Disable zchunk and deltarpm during template build

This disables zchunk as well as deltarpm, reducing DNF's attack surface.
A change to core-agent-linux will do the same for the built templates
once they are installed.

dnf/bootstrap-dnf-centos-stream.conf

@@ -10,6 +10,8 @@ repo_gpgcheck=1
 plugins=1
 installonly_limit=3
 color=never
+deltarpm=False
+zchunk=False
 
 reposdir=/var/empty
 

dnf/bootstrap-dnf-fedora.conf

@@ -9,6 +9,8 @@ gpgcheck=1
 plugins=1
 installonly_limit=3
 color=never
+deltarpm=False
+zchunk=False
 
 reposdir=/var/empty
 

scripts/prepare-chroot-base

@@ -52,7 +52,9 @@ else
 fi
 
 DNF=dnf
-DNF_OPTS+=(--releasever "$DIST_VER" --installroot="${INSTALL_DIR}" "--downloaddir=$DOWNLOAD_DIR" --downloadonly)
+# Delta RPMs and zchunk are unnecessary attack surface
+DNF_SEC_OPTS=(--setopt=deltarpm=False --setopt=deltarpm_percentage=0 --setopt=zchunk=0)
+DNF_OPTS+=(--releasever "$DIST_VER" --installroot="${INSTALL_DIR}" "--downloaddir=$DOWNLOAD_DIR" --downloadonly "${DNF_SEC_OPTS[@]}")
 
 # Ensure INSTALL_DIR exists
 mkdir -p "$INSTALL_DIR"
@@ -61,8 +63,6 @@ if ! [ -f "${INSTALL_DIR}/tmp/.prepared_base" ]; then
     echo "INFO: Initializing RPM database..."
     # We want signature checks.
     RPM_OPTS=('--define=_pkgverify_level all' '--define=_pkgverify_flags 0x0')
-    # Delta RPMs and zchunk are unnecessary attack surface
-    DNF_OPTS+=(--setopt=deltarpm=False --setopt=deltarpm_percentage=0 --setopt=zchunk=0)
     if [ "$(getenforce || :)" = Enforcing ]; then
         dbpath=$(rpm --eval '%{_dbpath}')
         mkdir -p "${INSTALL_DIR}${dbpath}"

template_rpm/distribution.sh

@@ -37,7 +37,11 @@ if [ -z "${DIST_VER}" ]; then
     error "Please provide DIST_VER in environment."
 fi
 
-DNF_OPTS=(-y --releasever "${DIST_VER}")
+DNF_OPTS=(-y
+          "--releasever=${DIST_VER}"
+          --setopt=deltarpm=False
+          --setopt=zchunk=False
+          --setopt=gpgcheck=1)
 
 if [ -n "${REPO_PROXY}" ]; then
     DNF_OPTS+=("--setopt=proxy=${REPO_PROXY}")