From 62ac5b94b3842322f267df28ff90ad3c9d4060a7 Mon Sep 17 00:00:00 2001
From: Folke Behrens <folke@neon.tech>
Date: Tue, 6 May 2025 09:28:25 +0000
Subject: [PATCH] proxy: Include the exp/nbf timestamps in the errors (#11828)

## Problem

It's difficult to tell when the JWT expired from current logs and error
messages.

## Summary of changes

Add exp/nbf timestamps to the respective error variants.
Also use checked_add when deserializing a SystemTime from JWT.

Related to INC-509
---
 proxy/src/auth/backend/jwt.rs | 41 ++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/proxy/src/auth/backend/jwt.rs b/proxy/src/auth/backend/jwt.rs
index 44a6a42665..a48f67199a 100644
--- a/proxy/src/auth/backend/jwt.rs
+++ b/proxy/src/auth/backend/jwt.rs
@@ -409,14 +409,22 @@ impl JwkCacheEntryLock {
 
         if let Some(exp) = payload.expiration {
             if now >= exp + CLOCK_SKEW_LEEWAY {
-                return Err(JwtError::InvalidClaims(JwtClaimsError::JwtTokenHasExpired));
+                return Err(JwtError::InvalidClaims(JwtClaimsError::JwtTokenHasExpired(
+                    exp.duration_since(SystemTime::UNIX_EPOCH)
+                        .unwrap_or_default()
+                        .as_secs(),
+                )));
             }
         }
 
         if let Some(nbf) = payload.not_before {
             if nbf >= now + CLOCK_SKEW_LEEWAY {
                 return Err(JwtError::InvalidClaims(
-                    JwtClaimsError::JwtTokenNotYetReadyToUse,
+                    JwtClaimsError::JwtTokenNotYetReadyToUse(
+                        nbf.duration_since(SystemTime::UNIX_EPOCH)
+                            .unwrap_or_default()
+                            .as_secs(),
+                    ),
                 ));
             }
         }
@@ -534,10 +542,10 @@ struct JwtPayload<'a> {
     #[serde(rename = "aud", default)]
     audience: OneOrMany,
     /// Expiration - Time after which the JWT expires
-    #[serde(deserialize_with = "numeric_date_opt", rename = "exp", default)]
+    #[serde(rename = "exp", deserialize_with = "numeric_date_opt", default)]
     expiration: Option<SystemTime>,
-    /// Not before - Time after which the JWT expires
-    #[serde(deserialize_with = "numeric_date_opt", rename = "nbf", default)]
+    /// Not before - Time before which the JWT is not valid
+    #[serde(rename = "nbf", deserialize_with = "numeric_date_opt", default)]
     not_before: Option<SystemTime>,
 
     // the following entries are only extracted for the sake of debug logging.
@@ -609,8 +617,15 @@ impl<'de> Deserialize<'de> for OneOrMany {
 }
 
 fn numeric_date_opt<'de, D: Deserializer<'de>>(d: D) -> Result<Option<SystemTime>, D::Error> {
-    let d = <Option<u64>>::deserialize(d)?;
-    Ok(d.map(|n| SystemTime::UNIX_EPOCH + Duration::from_secs(n)))
+    <Option<u64>>::deserialize(d)?
+        .map(|t| {
+            SystemTime::UNIX_EPOCH
+                .checked_add(Duration::from_secs(t))
+                .ok_or_else(|| {
+                    serde::de::Error::custom(format_args!("timestamp out of bounds: {t}"))
+                })
+        })
+        .transpose()
 }
 
 struct JwkRenewalPermit<'a> {
@@ -746,11 +761,11 @@ pub enum JwtClaimsError {
     #[error("invalid JWT token audience")]
     InvalidJwtTokenAudience,
 
-    #[error("JWT token has expired")]
-    JwtTokenHasExpired,
+    #[error("JWT token has expired (exp={0})")]
+    JwtTokenHasExpired(u64),
 
-    #[error("JWT token is not yet ready to use")]
-    JwtTokenNotYetReadyToUse,
+    #[error("JWT token is not yet ready to use (nbf={0})")]
+    JwtTokenNotYetReadyToUse(u64),
 }
 
 #[allow(dead_code, reason = "Debug use only")]
@@ -1233,14 +1248,14 @@ X0n5X2/pBLJzxZc62ccvZYVnctBiFs6HbSnxpuMQCfkt/BcR/ttIepBQQIW86wHL
                     "nbf": now + 60,
                     "aud": "neon",
                 }},
-                error: JwtClaimsError::JwtTokenNotYetReadyToUse,
+                error: JwtClaimsError::JwtTokenNotYetReadyToUse(now + 60),
             },
             Test {
                 body: json! {{
                     "exp": now - 60,
                     "aud": ["neon"],
                 }},
-                error: JwtClaimsError::JwtTokenHasExpired,
+                error: JwtClaimsError::JwtTokenHasExpired(now - 60),
             },
             Test {
                 body: json! {{