Re: HTTP server invalid date header

[Ricardo Wurmus <rekado@elephly.net>]

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Ludovic Courtès <ludo@gnu.org> writes:

> Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de> skribis:
>
>> I tested JUnit previously with the log4j-api package, but I cannot
>> submit this right now due to a bug(?) in Guile’s HTTP client, which
>> makes it impossible for me to download the sources of its dependencies,
>> such as this one:
>>
>>     http://central.maven.org/maven2/org/osgi/org.osgi.core/6.0.0/org.osgi.core-6.0.0-sources.jar
>>     ERROR: Bad Date header: Wed, 30 Jul 2014  3:47:42 GMT
>
> ISTR you were working on a workaround for this issue.  What’s the
> status?

I got it fixed (after wasting a lot of time wondering why it would not
work as I had patched the wrong file), but the fix isn’t really pretty.
It’s attached.

> Once this is done, and since you did not get feedback, I would suggest
> committing these packages.

Okay!

~~ Ricardo



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From c98ca436bafe8077edaf3125b529ea32fbd48611 Mon Sep 17 00:00:00 2001
From: Ricardo Wurmus <rekado@elephly.net>
Date: Fri, 29 Apr 2016 22:12:24 +0200
Subject: [PATCH] build: Accept dates with space-padded hour field.

* guix/build/download.scm: Replace "parse-rfc-822-date" from the (web
  http) module.
---
 guix/build/download.scm | 73 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)

diff --git a/guix/build/download.scm b/guix/build/download.scm
index fec4cec..3b2901b 100644
--- a/guix/build/download.scm
+++ b/guix/build/download.scm
@@ -426,6 +426,79 @@ port if PORT is a TLS session record port."
 (module-define! (resolve-module '(web client))
                 'shutdown (const #f))
 
+
+;; XXX: Guile's date validation procedure rejects dates in which the hour is
+;; not padded with a zero but with whitespace.
+(begin
+  (define-syntax string-match?
+    (lambda (x)
+      (syntax-case x ()
+        ((_ str pat) (string? (syntax->datum #'pat))
+         (let ((p (syntax->datum #'pat)))
+           #`(let ((s str))
+               (and
+                (= (string-length s) #,(string-length p))
+                #,@(let lp ((i 0) (tests '()))
+                     (if (< i (string-length p))
+                         (let ((c (string-ref p i)))
+                           (lp (1+ i)
+                               (case c
+                                 ((#\.)  ; Whatever.
+                                  tests)
+                                 ((#\d)  ; Digit.
+                                  (cons #`(char-numeric? (string-ref s #,i))
+                                        tests))
+                                 ((#\a)  ; Alphabetic.
+                                  (cons #`(char-alphabetic? (string-ref s #,i))
+                                        tests))
+                                 (else   ; Literal.
+                                  (cons #`(eqv? (string-ref s #,i) #,c)
+                                        tests)))))
+                         tests)))))))))
+
+  (define (parse-rfc-822-date str space zone-offset)
+    (let ((parse-non-negative-integer (@@ (web http) parse-non-negative-integer))
+          (parse-month (@@ (web http) parse-month))
+          (bad-header (@@ (web http) bad-header)))
+      ;; We could verify the day of the week but we don't.
+      (cond ((string-match? (substring str 0 space) "aaa, dd aaa dddd dd:dd:dd")
+             (let ((date (parse-non-negative-integer str 5 7))
+                   (month (parse-month str 8 11))
+                   (year (parse-non-negative-integer str 12 16))
+                   (hour (parse-non-negative-integer str 17 19))
+                   (minute (parse-non-negative-integer str 20 22))
+                   (second (parse-non-negative-integer str 23 25)))
+               (make-date 0 second minute hour date month year zone-offset)))
+            ((string-match? (substring str 0 space) "aaa, d aaa dddd dd:dd:dd")
+             (let ((date (parse-non-negative-integer str 5 6))
+                   (month (parse-month str 7 10))
+                   (year (parse-non-negative-integer str 11 15))
+                   (hour (parse-non-negative-integer str 16 18))
+                   (minute (parse-non-negative-integer str 19 21))
+                   (second (parse-non-negative-integer str 22 24)))
+               (make-date 0 second minute hour date month year zone-offset)))
+            ((string-match? (substring str 0 space) "aaa, dd aaa dddd  d:dd:dd")
+             (let ((date (parse-non-negative-integer str 5 7))
+                   (month (parse-month str 8 11))
+                   (year (parse-non-negative-integer str 12 16))
+                   (hour (parse-non-negative-integer str 18 19))
+                   (minute (parse-non-negative-integer str 20 22))
+                   (second (parse-non-negative-integer str 23 25)))
+               (make-date 0 second minute hour date month year zone-offset)))
+            ((string-match? (substring str 0 space) "aaa, d aaa dddd  d:dd:dd")
+             (let ((date (parse-non-negative-integer str 5 6))
+                   (month (parse-month str 7 10))
+                   (year (parse-non-negative-integer str 11 15))
+                   (hour (parse-non-negative-integer str 17 18))
+                   (minute (parse-non-negative-integer str 19 21))
+                   (second (parse-non-negative-integer str 22 24)))
+               (make-date 0 second minute hour date month year zone-offset)))
+            (else
+             (bad-header 'date str)        ; prevent tail call
+             #f))))
+  (module-set! (resolve-module '(web http))
+               'parse-rfc-822-date parse-rfc-822-date))
+
 ;; XXX: Work around <http://bugs.gnu.org/19840>, present in Guile
 ;; up to 2.0.11.
 (unless (or (> (string->number (major-version)) 2)
-- 
2.7.3