[16555] in bugtraq
Re: [PHP-DEV] RE: (SRADV00001) Arbitrary file disclosure through
daemon@ATHENA.MIT.EDU (Rasmus Lerdorf)
Mon Sep 4 21:45:25 2000
Errors-To: <rasmus@linuxcare.com>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Message-Id: <Pine.LNX.4.21.0009032345020.2340-100000@thinkpad.php.net>
Date: Sun, 3 Sep 2000 23:50:15 -0700
Reply-To: Rasmus Lerdorf <rasmus@LINUXCARE.COM>
From: Rasmus Lerdorf <rasmus@LINUXCARE.COM>
X-To: Signal 11 <signal11@mediaone.net>
To: BUGTRAQ@SECURITYFOCUS.COM
In-Reply-To: <NEBBKPCNALMEJENIHFBIOEGECAAA.signal11@mediaone.net>
The fix for this particular variation of the exploit is already in CVS and
is included below. Note that this has nothing to do with track_vars nor
with register_globals despite what the bugtraq posting said. And your
user-level data validation solution is pretty good. An attacker would
have to know the exact size of a file on your system in order to get at
it. Chances are that if the exact size is already know, the contents will
be as well.
Index: php4/main/rfc1867.c
diff -u php4/main/rfc1867.c:1.38 php4/main/rfc1867.c:1.39
--- php4/main/rfc1867.c:1.38 Sat Aug 5 23:40:28 2000
+++ php4/main/rfc1867.c Sun Sep 3 22:09:46 2000
@@ -15,7 +15,7 @@
| Authors: Rasmus Lerdorf <rasmus@php.net> |
+----------------------------------------------------------------------+
*/
-/* $Id: rfc1867.c,v 1.38 2000/08/06 06:40:28 rasmus Exp $ */
+/* $Id: rfc1867.c,v 1.39 2000/09/04 05:09:46 rasmus Exp $ */
#include <stdio.h>
#include "php.h"
@@ -64,7 +64,7 @@
int eolsize;
long bytes, max_file_size = 0;
char *namebuf=NULL, *filenamebuf=NULL, *lbuf=NULL,
- *abuf=NULL, *start_arr=NULL, *end_arr=NULL, *arr_index=NULL;
+ *abuf=NULL, *start_arr=NULL, *end_arr=NULL, *arr_index=NULL, *sbuf=NULL;
FILE *fp;
int itype, is_arr_upload=0, arr_len=0;
zval *http_post_files=NULL;
@@ -172,8 +172,10 @@
}
abuf = estrndup(namebuf, strlen(namebuf)-arr_len);
sprintf(lbuf, "%s_name[%s]", abuf, arr_index);
+ sbuf = estrdup(abuf);
} else {
sprintf(lbuf, "%s_name", namebuf);
+ sbuf = estrdup(abuf);
}
s = strrchr(filenamebuf, '\\');
if (s && s > filenamebuf) {
@@ -252,7 +254,11 @@
}
*(loc - 4) = '\0';
- php_register_variable(namebuf, ptr, array_ptr ELS_CC PLS_CC);
+ /* Check to make sure we are not overwriting special file
+ * upload variables */
+ if(memcmp(namebuf,sbuf,strlen(sbuf))) {
+ php_register_variable(namebuf, ptr, array_ptr ELS_CC PLS_CC);
+ }
/* And a little kludge to pick out special
* MAX_FILE_SIZE */
itype = php_check_ident_type(namebuf);
@@ -353,6 +359,7 @@
break;
}
}
+ if(sbuf) efree(sbuf);
SAFE_RETURN;
}
