curl_easy_duphandle: CURLOPT_COPYPOSTFIELDS read out of bounds

When duplicating a handle, the data to post was duplicated using
strdup() when it could be binary and contain zeroes and it was not even
zero terminated! This caused read out of bounds crashes/segfaults.

Since the lib/strdup.c file no longer is easily shared with the curl
tool with this change, it now uses its own version instead.

Bug: http://curl.haxx.se/docs/adv_20141105.html
CVE: CVE-2014-3707
Reported-By: Symeon Paraschoudis

src/Makefile.inc

@@ -11,7 +11,6 @@
 # the official API, but we re-use the code here to avoid duplication.
 CURLX_CFILES = \
 	../lib/strtoofft.c \
-	../lib/strdup.c \
 	../lib/rawstr.c \
 	../lib/nonblock.c \
 	../lib/warnless.c
@@ -19,7 +18,6 @@ CURLX_CFILES = \
 CURLX_HFILES = \
 	../lib/curl_setup.h \
 	../lib/strtoofft.h \
-	../lib/strdup.h \
 	../lib/rawstr.h \
 	../lib/nonblock.h \
 	../lib/warnless.h
@@ -55,6 +53,7 @@ CURL_CFILES = \
 	tool_panykey.c \
 	tool_paramhlp.c \
 	tool_parsecfg.c \
+	tool_strdup.c \
 	tool_setopt.c \
 	tool_sleep.c \
 	tool_urlglob.c \
@@ -99,6 +98,7 @@ CURL_HFILES = \
 	tool_setopt.h \
 	tool_setup.h \
 	tool_sleep.h \
+	tool_strdup.h \
 	tool_urlglob.h \
 	tool_util.h \
 	tool_version.h \

src/tool_setup.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -67,8 +67,7 @@
 #endif
 
 #ifndef HAVE_STRDUP
-#  include "strdup.h"
-#  define strdup(ptr) curlx_strdup(ptr)
+#  include "tool_strdup.h"
 #endif
 
 #endif /* HEADER_CURL_TOOL_SETUP_H */

src/tool_strdup.c

@@ -0,0 +1,47 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "strdup.h"
+
+#ifndef HAVE_STRDUP
+char *strdup(const char *str)
+{
+  size_t len;
+  char *newstr;
+
+  if(!str)
+    return (char *)NULL;
+
+  len = strlen(str);
+
+  if(len >= ((size_t)-1) / sizeof(char))
+    return (char *)NULL;
+
+  newstr = malloc((len+1)*sizeof(char));
+  if(!newstr)
+    return (char *)NULL;
+
+  memcpy(newstr,str,(len+1)*sizeof(char));
+
+  return newstr;
+
+}
+#endif

src/tool_strdup.h

@@ -0,0 +1,30 @@
+#ifndef HEADER_TOOL_STRDUP_H
+#define HEADER_TOOL_STRDUP_H
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "tool_setup.h"
+
+#ifndef HAVE_STRDUP
+extern char *strdup(const char *str);
+#endif
+
+#endif /* HEADER_TOOL_STRDUP_H */