fix eq check for TicketName

Cargo.toml

@@ -86,6 +86,7 @@ thiserror = "1.0"
 rand = "0.8"
 fastrand = "2.0"
 memchr = "2.4"
+constant_time_eq = "0.3"
 uuid = "1.3"
 base64 = "0.22"
 regex = "1.11"

lib/g3-types/Cargo.toml

@@ -23,6 +23,7 @@ crc32fast = "1.4"
 smallvec.workspace = true
 smol_str.workspace = true
 memchr.workspace = true
+constant_time_eq.workspace = true
 url.workspace = true
 num-traits.workspace = true
 arc-swap.workspace = true

lib/g3-types/src/net/tls/ticket_name.rs

@@ -18,7 +18,7 @@ use std::hash::{Hash, Hasher};
 
 pub const TICKET_KEY_NAME_LENGTH: usize = 16;
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 pub struct TicketKeyName([u8; TICKET_KEY_NAME_LENGTH]);
 
 impl From<[u8; TICKET_KEY_NAME_LENGTH]> for TicketKeyName {
@@ -53,12 +53,7 @@ impl Hash for TicketKeyName {
 
 impl PartialEq for TicketKeyName {
     fn eq(&self, other: &Self) -> bool {
-        // use Constant Time Eq
-        let mut xor_sum: u32 = 0;
-        for i in 0..TICKET_KEY_NAME_LENGTH {
-            xor_sum += (self.0[i] ^ other.0[0]) as u32;
-        }
-        xor_sum == 0
+        constant_time_eq::constant_time_eq_n(&self.0, &other.0)
     }
 }
 
@@ -70,11 +65,7 @@ impl TicketKeyName {
             return false;
         }
 
-        let mut xor_sum: u32 = 0;
-        for i in 0..TICKET_KEY_NAME_LENGTH {
-            xor_sum += (self.0[i] ^ buf[0]) as u32;
-        }
-        xor_sum == 0
+        constant_time_eq::constant_time_eq(&self.0, buf)
     }
 
     /// Safety: `b` should be of size `TICKET_KEY_NAME_LENGTH`
@@ -84,3 +75,16 @@ impl TicketKeyName {
         TicketKeyName(v)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn constant_eq() {
+        let name1 = TicketKeyName([0u8; 16]);
+        let name2 = TicketKeyName([0u8; 16]);
+        assert_eq!(name1, name2);
+        assert!(name1.constant_time_eq(name2.as_ref()));
+    }
+}