------------------------------------------------------------
revno: 12418
revision-id: squid3@treenet.co.nz-20121129103722-026c5061p2pxzkge
parent: squid3@treenet.co.nz-20121129103627-ljhpd8ewbjc7nirk
author: Alex Rousskov <rousskov@measurement-factory.com>
committer: Amos Jeffries <squid3@treenet.co.nz>
branch nick: 3.3
timestamp: Thu 2012-11-29 03:37:22 -0700
message:
  Make it possible to match empty header field values using req_header and rep_header.
  
  Warning: Some req_header and rep_header ACLs that were [accidentally] not
  matching empty headers (e.g., "^$" or ".*") will now start matching them.
  
  
  A new HttpHeader::getByNameIfPresent() method is added to be able to detect
  presence of empty header fields while ACLHTTPHeaderData::match() is adjusted
  to convert undefined String values into empty c-strings ("") for
  ACLRegexData::match() to work.
  
  Prior to these changes, when trying to match an empty header value with a
  regex like "^$", ACLHTTPHeaderData::match() would return false because:
  
    * HttpHeader::getStrOrList() and getByName() return an undefined String.
    * String::termedBuf() returns NULL for undefined Strings; and
    * ACLRegexData::match() always fails on NULL c-strings.
------------------------------------------------------------
# Bazaar merge directive format 2 (Bazaar 0.90)
# revision_id: squid3@treenet.co.nz-20121129103722-026c5061p2pxzkge
# target_branch: http://bzr.squid-cache.org/bzr/squid3/3.3
# testament_sha1: ea725c4dd319d85a17c9e6c0c2e25ef560c53e0b
# timestamp: 2012-11-29 10:40:23 +0000
# source_branch: http://bzr.squid-cache.org/bzr/squid3/3.3
# base_revision_id: squid3@treenet.co.nz-20121129103627-\
#   ljhpd8ewbjc7nirk
# 
# Begin patch
=== modified file 'src/HttpHeader.cc'
--- src/HttpHeader.cc	2012-09-20 16:36:22 +0000
+++ src/HttpHeader.cc	2012-11-29 10:37:22 +0000
@@ -1020,11 +1020,20 @@
 }
 
 /*
- * Returns the value of the specified header.
+ * Returns the value of the specified header and/or an undefined String.
  */
 String
 HttpHeader::getByName(const char *name) const
 {
+    String result;
+    // ignore presence: return undefined string if an empty header is present
+    (void)getByNameIfPresent(name, result);
+    return result;
+}
+
+bool
+HttpHeader::getByNameIfPresent(const char *name, String &result) const
+{
     http_hdr_type id;
     HttpHeaderPos pos = HttpHeaderInitPos;
     HttpHeaderEntry *e;
@@ -1034,19 +1043,23 @@
     /* First try the quick path */
     id = httpHeaderIdByNameDef(name, strlen(name));
 
-    if (id != -1)
-        return getStrOrList(id);
-
-    String result;
+    if (id != -1) {
+        if (!has(id))
+            return false;
+        result = getStrOrList(id);
+        return true;
+    }
 
     /* Sorry, an unknown header name. Do linear search */
+    bool found = false;
     while ((e = getEntry(&pos))) {
         if (e->id == HDR_OTHER && e->name.caseCmp(name) == 0) {
+            found = true;
             strListAdd(&result, e->value.termedBuf(), ',');
         }
     }
 
-    return result;
+    return found;
 }
 
 /*

=== modified file 'src/HttpHeader.h'
--- src/HttpHeader.h	2012-09-25 16:38:36 +0000
+++ src/HttpHeader.h	2012-11-29 10:37:22 +0000
@@ -246,6 +246,8 @@
     bool getList(http_hdr_type id, String *s) const;
     String getStrOrList(http_hdr_type id) const;
     String getByName(const char *name) const;
+    /// sets value and returns true iff a [possibly empty] named field is there
+    bool getByNameIfPresent(const char *name, String &value) const;
     String getByNameListMember(const char *name, const char *member, const char separator) const;
     String getListMember(http_hdr_type id, const char *member, const char separator) const;
     int has(http_hdr_type id) const;

=== modified file 'src/acl/HttpHeaderData.cc'
--- src/acl/HttpHeaderData.cc	2012-08-31 16:57:39 +0000
+++ src/acl/HttpHeaderData.cc	2012-11-29 10:37:22 +0000
@@ -65,9 +65,23 @@
 
     debugs(28, 3, "aclHeaderData::match: checking '" << hdrName << "'");
 
-    String value = hdrId != HDR_BAD_HDR ? hdr->getStrOrList(hdrId) : hdr->getByName(hdrName.termedBuf());
+    String value;
+    if (hdrId != HDR_BAD_HDR) {
+        if (!hdr->has(hdrId))
+            return false;
+        value = hdr->getStrOrList(hdrId);
+    } else {
+        if (!hdr->getByNameIfPresent(hdrName.termedBuf(), value))
+            return false;
+    }
 
-    return regex_rule->match(value.termedBuf());
+    // By now, we know the header is present, but:
+    // HttpHeader::get*() return an undefined String for empty header values;
+    // String::termedBuf() returns NULL for undefined Strings; and
+    // ACLRegexData::match() always fails on NULL strings.
+    // This makes it possible to detect an empty header value using regex:
+    const char *cvalue = value.defined() ? value.termedBuf() : "";
+    return regex_rule->match(cvalue);
 }
 
 wordlist *