sm2: Fix heap allocation

sm2/Cargo.toml

@@ -18,24 +18,30 @@ edition = "2024"
 rust-version = "1.85"
 
 [dependencies]
-elliptic-curve = { version = "0.14.0-rc.0", default-features = false, features = ["sec1"] }
+elliptic-curve = { version = "0.14.0-rc.0", default-features = false, features = [
+    "sec1",
+] }
 rand_core = { version = "0.9", default-features = false }
 
 # optional dependencies
 primeorder = { version = "=0.14.0-pre.2", optional = true, path = "../primeorder" }
 rfc6979 = { version = "=0.5.0-pre.4", optional = true }
 serdect = { version = "0.3", optional = true, default-features = false }
-signature = { version = "=2.3.0-pre.6", optional = true, features = ["rand_core"] }
+signature = { version = "=2.3.0-pre.6", optional = true, features = [
+    "rand_core",
+    "digest",
+] }
 sm3 = { version = "=0.5.0-pre.5", optional = true, default-features = false }
 
 [dev-dependencies]
 hex-literal = "1"
 proptest = "1"
 rand_core = { version = "0.9", features = ["os_rng"] }
+rand = "0.9"
 
 [features]
-default = ["arithmetic", "dsa", "pke", "pem", "std"]
-alloc = ["elliptic-curve/alloc"]
+default = ["arithmetic", "dsa", "pke", "pem"]
+alloc = ["elliptic-curve/alloc", "signature?/alloc", "elliptic-curve/alloc"]
 std = ["alloc", "elliptic-curve/std", "signature?/std"]
 
 arithmetic = ["dep:primeorder", "elliptic-curve/arithmetic"]

sm2/src/dsa.rs

@@ -50,12 +50,11 @@ use signature::{Error, Result, SignatureEncoding};
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 
-#[cfg(feature = "pkcs8")]
+#[cfg(all(feature = "alloc", feature = "pkcs8"))]
 use crate::pkcs8::{
-    AlgorithmIdentifierRef, ObjectIdentifier, der::AnyRef, spki::AssociatedAlgorithmIdentifier,
+    AlgorithmIdentifierRef, ObjectIdentifier, der, der::AnyRef,
+    spki::AssociatedAlgorithmIdentifier, spki::SignatureBitStringEncoding,
 };
-#[cfg(all(feature = "alloc", feature = "pkcs8"))]
-use crate::pkcs8::{der, spki::SignatureBitStringEncoding};
 
 /// SM2DSA signature serialized as bytes.
 pub type SignatureBytes = [u8; Signature::BYTE_SIZE];

sm2/src/dsa/signing.rs

@@ -33,7 +33,7 @@ use signature::{
 };
 use sm3::Sm3;
 
-#[cfg(feature = "pkcs8")]
+#[cfg(all(feature = "pkcs8", feature = "alloc"))]
 use crate::pkcs8::{
     der::AnyRef,
     spki::{AlgorithmIdentifier, AssociatedAlgorithmIdentifier, SignatureAlgorithmIdentifier},
@@ -230,7 +230,7 @@ fn sign_prehash_rfc6979(secret_scalar: &Scalar, prehash: &[u8], data: &[u8]) ->
     Signature::from_scalars(r, s)
 }
 
-#[cfg(feature = "pkcs8")]
+#[cfg(all(feature = "alloc", feature = "pkcs8"))]
 impl SignatureAlgorithmIdentifier for SigningKey {
     type Params = AnyRef<'static>;
 

sm2/src/dsa/verifying.rs

@@ -31,10 +31,10 @@ use sm3::{Sm3, digest::Digest};
 use alloc::{boxed::Box, string::String};
 
 #[cfg(all(feature = "alloc", feature = "pkcs8"))]
-use crate::pkcs8::{self, EncodePublicKey, spki};
-#[cfg(feature = "pkcs8")]
 use crate::pkcs8::{
+    self, EncodePublicKey,
     der::AnyRef,
+    spki,
     spki::{AlgorithmIdentifier, AssociatedAlgorithmIdentifier, SignatureAlgorithmIdentifier},
 };
 
@@ -217,7 +217,7 @@ impl EncodePublicKey for VerifyingKey {
     }
 }
 
-#[cfg(feature = "pkcs8")]
+#[cfg(all(feature = "alloc", feature = "pkcs8"))]
 impl SignatureAlgorithmIdentifier for VerifyingKey {
     type Params = AnyRef<'static>;