Flash: heap-based buffer overflow due to indexing error when loading FLV file

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To reproduce, host the attached files appropriately, and:

http://localhost/LoadMP4.swf?file=crash3006694.flv

If there is no crash at first, refresh the page a few times.

With a debugger attached to 64-bit Flash in Chrome Linux, the crash manifests 
like this:

=> 0x00007f7779846eee:  mov    %ax,(%rdi,%rdx,2)

rax            0xff69
rdi            0x7f7778b70000
rdx            0x160b

7f777861e000-7f7778b72000 rw-p 00000000 00:00 0 
7f7778b72000-7f7779228000 ---p 00000000 00:00 0 

It looks like an indexing error; the rdi "base" address is in bounds but add on 
2*rdx and the address is not in bounds.

This bug is subject to a 90 day disclosure deadline. If 90 days elapse
without a broadly available patch, then the bug report will automatically
become visible to the public.

Original issue reported on code.google.com by cev...@google.com on 3 Jun 2015 at 2:56

Attachments:

• LoadMP4.as
• LoadMP4.swf
• crash3006694.flv

[GoogleCodeExporter]

PSIRT-3791

Original comment by natashe...@google.com on 3 Jun 2015 at 9:42

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Original comment by cev...@google.com on 4 Jun 2015 at 8:33

• Added labels: Id-3791

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Original comment by cev...@google.com on 5 Jul 2015 at 6:35

• Added labels: CVE-2015-5118

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Fixed: https://helpx.adobe.com/security/products/flash-player/apsb15-16.html

Original comment by cev...@google.com on 9 Jul 2015 at 12:37

• Changed state: Fixed
• Added labels: Fixed-2015-Jul-8

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Original comment by natashe...@google.com on 18 Aug 2015 at 7:43

• Removed labels: Restrict-View-Commit