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Status: Fixed
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Closed: Jun 29
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LG: Stack overflows in ASFParser::SetMetaData
Project Member Reported by markbrand@google.com, Mar 27 2017 Back to list
There are three variants of the below crash, all of which stemming from an unbound copy into a fixed size stack buffer allocated in the function ASFParser::SetMetaData, used as an argument to each of the three calls to the function unicodeToUtf_8 without checking that the output length will be less than the size of the buffer. You can see in the crashdump that the argv array has been overwritten by junk unicode output, resulting in the corrupted binary path displayed in the output.

I believe that this issue is mitigated by compiling with stack cookies, so I'm not applying the 90 day deadline to this issue since I don't think it's exploitable except as a denial-of-service.

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
Build fingerprint: 'lge/p1_global_com/p1:6.0/MRA58K/1624210305d45:user/release-keys'
Revision: '11'
ABI: 'arm'
pid: 435, tid: 435, name: mediaserver  >>> �ు둢吟ѷἃ舄㹂慮춎䇛㾾攞䎤➹뽉龂팆顯浃桡>￿큾略혭拴畹㿺㬭똦৿➦쎪悸ꪰ뒇᭥릧㠙���褓悀䳘牀⛕鑆ࡢ���㹇䊌⾩ʘỬ操陊ꦑ䤮峇ᇱ빌屸쒫羮죾‘궈砜톢庋_䔗蛴ᰦ꿚肁࿗砘搒깷옮豩烙켯펤傁䅥툺帰Ŧ䥎ᢘ퐢옥ꤤࠨ᪗@���Ԃ깛Ȯ댁ૃ⒨待讍ꄌ鈤䄚戬㸵Ṣ䙌䠖咂徕琣༔ৰ씊塀⏆ð厔⁀呕!谀櫰ុì⪌跔띦䳊薵結စ䌷﷌���๑髇#쀇붭
signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0xff951000
    r0 ff951002  r1 f023b0ba  r2 0000100e  r3 ffffff8f
AM write failed: Broken pipe
    r4 00000792  r5 f023bfde  r6 f5f1c080  r7 efdfca69
    r8 f1282348  r9 ff94fc70  sl f1282348  fp 00000012
    ip 0000a3c6  sp ff94fc5c  lr efdf7457  pc efdf4a9a  cpsr 800f0030

backtrace:
    #00 pc 00003a9a  /system/lib/liblg_parser_asf.so (_Z14unicodeToUtf_8PhPti+85)
    #01 pc 00006453  /system/lib/liblg_parser_asf.so (_ZN9ASFParser11SetMetaDataEP15meta_descriptor+186)
    #02 pc 6b203432  <unknown>
 
asan_generic_b9a5e7b8_888_6ce9fad673233d7cae8574890ab4521d.wma
2.3 KB Download
Project Member Comment 1 by markbrand@google.com, Mar 27 2017
Note: this issue was originally reported to LG on 2017-Mar-23 as above, without the deadline applied.

I've just noticed that there are some builds of these libraries that don't appear to be compiled with stack cookies, rendering the stack overflow issues likely exploitable on some devices. I'm applying the 90-day deadline to the stack overflow issues reported as though they had been reported today; that is, that the 90-day deadline for the files in the stack-overflows.tar.gz will be on 26 June 2017.

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.
Project Member Comment 2 by markbrand@google.com, Jun 29
Labels: -Restrict-View-Commit LVE-SMP-170009
Status: Fixed
There was some confusion in the LG bulletins about this issue, and since it was believed to be fixed I held off on disclosing after 90 days as a miss.

The issue was indeed fixed under deadline, and can be seen on the LG bulletins page now.
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