Building Falco

Building Falco

The instructions provided below specify the steps to build Falco version 0.35.0 on Linux on IBM Z for following distributions:

• RHEL (7.8, 7.9, 8.6, 8.7, 8.8, 9.0, 9.1, 9.2)
• SLES (12 SP5, 15 SP4)
• Ubuntu (20.04, 22.04, 23.04)

Falco supports all three kernel drivers starting with 0.34.x releases on s390x: Kernel module, eBPF probe and Modern eBPF probe. Please check driver - kernel version support matrix for detailed information.

General Notes:

• When following the steps below please use standard permission user unless otherwise specified.
• A directory /<source_root>/ will be referred to in these instructions, this is a temporary writable directory anywhere you'd like to place it.

Step 1: Build using script

If you want to build Falco using manual steps, go to step 2.

Use the following commands to build Falco using the build script. Please make sure you have wget installed.

wget https://raw.githubusercontent.com/linux-on-ibm-z/scripts/master/Falco/0.35.0/build_falco.sh

# Run bash build_falco.sh -h to see all available options
bash build_falco.sh

In case of error, check logs for more details or go to Step 2 to follow manual build steps.

Step 2: Install dependencies

export SOURCE_ROOT=/<source_root>/

• RHEL (7.8, 7.9)

  sudo yum install -y devtoolset-9-gcc devtoolset-9-gcc-c++ devtoolset-9-toolchain devtoolset-9-libstdc++-devel glibc-static openssl-devel autoconf automake libtool createrepo expect git which rpm-build git libarchive wget bzip2 perl-FindBin make autoconf automake pkg-config patch elfutils-libelf-devel diffutils kernel-devel-$(uname -r) kmod
  source /opt/rh/devtoolset-9/enable

• RHEL (8.6, 8.7, 8.8)

  sudo yum install -y gcc gcc-c++ git make cmake autoconf automake pkg-config patch libtool elfutils-libelf-devel diffutils which createrepo libarchive wget curl rpm-build kmod kernel-devel-$(uname -r)

• RHEL (9.0, 9.1, 9.2)

  sudo yum install --allowerasing -y gcc gcc-c++ git make cmake autoconf automake pkg-config patch perl-FindBin libtool elfutils-libelf-devel diffutils which createrepo libarchive wget curl rpm-build kmod kernel-devel-$(uname -r) go clang llvm bpftool
  go version

• SLES 12 SP5

  SLES_KERNEL_VERSION=$(uname -r | sed 's/-default//')
  SLES_KERNEL_PKG_VERSION=$(sudo zypper se -s 'kernel-default-devel' | grep ${SLES_KERNEL_VERSION} | head -n 1 | cut -d "|" -f 4 - | tr -d '[:space:]')
  
  sudo zypper install -y --force-resolution gcc gcc9 gcc9-c++ git-core patch which automake autoconf libtool libopenssl-devel libcurl-devel libelf-devel "kernel-default-devel=${SLES_KERNEL_PKG_VERSION}" tar curl make
  
  sudo ln -sf /usr/bin/gcc /usr/bin/s390x-linux-gnu-gcc
  sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 50
  sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.8 20
  sudo update-alternatives --skip-auto --config gcc
  sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-9 50
  export CC=$(which gcc)
  export CXX=$(which g++)

• SLES 15 SP4

  SLES_KERNEL_VERSION=$(uname -r | sed 's/-default//')
  SLES_KERNEL_PKG_VERSION=$(sudo zypper se -s 'kernel-default-devel' | grep ${SLES_KERNEL_VERSION} | head -n 1 | cut -d "|" -f 4 - | tr -d '[:space:]')
  sudo zypper install -y gcc gcc-c++ git-core cmake patch which automake autoconf libtool libelf-devel tar curl vim wget pkg-config glibc-devel-static go1.18 "kernel-default-devel=${SLES_KERNEL_PKG_VERSION}" kmod clang llvm bpftool
  go version

• Ubuntu 20.04

  sudo apt-get update
  sudo apt-get install -y git cmake build-essential pkg-config autoconf wget curl patch libtool libelf-dev gcc rpm linux-headers-$(uname -r) kmod

• Ubuntu (22.04, 23.04)

  For Ubuntu 22.04, if the current kernel version is 5.15.0-71-generic, please upgrade it to a higher version such as 5.15.0-73-generic first, since linux-tools-5.15.0-71-generic package doesn't exist in the repository.

  sudo apt-get update
  sudo apt-get install -y git cmake build-essential pkg-config autoconf wget curl patch libtool libelf-dev gcc rpm linux-headers-$(uname -r) linux-tools-$(uname -r) kmod clang llvm

• Install Go v1.18.8 (Only for RHEL(7.x, 8.x), SLES 12 SP5 and Ubuntu)

  cd $SOURCE_ROOT
  wget -q https://raw.githubusercontent.com/linux-on-ibm-z/scripts/master/Go/1.18.4/build_go.sh 
  bash build_go.sh -y -v 1.18.8
  export GOPATH=$SOURCE_ROOT 
  export PATH=$GOPATH/bin:$PATH
  export CC=$(which gcc)
  export CXX=$(which g++)
  go version

• Install CMake v3.22.5 (Only for RHEL 7.x and SLES 12 SP5)

  cd $SOURCE_ROOT
  wget https://github.com/Kitware/CMake/releases/download/v3.22.5/cmake-3.22.5.tar.gz
  tar -xf cmake-3.22.5.tar.gz
  cd cmake-3.22.5
  ./bootstrap -- -DCMAKE_BUILD_TYPE:STRING=Release
  # In case of error: "/lib64/libstdc++.so.6: version `GLIBCXX_3.4.26` not found" do following `ln`
  sudo ln -sf /usr/local/lib64/libstdc++.so.6.0.28 /lib64/libstdc++.so.6
  make
  sudo make install
  sudo ln -sf /usr/local/bin/cmake /usr/bin/cmake

Step 3: Download, configure and build Falco

3.1) Download Falco

cd $SOURCE_ROOT
git clone https://github.com/falcosecurity/falco.git
cd falco
git checkout 0.35.0

3.2) Patch the cmake options for certain plugins

curl -sSL https://raw.githubusercontent.com/linux-on-ibm-z/scripts/master/Falco/0.35.0/patch/plugins.cmake.patch | git apply -

3.3) Patch Clang flags for building modern BPF object code (Only on Ubuntu (22.04, 23.04))

curl -sSL https://raw.githubusercontent.com/linux-on-ibm-z/scripts/master/Falco/0.35.0/patch/modern_bpf_clang_flags.patch | git apply -

3.4) Build Falco

mkdir -p $SOURCE_ROOT/falco/build
cd $SOURCE_ROOT/falco/build

• Configure Falco

  CMAKE_TEST_FLAG="-DBUILD_FALCO_UNIT_TESTS=On"   # Only when unit tests are expected to be run after building Falco
  CMAKE_TEST_FLAG=""  # Only when unit tests are not needed
  CMAKE_FLAGS="-DFALCO_ETC_DIR=/etc/falco -DUSE_BUNDLED_DEPS=On -DCMAKE_BUILD_TYPE=Release -DBUILD_DRIVER=On ${CMAKE_TEST_FLAG}"  # Only for RHEL (7.x, 8.x), SLES 12 SP5 and Ubuntu 20.04
  CMAKE_FLAGS="-DFALCO_ETC_DIR=/etc/falco -DUSE_BUNDLED_DEPS=On -DCMAKE_BUILD_TYPE=Release -DBUILD_DRIVER=On -DBUILD_BPF=On -DBUILD_FALCO_MODERN_BPF=ON ${CMAKE_TEST_FLAG}"   # Only for RHEL 9.x, SLES 15 SP4 and Ubuntu (22.04, 23.04)
  cmake $CMAKE_FLAGS ../

• Build and Install

  cd $SOURCE_ROOT/falco/build
  make -j$(nproc)
  make package            # build deb/rpm packages (optional and only on Ubuntu and RHEL)
  sudo make install

3.5) Load kernel module

• Unload any existing module using

  sudo rmmod falco

• Insert locally built version

  cd $SOURCE_ROOT/falco/build
  sudo insmod driver/falco.ko

3.6) Copy eBPF driver object file to the default location (Only on RHEL 9.x, SLES 15 SP4 and Ubuntu (22.04, 23.04))

sudo mkdir /root/.falco
sudo cp -f $SOURCE_ROOT/falco/build/driver/bpf/probe.o /root/.falco/falco-bpf.o

Step 4: Testing (optional)

cd $SOURCE_ROOT/falco/build
sudo ./unit_tests/falco_unit_tests 

A separate falco project https://github.com/falcosecurity/event-generator can be used to run further tests.

Step 5: Validate installation (optional)

• Run Falco with Kernel module (default driver)

  sudo falco

  Note: Run sudo falco --help to see available options to run falco. By default, falco logs events to standard error.

  Output similar to following will be seen

  Fri Jun 16 11:51:34 2023: Falco version: 0.35.0 (s390x)
  Fri Jun 16 11:51:34 2023: Falco initialized with configuration file: /etc/falco/falco.yaml
  Fri Jun 16 11:51:34 2023: Loading rules from file /etc/falco/falco_rules.yaml
  Fri Jun 16 11:51:35 2023: Loading rules from file /etc/falco/falco_rules.local.yaml
  Fri Jun 16 11:51:35 2023: The chosen syscall buffer dimension is: 8388608 bytes (8 MBs)
  Fri Jun 16 11:51:35 2023: Starting health webserver with threadiness 8, listening on port 8765
  Fri Jun 16 11:51:35 2023: Enabled event sources: syscall
  Fri Jun 16 11:51:35 2023: Opening 'syscall' source with Kernel module
  

• Run Falco with eBPF probe driver (Only on RHEL 9.x, SLES 15 SP4 and Ubuntu (22.04, 23.04))

  sudo FALCO_BPF_PROBE="" falco

  Output similar to following will be seen

  Fri Jun 16 11:52:58 2023: Falco version: 0.35.0 (s390x)
  Fri Jun 16 11:52:58 2023: Falco initialized with configuration file: /etc/falco/falco.yaml
  Fri Jun 16 11:52:58 2023: Loading rules from file /etc/falco/falco_rules.yaml
  Fri Jun 16 11:52:58 2023: Loading rules from file /etc/falco/falco_rules.local.yaml
  Fri Jun 16 11:52:58 2023: The chosen syscall buffer dimension is: 8388608 bytes (8 MBs)
  Fri Jun 16 11:52:58 2023: Starting health webserver with threadiness 8, listening on port 8765
  Fri Jun 16 11:52:58 2023: Enabled event sources: syscall
  Fri Jun 16 11:52:58 2023: Opening 'syscall' source with BPF probe. BPF probe path: /root/.falco/falco-bpf.o
  

• Run Falco with modern eBPF probe driver (Only on RHEL 9.x, SLES 15 SP4 and Ubuntu (22.04, 23.04))

  sudo falco --modern-bpf

  Output similar to following will be seen

  Fri Jun 16 11:54:19 2023: Falco version: 0.35.0 (s390x)
  Fri Jun 16 11:54:19 2023: Falco initialized with configuration file: /etc/falco/falco.yaml
  Fri Jun 16 11:54:19 2023: Loading rules from file /etc/falco/falco_rules.yaml
  Fri Jun 16 11:54:20 2023: Loading rules from file /etc/falco/falco_rules.local.yaml
  Fri Jun 16 11:54:20 2023: The chosen syscall buffer dimension is: 8388608 bytes (8 MBs)
  Fri Jun 16 11:54:20 2023: Starting health webserver with threadiness 8, listening on port 8765
  Fri Jun 16 11:54:20 2023: Enabled event sources: syscall
  Fri Jun 16 11:54:20 2023: Opening 'syscall' source with modern BPF probe.
  Fri Jun 16 11:54:20 2023: One ring buffer every '2' CPUs.
  

Reference:

• https://falco.org/docs/ - Official Falco documentation