Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Update README.md #23

Merged
merged 1 commit into from
Jun 4, 2024
Merged

Update README.md #23

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 14 additions & 1 deletion fuzzers/cva6-vcs-fuzzer/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,17 @@ Follow the installation instructions from the Spike GitHub repository.

* [RISC-V GNU Compiler Toolchain] (https://github.com/riscv-collab/riscv-gnu-toolchain)

With everything properly installed, please make sure to set the right environment variables in your `bashrc` or equivalent file. The fuzzer expects the following configuration in bash:

Please, find below an example of configuratio
```bash
export RISCV=$HOME/riscv
export VERDI_HOME=/usr/synopsys/verdi/U-2023.03-SP2
export VCS_HOME=/usr/synopsys/vcs/U-2023.03-SP2
export [email protected]
export LD_LIBRARY_PATH=$VERDI_HOME/share/NPI/lib/linux64
```

## Building

The build.rs script performs the following tasks:
Expand Down Expand Up @@ -58,10 +69,12 @@ for i in {1..10}; do AFL_LAUNCHER_CLIENT=$i ./cva6_vcs_fuzzer & done
The fuzzer is bootstraped using the seed files into the `seeds` folder. Feel free to customize the content of this file with any interesting seed.
When starting the fuzzer loads the initial inputs (i.e., the seeds), and only keep interesting ones in the corpus (i.e., coverage novelty).
Coverage novelty consider any changes for all supported code coverage metrics on vcs, i.e., branch, conditional, line, toggle, and FSM.

Then, starts the fuzzer loop that iteratively calls the different stages.
StdMutationalStage is responsible for generating new mutant by applying mutation to the existing testcase in the corpus.
The mutations work at the ISA level by first deserializing the binary testcase into stream of instruction, then different mutations might be applied (e.g., adding instruction, removing instruction, changing opcode, ..).
The mutation can easily be customized by changing `../../libpresifuzz_mutators/src/riscv_isa.rs`.

The generated testcase is then inserted into a template ELF file by simplify injecting the code after the `payload` label.
This template contains epilogue and prologue code.
The current version is very simple. We first init registers to some known values, and we change the `mtvec` to points to our own trap handler.
Expand All @@ -79,4 +92,4 @@ python3 ./plot.py -m branch -d ./sync
```

The `-m` option is there to provide the coverage metric that is either tgl, cond, branch, line, fsm.
The `-d` points to the directory where stats are saved.
The `-d` points to the directory where stats are saved.
Loading