From a539f4621e74a1ab722f96d152278d87121550c5 Mon Sep 17 00:00:00 2001
From: ivmarkov <ivan.markov@gmail.com>
Date: Thu, 4 May 2023 06:13:36 +0000
Subject: [PATCH] More crypto fixes

---
 matter/Cargo.toml                      |  2 +-
 matter/src/crypto/crypto_rustcrypto.rs | 14 ++++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/matter/Cargo.toml b/matter/Cargo.toml
index 4eb2a74..b077a7a 100644
--- a/matter/Cargo.toml
+++ b/matter/Cargo.toml
@@ -69,7 +69,7 @@ p256 = { version = "0.13.0", default-features = false, features = ["arithmetic",
 elliptic-curve = { version = "0.13.2", optional = true }
 crypto-bigint = { version = "0.4", default-features = false, optional = true }
 rand_core = { version = "0.6", default-features = false, optional = true }
-x509-cert = { version = "0.2.0", default-features = false, features = ["pem", "std"], optional = true } # TODO: requires `alloc`
+x509-cert = { version = "0.2.0", default-features = false, features = ["pem"], optional = true } # TODO: requires `alloc`
 
 # to compute the check digit
 verhoeff = "1"
diff --git a/matter/src/crypto/crypto_rustcrypto.rs b/matter/src/crypto/crypto_rustcrypto.rs
index 6f975cb..6212c96 100644
--- a/matter/src/crypto/crypto_rustcrypto.rs
+++ b/matter/src/crypto/crypto_rustcrypto.rs
@@ -34,7 +34,7 @@ use p256::{
 use sha2::Digest;
 use x509_cert::{
     attr::AttributeType,
-    der::{asn1::BitString, Any, Encode},
+    der::{asn1::BitString, Any, Encode, Writer},
     name::RdnSequence,
     request::CertReq,
     spki::{AlgorithmIdentifier, SubjectPublicKeyInfoOwned},
@@ -205,7 +205,7 @@ impl KeyPair {
             attributes: Default::default(),
         };
         let mut message = vec![];
-        info.encode(&mut message).unwrap();
+        info.encode(&mut VecWriter(&mut message)).unwrap();
 
         // Can't use self.sign_msg as the signature has to be in DER format
         let private_key = self.private_key()?;
@@ -375,3 +375,13 @@ impl<'a> ccm::aead::Buffer for SliceBuffer<'a> {
         self.len = len;
     }
 }
+
+struct VecWriter<'a>(&'a mut alloc::vec::Vec<u8>);
+
+impl<'a> Writer for VecWriter<'a> {
+    fn write(&mut self, slice: &[u8]) -> x509_cert::der::Result<()> {
+        self.0.extend_from_slice(slice);
+
+        Ok(())
+    }
+}