Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/ehsanmok/smartalloc-rs
Orphaned memory buffer detector
https://github.com/ehsanmok/smartalloc-rs
allocator debug-tool no-std orphaned-buffer-detector unsafe-code
Last synced: 19 days ago
JSON representation
Orphaned memory buffer detector
- Host: GitHub
- URL: https://github.com/ehsanmok/smartalloc-rs
- Owner: ehsanmok
- License: apache-2.0
- Created: 2022-09-06T01:43:59.000Z (about 2 years ago)
- Default Branch: main
- Last Pushed: 2022-09-08T17:34:55.000Z (about 2 years ago)
- Last Synced: 2024-10-11T18:12:49.034Z (about 1 month ago)
- Topics: allocator, debug-tool, no-std, orphaned-buffer-detector, unsafe-code
- Language: Rust
- Homepage: https://docs.rs/smartalloc
- Size: 30.3 KB
- Stars: 2
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE-APACHE
Awesome Lists containing this project
README
# Smartalloc-rs
[](https://github.com/ehsanmok/smartalloc-rs/actions/workflows/build.yml)
[](https://img.shields.io/badge/no-std-red)
[](https://crates.io/crates/smartalloc)
[](https://docs.rs/smartalloc)
This crate provides a `no_std` idiomatic Rust binding to [smartalloc](https://www.fourmilab.ch/smartall/) used for
**detecting orphaned buffer allocation** which is a type of heap memory leak that the program has lost all access to it.
The primary usecase is as a *debugging* tool when writing **unsafe** code where normal Rust static checks are not available.
It is best used along side [SANs](https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html) where SANs
alone are either unable to detect or their outputs are cumbersome to work through.
To get the best experience, `RUSTFLAGS=-Zsanitizer=leak` is used and is included in `.cargo/config.toml`.
## Usage
```ini
[dev-dependencies]
smartalloc = "0.2"
```
In fact, with `#![cfg(debug_assertions)]` the crate does **not** compile in the `--release` mode so preventing from any accidental usage.
The crate **requires nightly** Rust toolchain (MSRV 1.65).
## Example
During debugging, configure the `SmartAlloc` as the global allocator. Then include `sm_dump(true)` at the end of an unsafe code block.
Here is the [examples/orphan.rs](https://github.com/ehsanmok/smartalloc-rs/blob/main/examples/orphan.rs)
```rust
use core::alloc::{GlobalAlloc, Layout};
use smartalloc::{sm_dump, SmartAlloc};
#[global_allocator]
static GLOBAL: SmartAlloc = SmartAlloc;
fn main() {
unsafe {
let alloc = SmartAlloc;
let layout = Layout::from_size_align(8, 8).unwrap();
alloc.alloc(layout); // orphaned memory leak as it's pointer is lost
// and there's no alloc.dealloc(ptr, layout)
sm_dump(true);
}
}
```
which outputs
```txt
Orphaned buffer: 8 bytes allocated at line 12 of examples/orphan.rs
```
*Note* that the detector throws
```txt
Orphaned buffer: 5 bytes allocated at line 5 of examples/orphan.rs
Orphaned buffer: 48 bytes allocated at line 5 of examples/orphan.rs
```
which refers to the `#[global_allocator]` itself and can be ignored.
## Features
The detector can be turned off using `sm_static(true)` and turned back on `sm_static(false)` to wrap cases where allocation is done through std or safe cases such as [examples/native.rs](https://github.com/ehsanmok/smartalloc-rs/blob/main/examples/native.rs). For more details, checkout the original [docs](https://www.fourmilab.ch/smartall/).
## Aren't SANs alone supposed to detect such errors?
Neither of the `leak/address/memory` [sanitizers](https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html) are sufficient and can detect such errors *easily*.
In fact, running
```txt
RUSTFLAGS="-Zsanitizer=leak" cargo +nightly run --example undetected
// OR
RUSTFLAGS="-Zsanitizer=address" cargo +nightly run --example undetected
```
for [examples/undetected.rs](https://github.com/ehsanmok/smartalloc-rs/blob/main/examples/undetected.rs) which is
```rust
unsafe {
let alloc = SmartAlloc;
let layout = Layout::from_size_align(8, 8).unwrap();
alloc.alloc(layout);
}
```
with no `sm_dump(true)` at the end, does not show anything, mainly because we specified
```ini
[profile.dev]
opt-level = 0
```
for the SmartAlloc to work with introspection as opposed to what has been advised to include (at least `opt-level=1`) [here](https://github.com/japaric/rust-san#unrealiable-leaksanitizer)
to cirvumvent such a limitation but when is done the context gets destroyed. Also
```txt
RUSTFLAGS="-Zsanitizer=memory -Zsanitizer-memory-track-origins" cargo +nightly run --example undetected
```
cannot compile and it throws unhelpful messages
```txt
error: failed to run custom build command for `libc v0.2.132`
Caused by:
process didn't exit successfully: `/home/workspace/smartalloc-rs/target/debug/build/libc-02d4e594eff5723f/build-script-build` (exit status: 1)
--- stdout
cargo:rerun-if-changed=build.rs
--- stderr
==186416==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x56367729226c (/home/workspace/smartalloc-rs/target/debug/build/libc-02d4e594eff5723f/build-script-build+0x7a26c) (BuildId: ff090caba1904387acf3f0fecb58801c6fa5caed)
#1 0x56367728e95d (/home/workspace/smartalloc-rs/target/debug/build/libc-02d4e594eff5723f/build-script-build+0x7695d) (BuildId: ff090caba1904387acf3f0fecb58801c6fa5caed)
...
Uninitialized value was created by an allocation of '_2' in the stack frame of function '_ZN18build_script_build19rustc_minor_nightly17hfbf53e202478a57bE'
#0 0x563677291e70 (/home/workspace/smartalloc-rs/target/debug/build/libc-02d4e594eff5723f/build-script-build+0x79e70) (BuildId: ff090caba1904387acf3f0fecb58801c6fa5caed)
SUMMARY: MemorySanitizer: use-of-uninitialized-value (/home/workspace/smartalloc-rs/target/debug/build/libc-02d4e594eff5723f/build-script-build+0x7a26c) (BuildId: ff090caba1904387acf3f0fecb58801c6fa5caed)
Exiting
```
so it needs more work!
## Known issue
[smartalloc-sys/csrc/smartall.c](https://github.com/ehsanmok/smartalloc-rs/blob/main/smartalloc-sys/csrc/smartall.c)
writes into the passed filename pointer tracked by `#[track_caller]` (which is immutable)
which is an UB that could result into displaying more garbage after the filename in its report using this binding.
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your own will.
## Contribution
Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.