ropr: a multithreaded ROP gadget finder with quality filters

What the tool actually finds

ropr is a blazing fast multithreaded ROP Gadget finder, and the README spends its first few paragraphs explaining what a gadget is and why anyone would want them.

ROP, Return Oriented Programming, Gadgets are small snippets of a few assembly instructions typically ending in a ret instruction which already exist as executable code within each binary or library. These gadgets may be used for binary exploitation and to subvert vulnerable executables.

When the addresses of many ROP Gadgets are written into a buffer you have formed a ROP Chain. If an attacker can move the stack pointer into this ROP Chain then control can be completely transferred to the attacker.

The paragraph that follows explains the standard fallbacks. Most executables contain enough gadgets to write a turing-complete ROP Chain. For those that don't, one can always use dynamic libraries contained in the same address-space such as libc once we know their addresses. And the summary of the appeal is that no new executable code needs to be written anywhere, since an attacker may achieve their objective using only the code that already exists in the program.

That is a research and analysis tool in the same family as ropper and ROPgadget, both of which are named in the repository description as alternatives. The difference is in the filtering, which is the part of the design that this README spends most of its space on.

Installation is cargo, and there are three ways to do it

The only requirement is cargo, the rust build system, and there are three routes.

The easy install is:

cargo install ropr

and the application will install to ~/.cargo/bin.

From source you clone and build a release binary:

git clone https://github.com/Ben-Lichtman/ropr
cd ropr
cargo build --release

where the resulting binary will be located in target/release/ropr.

The third route clones and installs in place:

git clone https://github.com/Ben-Lichtman/ropr
cd ropr
cargo install --path .

and the application installs to ~/.cargo/bin again.

The first and third routes are the same outcome by different paths, so the choice is between the released crate and your own checkout. The second is the one to use when you want to profile or patch the code.

The project is written in Rust with the 2024 edition, the crate is named ropr at version 0.2.27, and the manifest lists the licence as MIT OR Apache-2.0. The dependency list is short and tells you how the tool is built: clap with derive for the command line, goblin for reading the executable format, iced-x86 for the x86 decoder, rayon for the parallelism, regex for the search filter, colored for the output colouring, rustc-hash for fast hashing, and thiserror for the error types.

The default branch is master, the repository is not archived, and the last push was on 2026-04-25. There are no GitHub releases, so the version lives in the manifest and on crates.io.

The filter flags are the actual feature

The usage block lists a single positional argument, the path of the file to inspect, and then a set of options that are mostly about excluding gadgets rather than finding them.

The -j, --nojop flag removes JOP Gadgets, which may have a controllable branch, call, etc. instead of a simple ret at the end. The -r, --norop flag removes normal ROP Gadgets, which is how you ask for the JOP ones specifically. The -s, --nosys flag removes syscalls and other interrupts, because a gadget that ends in a syscall is not a clean chain link.

The -p, --stack-pivot flag filters for gadgets which alter the stack pointer, and -b, --base-pivot filters for gadgets which alter the base pointer. Those two are how you find the entry point for a chain, since a chain needs somewhere to be written and a way to point the stack at it.

The -n, --noisy flag is the opposite of a filter, and it is the one that tells you what the tool is doing by default. It includes potentially low-quality gadgets such as prefixes, conditional branches, and near branches, and the help text notes it will find significantly more gadgets. So the default behaviour is deliberately broad, and the flags let you narrow it.

The remaining options are about scope. The -m, --max-instr option caps the number of instructions in a gadget and defaults to 6, which is a chain budget as much as a quality filter. The --range option searches between address ranges in hexadecimal, with an example given, and the --raw option treats the input file as a blob of code rather than parsing it as an executable. The -R, --regex option performs a regex search on the returned gadgets, and -c, --colour forces the output to be colour or plain text with a true or false value.

So the model is: scan everything, then subtract, then search, then bound.

The worked example shows why the filters matter

The README gives a concrete session, and the numbers are the argument for the filters.

The first command is a regex search with no filters at all:

❯ ropr /usr/lib/libc.so.6 -R "^mov eax, ...;" > /dev/null

==> Found 197 gadgets in 0.118 seconds

Then the same search with the quality filters added:

❯ ropr /usr/lib/libc.so.6 -m 2 -j -s -R "^mov eax, ...;"
0x000353e7: mov eax, eax; ret;
0x000788c8: mov eax, ecx; ret;
0x00052252: mov eax, edi; ret;
0x0003ae43: mov eax, edx; ret;
0x000353e6: mov eax, r8d; ret;
0x000788c7: mov eax, r9d; ret;

==> Found 6 gadgets in 0.046 seconds

Two hundred and thirty times fewer results from the same binary, in less than half the time, and every one of the six is a clean two-instruction sequence ending in a ret. That is the whole argument for a gadget finder with filters: an unfiltered scan of libc gives you hundreds of near misses where a register is set but the instruction sequence is longer than you want or the ending is not a simple return.

The -m 2 in the second command is what reduces the gadget to a mov and a ret, and the -j and -s flags remove the endings that would not link cleanly into a chain.

The final note in the README points at the payoff: a good mov gadget candidate at address 0x00052252, which is a specific instruction that sets eax from edi and returns.

What the tool does not do, and the scope of the README

The scope is narrow in a way worth stating before you build a workflow on it.

First, it is x86 only. The repository description says so directly, currently x86 only, and the decoder dependency, iced-x86, confirms it. There is no ARM or RISC-V support, and the iced-x86 library is an x86 decoder, so this is a design decision rather than a missing feature that might arrive later.

Second, it is a gadget finder, not a disassembler. The output is a list of candidate gadgets with their addresses, not a listing of the file. If you want to understand what a function does, this is the wrong tool. If you want to find a ret-ending instruction that moves a register in a particular way, it is the right one.

Third, the README is a gadget finder manual, not a tutorial on exploitation. The first two sections explain what gadgets are and how a chain is put together, including the requirement to have somewhere to write the chain and to be able to control the stack, either through a stack overflow that writes the chain directly under the stack pointer or through a stack pivot, which is usually a single gadget that moves the stack pointer to the rest of the chain. It also covers adding function pointers into a chain, taking care that function arguments are supplied after the next element, typically combined with a pop gadget that pops the arguments off the stack to transition smoothly to the next gadget.

That framing is consistent with the tool's position as an analysis aid rather than an exploitation framework, and it is why the licence is a permissive dual MIT or Apache-2.0.

Editorial conclusion

Adopt ropr if you are analysing binaries for usable ROP gadgets and want the results filtered down to things you would actually put in a chain, and you are working on x86 binaries. Do not adopt it for other architectures, since the repository description says it is currently x86 only, and do not expect it to replace a full disassembler, since it prints gadget candidates rather than a listing of the file. Before you rely on it, run it with no filters first to see the baseline count, then add the filters, and note that the crate version is 0.2.27 under a dual MIT or Apache-2.0 licence with no tagged releases published on GitHub.

Frequently asked questions

Official sources

1. Ben-Lichtman/ropr on GitHub
2. Issues
3. README