cookies: do not take cookie name as a parameter

RFC 6265 section 4.2.1 does not set restrictions on cookie names.
This is a follow-up to commit 7f7fcd0.
Also explicitly check proper syntax of cookie name/value pair.

New test 1155 checks that cookie names are not reserved words.

Reported-By: anshnd at github
Fixes #2564
Closes #2566

lib/cookie.c

@@ -528,10 +528,16 @@ Curl_cookie_add(struct Curl_easy *data,
         while(*whatptr && ISBLANK(*whatptr))
           whatptr++;
 
-        if(!co->name && sep) {
+        if(!co->name) {
           /* The very first name/value pair is the actual cookie name */
+          if(!sep) {
+            /* Bad name/value pair. */
+            badcookie = TRUE;
+            break;
+          }
           co->name = strdup(name);
           co->value = strdup(whatptr);
+          done = TRUE;
           if(!co->name || !co->value) {
             badcookie = TRUE;
             break;

tests/data/Makefile.inc

@@ -127,7 +127,7 @@ test1120 test1121 test1122 test1123 test1124 test1125 test1126 test1127 \
 test1128 test1129 test1130 test1131 test1132 test1133 test1134 test1135 \
 test1136 test1137 test1138 test1139 test1140 test1141 test1142 test1143 \
 test1144 test1145 test1146 test1147 test1148 test1149 test1150 test1151 \
-test1152 test1153 test1154 \
+test1152 test1153 test1154 test1155 \
 \
 test1160 test1161 test1162 test1163 test1164 \
 test1170 test1171 \

tests/data/test1155

@@ -0,0 +1,54 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+cookies
+</keywords>
+</info>
+
+# Server-side
+<reply>
+
+<data>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Content-Length: 0
+Set-Cookie: domain=value;secure;path=/
+
+</data>
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+HTTP cookie with parameter word as name
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/1155 -c log/cookies1155.txt
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<strip>
+^User-Agent:.*
+</strip>
+<protocol>
+GET /1155 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+</protocol>
+<file name="log/cookies1155.txt">
+# Netscape HTTP Cookie File
+# https://curl.haxx.se/docs/http-cookies.html
+# This file was generated by libcurl! Edit at your own risk.
+
+127.0.0.1	FALSE	/	TRUE	0	domain	value
+</file>
+</verify>
+</testcase>