Use checked arithmetic when decoding into chrono types

This avoids an overflow panic if the timestamp is the special "infinity"
or "-infinity" value and produces an error instead.

Fix #640.

postgres-types/src/chrono_04.rs

@@ -12,7 +12,9 @@ fn base() -> NaiveDateTime {
 impl<'a> FromSql<'a> for NaiveDateTime {
     fn from_sql(_: &Type, raw: &[u8]) -> Result<NaiveDateTime, Box<dyn Error + Sync + Send>> {
         let t = types::timestamp_from_sql(raw)?;
-        Ok(base() + Duration::microseconds(t))
+        base()
+            .checked_add_signed(Duration::microseconds(t))
+            .ok_or_else(|| "value too large to decode".into())
     }
 
     accepts!(TIMESTAMP);
@@ -104,7 +106,10 @@ impl ToSql for DateTime<FixedOffset> {
 impl<'a> FromSql<'a> for NaiveDate {
     fn from_sql(_: &Type, raw: &[u8]) -> Result<NaiveDate, Box<dyn Error + Sync + Send>> {
         let jd = types::date_from_sql(raw)?;
-        Ok(base().date() + Duration::days(i64::from(jd)))
+        base()
+            .date()
+            .checked_add_signed(Duration::days(i64::from(jd)))
+            .ok_or_else(|| "value too large to decode".into())
     }
 
     accepts!(DATE);

tokio-postgres/tests/test/types/chrono_04.rs

@@ -1,6 +1,9 @@
 use chrono_04::{DateTime, NaiveDate, NaiveDateTime, NaiveTime, TimeZone, Utc};
-use tokio_postgres::types::{Date, Timestamp};
+use std::fmt;
+use tokio_postgres::types::{Date, FromSqlOwned, Timestamp};
+use tokio_postgres::Client;
 
+use crate::connect;
 use crate::types::test_type;
 
 #[tokio::test]
@@ -153,3 +156,33 @@ async fn test_time_params() {
     )
     .await;
 }
+
+#[tokio::test]
+async fn test_special_params_without_wrapper() {
+    async fn assert_overflows<T>(client: &mut Client, val: &str, sql_type: &str)
+    where
+        T: FromSqlOwned + fmt::Debug,
+    {
+        let err = client
+            .query_one(&*format!("SELECT {}::{}", val, sql_type), &[])
+            .await
+            .unwrap()
+            .try_get::<_, T>(0)
+            .unwrap_err();
+        assert_eq!(
+            err.to_string(),
+            "error deserializing column 0: value too large to decode"
+        );
+    }
+
+    let mut client = connect("user=postgres").await;
+
+    assert_overflows::<DateTime<Utc>>(&mut client, "'-infinity'", "timestamptz").await;
+    assert_overflows::<DateTime<Utc>>(&mut client, "'infinity'", "timestamptz").await;
+
+    assert_overflows::<NaiveDateTime>(&mut client, "'-infinity'", "timestamp").await;
+    assert_overflows::<NaiveDateTime>(&mut client, "'infinity'", "timestamp").await;
+
+    assert_overflows::<NaiveDate>(&mut client, "'-infinity'", "date").await;
+    assert_overflows::<NaiveDate>(&mut client, "'infinity'", "date").await;
+}