Infer on Linux Kernel

In C infer analyzes the code and checks for null pointer dereferences, memory leaks, quandary taints, resource leaks, dead stores. The version information is present in the readme. Infer only runs if the kernel is built using Clang, to make sure Infer run on the kernel version check if the kernel compiles per Clang. After Clang compiled Kernel, running infer might result in errors as described in the readme, apply the patches linked in this readme.

Dist Information

OS information

lsb_release -a
Distributor ID: Ubuntu
Description:  Ubuntu 18.10 LTS
Release:  18.10
Codename: cosmic

Infer version information

infer --version
Infer version v0.15.0-832e013

Clang version information

clang --version
clang version 3.8.0-2ubuntu4 (tags/RELEASE_380/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

Kernel version

• 5.0.rc-8 tree
• staging tree

Kernel compilation comfiguration

• defconfig

CMake version

cmake --version
cmake version 3.5.1

GCC version

gcc --version
gcc (Ubuntu 8.1.0-5ubuntu1~16.04) 8.1.0

Docker setup

Dockerfile

Installations

Installing Infer

• Install infer dependencies for linux, few packages to be installed are present in the Dockerfile

  • Install cmake using sudo apt install cmake

• clone infer using git clone git@github.com:facebook/infer.git

• Compile infer: ./build-infer.sh

• Install infer: sudo apt install infer

• To run Infer on kernel few directories have to be added to skipped in the code

  • vim infer/src/clang/cLocation.ml
  • Replace let paths = Config.skip_analysis_in_path in with

    let paths = ["[<directory>/git/staging/arch/x86";"<directory>/git/staging/arch/x86/entry/vdso";"<directory>/git/    staging/arch/x86/kernel";"<directory>/git/staging/arch/x86/boot";"<directory>/git/staging/arch/mm";"<directory>/g    it/staging/mm";"<directory>/git/staging/drivers/acpi";"<directory>/git/staging/fs";"<directory>/git/staging/kerne    l/bpf";"<directory>/git/staging/net/mac80211"] in
    
    

  or apply this patch with git apply <patch-name>

• To install after any code changes:

  make clean
  make or ./build-install.sh
  make install

• The make can run out of core even with make (without a -j n) at the stage of building Clang as that is very memory intensive. After multiple runs infer build stops at > 95% if runs out of cores in a system as during that phase facebook/facebook-clang-plugins are installed. Change this line to hardcode it to run one core since the start so that it can utilize cores at installing clang phase.

There should be no errors.

Kernel setup

• Clone kernel trees linked above
• Install libelf-dev sudo apt-get install libelf-dev
• Install libssl-dev sudo apt-get install libssl-dev
• Clang should be set as default compiler to run infer capture. As Linux Makefiles uses gcc and infer compiles with Clang, compiler flag in the Makefile should be using Clang. Add below lines to the Makefile

override CC=clang
override HOSTCC=clang

or apply this patch to setup compilation using Clang.

• asm-goto check error on gcc-8.1 and clang 6.0 when it supposed to be just limiting anything before gcc-4.5.
• Apply this patch to delete the asm goto check in compiler or update the Makefile in and arch/x86 Makefile per the above patch.

Reproducing The Work

• cd <linux-kernel-directory>
• make clean && make defconfig
• infer capture -- make
• After completion of above command, run infer analyze. Infer creates a infer-out folder. Running the command takes a lot of time and need huge computing power.
• Find reports in cat /infer-out/bugs.txt, finds the reports from this setup here

Setup multiple versions of Infer

There are few code changes in the ./configure script in Infer to use pkg-config, apply this patch to setup.

Reports

The reports dir/ has the reports generated by running Infer on Linux.

Analysis

The analysis dir/ has each report studied manually and reviewed by a reviewer.

Publication

You can find the complete research performed, tools used, reports generated, results and anaylsis per kernel dir and issue type here.

Patches

You can find the patches applied on current version on the tree. Patches (Sent, Applied, Acked, Approved) are present in kernel-infer-patches dir.

Future Work

The future work is enabling infer run on recent kernel versions and on Clang Linux linux kernel.

Other Publications

• Finding User/Kernel Pointer Bugs With Type Inference
• Efficiently Retrieving Function Dependencies in the Linux Kernel Using XSB
• Apply Infer to Linux Kernel Source Code
• Linux in Safety Critical Systems
• Automatic Inference and Enforcement of Kernel Data Structure
• Safety Critical Operating Systems
• A Soundy Analysis for Linux Kernel Drivers
• Static Code Checking in the Linux Kernel
• Faults in Linux