Add KMIP HSM signing support

Cargo.toml

@@ -33,13 +33,17 @@ chrono         = { version = "0.4.35", optional = true, default-features = false
 futures-util   = { version = "0.3", optional = true }
 hashbrown      = { version = "0.14.2", optional = true, default-features = false, features = ["allocator-api2", "inline-more"] } # 0.14.2 introduces explicit hashing
 heapless       = { version = "0.8", optional = true }
+kmip           = { git = "https://github.com/NLnetLabs/kmip-protocol", branch = "next", package = "kmip-protocol", version = "0.5.0", optional = true, features = ["tls-with-openssl-vendored"] } # TODO: use the async feature instead
 libc           = { version = "0.2.153", default-features = false, optional = true } # 0.2.79 is the first version that has IP_PMTUDISC_OMIT
 log            = { version = "0.4.22", optional = true }
 parking_lot    = { version = "0.12", optional = true }
 moka           = { version = "0.12.3", optional = true, features = ["future"] }
 openssl        = { version = "0.10.72", optional = true } # 0.10.70 upgrades to 'bitflags' 2.x
 proc-macro2    = { version = "1.0.69", optional = true } # Force proc-macro2 to at least 1.0.69 for minimal-version build
+r2d2           = { version = "0.8.9", optional = true }
 ring           = { version = "0.17.2", optional = true }
+bcder          = { version = "0.7", optional = true }
+rpki           = { version = "0.18", optional = true, features = ["crypto"] }
 rustversion    = { version = "1", optional = true }
 secrecy        = { version = "0.10", optional = true }
 serde          = { version = "1.0.130", optional = true, features = ["derive"] }
@@ -50,6 +54,8 @@ tokio-rustls   = { version = "0.26", optional = true, default-features = false }
 tokio-stream   = { version = "0.1.1", optional = true }
 tracing        = { version = "0.1.40", optional = true, features = ["log"] }
 tracing-subscriber = { version = "0.3.18", optional = true, features = ["env-filter"] }
+url            = { version = "2.5.4", optional = true }
+uuid           = { version = "1.18.0", features = ["v4"], optional = true }
 
 [features]
 default     = ["std", "rand"]
@@ -65,8 +71,9 @@ std         = ["alloc", "dep:hashbrown", "bumpalo?/std", "bytes?/std", "octseq/s
 tracing     = ["dep:log", "dep:tracing"]
 
 # Cryptographic backends
-ring    = ["dep:ring"]
-openssl = ["dep:openssl"]
+ring        = ["dep:ring"]
+openssl     = ["dep:openssl"]
+kmip        = ["dep:kmip", "dep:bcder", "dep:url", "dep:uuid", "dep:openssl"]
 
 # Crate features
 net         = ["bytes", "futures-util", "rand", "std", "tokio"]
@@ -90,6 +97,8 @@ unstable-zonetree = ["futures-util", "parking_lot", "rustversion", "serde", "std
 
 # Support for testing
 arbitrary = ["dep:arbitrary"]
+url = ["dep:url"]
+uuid = ["dep:uuid"]
 
 [dev-dependencies]
 itertools         = "0.13.0"

src/crypto/common.rs

@@ -209,10 +209,22 @@ pub fn rsa_exponent_modulus(
 }
 
 /// Encode the RSA exponent and modulus components in DNSKEY record data
-/// format.
-pub fn rsa_encode(e: &[u8], n: &[u8]) -> Vec<u8> {
+/// format. Leading zeroes will be ignored per RFC 3110 section 2.
+pub fn rsa_encode(mut e: &[u8], mut n: &[u8]) -> Vec<u8> {
+    fn trim_leading_zeroes(bytes: &[u8]) -> &[u8] {
+        bytes
+            .iter()
+            .position(|&v| v != 0)
+            .map(|idx| &bytes[idx..])
+            .unwrap_or_default()
+    }
+
     let mut key = Vec::new();
 
+    // Trim leading zeroes.
+    e = trim_leading_zeroes(e);
+    n = trim_leading_zeroes(n);
+
     // Encode the exponent length.
     if let Ok(exp_len) = u8::try_from(e.len()) {
         key.reserve_exact(1 + e.len() + n.len());
@@ -288,3 +300,35 @@ impl fmt::Display for FromDnskeyError {
 }
 
 impl error::Error for FromDnskeyError {}
+
+//----------- Tests ----------------------------------------------------------
+
+#[cfg(test)]
+mod tests {
+    use crate::crypto::common::rsa_encode;
+
+    #[test]
+    fn test_rsa_encode() {
+        assert_eq!(rsa_encode(&[], &[]), &[0]);
+
+        assert_eq!(rsa_encode(&[1], &[]), &[1, 1]);
+        assert_eq!(rsa_encode(&[], &[1]), &[0, 1]);
+        assert_eq!(rsa_encode(&[1], &[1]), &[1, 1, 1]);
+
+        assert_eq!(rsa_encode(&[0, 1], &[1]), &[1, 1, 1]);
+        assert_eq!(rsa_encode(&[1], &[0, 1]), &[1, 1, 1]);
+        assert_eq!(rsa_encode(&[0, 1], &[0, 1]), &[1, 1, 1]);
+
+        assert_eq!(rsa_encode(&[0, 0, 1], &[0, 1]), &[1, 1, 1]);
+        assert_eq!(rsa_encode(&[0, 1], &[0, 0, 1]), &[1, 1, 1]);
+        assert_eq!(rsa_encode(&[0, 1, 1], &[0, 0, 1]), &[2, 1, 1, 1]);
+
+        assert_eq!(rsa_encode(&[1, 2], &[]), &[2, 1, 2]);
+        assert_eq!(rsa_encode(&[], &[1, 2]), &[0, 1, 2]);
+        assert_eq!(rsa_encode(&[1, 2], &[1, 2]), &[2, 1, 2, 1, 2]);
+
+        assert_eq!(rsa_encode(&[0, 1, 2], &[1]), &[2, 1, 2, 1]);
+        assert_eq!(rsa_encode(&[1], &[0, 1, 2]), &[1, 1, 1, 2]);
+        assert_eq!(rsa_encode(&[0, 1, 2], &[0, 1, 2]), &[2, 1, 2, 1, 2]);
+    }
+}