This repository contains the code for SAWScript, the scripting language that forms the primary user interface to the Software Analysis Workbench (SAW). It provides the ability to reason about formal models describing the denotation of programs written in languages such as C, Java, and Cryptol. It also provides experimental, incomplete support for the Rust language.
There are two SAWScript tutorials that give an introduction to using the SAWScript interpreter:
- This tutorial gives an introduction to verifying C code (using LLVM) and Java code (using JVM).
- This tutorial gives an introduction to verifying Rust code (using MIR).
There is also a longer manual that describes the breadth of SAWScript's features.
Precompiled SAWScript binaries for a variety of platforms are available on the releases page.
SAW can use many theorem provers, but because of its use of Cryptol it always needs to have Microsoft Research's Z3 SMT solver installed. You can download Z3 binaries for a variety of platforms from their releases page.
We currently recommend Z3 4.8.10. If you plan to use path satisfiability checking, you'll also need Yices version 2.6.1 or newer.
After installation, make sure that z3
(or z3.exe
on Windows)
is on your PATH.
To build SAWScript and related utilities from source:
-
Ensure that you have the
cabal
andghc
executables in yourPATH
. If you don't already have them, we recommend usingghcup
to install them: https://www.haskell.org/ghcup/. We recommend Cabal 3.10 or newer, and GHC 9.4, 9.6, or 9.8. -
Ensure that you have the C libraries and header files for
terminfo
, which generally comes as part ofncurses
on most platforms. On Fedora, it is part of thencurses-compat-libs
package. You will also need the C headers forzlib
. -
Ensure that you have the programs
javac
andz3
on yourPATH
. Z3 binaries are available at https://github.com/Z3Prover/z3/releases -
Optionally, put in place dependency version freeze files:
ln -s cabal.<ghc version>.config cabal.project.freeze
-
Build SAWScript by running
./build.sh
The SAWScript executables will be available in the
bin
directory. -
Optionally, run ./stage.sh to create a binary tarball.
SAW can analyze LLVM programs (usually derived from C, but potentially
for other languages). The only tool strictly required for this is a
compiler that can generate LLVM bitcode, such as clang
. However,
having the full LLVM tool suite available can be useful. We have tested
SAW with LLVM and clang
versions from 3.5 to 16.0, as well as the
version of clang
bundled with Apple Xcode. We welcome bug reports on
any failure to parse bitcode from LLVM versions in that range.
Note that successful parsing doesn't necessarily mean that verification
will be possible for all language constructs. There are various
instructions that are not supported during verification. However,
any failure during llvm_load_module
should be considered a bug.
If you have trouble loading the SAW REPL on Windows, try invoking it
with the --no-color
option.
Many dependencies are automatically downloaded into deps/
when you
build using build.sh
; see
Manual Installation above. Key automatically
downloaded dependencies include:
deps/crucible/
: Crucible symbolic execution enginedeps/cryptol/
: Cryptol
Presently, the saw-script
main executable cannot be loaded into GHCi due to a
linker issue. However, the rest of the library can be manipulated in GHCi, with
a little convincing.
If you are using cabal
to build, select the saw-script
target:
$ cabal new-repl saw-script
In order to use interactive tools like intero
, you need to configure them with
this target. You can configure intero-mode
in Emacs to use the saw-script
library target by setting the variable intero-targets
to the string
"saw-script:lib"
. To make this setting persistent for all files in this
project, place the following snippet in the file src/.dir-locals.el
:
((haskell-mode
(intero-targets "saw-script:lib")))
We use the cabal.GHC-*.config
files to constrain dependency versions
in CI, and recommend using the following command for best results before
building locally:
ln -s cabal.GHC-<VER>.config cabal.project.freeze
These configuration files were generated using cabal freeze
, but with
some manual changes to allow cross-platfom builds, since Unix-like
systems and Windows systems end up with different package dependencies.
Specifically, we remove lines for the following packages or flags:
cryptol-saw-core
regex-posix
saw-remote-api
saw-script
tasty +unix
unix
unix-compat
unix-time
Much of the work on SAW has been funded by, and lots of design input was provided by the team at the NSA's Laboratory for Advanced Cybersecurity Research, including Brad Martin, Frank Taylor, and Sean Weaver.
Portions of SAW are also based upon work supported by the Office of Naval Research under Contract No. N68335-17-C-0452. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the Office of Naval Research.