mirror/curl
2
0
Fork 0
mirror of https://github.com/curl/curl.git synced 2024-11-21 01:16:58 +08:00
Code Issues Packages Projects Releases Wiki Activity

Curl_urldecode: no peeking beyond end of input buffer

Browse Source 
Security problem: CVE-2013-2174

If a program would give a string like "%FF" to curl_easy_unescape() but
ask for it to decode only the first byte, it would still parse and
decode the full hex sequence. The function then not only read beyond the
allowed buffer but it would also deduct the *unsigned* counter variable
for how many more bytes there's left to read in the buffer by two,
making the counter wrap. Continuing this, the function would go on
reading beyond the buffer and soon writing beyond the allocated target
buffer...

Bug: http://curl.haxx.se/docs/adv_20130622.html
Reported-by: Timo Sirainen
This commit is contained in:
Daniel Stenberg 2013-05-19 23:24:29 +02:00
parent da0db499fd
commit 192c4f788d
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
lib/escape.c
View File

@ -5,7 +5,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
* Copyright (C) 1998 - 2013, 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
@ -159,7 +159,8 @@ CURLcode Curl_urldecode(struct SessionHandle *data,
while(--alloc > 0) {
in = *string;
if(('%' == in) && ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
if(('%' == in) && (alloc > 2) &&
ISXDIGIT(string[1]) && ISXDIGIT(string[2])) {
/* this is two hexadecimal digits following a '%' */
char hexstr[3];
char *ptr;