1 files changed, 70 insertions, 0 deletions
diff --git a/third_party/rust/neqo-crypto/src/aead_fuzzing.rs b/third_party/rust/neqo-crypto/src/aead_fuzzing.rs
new file mode 100644
index 0000000000..2c5cc6c56e
--- /dev/null
+++ b/third_party/rust/neqo-crypto/src/aead_fuzzing.rs
@@ -0,0 +1,70 @@
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use crate::constants::{Cipher, Version};
+use crate::err::{sec::SEC_ERROR_BAD_DATA, Error, Res};
+use crate::p11::SymKey;
+use std::fmt;
+
+pub const FIXED_TAG_FUZZING: &[u8] = &[0x0a; 16];
+pub struct Aead {}
+
+#[allow(clippy::unused_self)]
+impl Aead {
+    pub fn new(_version: Version, _cipher: Cipher, _secret: &SymKey, _prefix: &str) -> Res<Self> {
+        Ok(Self {})
+    }
+
+    #[must_use]
+    pub fn expansion(&self) -> usize {
+        FIXED_TAG_FUZZING.len()
+    }
+
+    pub fn encrypt<'a>(
+        &self,
+        _count: u64,
+        _aad: &[u8],
+        input: &[u8],
+        output: &'a mut [u8],
+    ) -> Res<&'a [u8]> {
+        let l = input.len();
+        output[..l].copy_from_slice(input);
+        output[l..l + 16].copy_from_slice(FIXED_TAG_FUZZING);
+        Ok(&output[..l + 16])
+    }
+
+    pub fn decrypt<'a>(
+        &self,
+        _count: u64,
+        _aad: &[u8],
+        input: &[u8],
+        output: &'a mut [u8],
+    ) -> Res<&'a [u8]> {
+        if input.len() < FIXED_TAG_FUZZING.len() {
+            return Err(Error::from(SEC_ERROR_BAD_DATA));
+        }
+
+        let len_encrypted = input.len() - FIXED_TAG_FUZZING.len();
+        // Check that:
+        // 1) expansion is all zeros and
+        // 2) if the encrypted data is also supplied that at least some values
+        //    are no zero (otherwise padding will be interpreted as a valid packet)
+        if &input[len_encrypted..] == FIXED_TAG_FUZZING
+            && (len_encrypted == 0 || input[..len_encrypted].iter().any(|x| *x != 0x0))
+        {
+            output[..len_encrypted].copy_from_slice(&input[..len_encrypted]);
+            Ok(&output[..len_encrypted])
+        } else {
+            Err(Error::from(SEC_ERROR_BAD_DATA))
+        }
+    }
+}
+
+impl fmt::Debug for Aead {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "[FUZZING AEAD]")
+    }
+}