1 files changed, 78 insertions, 0 deletions
diff --git a/third_party/rust/neqo-crypto/src/replay.rs b/third_party/rust/neqo-crypto/src/replay.rs
new file mode 100644
index 0000000000..7a493fbc1b
--- /dev/null
+++ b/third_party/rust/neqo-crypto/src/replay.rs
@@ -0,0 +1,78 @@
+// 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::err::Res;
+use crate::ssl::PRFileDesc;
+use crate::time::{Interval, PRTime, Time};
+
+use std::convert::{TryFrom, TryInto};
+use std::ops::{Deref, DerefMut};
+use std::os::raw::c_uint;
+use std::ptr::null_mut;
+use std::time::{Duration, Instant};
+
+// This is an opaque struct in NSS.
+#[allow(clippy::upper_case_acronyms)]
+#[allow(clippy::empty_enum)]
+pub enum SSLAntiReplayContext {}
+
+experimental_api!(SSL_CreateAntiReplayContext(
+    now: PRTime,
+    window: PRTime,
+    k: c_uint,
+    bits: c_uint,
+    ctx: *mut *mut SSLAntiReplayContext,
+));
+experimental_api!(SSL_ReleaseAntiReplayContext(ctx: *mut SSLAntiReplayContext));
+experimental_api!(SSL_SetAntiReplayContext(
+    fd: *mut PRFileDesc,
+    ctx: *mut SSLAntiReplayContext,
+));
+
+scoped_ptr!(
+    AntiReplayContext,
+    SSLAntiReplayContext,
+    SSL_ReleaseAntiReplayContext
+);
+
+/// `AntiReplay` is used by servers when processing 0-RTT handshakes.
+/// It limits the exposure of servers to replay attack by rejecting 0-RTT
+/// if it appears to be a replay.  There is a false-positive rate that can be
+/// managed by tuning the parameters used to create the context.
+#[allow(clippy::module_name_repetitions)]
+pub struct AntiReplay {
+    ctx: AntiReplayContext,
+}
+
+impl AntiReplay {
+    /// Make a new anti-replay context.
+    /// See the documentation in NSS for advice on how to set these values.
+    ///
+    /// # Errors
+    /// Returns an error if `now` is in the past relative to our baseline or
+    /// NSS is unable to generate an anti-replay context.
+    pub fn new(now: Instant, window: Duration, k: usize, bits: usize) -> Res<Self> {
+        let mut ctx: *mut SSLAntiReplayContext = null_mut();
+        unsafe {
+            SSL_CreateAntiReplayContext(
+                Time::from(now).try_into()?,
+                Interval::from(window).try_into()?,
+                c_uint::try_from(k)?,
+                c_uint::try_from(bits)?,
+                &mut ctx,
+            )
+        }?;
+
+        Ok(Self {
+            ctx: AntiReplayContext::from_ptr(ctx)?,
+        })
+    }
+
+    /// Configure the provided socket with this anti-replay context.
+    pub(crate) fn config_socket(&self, fd: *mut PRFileDesc) -> Res<()> {
+        unsafe { SSL_SetAntiReplayContext(fd, *self.ctx) }
+    }
+}