crypto: replace ring AEAD API

This is currently only used for generating header protection masks, which, again, doesn't seem like something worth pulling a whole dependency for. This may or may not fall under FIPS scope.
cloudflare · Jan 10, 2025 · 447970c · 447970c
1 parent b17904e
commit 447970c
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Showing 3 changed files with 251 additions and 86 deletions.
diff --git a/quiche/src/crypto/boringssl.rs b/quiche/src/crypto/boringssl.rs
@@ -3,6 +3,8 @@ use super::*;
 use std::mem::MaybeUninit;
 
 use libc::c_int;
+use libc::c_uint;
+use libc::c_void;
 
 // NOTE: This structure is copied from <openssl/aead.h> in order to be able to
 // statically allocate it. While it is not often modified upstream, it needs to
@@ -15,6 +17,13 @@ struct EVP_AEAD_CTX {
     tag_len: u8,
 }
 
+#[derive(Clone)]
+#[repr(C)]
+struct AES_KEY {
+    rd_key: [u32; 4 * (14 + 1)],
+    rounds: c_int,
+}
+
 impl Algorithm {
     fn get_evp_aead(self) -> *const EVP_AEAD {
         match self {
@@ -126,29 +135,87 @@ impl Seal {
     }
 }
 
-fn make_aead_ctx(alg: Algorithm, key: &[u8]) -> Result<EVP_AEAD_CTX> {
-    let mut ctx = MaybeUninit::uninit();
+#[derive(Clone)]
+pub(crate) enum HeaderProtectionKey {
+    Aes(AES_KEY),
 
-    let ctx = unsafe {
-        let aead = alg.get_evp_aead();
+    ChaCha(Vec<u8>),
+}
 
-        let rc = EVP_AEAD_CTX_init(
-            ctx.as_mut_ptr(),
-            aead,
-            key.as_ptr(),
-            alg.key_len(),
-            alg.tag_len(),
-            std::ptr::null_mut(),
-        );
+impl HeaderProtectionKey {
+    pub fn new(alg: Algorithm, hp_key: Vec<u8>) -> Result<Self> {
+        match alg {
+            Algorithm::AES128_GCM => unsafe {
+                let mut aes_key = MaybeUninit::<AES_KEY>::uninit();
 
-        if rc != 1 {
-            return Err(Error::CryptoFail);
+                let rc = AES_set_encrypt_key(
+                    (&hp_key).as_ptr(),
+                    128,
+                    aes_key.as_mut_ptr(),
+                );
+
+                if rc != 0 {
+                    return Err(Error::CryptoFail);
+                }
+
+                let aes_key = aes_key.assume_init();
+                Ok(Self::Aes(aes_key))
+            },
+
+            Algorithm::AES256_GCM => unsafe {
+                let mut aes_key = MaybeUninit::<AES_KEY>::uninit();
+
+                let rc = AES_set_encrypt_key(
+                    (&hp_key).as_ptr(),
+                    256,
+                    aes_key.as_mut_ptr(),
+                );
+
+                if rc != 0 {
+                    return Err(Error::CryptoFail);
+                }
+
+                let aes_key = aes_key.assume_init();
+                Ok(Self::Aes(aes_key))
+            },
+
+            Algorithm::ChaCha20_Poly1305 => Ok(Self::ChaCha(hp_key)),
         }
+    }
 
-        ctx.assume_init()
-    };
+    pub fn new_mask(&self, sample: &[u8]) -> Result<[u8; 5]> {
+        let mut new_mask = [0_u8; 5];
 
-    Ok(ctx)
+        match self {
+            Self::Aes(aes_key) => unsafe {
+                AES_ecb_encrypt(
+                    sample.as_ptr(),
+                    (&mut new_mask).as_mut_ptr(),
+                    aes_key as _,
+                    1,
+                );
+            },
+
+            Self::ChaCha(key) => unsafe {
+                const PLAINTEXT: &[u8; 5] = b"\x00\x00\x00\x00\x00";
+
+                let counter = u32::from_le_bytes([
+                    sample[0], sample[1], sample[2], sample[3]
+                ]);
+
+                CRYPTO_chacha_20(
+                    (&mut new_mask).as_mut_ptr(),
+                    PLAINTEXT.as_ptr(),
+                    PLAINTEXT.len(),
+                    (&key).as_ptr(),
+                    (&sample[std::mem::size_of::<u32>()..]).as_ptr(),
+                    counter,
+                );
+            },
+        }
+
+        Ok(new_mask)
+    }
 }
 
 pub(crate) struct PacketKey {
@@ -180,6 +247,31 @@ impl PacketKey {
     }
 }
 
+fn make_aead_ctx(alg: Algorithm, key: &[u8]) -> Result<EVP_AEAD_CTX> {
+    let mut ctx = MaybeUninit::uninit();
+
+    let ctx = unsafe {
+        let aead = alg.get_evp_aead();
+
+        let rc = EVP_AEAD_CTX_init(
+            ctx.as_mut_ptr(),
+            aead,
+            key.as_ptr(),
+            alg.key_len(),
+            alg.tag_len(),
+            std::ptr::null_mut(),
+        );
+
+        if rc != 1 {
+            return Err(Error::CryptoFail);
+        }
+
+        ctx.assume_init()
+    };
+
+    Ok(ctx)
+}
+
 pub(crate) fn hkdf_extract(
     alg: Algorithm, out: &mut [u8], secret: &[u8], salt: &[u8],
 ) -> Result<()> {
@@ -262,4 +354,19 @@ extern {
         nonce_len: usize, inp: *const u8, in_len: usize, extra_in: *const u8,
         extra_in_len: usize, ad: *const u8, ad_len: usize,
     ) -> c_int;
+
+    // AES
+    fn AES_set_encrypt_key(
+        key: *const u8, bits: c_uint, aeskey: *mut AES_KEY,
+    ) -> c_int;
+
+    fn AES_ecb_encrypt(
+        inp: *const u8, out: *mut u8, key: *const AES_KEY, enc: c_int,
+    ) -> c_void;
+
+    // ChaCha20
+    fn CRYPTO_chacha_20(
+        out: *mut u8, inp: *const u8, in_len: usize, key: *const u8,
+        nonce: *const u8, counter: u32,
+    ) -> c_void;
 }
diff --git a/quiche/src/crypto/mod.rs b/quiche/src/crypto/mod.rs
@@ -66,17 +66,9 @@ pub enum Algorithm {
     ChaCha20_Poly1305,
 }
 
+// Note: some vendor-specific methods are implemented by each vendor's submodule
+// (openssl-quictls / boringssl).
 impl Algorithm {
-    // Note: some vendor-specific methods are implemented by each vendor's
-    // submodule (openssl-quictls / boringssl).
-    fn get_ring_hp(self) -> &'static aead::quic::Algorithm {
-        match self {
-            Algorithm::AES128_GCM => &aead::quic::AES_128,
-            Algorithm::AES256_GCM => &aead::quic::AES_256,
-            Algorithm::ChaCha20_Poly1305 => &aead::quic::CHACHA20,
-        }
-    }
-
     fn get_evp_digest(self) -> *const EVP_MD {
         match self {
             Algorithm::AES128_GCM => unsafe { EVP_sha256() },
@@ -173,13 +165,7 @@ impl Open {
             return Ok(<[u8; 5]>::default());
         }
 
-        let mask = self
-            .header
-            .hpk
-            .new_mask(sample)
-            .map_err(|_| Error::CryptoFail)?;
-
-        Ok(mask)
+        self.header.new_mask(sample)
     }
 
     pub fn alg(&self) -> Algorithm {
@@ -197,10 +183,7 @@ impl Open {
 
             secret: next_secret,
 
-            header: HeaderProtectionKey::new(
-                self.alg,
-                self.header.hp_key.clone(),
-            )?,
+            header: self.header.clone(),
 
             packet: next_packet_key,
         })
@@ -264,13 +247,7 @@ impl Seal {
             return Ok(<[u8; 5]>::default());
         }
 
-        let mask = self
-            .header
-            .hpk
-            .new_mask(sample)
-            .map_err(|_| Error::CryptoFail)?;
-
-        Ok(mask)
+        self.header.new_mask(sample)
     }
 
     pub fn alg(&self) -> Algorithm {
@@ -288,29 +265,15 @@ impl Seal {
 
             secret: next_secret,
 
-            header: HeaderProtectionKey::new(
-                self.alg,
-                self.header.hp_key.clone(),
-            )?,
+            header: self.header.clone(),
 
             packet: next_packet_key,
         })
     }
 }
 
-pub struct HeaderProtectionKey {
-    hpk: aead::quic::HeaderProtectionKey,
-
-    hp_key: Vec<u8>,
-}
 
 impl HeaderProtectionKey {
-    pub fn new(alg: Algorithm, hp_key: Vec<u8>) -> Result<Self> {
-        aead::quic::HeaderProtectionKey::new(alg.get_ring_hp(), &hp_key)
-            .map(|hpk| Self { hpk, hp_key })
-            .map_err(|_| Error::CryptoFail)
-    }
-
     pub fn from_secret(aead: Algorithm, secret: &[u8]) -> Result<Self> {
         let key_len = aead.key_len();