Implement logic to convert a RFC 850 two-digit year into a full length year, and organize time parsing related functions

actix-http/src/cookie/parse.rs

@@ -10,6 +10,8 @@ use time::{Duration, PrimitiveDateTime, UtcOffset};
 
 use super::{Cookie, CookieStr, SameSite};
 
+use crate::time_parser;
+
 /// Enum corresponding to a parsing error.
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum ParseError {
@@ -182,12 +184,10 @@ fn parse_inner<'c>(s: &str, decode: bool) -> Result<Cookie<'c>, ParseError> {
                 // Try parsing with three date formats according to
                 // http://tools.ietf.org/html/rfc2616#section-3.3.1. Try
                 // additional ones as encountered in the real world.
-                let tm = PrimitiveDateTime::parse(v, "%a, %d %b %Y %H:%M:%S")
-                    .or_else(|_| PrimitiveDateTime::parse(v, "%A, %d-%b-%y %H:%M:%S"))
-                    .or_else(|_| PrimitiveDateTime::parse(v, "%a, %d-%b-%Y %H:%M:%S"))
-                    .or_else(|_| PrimitiveDateTime::parse(v, "%a %b %d %H:%M:%S %Y"));
+                let tm = time_parser::parse_http_date(v)
+                    .or_else(|| PrimitiveDateTime::parse(v, "%a, %d-%b-%Y %H:%M:%S").ok());
 
-                if let Ok(time) = tm {
+                if let Some(time) = tm {
                     cookie.expires = Some(time.using_offset(UtcOffset::UTC))
                 }
             }

actix-http/src/header/shared/httpdate.rs

@@ -9,6 +9,7 @@ use time::{PrimitiveDateTime, OffsetDateTime, UtcOffset};
 
 use crate::error::ParseError;
 use crate::header::IntoHeaderValue;
+use crate::time_parser;
 
 /// A timestamp with HTTP formatting and parsing
 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
@@ -18,14 +19,9 @@ impl FromStr for HttpDate {
     type Err = ParseError;
 
     fn from_str(s: &str) -> Result<HttpDate, ParseError> {
-        match PrimitiveDateTime::parse(s, "%a, %d %b %Y %H:%M:%S")
-            .or_else(|_| PrimitiveDateTime::parse(s, "%A, %d-%b-%y %H:%M:%S"))
-            .or_else(|_| PrimitiveDateTime::parse(s, "%c"))
-        {
-            Ok(t) => Ok(HttpDate(t.using_offset(UtcOffset::UTC))),
-            Err(_) => {
-                Err(ParseError::Header)
-            },
+        match time_parser::parse_http_date(s) {
+            Some(t) => Ok(HttpDate(t.using_offset(UtcOffset::UTC))),
+            None => Err(ParseError::Header)
         }
     }
 }
@@ -37,7 +33,7 @@ impl Display for HttpDate {
 }
 
 impl From<OffsetDateTime> for HttpDate {
-    fn from(dt: time::OffsetDateTime) -> HttpDate {
+    fn from(dt: OffsetDateTime) -> HttpDate {
         HttpDate(dt)
     }
 }

actix-http/src/lib.rs

@@ -27,6 +27,7 @@ mod payload;
 mod request;
 mod response;
 mod service;
+mod time_parser;
 
 pub mod cookie;
 pub mod error;

actix-http/src/time_parser.rs

@@ -0,0 +1,42 @@
+use time::{PrimitiveDateTime, Date};
+
+/// Attempt to parse a `time` string as one of either RFC 1123, RFC 850, or asctime.
+pub fn parse_http_date(time: &str) -> Option<PrimitiveDateTime> {
+    try_parse_rfc_1123(time)
+        .or_else(|| try_parse_rfc_850(time))
+        .or_else(|| try_parse_asctime(time))
+}
+
+/// Attempt to parse a `time` string as a RFC 1123 formatted date time string.
+fn try_parse_rfc_1123(time: &str) -> Option<PrimitiveDateTime> {
+    PrimitiveDateTime::parse(time, "%a, %d %b %Y %H:%M:%S").ok()
+}
+
+/// Attempt to parse a `time` string as a RFC 850 formatted date time string.
+fn try_parse_rfc_850(time: &str) -> Option<PrimitiveDateTime> {
+    match PrimitiveDateTime::parse(time, "%A, %d-%b-%y %H:%M:%S") {
+        Ok(dt) => {
+            // If the `time` string contains a two-digit year, then as per RFC 2616 § 19.3,
+            // we consider the year as part of this century if it's within the next 50 years,
+            // otherwise we consider as part of the previous century.
+            let now = PrimitiveDateTime::now();
+            let century_start_year = (now.year() / 100) * 100;
+            let mut expanded_year = century_start_year + dt.year();
+
+            if expanded_year > now.year() + 50 {
+                expanded_year -= 100;
+            }
+
+            match Date::try_from_ymd(expanded_year, dt.month(), dt.day()) {
+                Ok(date) => Some(PrimitiveDateTime::new(date, dt.time())),
+                Err(_) => None
+            }
+        }
+        Err(_) => None
+    }
+}
+
+/// Attempt to parse a `time` string using ANSI C's `asctime` format.
+fn try_parse_asctime(time: &str) -> Option<PrimitiveDateTime> {
+    PrimitiveDateTime::parse(time, "%c").ok()
+}