commit af182d4ab51d6a1a70559bbdcd4ab842aa855684 Author: Isis Lovecruft isis@torproject.org Date: Sat Apr 21 01:01:04 2018 +0000
rust: Add crypto crate and implement Rust wrappers for SHA2 code.
* FIXES #24659: https://bugs.torproject.org/24659 --- configure.ac | 5 +- src/common/crypto_digest.c | 15 +- src/rust/Cargo.lock | 35 ++++ src/rust/Cargo.toml | 11 +- src/rust/crypto/Cargo.toml | 21 ++ src/rust/crypto/digests/mod.rs | 7 + src/rust/crypto/digests/sha2.rs | 213 ++++++++++++++++++++ src/rust/crypto/lib.rs | 36 ++++ src/rust/external/Cargo.toml | 3 + src/rust/external/crypto_digest.rs | 402 +++++++++++++++++++++++++++++++++++++ src/rust/external/lib.rs | 4 +- src/rust/include.am | 5 + 12 files changed, 752 insertions(+), 5 deletions(-)
diff --git a/configure.ac b/configure.ac index 387fc6fbe..3bf436203 100644 --- a/configure.ac +++ b/configure.ac @@ -306,7 +306,10 @@ fi AM_CONDITIONAL(USEPYTHON, [test "x$PYTHON" != "x"])
dnl List all external rust crates we depend on here. Include the version -rust_crates="libc-0.2.39" +rust_crates=" \ + digest-0.7.2 \ + libc-0.2.39 \ +" AC_SUBST(rust_crates)
ifdef([AC_C_FLEXIBLE_ARRAY_MEMBER], [ diff --git a/src/common/crypto_digest.c b/src/common/crypto_digest.c index f7163de13..9f9a1a1e2 100644 --- a/src/common/crypto_digest.c +++ b/src/common/crypto_digest.c @@ -268,7 +268,11 @@ crypto_digest_new(void) }
/** Allocate and return a new digest object to compute 256-bit digests - * using <b>algorithm</b>. */ + * using <b>algorithm</b>. + * + * C_RUST_COUPLED: `external::crypto_digest::crypto_digest256_new` + * C_RUST_COUPLED: `crypto::digest::Sha256::default` + */ crypto_digest_t * crypto_digest256_new(digest_algorithm_t algorithm) { @@ -298,6 +302,9 @@ crypto_digest_free_(crypto_digest_t *digest) }
/** Add <b>len</b> bytes from <b>data</b> to the digest object. + * + * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_add_bytess` + * C_RUST_COUPLED: `crypto::digest::Sha256::process` */ void crypto_digest_add_bytes(crypto_digest_t *digest, const char *data, @@ -335,6 +342,9 @@ crypto_digest_add_bytes(crypto_digest_t *digest, const char *data, /** Compute the hash of the data that has been passed to the digest * object; write the first out_len bytes of the result to <b>out</b>. * <b>out_len</b> must be <= DIGEST512_LEN. + * + * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_get_digest` + * C_RUST_COUPLED: `impl digest::FixedOutput for Sha256` */ void crypto_digest_get_digest(crypto_digest_t *digest, @@ -383,6 +393,9 @@ crypto_digest_get_digest(crypto_digest_t *digest,
/** Allocate and return a new digest object with the same state as * <b>digest</b> + * + * C_RUST_COUPLED: `external::crypto_digest::crypto_digest_dup` + * C_RUST_COUPLED: `impl Clone for crypto::digest::Sha256` */ crypto_digest_t * crypto_digest_dup(const crypto_digest_t *digest) diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock index 2ac32809d..ddbc0ac2b 100644 --- a/src/rust/Cargo.lock +++ b/src/rust/Cargo.lock @@ -1,8 +1,35 @@ [[package]] +name = "crypto" +version = "0.0.1" +dependencies = [ + "digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)", + "external 0.0.1", + "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)", + "smartlist 0.0.1", +] + +[[package]] +name = "digest" +version = "0.7.2" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)", +] + +[[package]] name = "external" version = "0.0.1" dependencies = [ "libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)", + "smartlist 0.0.1", +] + +[[package]] +name = "generic-array" +version = "0.9.0" +source = "registry+https://github.com/rust-lang/crates.io-index" +dependencies = [ + "typenum 1.9.0 (registry+https://github.com/rust-lang/crates.io-index)", ]
[[package]] @@ -87,7 +114,15 @@ dependencies = [ "tor_log 0.1.0", ]
+[[package]] +name = "typenum" +version = "1.9.0" +source = "registry+https://github.com/rust-lang/crates.io-index" + [metadata] +"checksum digest 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "00a49051fef47a72c9623101b19bd71924a45cca838826caae3eaa4d00772603" +"checksum generic-array 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ef25c5683767570c2bbd7deba372926a55eaae9982d7726ee2a1050239d45b9d" "checksum libc 0.2.39 (registry+https://github.com/rust-lang/crates.io-index)" = "f54263ad99207254cf58b5f701ecb432c717445ea2ee8af387334bdd1a03fdff" "checksum rand 0.5.0-pre.1 (registry+https://github.com/rust-lang/crates.io-index)" = "7d7a7728c20bfd9fcc6e713e748e787c3d00e5ffd139b3ad1b5be92c5dfbaad5" "checksum rand_core 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0224284424a4b818387b58d59336c288f99b48f69681aa60cc681fe038bbca5d" +"checksum typenum 1.9.0 (registry+https://github.com/rust-lang/crates.io-index)" = "13a99dc6780ef33c78780b826cf9d2a78840b72cae9474de4bcaf9051e60ebbd" diff --git a/src/rust/Cargo.toml b/src/rust/Cargo.toml index d47cd6422..1aaab0c4f 100644 --- a/src/rust/Cargo.toml +++ b/src/rust/Cargo.toml @@ -1,7 +1,14 @@ [workspace] -members = ["tor_util", "protover", "smartlist", "external", "tor_allocate", -"tor_rust", "tor_log", +members = [ + "crypto", + "external", + "protover", "rand", + "smartlist", + "tor_allocate", + "tor_log", + "tor_rust", + "tor_util", ]
[profile.release] diff --git a/src/rust/crypto/Cargo.toml b/src/rust/crypto/Cargo.toml new file mode 100644 index 000000000..e6a8bffa2 --- /dev/null +++ b/src/rust/crypto/Cargo.toml @@ -0,0 +1,21 @@ +[package] +authors = ["The Tor Project", + "Isis Lovecruft isis@torproject.org"] +name = "crypto" +version = "0.0.1" +publish = false + +[lib] +name = "crypto" +path = "lib.rs" +crate_type = ["rlib", "staticlib"] + +[dependencies] +libc = "=0.2.39" +digest = "=0.7.2" + +[dependencies.external] +path = "../external" + +[dependencies.smartlist] +path = "../smartlist" diff --git a/src/rust/crypto/digests/mod.rs b/src/rust/crypto/digests/mod.rs new file mode 100644 index 000000000..a2463b89e --- /dev/null +++ b/src/rust/crypto/digests/mod.rs @@ -0,0 +1,7 @@ +// Copyright (c) 2018, The Tor Project, Inc. +// Copyright (c) 2018, isis agora lovecruft +// See LICENSE for licensing information + +//! Hash Digests and eXtendible Output Functions (XOFs) + +pub mod sha2; diff --git a/src/rust/crypto/digests/sha2.rs b/src/rust/crypto/digests/sha2.rs new file mode 100644 index 000000000..1cbb6c581 --- /dev/null +++ b/src/rust/crypto/digests/sha2.rs @@ -0,0 +1,213 @@ +// Copyright (c) 2018, The Tor Project, Inc. +// Copyright (c) 2018, isis agora lovecruft +// See LICENSE for licensing information + +//! Hash Digests and eXtendible Output Functions (XOFs) + +pub use digest::Digest; + +use digest::BlockInput; +use digest::FixedOutput; +use digest::Input; +use digest::generic_array::GenericArray; +use digest::generic_array::typenum::U32; +use digest::generic_array::typenum::U64; + +use external::crypto_digest::CryptoDigest; +use external::crypto_digest::DigestAlgorithm; +use external::crypto_digest::get_256_bit_digest; +use external::crypto_digest::get_512_bit_digest; + +pub use external::crypto_digest::DIGEST256_LEN; +pub use external::crypto_digest::DIGEST512_LEN; + +/// The block size for both SHA-256 and SHA-512 digests is 512 bits/64 bytes. +/// +/// Unfortunately, we have to use the generic_array crate currently to express +/// this at compile time. Later, in the future, when Rust implements const +/// generics, we'll be able to remove this dependency (actually, it will get +/// removed from the digest crate, which is currently `pub use`ing it). +type BlockSize = U64; + +/// A SHA2-256 digest. +/// +/// # C_RUST_COUPLED +/// +/// * `crypto_digest_dup` +#[derive(Clone)] +pub struct Sha256 { + engine: CryptoDigest, +} + +/// Construct a new, default instance of a `Sha256` hash digest function. +/// +/// # Examples +/// +/// ``` +/// use crypto::digest::Sha256; +/// +/// let hasher: Sha256 = Sha256::default(); +/// ``` +/// +/// # Returns +/// +/// A new `Sha256` digest. +impl Default for Sha256 { + fn default() -> Sha256 { + Sha256{ engine: CryptoDigest::new(Some(DigestAlgorithm::SHA2_256)) } + } +} + +impl BlockInput for Sha256 { + type BlockSize = BlockSize; +} + +/// Input `msg` into the digest. +/// +/// # Examples +/// +/// ``` +/// use crypto::digest::Sha256; +/// +/// let hasher: Sha256 = Sha256::default(); +/// +/// hasher.process(b"foo"); +/// hasher.process(b"bar"); +/// ``` +impl Input for Sha256 { + fn process(&mut self, msg: &[u8]) { + self.engine.add_bytes(&msg); + } +} + +/// Retrieve the output hash from everything which has been fed into this +/// `Sha256` digest thus far. +/// +// +// FIXME: Once const generics land in Rust, we should genericise calling +// crypto_digest_get_digest in external::crypto_digest. +impl FixedOutput for Sha256 { + type OutputSize = U32; + + fn fixed_result(self) -> GenericArray<u8, Self::OutputSize> { + let buffer: [u8; DIGEST256_LEN] = get_256_bit_digest(self.engine); + + GenericArray::from(buffer) + } +} + +/// A SHA2-512 digest. +/// +/// # C_RUST_COUPLED +/// +/// * `crypto_digest_dup` +#[derive(Clone)] +pub struct Sha512 { + engine: CryptoDigest, +} + +/// Construct a new, default instance of a `Sha512` hash digest function. +/// +/// # Examples +/// +/// ``` +/// use crypto::digest::Sha512; +/// +/// let hasher: Sha256 = Sha512::default(); +/// ``` +/// +/// # Returns +/// +/// A new `Sha512` digest. +impl Default for Sha512 { + fn default() -> Sha512 { + Sha512{ engine: CryptoDigest::new(Some(DigestAlgorithm::SHA2_512)) } + } +} + +impl BlockInput for Sha512 { + type BlockSize = BlockSize; +} + +/// Input `msg` into the digest. +/// +/// # Examples +/// +/// ``` +/// use crypto::digest::Sha512; +/// +/// let hasher: Sha512 = Sha512::default(); +/// +/// hasher.process(b"foo"); +/// hasher.process(b"bar"); +/// ``` +impl Input for Sha512 { + fn process(&mut self, msg: &[u8]) { + self.engine.add_bytes(&msg); + } +} + +/// Retrieve the output hash from everything which has been fed into this +/// `Sha512` digest thus far. +/// +// +// FIXME: Once const generics land in Rust, we should genericise calling +// crypto_digest_get_digest in external::crypto_digest. +impl FixedOutput for Sha512 { + type OutputSize = U32; + + fn fixed_result(self) -> GenericArray<u8, Self::OutputSize> { + let buffer: [u8; DIGEST512_LEN] = get_512_bit_digest(self.engine); + + GenericArray::clone_from_slice(&buffer) + } +} + +#[cfg(test)] +mod test { + use digest::Digest; + + use super::*; + + #[test] + fn sha256_default() { + let _: Sha256 = Sha256::default(); + } + + #[test] + fn sha256_digest() { + let mut h: Sha256 = Sha256::new(); + let mut result: [u8; DIGEST256_LEN] = [0u8; DIGEST256_LEN]; + + h.input(b"foo"); + h.input(b"bar"); + h.input(b"baz"); + + result.copy_from_slice(h.fixed_result().as_slice()); + + println!("{:?}", &result[..]); + + assert_eq!(&result[..], &b"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"[..]); + } + + #[test] + fn sha512_default() { + let _: Sha512 = Sha512::default(); + } + + #[test] + fn sha512_digest() { + let mut h: Sha512 = Sha512::new(); + let mut result: [u8; DIGEST512_LEN] = [0u8; DIGEST512_LEN]; + + h.input(b"foo"); + h.input(b"bar"); + h.input(b"baz"); + + result.copy_from_slice(h.fixed_result().as_slice()); + + println!("{:?}", &result[..]); + + assert_eq!(&result[..], &b"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"[..]); + } +} diff --git a/src/rust/crypto/lib.rs b/src/rust/crypto/lib.rs new file mode 100644 index 000000000..d0793a857 --- /dev/null +++ b/src/rust/crypto/lib.rs @@ -0,0 +1,36 @@ +// Copyright (c) 2018, The Tor Project, Inc. +// Copyright (c) 2018, isis agora lovecruft +// See LICENSE for licensing information + +//! Common cryptographic functions and utilities. +//! +//! # Hash Digests and eXtendable Output Functions (XOFs) +//! +//! The `digests` module contains submodules for specific hash digests +//! and extendable output functions. +//! +//! ``` +//! use crypto::digests::sha256::Sha256; +//! +//! let hasher: Sha256 = Sha256::default(); +//! let mut result: [u8; 32] = [0u8; 32]; +//! +//! hasher.input("foo"); +//! hasher.input("bar"); +//! hasher.input("baz"); +//! +//! result.copy_from_slice(hasher.result().as_bytes()); +//! +//! assert!(result == "XXX"); +//! ``` + +#[deny(missing_docs)] + +// External crates from cargo or TOR_RUST_DEPENDENCIES. +extern crate digest; +extern crate libc; + +// Our local crates. +extern crate external; + +mod digests; // Unfortunately named "digests" plural to avoid name conflict with the digest crate diff --git a/src/rust/external/Cargo.toml b/src/rust/external/Cargo.toml index b5957b107..60ec03be4 100644 --- a/src/rust/external/Cargo.toml +++ b/src/rust/external/Cargo.toml @@ -6,6 +6,9 @@ name = "external" [dependencies] libc = "=0.2.39"
+[dependencies.smartlist] +path = "../smartlist" + [lib] name = "external" path = "lib.rs" diff --git a/src/rust/external/crypto_digest.rs b/src/rust/external/crypto_digest.rs new file mode 100644 index 000000000..bc49e6124 --- /dev/null +++ b/src/rust/external/crypto_digest.rs @@ -0,0 +1,402 @@ +// Copyright (c) 2018, The Tor Project, Inc. +// Copyright (c) 2018, isis agora lovecruft +// See LICENSE for licensing information + +//! Bindings to external digest and XOF functions which live within +//! src/common/crypto_digest.[ch]. +//! +//! We wrap our C implementations in src/common/crypto_digest.[ch] with more +//! Rusty types and interfaces in src/rust/crypto/digest/. + +use std::process::abort; + +use libc::c_char; +use libc::c_int; +use libc::size_t; +use libc::uint8_t; + +use smartlist::Stringlist; + +/// Length of the output of our message digest. +pub const DIGEST_LEN: usize = 20; + +/// Length of the output of our second (improved) message digests. (For now +/// this is just sha256, but it could be any other 256-bit digest.) +pub const DIGEST256_LEN: usize = 32; + +/// Length of the output of our 64-bit optimized message digests (SHA512). +pub const DIGEST512_LEN: usize = 64; + +/// Length of a sha1 message digest when encoded in base32 with trailing = signs +/// removed. +pub const BASE32_DIGEST_LEN: usize = 32; + +/// Length of a sha1 message digest when encoded in base64 with trailing = signs +/// removed. +pub const BASE64_DIGEST_LEN: usize = 27; + +/// Length of a sha256 message digest when encoded in base64 with trailing = +/// signs removed. +pub const BASE64_DIGEST256_LEN: usize = 43; + +/// Length of a sha512 message digest when encoded in base64 with trailing = +/// signs removed. +pub const BASE64_DIGEST512_LEN: usize = 86; + +/// Length of hex encoding of SHA1 digest, not including final NUL. +pub const HEX_DIGEST_LEN: usize = 40; + +/// Length of hex encoding of SHA256 digest, not including final NUL. +pub const HEX_DIGEST256_LEN: usize = 64; + +/// Length of hex encoding of SHA512 digest, not including final NUL. +pub const HEX_DIGEST512_LEN: usize = 128; + +/// Our C code uses an enum to declare the digest algorithm types which we know +/// about. However, because enums are implementation-defined in C, we can +/// neither work with them directly nor translate them into Rust enums. +/// Instead, we represent them as a u8 (under the assumption that we'll never +/// support more than 256 hash functions). +#[allow(non_camel_case_types)] +type digest_algorithm_t = u8; + +const DIGEST_SHA1: digest_algorithm_t = 0; +const DIGEST_SHA256: digest_algorithm_t = 1; +const DIGEST_SHA512: digest_algorithm_t = 2; +const DIGEST_SHA3_256: digest_algorithm_t = 3; +const DIGEST_SHA3_512: digest_algorithm_t = 4; + +/// The total number of digest algorithms we currently support. +/// +/// We can't access these from Rust, because their definitions in C require +/// introspecting the `digest_algorithm_t` typedef, which is an enum, so we have +/// to redefine them here. +const N_DIGEST_ALGORITHMS: usize = DIGEST_SHA3_512 as usize + 1; + +/// The number of hash digests we produce for a `common_digests_t`. +/// +/// We can't access these from Rust, because their definitions in C require +/// introspecting the `digest_algorithm_t` typedef, which is an enum, so we have +/// to redefine them here. +const N_COMMON_DIGEST_ALGORITHMS: usize = DIGEST_SHA256 as usize + 1; + +/// A digest function. +#[repr(C)] +#[derive(Debug, Copy, Clone)] +#[allow(non_camel_case_types)] +struct crypto_digest_t { + // This private, zero-length field forces the struct to be treated the same + // as its opaque C couterpart. + _unused: [u8; 0], +} + +/// An eXtendible Output Function (XOF). +#[repr(C)] +#[derive(Debug, Copy, Clone)] +#[allow(non_camel_case_types)] +struct crypto_xof_t { + // This private, zero-length field forces the struct to be treated the same + // as its opaque C couterpart. + _unused: [u8; 0], +} + +/// A set of all the digests we commonly compute, taken on a single +/// string. Any digests that are shorter than 512 bits are right-padded +/// with 0 bits. +/// +/// Note that this representation wastes 44 bytes for the SHA1 case, so +/// don't use it for anything where we need to allocate a whole bunch at +/// once. +#[repr(C)] +#[derive(Debug, Copy, Clone)] +#[allow(non_camel_case_types)] +struct common_digests_t { + pub d: [[c_char; N_COMMON_DIGEST_ALGORITHMS]; DIGEST256_LEN], +} + +/// A `smartlist_t` is just an alias for the `#[repr(C)]` type `Stringlist`, to +/// make it more clear that we're working with a smartlist which is owned by C. +#[allow(non_camel_case_types)] +type smartlist_t = Stringlist; + +/// All of the external functions from `src/common/crypto_digest.h`. +/// +/// These are kept private because they should be wrapped with Rust to make their usage safer. +// +// BINDGEN_GENERATED: These definitions were generated with bindgen and cleaned +// up manually. As such, there are more bindings than are likely necessary or +// which are in use. +#[allow(dead_code)] +extern "C" { + fn crypto_digest(digest: *mut c_char, m: *const c_char, len: size_t) -> c_int; + fn crypto_digest256(digest: *mut c_char, m: *const c_char, len: size_t, + algorithm: digest_algorithm_t) -> c_int; + fn crypto_digest512(digest: *mut c_char, m: *const c_char, len: size_t, + algorithm: digest_algorithm_t) -> c_int; + fn crypto_common_digests(ds_out: *mut common_digests_t, m: *const c_char, len: size_t) -> c_int; + fn crypto_digest_smartlist_prefix(digest_out: *mut c_char, len_out: size_t, prepend: *const c_char, + lst: *const smartlist_t, append: *const c_char, alg: digest_algorithm_t); + fn crypto_digest_smartlist(digest_out: *mut c_char, len_out: size_t, + lst: *const smartlist_t, append: *const c_char, alg: digest_algorithm_t); + fn crypto_digest_algorithm_get_name(alg: digest_algorithm_t) -> *const c_char; + fn crypto_digest_algorithm_get_length(alg: digest_algorithm_t) -> size_t; + fn crypto_digest_algorithm_parse_name(name: *const c_char) -> c_int; + fn crypto_digest_new() -> *mut crypto_digest_t; + fn crypto_digest256_new(algorithm: digest_algorithm_t) -> *mut crypto_digest_t; + fn crypto_digest512_new(algorithm: digest_algorithm_t) -> *mut crypto_digest_t; + fn crypto_digest_free(digest: *mut crypto_digest_t); + fn crypto_digest_add_bytes(digest: *mut crypto_digest_t, data: *const c_char, len: size_t); + fn crypto_digest_get_digest(digest: *mut crypto_digest_t, out: *mut c_char, out_len: size_t); + fn crypto_digest_dup(digest: *const crypto_digest_t) -> *mut crypto_digest_t; + fn crypto_digest_assign(into: *mut crypto_digest_t, from: *const crypto_digest_t); + fn crypto_hmac_sha256(hmac_out: *mut c_char, key: *const c_char, key_len: size_t, + msg: *const c_char, msg_len: size_t); + fn crypto_mac_sha3_256(mac_out: *mut uint8_t, len_out: size_t, + key: *const uint8_t, key_len: size_t, + msg: *const uint8_t, msg_len: size_t); + fn crypto_xof_new() -> *mut crypto_xof_t; + fn crypto_xof_add_bytes(xof: *mut crypto_xof_t, data: *const uint8_t, len: size_t); + fn crypto_xof_squeeze_bytes(xof: *mut crypto_xof_t, out: *mut uint8_t, len: size_t); + fn crypto_xof_free(xof: *mut crypto_xof_t); +} + +/// A wrapper around a `digest_algorithm_t`. +pub enum DigestAlgorithm { + SHA2_256, + SHA2_512, + SHA3_256, + SHA3_512, +} + +impl From<DigestAlgorithm> for digest_algorithm_t { + fn from(digest: DigestAlgorithm) -> digest_algorithm_t { + match digest { + DigestAlgorithm::SHA2_256 => DIGEST_SHA256, + DigestAlgorithm::SHA2_512 => DIGEST_SHA512, + DigestAlgorithm::SHA3_256 => DIGEST_SHA3_256, + DigestAlgorithm::SHA3_512 => DIGEST_SHA3_512, + } + } +} + +/// A wrapper around a mutable pointer to a `crypto_digest_t`. +pub struct CryptoDigest(*mut crypto_digest_t); + +/// Explicitly copy the state of a `CryptoDigest` hash digest context. +/// +/// # C_RUST_COUPLED +/// +/// * `crypto_digest_dup` +impl Clone for CryptoDigest { + fn clone(&self) -> CryptoDigest { + let digest: *mut crypto_digest_t; + + unsafe { + digest = crypto_digest_dup(self.0 as *const crypto_digest_t); + } + + // See the note in the implementation of CryptoDigest for the + // reasoning for `abort()` here. + if digest.is_null() { + abort(); + } + + CryptoDigest(digest) + } +} + +impl CryptoDigest { + /// A wrapper to call one of the C functions `crypto_digest_new`, + /// `crypto_digest256_new`, or `crypto_digest512_new`. + /// + /// # Warnings + /// + /// This function will `abort()` the entire process in an "abnormal" fashion, + /// i.e. not unwinding this or any other thread's stack, running any + /// destructors, or calling any panic/exit hooks) if `tor_malloc()` (called in + /// `crypto_digest256_new()`) is unable to allocate memory. + /// + /// # Returns + /// + /// A new `CryptoDigest`, which is a wrapper around a opaque representation + /// of a `crypto_digest_t`. The underlying `crypto_digest_t` _MUST_ only + /// ever be handled via a raw pointer, and never introspected. + /// + /// # C_RUST_COUPLED + /// + /// * `crypto_digest_new` + /// * `crypto_digest256_new` + /// * `crypto_digest512_new` + /// * `tor_malloc` (called by `crypto_digest256_new`, but we make + /// assumptions about its behvaiour and return values here) + pub fn new(algorithm: Option<DigestAlgorithm>) -> CryptoDigest { + let digest: *mut crypto_digest_t; + + if algorithm.is_none() { + unsafe { + digest = crypto_digest_new(); + } + } else { + let algo: digest_algorithm_t = algorithm.unwrap().into(); // can't fail because it's Some + + unsafe { + // XXX This is a pretty awkward API to use from Rust... + digest = match algo { + DIGEST_SHA1 => crypto_digest_new(), + DIGEST_SHA256 => crypto_digest256_new(DIGEST_SHA256), + DIGEST_SHA3_256 => crypto_digest256_new(DIGEST_SHA3_256), + DIGEST_SHA512 => crypto_digest512_new(DIGEST_SHA512), + DIGEST_SHA3_512 => crypto_digest512_new(DIGEST_SHA3_512), + _ => abort(), + } + } + } + + // In our C code, `crypto_digest*_new()` allocates memory with + // `tor_malloc()`. In `tor_malloc()`, if the underlying malloc + // implementation fails to allocate the requested memory and returns a + // NULL pointer, we call `exit(1)`. In the case that this `exit(1)` is + // called within a worker, be that a process or a thread, the inline + // comments within `tor_malloc()` mention "that's ok, since the parent + // will run out of memory soon anyway". However, if it takes long + // enough for the worker to die, and it manages to return a NULL pointer + // to our Rust code, our Rust is now in an irreparably broken state and + // may exhibit undefined behaviour. An even worse scenario, if/when we + // have parent/child processes/threads controlled by Rust, would be that + // the UB contagion in Rust manages to spread to other children before + // the entire process (hopefully terminates). + // + // However, following the assumptions made in `tor_malloc()` that + // calling `exit(1)` in a child is okay because the parent will + // eventually run into the same errors, and also to stymie any UB + // contagion in the meantime, we call abort!() here to terminate the + // entire program immediately. + if digest.is_null() { + abort(); + } + + CryptoDigest(digest) + } + + /// A wrapper to call the C function `crypto_digest_add_bytes`. + /// + /// # Inputs + /// + /// * `bytes`: a byte slice of bytes to be added into this digest. + /// + /// # C_RUST_COUPLED + /// + /// * `crypto_digest_add_bytes` + pub fn add_bytes(&self, bytes: &[u8]) { + unsafe { + crypto_digest_add_bytes(self.0 as *mut crypto_digest_t, + bytes.as_ptr() as *const c_char, + bytes.len() as size_t) + } + } +} + +/// Get the 256-bit digest output of a `crypto_digest_t`. +/// +/// # Inputs +/// +/// * `digest`: A `CryptoDigest` which wraps either a `DIGEST_SHA256` or a +/// `DIGEST_SHA3_256`. +/// +/// # Warning +/// +/// Calling this function with a `CryptoDigest` which is neither SHA2-256 or +/// SHA3-256 is a programming error. Since we cannot introspect the opaque +/// struct from Rust, however, there is no way for us to check that the correct +/// one is being passed in. That is up to you, dear programmer. If you mess +/// up, you will get a incorrectly-sized hash digest in return, and it will be +/// your fault. Don't do that. +/// +/// # Returns +/// +/// A 256-bit hash digest, as a `[u8; 32]`. +/// +/// # C_RUST_COUPLED +/// +/// * `crypto_digest_get_digest` +/// * `DIGEST256_LEN` +// +// FIXME: Once const generics land in Rust, we should genericise calling +// crypto_digest_get_digest w.r.t. output array size. +pub fn get_256_bit_digest(digest: CryptoDigest) -> [u8; DIGEST256_LEN] { + let mut buffer: [u8; DIGEST256_LEN] = [0u8; DIGEST256_LEN]; + + unsafe { + crypto_digest_get_digest(digest.0, + buffer.as_mut_ptr() as *mut c_char, + DIGEST256_LEN as size_t); + + if buffer.as_ptr().is_null() { + abort(); + } + } + buffer +} + +/// Get the 512-bit digest output of a `crypto_digest_t`. +/// +/// # Inputs +/// +/// * `digest`: A `CryptoDigest` which wraps either a `DIGEST_SHA512` or a +/// `DIGEST_SHA3_512`. +/// +/// # Warning +/// +/// Calling this function with a `CryptoDigest` which is neither SHA2-512 or +/// SHA3-512 is a programming error. Since we cannot introspect the opaque +/// struct from Rust, however, there is no way for us to check that the correct +/// one is being passed in. That is up to you, dear programmer. If you mess +/// up, you will get a incorrectly-sized hash digest in return, and it will be +/// your fault. Don't do that. +/// +/// # Returns +/// +/// A 512-bit hash digest, as a `[u8; 64]`. +/// +/// # C_RUST_COUPLED +/// +/// * `crypto_digest_get_digest` +/// * `DIGEST512_LEN` +// +// FIXME: Once const generics land in Rust, we should genericise calling +// crypto_digest_get_digest w.r.t. output array size. +pub fn get_512_bit_digest(digest: CryptoDigest) -> [u8; DIGEST512_LEN] { + let mut buffer: [u8; DIGEST512_LEN] = [0u8; DIGEST512_LEN]; + + unsafe { + crypto_digest_get_digest(digest.0, + buffer.as_mut_ptr() as *mut c_char, + DIGEST512_LEN as size_t); + + if buffer.as_ptr().is_null() { + abort(); + } + } + buffer +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn test_layout_common_digests_t() { + assert_eq!(::std::mem::size_of::<common_digests_t>(), 64usize, + concat!("Size of: ", stringify!(common_digests_t))); + assert_eq!(::std::mem::align_of::<common_digests_t>(), 1usize, + concat!("Alignment of ", stringify!(common_digests_t))); + } + + #[test] + fn test_layout_crypto_digest_t() { + assert_eq!(::std::mem::size_of::<crypto_digest_t>(), 0usize, + concat!("Size of: ", stringify!(crypto_digest_t))); + assert_eq!(::std::mem::align_of::<crypto_digest_t>(), 1usize, + concat!("Alignment of ", stringify!(crypto_digest_t))); + } +} diff --git a/src/rust/external/lib.rs b/src/rust/external/lib.rs index 5fd74cf4c..ffd38ac5d 100644 --- a/src/rust/external/lib.rs +++ b/src/rust/external/lib.rs @@ -9,8 +9,10 @@
extern crate libc;
+extern crate smartlist; + +pub mod crypto_digest; mod crypto_rand; mod external;
-pub use crypto_rand::*; pub use external::*; diff --git a/src/rust/include.am b/src/rust/include.am index 3edc87e1e..ba652bda0 100644 --- a/src/rust/include.am +++ b/src/rust/include.am @@ -4,7 +4,12 @@ EXTRA_DIST +=\ src/rust/Cargo.toml \ src/rust/Cargo.lock \ src/rust/.cargo/config.in \ + src/rust/crypto/Cargo.toml \ + src/rust/crypto/lib.rs \ + src/rust/crypto/digests/mod.rs \ + src/rust/crypto/digests/sha2.rs \ src/rust/external/Cargo.toml \ + src/rust/external/crypto_digest.rs \ src/rust/external/crypto_rand.rs \ src/rust/external/external.rs \ src/rust/external/lib.rs \