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Posted to cvs@httpd.apache.org by yl...@apache.org on 2022/05/24 08:55:16 UTC

svn commit: r1901196 - in /httpd/httpd/branches/2.4.x: ./ CHANGES server/util.c

Author: ylavic
Date: Tue May 24 08:55:16 2022
New Revision: 1901196

URL: http://svn.apache.org/viewvc?rev=1901196&view=rev
Log:
*) core: make ap_escape_quotes() work correctly on strings
   with more than MAX_INT/2 characters, counting quotes double.
   Credit to <ge...@zippenhop.com> for finding this.


*) core: improved checks in ap_escape_quotes() for
   extra long strings (or resulting strings) that
   exceed ptrdiff_t ranges.


Merge r1899609, r1899905 from trunk.
Reviewed by: icing, rpluem, ylavic
Submitted by: icing, ylavic

Modified:
    httpd/httpd/branches/2.4.x/   (props changed)
    httpd/httpd/branches/2.4.x/CHANGES
    httpd/httpd/branches/2.4.x/server/util.c

Propchange: httpd/httpd/branches/2.4.x/
------------------------------------------------------------------------------
  Merged /httpd/httpd/trunk:r1899609,1899905

Modified: httpd/httpd/branches/2.4.x/CHANGES
URL: http://svn.apache.org/viewvc/httpd/httpd/branches/2.4.x/CHANGES?rev=1901196&r1=1901195&r2=1901196&view=diff
==============================================================================
--- httpd/httpd/branches/2.4.x/CHANGES [utf-8] (original)
+++ httpd/httpd/branches/2.4.x/CHANGES [utf-8] Tue May 24 08:55:16 2022
@@ -1,6 +1,11 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.4.54
 
+  *) core: make ap_escape_quotes() work correctly on strings
+     with more than MAX_INT/2 characters, counting quotes double.
+     Credit to <ge...@zippenhop.com> for finding this.
+     [Stefan Eissing]
+
   *) mod_md: the `MDCertificateAuthority` directive can take more than one URL/name of
      an ACME CA. This gives a failover for renewals when several consecutive attempts
      to get a certificate failed.

Modified: httpd/httpd/branches/2.4.x/server/util.c
URL: http://svn.apache.org/viewvc/httpd/httpd/branches/2.4.x/server/util.c?rev=1901196&r1=1901195&r2=1901196&view=diff
==============================================================================
--- httpd/httpd/branches/2.4.x/server/util.c (original)
+++ httpd/httpd/branches/2.4.x/server/util.c Tue May 24 08:55:16 2022
@@ -2535,7 +2535,7 @@ AP_DECLARE(void) ap_content_type_tolower
  */
 AP_DECLARE(char *) ap_escape_quotes(apr_pool_t *p, const char *instring)
 {
-    int newlen = 0;
+    apr_size_t size, extra = 0;
     const char *inchr = instring;
     char *outchr, *outstring;
 
@@ -2544,9 +2544,8 @@ AP_DECLARE(char *) ap_escape_quotes(apr_
      * string up by an extra byte each time we find an unescaped ".
      */
     while (*inchr != '\0') {
-        newlen++;
         if (*inchr == '"') {
-            newlen++;
+            extra++;
         }
         /*
          * If we find a slosh, and it's not the last byte in the string,
@@ -2554,11 +2553,32 @@ AP_DECLARE(char *) ap_escape_quotes(apr_
          */
         else if ((*inchr == '\\') && (inchr[1] != '\0')) {
             inchr++;
-            newlen++;
         }
         inchr++;
     }
-    outstring = apr_palloc(p, newlen + 1);
+
+    if (!extra) {
+        return apr_pstrdup(p, instring);
+    }
+
+    /* How large will the string become, once we escaped all the quotes?
+     * The tricky cases are
+     * - an `instring` that is already longer than `ptrdiff_t`
+     *   can hold (which is an undefined case in C, as C defines ptrdiff_t as
+     *   a signed difference between pointers into the same array and one index
+     *   beyond).
+     * - an `instring` that, including the `extra` chars we want to add, becomes
+     *   even larger than apr_size_t can handle.
+     * Since this function was not designed to ever return NULL for failure, we
+     * can only trigger a hard assertion failure. It seems more a programming
+     * mistake (or failure to verify the input causing this) that leads to this
+     * situation.
+     */
+    ap_assert(inchr - instring > 0);
+    size = ((apr_size_t)(inchr - instring)) + 1;
+    ap_assert(size + extra > size);
+
+    outstring = apr_palloc(p, size + extra);
     inchr = instring;
     outchr = outstring;
     /*