This PR implements a `non_secure_erase()` method on SecretKey,
KeyPair, SharedSecret, Scalar, and DisplaySecret. The purpose
of this method is to (attempt to) overwrite secret data with
valid default values. This method can be used by libraries
to implement Zeroize on structs containing secret values.
`non_secure_erase()` attempts to avoid being optimized away or
reordered using the same mechanism as the zeroize crate: first,
using `std::ptr::write_volatile` (which will not be optimized
away) to overwrite the memory, then using a memory fence to
prevent subtle issues due to load or store reordering.
Note, however, that this method is *very unlikely* to do anything
useful on its own. Effective use involves carefully placing these
values inside non-Copy structs and pinning those structs in place.
See the [`zeroize`](https://docs.rs/zeroize) documentation for tips
and tricks, and for further discussion.
[this commit includes a squashed-in commit from tcharding to fix docs
and helpful suggestions from apoelstra and Kixunil]
Currently we are not running the formatter in CI, in preparation for
doing so run `cargo +nightly fmt` to clear all current formatting
issues.
No manual changes.
9850550734 Move AsRef impl block next to Index (Tobin C. Harding)
4d42e8e906 Derive Copy and Clone (Tobin C. Harding)
b38ae97eaf Implement stable comparison functionality (Tobin C. Harding)
630fc1fcb6 Remove len and is_empty from impl_array_newtype macros (Tobin C. Harding)
9788b6df88 Remove leading colons from impl_array_newtype methods (Tobin C. Harding)
2bb08c21e5 Remove as_[mut_]ptr from impl_array_newtype macros (Tobin C. Harding)
3e28070187 Duplicate impl_array_newtype (Tobin C. Harding)
635890322a Add newline to end of file (Tobin C. Harding)
Pull request description:
Supersedes #515
The primary aim of this PR is to fix the fact that we currently implement various comparison traits (`Ord`, `PartialEq`) by comparing the inner byte arrays. These bytes are meant to be opaque and are not guaranteed across versions of `libsecp256k1`.
This PR is a bit involved because I had to detangle all the various types (across both `secp256k1` and `secp256k1-sys`) that use the `impl_array_newtype` macro.
- Patch 1: is trivial cleanup
- Patch 2: Step one of the PR is duplicating the macro into both crates so we can tease them apart.
- Patch 3-5: Are cleanup of the now duplicated `impl_array_newtype` macros
- Patch 6: Is the meat and potatoes
- Patch 7,8: Further minor clean ups to the macro
I had a lot of fun with this PR, I hope you enjoy it too.
Fix: #463
ACKs for top commit:
apoelstra:
ACK 9850550734
Tree-SHA512: 160381e53972ff882ceb1d2d47bac56a7301a2d13bfe75d3f6ff658ab2c6fbe516ad856587c4d23f98524205918ca1a5f9b737e35c23c7a01b476c92d8d1792f
Currently we have a few problems with our feature gating, attempt to
audit all feature gating and fix it by doing:
1. Do not enable features on optional dependencies (`rand` and
`bitcoin-hashes`) in dev-dependencies, doing so hides broken feature
gating in unit tests.
2. Do not use unnecessary feature combinations when one feature enables
another e.g. `any(feature = "std", feature = "alloc")`.
3. Enable "std" from "rand-std" and "bitcoin-std" (and fix features
gating as for point 2).
4. Clean up code around `rand::thread_rng`, this is part of this patch
because `thread_rng` requires the "rand-std" feature.
5. Clean up CI test script to test each feature individually now that
"rand-std" and "bitcoin-hashes-std" enable "std".
Run the command `cargo +nightly fmt` to fix formatting issues.
The formatter got confused in one place, adding an incorrect
indentation, this was manually fixed.
b0d0b2afcb Improve feature usage bitcoin-hashes[-std] (Tobin C. Harding)
Pull request description:
Currently we have a feature `bitcoin-hashes-std` and a dependency `bitcoin_hashes`, this means one has to think about and change the `_` and `-` when coding. The underscore in `bitcoin_hashes` is an artifact of days gone by and we cannot fix it but we can cover it up and make our lives easier, especially now we have `bitcoin-hashes-std`.
Improve feature usage of the `bitcoin_hashes` library by:
- Add a feature `bitcoin-hashes` that enables `bitcoin_hashes`.
- Use the new feature in all feature gated code
- Use `bitcoin-hashes-std` in feature gated code that includes other `std` features (e.g. `rand-std`)
ACKs for top commit:
apoelstra:
ACK b0d0b2afcb
Tree-SHA512: e6a86fe2c5b249a6c32b0fdedaeb8e25c47a30a4709f4fc4020cc1762747fe5d25883e2340ff77698079c9ee397491984889d3c1aaf195ca27eec09a77f62978
Currently we have a feature `bitcoin-hashes-std` and a dependency
`bitcoin_hashes`, this means one has to think about and change the `_`
and `-` when coding. The underscore in `bitcoin_hashes` is an artifact
of days gone by and we cannot fix it but we can cover it up and make our
lives easier, especially now we have `bitcoin-hashes-std`.
Improve feature usage of the `bitcoin_hashes` library by:
- Add a feature `bitcoin-hashes` that enables `bitcoin_hashes`.
- Use the new feature in all feature gated code
- Use `bitcoin-hashes-std` in feature gated code that includes other
`std` features (e.g. `rand-std`)
Normal users should never need to directly interact with the FFI layer.
Audit and reduce the use of `ffi` types in the public API of various
types. Leave only the implementation of `CPtr`, and document this
clearly as not required by normal users. Done for:
- PublicKey
- XOnlyPublicKey
- KeyPair
- ecdsa::Signature
- ecdsa::RecoverableSignature
As we did in rust-bitcoin [0] create a configuration conditional `bench`
that we can use to guard bench mark code. This has the benefit of
making our features additive i.e., we can now test with `--all-features`
with a stable toolchain (currently this fails because of our use of the
`test` crate).
[0] - https://github.com/rust-bitcoin/rust-bitcoin/pull/1092
As we do for other keys implement serde de/serialization for the
`SharedSecret`. Includes implementation of `from_slice` method that is
the borrowed version of `from_bytes` as well as a `FromStr`
implementation that parses a hex string.
Currently printing the `SharedSecret` using `Display` or `Debug` prints
the real secret, this is sub-optimal. We have a solution for other
secrets in the project where printing is obfuscated and we provide a
`display_secret` method for explicitly printing.
Mirror the logic for other secrets and obfuscate the `SharedSecret` when printing.
The `SharedSecret` uses sha256 to hash the secret, this implies the
secret is 32 bytes of data.
Currently we use a buffer of 256 bytes, this is unnecessary.
Change the implementation of `SharedSecret` to use a 32 byte buffer.
In test code we use multiple pub/sec keys. It is more intuitive if the
'secret 1' is generated by the owner of secret key 1.
Refactor only, no logic changes.
In preparation for simplifying the `SharedSecret` internals pull the
`new_with_hash` function logic out into a standalone public function
that provides similar functionality without use of the `SharedSecret`
struct. Function now returns the 64 bytes of data representing a shared
point on the curve, callers are expected to the hash these bytes to get
a shared secret.
Recently we fixed a bunch of feature gates to use `rand-std` instead
of `rand` but in doing so did not notice that the same feature gates
were using `alloc` which is meaningless if `std` is enabled.
Feature gate on `std` if we are using `rand-std`.
Recently we introduced uniform styling for module docs over in
`rust-bitcoin` repo. We can do the same here but its a bit controversial
because it removes the heading from module docs and every single public
module in rust-secp256k1 uses a heading. Instead we use a full
sentences. Also makes uniform the trailing `//!`.
As is typical in the Rust ecosystem use the third person tense when
documenting functions. E.g.,
```
/// Creates a new Foo.
```
As opposed to
```
/// Create a new Foo.
```
Currently the rustdoc on `SharedSecret` is wildly incorrect (possibly a
cut'n'pasta error).
Fix the rustdoc for `SharedSecret` and add an examples section to assist
testing the public API.
Fixes: 249
Currently various features fail to build when enabled without default
features. This is because many tests need feature gating.
Feature gating the import statements quickly turns into spaghetti when
trying to cover all combinations of two features correctly, instead just
allow unused imports on `tests` modules where needed.
Add correct feature requirements to the examples so they also can be run
without default features.
Improve the CI script by doing:
- Add `std` to the feature matrix.
- Add `--no-default-features` to test runs in the CI script.
Instead of repeating ourselves in defining one big test for the wasm
target, we can override the `test` attribute with the `wasm-bindgen-test`
one and therefore automatically run all (supported) tests in wasm.
Unfortunately, wasm doesn't support catching panics yet which means we
have to disable the `test_panic_raw_ctx` test.
Andrew Poelstra
Tobin C. Harding
kwantam
Elichai Turkel
Dominik Spicher
Thomas Eizinger