452786 - Crash due to insufficient class checking in Date class

Status: VERIFIED FIXED

(Core :: JavaScript Engine, defect)

Description

[Joachim Kuebart]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
Build Identifier: 

This bug crashes the browser without any possibility for user intervention. This is exploitable in the browser. Do *not* click the given link if you want to keep anything in your current Firefox session.


Reproducible: Always

Steps to Reproduce:

  (new Date()).getMonth.call(new Function())


Actual Results:  
jsshell (or Firefox) crash.

Expected Results:  
Exception.


The built-in Date class doesn't check the class of its "this" object sufficiently. Affected methods are getYear(), getMonth(), getDate() and so on.

This affects all of Date's methods that internally call GetLocalTime() (in jsdate.c) which doesn't check the class of object passed in (compare with JS_InstanceOf() call in GetUTCTime()). The object passed in needs to have at least 2 private slots, like

 a) the global object
 b) Function objects
 c) Iterator objects

The value from the private slot is passed to JSVAL_TO_DOUBLE() without further checks in GetLocalTime(), leading to bogus pointer dereference for objects not of class Date.

In addition to adding this to the test suite, this sort of thing could be added to jsparsefuzz.js (i.e. the fuzzer should be modified to use <method>.call() with random arguments if it's not already doing this).

I don't have time right now to check out a current tree and post a patch and will not get around to it until some time next week.

Comment 1

[Igor Bukanov]

Attachment: fix v1

The essence of the fix is the addition of the missing instanceof check for GetAndCacheLocalTime. I also took an opportunity in the patch to replace heavy JS_(Get|Set)ReservvedSlot calls with direct slot access for simpler code.

Comment 2

[Joachim Kuebart]

Igor's patch should fix the issue AFAICS. If needed I can report back next week when I get a chance to build trunk and verify.

Comment 3

[Brandon Sterne (:bsterne)]

Attachment: testcase crashes trunk

Preserving a copy of the testcase in Bugzilla.

Comment 4

[Brendan Eich [:brendan]]

Much nicer -- thanks, Igor.

/be

Comment 5

[Igor Bukanov]

landed on trunk - http://hg.mozilla.org/mozilla-central/rev/42b53b1f04e6

Comment 6

[Igor Bukanov]

Comment on attachment 336054 [details] [diff] [review]
fix v1

The patch applies to 1.9.0 branch as-is.

Comment 7

[Igor Bukanov]

The bug only exists on 1.9.0 and later and is an regression from the bug 340992.

Comment 8

[Mike Shaver (:shaver emeritus)]

Is it worth doing a version of the patch that only has the fix and not the cleanup, for risk reduction on 1.9.0.x?

Comment 9

[Brendan Eich [:brendan]]

(In reply to comment #8)
> Is it worth doing a version of the patch that only has the fix and not the
> cleanup, for risk reduction on 1.9.0.x?

There's no risk reduction in messing with a reviewed patch that cuts out overhead and doubt about reserved slot complexities that do not affect fslots' dimension or lifetime. Making more variation between trees adds tiny risk too, probably more than any risk in sticking this patch in as-is. But it's too tiny to estimate or measure, or to be worth arguing much about.

/be

Comment 10

[Daniel Veditz [:dveditz]]

1.9.0.2 is in release testing, this will have to sail with the next ship.

Comment 11

[Daniel Veditz [:dveditz]]

Comment on attachment 336054 [details] [diff] [review]
fix v1

Approved for 1.9.0.3, a=dveditz for release-drivers

Comment 12

[Igor Bukanov]

Attachment: fix for 1.9.0

It turned out the patch required a trivial change for 1.9.0. It applies as-is, but the trunk version uses const to define constant names. But that does not work with in C sources as in C such constants are not real constant expressions. So I replaced constants with the preprocessor macros. 

Here is the plain diff between the trunk and the branch patches:

diff  /home/igor/s/fix_date.patch /home/igor/s/fix_date.1.9.0.patch
7c7
< +++ jsdate.c	27 Oct 2008 17:22:47 -0000
---
> +++ jsdate.c	27 Oct 2008 17:21:59 -0000
19,20c19,20
< +const uint32 JSSLOT_UTC_TIME    = JSSLOT_PRIVATE;
< +const uint32 JSSLOT_LOCAL_TIME  = JSSLOT_PRIVATE + 1;
---
> +#define JSSLOT_UTC_TIME         JSSLOT_PRIVATE
> +#define JSSLOT_LOCAL_TIME       (JSSLOT_PRIVATE + 1)
22c22
< +const uint32 DATE_RESERVED_SLOTS = 2;
---
> +#define DATE_RESERVED_SLOTS     2

Comment 13

[Igor Bukanov]

I landed the patch from the comment 12 on 1.9.0 branch:

Checking in jsdate.c;
/cvsroot/mozilla/js/src/jsdate.c,v  <--  jsdate.c
new revision: 3.112; previous revision: 3.111
done

Comment 14

[Al Billings [:abillings - ex-MoCo]]

We now get the exception "TypeError on line 1: Date.prototype.getMonth called on incompatible Function"

Verified for 1.9.0.4 with  Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.4pre) Gecko/2008102804 GranParadiso/3.0.4pre.

Same behavior in Trunk as well with Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1b2pre) Gecko/20081028 Minefield/3.1b2pre.

Comment 15

[Bob Clary [:bc] (inactive)]

Checking in ecma_3/Date/regress-452786.js;
/cvsroot/mozilla/js/tests/ecma_3/Date/regress-452786.js,v  <--  regress-452786.js
initial revision: 1.1
done

Comment 16

[Shawn Wilsher :sdwilsh]

http://hg.mozilla.org/mozilla-central/rev/39f2f17c31ee