Bug 684815 (CVE-2011-2998)

Crash in the SpiderMonkey v.1.9.2 (FF 3.6.21) during regular expression evaluation




JavaScript Engine
6 years ago
3 years ago


(Reporter: Mark Kaplan, Assigned: cdleary)


({crash, testcase})

1.9.2 Branch
Windows 7
crash, testcase
Bug Flags:
sec-bounty +

Firefox Tracking Flags

(firefox6 unaffected, firefox7 unaffected, firefox8 unaffected, firefox9 unaffected, firefox10 unaffected, blocking1.9.2 .23+, status1.9.2 .23-fixed)


(Whiteboard: [sg:critical] wanted-standalone-js)


(2 attachments)



6 years ago
Created attachment 558436 [details]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.854.0 Safari/535.2

Steps to reproduce:

Originally I browsed to attached regx.htm file using FireFox 3.6.21 on Windows 7 x64

Actual results:

Browser crashed with a crash stack like

 	mozcrt19.dll!memcpy(unsigned char * dst, unsigned char * src, unsigned long count)  Line 188	Asm
	js3250.dll!PushBackTrackState(REGlobalData * gData, REOp op, unsigned char * target, REMatchState * x, const unsigned short * cp, unsigned int parenIndex, unsigned int parenCount)  Line 3477 + 0x17 bytes	C++
 	js3250.dll!js_ExecuteRegExp(JSContext * cx, JSRegExp * re, JSString * str, unsigned int * indexp, int test, int * rval)  Line 4897 + 0x8e bytes	C++
 	js3250.dll!regexp_exec_sub(JSContext * cx, JSObject * obj, unsigned int argc, int * argv, int test, int * rval)  Line 5716 + 0x3e bytes	C++
 	js3250.dll!regexp_test(JSContext * cx, unsigned int argc, int * vp)  Line 5741 + 0x71 bytes	C++
 	js3250.dll!js_Interpret(JSContext * cx)  Line 2208 + 0x1d bytes	C++
 	mozcrt19.dll!arena_malloc_small(arena_s * arena, unsigned int size, int zero)  Line 3737	C
 	mozcrt19.dll!malloc(unsigned int size)  Line 5790 + 0x2f bytes	C
 	js3250.dll!js_NewObjectWithGivenProto(JSContext * cx, JSClass * clasp, JSObject * proto, JSObject * parent, unsigned int objectSize)  Line 2090 + 0x2d bytes	C++
 	xul.dll!WrappedNative2WrapperMap::Add(WrappedNative2WrapperMap * head, JSObject * wrappedObject, JSObject * wrapper)  Line 726 + 0x8 bytes	C++
 	xul.dll!nsXPConnect::GetWrapperForObject(JSContext * aJSContext, JSObject * aObject, JSObject * aScope, nsIPrincipal * aPrincipal, unsigned int aFilenameFlags, int * _retval)  Line 2478 + 0x96 bytes	C++
 	xul.dll!XPC_WN_JSOp_ThisObject(JSContext * cx, JSObject * obj)  Line 1471	C++

The same crash happened on Ubuntu Linux and on Debian Linux 5.0. The I took sources from http://hg.mozilla.org/releases/mozilla-1.9.2/, built SpiderMonkey 1.9.2 and its shell demonstrate the same crash when run on extracted from HTML file JavaScript:

#0  0x00529caf in memcpy () from /lib/libc.so.6
#1  0x08119f01 in PushBackTrackState (gData=0xbf88a32c, op=REOP_EOL, target=0xb6d6451b ".\035\0030", 
    x=0x9d28d50, cp=0x9d24310, parenIndex=0, parenCount=0) at ../jsregexp.cpp:3477
#2  0x0811a4a1 in ExecuteREBytecode (gData=0xbf88a32c, x=0x9d28d50) at ../jsregexp.cpp:4261
#3  0x0811fcdc in MatchRegExp (gData=0xbf88a32c, x=0x9d28d50) at ../jsregexp.cpp:4754
#4  0x0811fef7 in js_ExecuteRegExp (cx=0x9cfce18, re=0xb6d4d008, str=0x9d1a690, indexp=0xbf88a440, test=1, 
    rval=0x9d244a8) at ../jsregexp.cpp:4883
#5  0x0812098e in regexp_exec_sub (cx=0x9cfce18, obj=0x9d1d0e0, argc=1, argv=0x9d244b0, test=1, rval=0x9d244a8)
    at ../jsregexp.cpp:5696
#6  0x08120a6e in regexp_test (cx=0x9cfce18, argc=1, vp=0x9d244a8) at ../jsregexp.cpp:5721
#7  0x081e39eb in js_Interpret (cx=0x9cfce18) at ../jsops.cpp:2208
#8  0x080c2cf6 in js_Execute (cx=0x9cfce18, chain=0x9d1d000, script=0x9d243b0, down=0x0, flags=0, result=0x0)
    at ../jsinterp.cpp:1601
#9  0x0805b1b3 in JS_ExecuteScript (cx=0x9cfce18, obj=0x9d1d000, script=0x9d243b0, rval=0x0) at ../jsapi.cpp:4964
#10 0x080530dc in Process (cx=0x9cfce18, obj=0x9d1d000, filename=0xbf88c7a1 "regexe.js", forceTTY=0)
    at ../../shell/js.cpp:442
#11 0x08053c7f in ProcessArgs (cx=0x9cfce18, obj=0x9d1d000, argv=0xbf88add8, argc=1) at ../../shell/js.cpp:849
#12 0x0805405f in main (argc=1, argv=0xbf88add8, envp=0xbf88ade0) at ../../shell/js.cpp:4853

(gdb) f 1
#1  0x08119f01 in PushBackTrackState (gData=0xbf88a32c, op=REOP_EOL, target=0xb6d6451b ".\035\0030", 
    x=0x9d28d50, cp=0x9d24310, parenIndex=0, parenCount=0) at ../jsregexp.cpp:3477
3477               sizeof(REProgState) * result->saveStateStackTop);
gdb) p/x result->saveStateStackTop
$4 = 0xfffffcea
(gdb) p sizeof(REProgState)
$5 = 24

For the best of my understanding this crash is exploitable, because memcpy function overrides both stack and heap - it tries to copy ~24*4GB of memory due to the integer underflow of result->saveStateStackTop and data to be copied is under control of web page author - both regular expression and string to search in. Before this crash happens valgrind reports about number of related invalid write(s) and read(s).

Expected results:

No crash

Comment 1

6 years ago
Created attachment 558437 [details] [diff] [review]
Proposed patch file
Assignee: general → cdleary
Whiteboard: [sg:critical]
blocking1.9.2: --- → ?
status1.9.2: --- → wanted
status-firefox6: --- → unaffected
status-firefox7: --- → unaffected
status-firefox8: --- → unaffected
status-firefox9: --- → unaffected


6 years ago
Attachment #558437 - Flags: review?(cdleary)
Attachment #558437 - Flags: review?(cdleary) → review+

Comment 2

6 years ago
Comment on attachment 558437 [details] [diff] [review]
Proposed patch file

Approved for mozilla-1.9.2, please land asap.
Attachment #558437 - Flags: approval1.9.2.23+

Comment 3

6 years ago
blocking1.9.2: ? → .23+
Last Resolved: 6 years ago
status1.9.2: wanted → .23-fixed
Resolution: --- → FIXED


6 years ago
Whiteboard: [sg:critical] → [sg:critical] wanted-standalone-js
Alias: CVE-2011-2998
Keywords: crash, testcase


6 years ago
status-firefox10: --- → unaffected
Group: core-security
Flags: sec-bounty+
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