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curl_easy_duphandle: CURLOPT_COPYPOSTFIELDS read out of bounds

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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
This commit is contained in:
Daniel Stenberg
2014-10-17 12:59:32 +02:00
parent d997c8b2f6
commit b387560692
9 changed files with 145 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
lib/formdata.c
View File

@@ -36,6 +36,7 @@
#include "strequal.h"
#include "curl_memory.h"
#include "sendf.h"
#include "strdup.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
@@ -208,46 +209,6 @@ static const char *ContentTypeForFilename(const char *filename,
return contenttype;
}
/***************************************************************************
*
* memdup()
*
* Copies the 'source' data to a newly allocated buffer buffer (that is
* returned). Uses buffer_length if not null, else uses strlen to determine
* the length of the buffer to be copied
*
* Returns the new pointer or NULL on failure.
*
***************************************************************************/
static char *memdup(const char *src, size_t buffer_length)
{
size_t length;
bool add = FALSE;
char *buffer;
if(buffer_length)
length = buffer_length;
else if(src) {
length = strlen(src);
add = TRUE;
}
else
/* no length and a NULL src pointer! */
return strdup("");
buffer = malloc(length+add);
if(!buffer)
return NULL; /* fail */
memcpy(buffer, src, length);
/* if length unknown do null termination */
if(add)
buffer[length] = '\0';
return buffer;
}
/***************************************************************************
*
* FormAdd()
@@ -678,9 +639,12 @@ CURLFORMcode FormAdd(struct curl_httppost **httppost,
(form == first_form) ) {
/* Note that there's small risk that form->name is NULL here if the
app passed in a bad combo, so we better check for that first. */
if(form->name)
if(form->name) {
/* copy name (without strdup; possibly contains null characters) */
form->name = memdup(form->name, form->namelength);
form->name = Curl_memdup(form->name, form->namelength?
form->namelength:
strlen(form->name)+1);
}
if(!form->name) {
return_value = CURL_FORMADD_MEMORY;
break;
@@ -691,7 +655,9 @@ CURLFORMcode FormAdd(struct curl_httppost **httppost,
HTTPPOST_PTRCONTENTS | HTTPPOST_PTRBUFFER |
HTTPPOST_CALLBACK)) && form->value) {
/* copy value (without strdup; possibly contains null characters) */
form->value = memdup(form->value, form->contentslength);
form->value = Curl_memdup(form->value, form->contentslength?
form->contentslength:
strlen(form->value)+1);
if(!form->value) {
return_value = CURL_FORMADD_MEMORY;
break;

32
lib/strdup.c
View File

@@ -5,7 +5,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* 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
@@ -19,12 +19,12 @@
* KIND, either express or implied.
*
***************************************************************************/
/*
* This file is 'mem-include-scan' clean. See test 1132.
*/
#include "curl_setup.h"
#include "strdup.h"
#include "curl_memory.h"
/* The last #include file should be: */
#include "memdebug.h"
#ifndef HAVE_STRDUP
char *curlx_strdup(const char *str)
@@ -50,3 +50,25 @@ char *curlx_strdup(const char *str)
}
#endif
/***************************************************************************
*
* Curl_memdup(source, length)
*
* Copies the 'source' data to a newly allocated buffer (that is
* returned). Copies 'length' bytes.
*
* Returns the new pointer or NULL on failure.
*
***************************************************************************/
char *Curl_memdup(const char *src, size_t length)
{
char *buffer = malloc(length);
if(!buffer)
return NULL; /* fail */
memcpy(buffer, src, length);
/* if length unknown do null termination */
return buffer;
}

3
lib/strdup.h
View File

@@ -7,7 +7,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2010, 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
@@ -26,5 +26,6 @@
#ifndef HAVE_STRDUP
extern char *curlx_strdup(const char *str);
#endif
char *Curl_memdup(const char *src, size_t buffer_length);
#endif /* HEADER_CURL_STRDUP_H */

22
lib/url.c
View File

@@ -125,6 +125,7 @@ int curl_win32_idn_to_ascii(const char *in, char **out);
#include "multihandle.h"
#include "pipeline.h"
#include "dotdot.h"
#include "strdup.h"
#define _MPRINTF_REPLACE /* use our functions only */
#include <curl/mprintf.h>
@@ -270,8 +271,9 @@ void Curl_freeset(struct SessionHandle *data)
{
/* Free all dynamic strings stored in the data->set substructure. */
enum dupstring i;
for(i=(enum dupstring)0; i < STRING_LAST; i++)
for(i=(enum dupstring)0; i < STRING_LAST; i++) {
Curl_safefree(data->set.str[i]);
}
if(data->change.referer_alloc) {
Curl_safefree(data->change.referer);
@@ -356,14 +358,24 @@ CURLcode Curl_dupset(struct SessionHandle *dst, struct SessionHandle *src)
memset(dst->set.str, 0, STRING_LAST * sizeof(char *));
/* duplicate all strings */
for(i=(enum dupstring)0; i< STRING_LAST; i++) {
for(i=(enum dupstring)0; i< STRING_LASTZEROTERMINATED; i++) {
result = setstropt(&dst->set.str[i], src->set.str[i]);
if(result)
break;
return result;
}
/* If a failure occurred, freeing has to be performed externally. */
return result;
/* duplicate memory areas pointed to */
i = STRING_COPYPOSTFIELDS;
if(src->set.postfieldsize && src->set.str[i]) {
/* postfieldsize is curl_off_t, Curl_memdup() takes a size_t ... */
dst->set.str[i] = Curl_memdup(src->set.str[i], src->set.postfieldsize);
if(!dst->set.str[i])
return CURLE_OUT_OF_MEMORY;
/* point to the new copy */
dst->set.postfields = dst->set.str[i];
}
return CURLE_OK;
}
/*

11
lib/urldata.h
View File

@@ -1372,7 +1372,6 @@ enum dupstring {
STRING_KRB_LEVEL, /* krb security level */
STRING_NETRC_FILE, /* if not NULL, use this instead of trying to find
$HOME/.netrc */
STRING_COPYPOSTFIELDS, /* if POST, set the fields' values here */
STRING_PROXY, /* proxy to use */
STRING_SET_RANGE, /* range, if used */
STRING_SET_REFERER, /* custom string for the HTTP referer field */
@@ -1415,7 +1414,15 @@ enum dupstring {
STRING_BEARER, /* <bearer>, if used */
/* -- end of strings -- */
/* -- end of zero-terminated strings -- */
STRING_LASTZEROTERMINATED,
/* -- below this are pointers to binary data that cannot be strdup'ed.
Each such pointer must be added manually to Curl_dupset() --- */
STRING_COPYPOSTFIELDS, /* if POST, set the fields' values here */
STRING_LAST /* not used, just an end-of-list marker */
};