}"
set -u
@ -229,6 +320,7 @@ verifySupported
checkDesiredVersion
if ! checkHelmInstalledVersion; then
downloadFile
verifyFile
installFile
fi
testVersion

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