From: Jay Satiro <raysatiro@yahoo.com>
Date: Thu, 26 Dec 2024 20:38:39 +0000 (-0500)
Subject: http: ignore invalid Retry-After times
X-Git-Tag: curl-8_12_0~238
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6c70ec16c7cb8c86e1bc6e619da51d6a38fd866c;p=thirdparty%2Fcurl.git

http: ignore invalid Retry-After times

- Treat negative Retry-After date-based times as 0.

- Treat Retry-After times greater than 6 hours as 6 hours.

Prior to this change Retry-After did not have a limited range and the
server could have set a time greater than 6 hours or a date in the past
that would result in a negative time, either of which may be unexpected
by the user.

The 6 hour limit is purposely not documented so that it can be changed
in the future if necessary.

Closes https://github.com/curl/curl/pull/15833
---

diff --git a/docs/libcurl/opts/CURLINFO_RETRY_AFTER.md b/docs/libcurl/opts/CURLINFO_RETRY_AFTER.md
index 0dca2e509d..87700bc331 100644
--- a/docs/libcurl/opts/CURLINFO_RETRY_AFTER.md
+++ b/docs/libcurl/opts/CURLINFO_RETRY_AFTER.md
@@ -36,6 +36,11 @@ While the HTTP header might contain a fixed date string, the
 CURLINFO_RETRY_AFTER(3) always returns the number of seconds to wait -
 or zero if there was no header or the header could not be parsed.
 
+This option used to return a negative wait time if the server provided a date
+in the past. Since 8.12.0, a negative wait time is returned as zero. In any
+case we recommend checking that the wait time is within an acceptable range for
+your circumstance.
+
 # DEFAULT
 
 Zero if there was no header.
diff --git a/lib/http.c b/lib/http.c
index 18eba54d89..e155200a52 100644
--- a/lib/http.c
+++ b/lib/http.c
@@ -2901,11 +2901,19 @@ static CURLcode http_header(struct Curl_easy *data,
       (void)curlx_strtoofft(v, NULL, 10, &retry_after);
       if(!retry_after) {
         time_t date = Curl_getdate_capped(v);
-        if((time_t)-1 != date)
+        time_t current = time(NULL);
+        if((time_t)-1 != date && date > current) {
           /* convert date to number of seconds into the future */
-          retry_after = date - time(NULL);
+          retry_after = date - current;
+        }
       }
-      data->info.retry_after = retry_after; /* store it */
+      if(retry_after < 0)
+        retry_after = 0;
+      /* limit to 6 hours max. this is not documented so that it can be changed
+         in the future if necessary. */
+      if(retry_after > 21600)
+        retry_after = 21600;
+      data->info.retry_after = retry_after;
       return CURLE_OK;
     }
     break;
diff --git a/tests/data/test1596 b/tests/data/test1596
index f05f0ec146..8b94cd12fa 100644
--- a/tests/data/test1596
+++ b/tests/data/test1596
@@ -13,9 +13,9 @@ If-Modified-Since
 <reply>
 <data nocheck="yes">
 HTTP/1.1 429 Too Many Requests
-Date: Thu, 11 Jul 2019 02:26:59 GMT
+Date: Wed, 31 Dec 2036 02:26:59 GMT
 Server: test-server/swsclose
-Retry-After: Thu, 11 Jul 2024 02:26:59 GMT
+Retry-After: Wed, 31 Dec 2036 02:26:59 GMT
 
 </data>
 </reply>
@@ -42,8 +42,9 @@ Host: %HOSTIP:%HTTPPORT
 Accept: */*
 
 </protocol>
+# Retry-After time is limited to 6 hours (21600 seconds)
 <stdout>
-Retry-After 172066
+Retry-After 21600
 </stdout>
 </verify>
 </testcase>
diff --git a/tests/libtest/lib1594.c b/tests/libtest/lib1594.c
index bf25ffbeb5..2a31a720e4 100644
--- a/tests/libtest/lib1594.c
+++ b/tests/libtest/lib1594.c
@@ -49,12 +49,6 @@ CURLcode test(char *URL)
   if(res)
     goto test_cleanup;
 
-#ifdef LIB1596
-  /* we get a relative number of seconds, so add the number of seconds
-     we're at to make it a somewhat stable number. Then remove accuracy. */
-  retry += time(NULL);
-  retry /= 10000;
-#endif
   printf("Retry-After %" CURL_FORMAT_CURL_OFF_T "\n", retry);
 
 test_cleanup: