dsa: Make compilation work on thumbv7em-none-eabi

Author: aumetra

.github/workflows/dsa.yml

@@ -24,7 +24,7 @@ jobs:
           - thumbv7em-none-eabi
           - wasm32-unknown-unknown
         toolchain:
-          - 1.60.0 # MSRV
+          - 1.57.0 # MSRV
           - stable
     steps:
       - uses: actions/checkout@v2
@@ -43,7 +43,7 @@ jobs:
           - macos-latest
           - windows-latest
         toolchain:
-          - 1.60.0 # MSRV
+          - 1.57.0 # MSRV
           - stable
     runs-on: ${{ matrix.platform }}
     steps:

dsa/Cargo.toml

@@ -6,22 +6,22 @@ license = "Apache-2.0 OR MIT"
 readme = "README.md"
 categories = ["cryptography"]
 keywords = ["crypto", "nist", "signature"]
-rust-version = "1.60" # MSRV because of the feature syntax
+rust-version = "1.57"
 
 [dependencies]
 digest = "0.10.3"
 num-bigint = { package = "num-bigint-dig", version = "0.8.1", default-features = false, features = ["prime", "rand", "zeroize"] }
 num-traits = { version = "0.2.15", default-features = false }
 opaque-debug = "0.3.0"
 paste = "1.0.7"
-pkcs8 = { version = "0.9.0", default-features = false, features = ["std"] }
+pkcs8 = { version = "0.9.0", default-features = false, features = ["alloc"] }
 rand = { version = "0.8.5", default-features = false }
 signature = { version = "1.5.0", optional = true }
 zeroize = { version = "1.5.5", default-features = false }
 
 [features]
-default = ["signature"]
-signature = ["dep:signature", "rand/std", "rand/std_rng"]
+default = ["signature-compat"]
+signature-compat = ["signature", "pkcs8/std", "rand/std", "rand/std_rng"]
 
 [dev-dependencies]
 pkcs8 = { version = "0.9.0", default-features = false, features = ["pem"] }

dsa/src/lib.rs

@@ -54,6 +54,7 @@
 //! ```
 //!
 
+#![cfg_attr(not(feature = "signature-compat"), no_std)]
 #![forbid(missing_docs, unsafe_code)]
 #![deny(rust_2018_idioms)]
 
@@ -68,8 +69,8 @@ pub use self::signature::Signature;
 // Re-export the types needed for de-/serialising keys to DER and PEM
 pub use pkcs8;
 
-#[cfg(feature = "signature")]
-#[cfg_attr(doc_cfg, doc(cfg(feature = "signature")))]
+#[cfg(feature = "signature-compat")]
+#[cfg_attr(doc_cfg, doc(cfg(feature = "signature-compat")))]
 pub mod compat;
 pub mod consts;
 

dsa/src/privatekey.rs

@@ -3,14 +3,14 @@
 //!
 
 use crate::{Components, PublicKey, Signature, DSA_OID};
+use core::cmp::min;
 use digest::Digest;
 use num_bigint::BigUint;
 use pkcs8::{
     der::{asn1::UIntRef, AnyRef, Decode, Encode},
     AlgorithmIdentifier, DecodePrivateKey, EncodePrivateKey, PrivateKeyInfo, SecretDocument,
 };
 use rand::{CryptoRng, RngCore};
-use std::cmp::min;
 use zeroize::Zeroizing;
 
 /// DSA private key

dsa/src/publickey.rs

@@ -3,14 +3,14 @@
 //!
 
 use crate::{Components, Signature, DSA_OID};
+use core::cmp::min;
 use digest::Digest;
 use num_bigint::{BigUint, ModInverse};
 use num_traits::One;
 use pkcs8::{
     der::{asn1::UIntRef, AnyRef, Decode, Encode},
     spki, AlgorithmIdentifier, DecodePublicKey, EncodePublicKey, SubjectPublicKeyInfo,
 };
-use std::cmp::min;
 
 /// DSA public key
 #[derive(Clone, PartialEq, PartialOrd)]