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Date: Mon, 14 Nov 2016 07:03:04 +0100
From: Ondřej Surý <ondrej@...y.org>
To: oss-security@...ts.openwall.com,
 Sam Trenholme <sam-k6mymjcnjpz3fmkieotlt7rbgvqt98qy@...iam.org>
Subject: Re: Remote crash in MaraDNS 2.0.13 and git master

And attachments.

O.
-- 
Ondřej Surý <ondrej@...y.org>
Knot DNS (https://www.knot-dns.cz/) – a high-performance DNS server
Knot Resolver (https://www.knot-resolver.cz/) – secure, privacy-aware,
fast DNS(SEC) resolver
Vše pro chleba (https://vseprochleba.cz) – Mouky ze mlýna a potřeby pro
pečení chleba všeho druhu

On Mon, Nov 14, 2016, at 06:53, Ondřej Surý wrote:
> Hi all,
> 
> AFL found another 5 crashes totaling to 6 unique crashes. Looking at the
> backtraces it
> looks like, it's just 3 unique crashes:
> 
> - js_readuint16
> - js_substr
> 
> - process_query -> this in fact looks like stack smashing, since it
> crashes on htons in an unrelated place
> 
> id:000000
> id:000002
> Program received signal SIGSEGV, Segmentation fault.
> js_readuint16 (js=js@...ry=0x6de290, offset=offset@...ry=4) at
> JsStr.c:1064
> 1064               (*(js->string + offset + 1) & 0xff);
> 
> 
> id:000001
> id:000005
> Program received signal SIGSEGV, Segmentation fault.
> js_substr (source=source@...ry=0x6de290, dest=dest@...ry=0x6e37f0,
> start=start@...ry=99, count=count@...ry=63743) at JsStr.c:731
> 731               *(source->string + counter + start *
> source->unit_size);
> 
> NOTE: id000001 cannot be reproduced on git master, but id000005 still
> crashes it, so they probably are separate issues after all.
> 
> id:000003
> id:000004
> Program received signal SIGSEGV, Segmentation fault.
> proc_query (raw=0x6de5d0, ect=0x7fffffffd940, sock=0) at MaraDNS.c:2615
> 2615        ip = htonl((z->sin_addr).s_addr);
> 
> This is after 58 AFL cycles.
> 
> It will be worth retesting with ASAN enabled.
> 
> Cheers,
> -- 
> Ondřej Surý <ondrej@...y.org>
> Knot DNS (https://www.knot-dns.cz/) – a high-performance DNS server
> Knot Resolver (https://www.knot-resolver.cz/) – secure, privacy-aware,
> fast DNS(SEC) resolver
> Vše pro chleba (https://vseprochleba.cz) – Mouky ze mlýna a potřeby pro
> pečení chleba všeho druhu
> 
> On Sat, Nov 12, 2016, at 09:39, Ondřej Surý wrote:
> > Hi,
> > 
> > while playing with fuzzing the DNS servers with AFL (2.35b) I found a
> > remote crash bug in MaraDNS 2.0.13 js_readuint16. It can be also
> > reproduced using https://github.com/samboy/MaraDNS/ master branch.
> > 
> > Attached is patch to allow the fuzzing (it overrides getudp() with
> > read(0, ..)), the input data that crashes MaraDNS, and the bt full
> > output.
> > 
> > Please assign CVE, I would provide a patch, but MaraDNS code is
> > extremely hard to navigate for me, so I'll leave the fix for the code
> > author.
> > 
> > AFL has finished only 1 cycle (and found the 1 unique crash), so I'll
> > keep it running for a while.
> > 
> > Cheers,
> > -- 
> > Ondřej Surý <ondrej@...y.org>
> > Knot DNS (https://www.knot-dns.cz/) – a high-performance DNS server
> > Knot Resolver (https://www.knot-resolver.cz/) – secure, privacy-aware,
> > fast DNS(SEC) resolver
> > Vše pro chleba (https://vseprochleba.cz) – Mouky ze mlýna a potřeby pro
> > pečení chleba všeho druhu
> > Email had 3 attachments:
> > + maradns.btfull
> >   5k (application/octet-stream)
> > + allow-fuzzing.patch
> >   2k (text/x-patch)
> > + id:000000,sig:11,src:007564,op:havoc,rep:32
> >   1k (application/octet-stream)

Download attachment "id:000000,sig:11,src:007564,op:havoc,rep:32" of type "application/octet-stream" (23 bytes)

Download attachment "id:000001,sig:11,src:009775,op:arith8,pos:2,val:+6" of type "application/octet-stream" (20 bytes)

Download attachment "id:000002,sig:11,src:009794+007532,op:splice,rep:2" of type "application/octet-stream" (21 bytes)

Download attachment "id:000003,sig:11,src:009819,op:flip1,pos:0" of type "application/octet-stream" (20 bytes)

Download attachment "id:000004,sig:11,src:009854,op:arith8,pos:0,val:-29" of type "application/octet-stream" (21 bytes)

Download attachment "id:000005,sig:11,src:009792,op:flip2,pos:2" of type "application/octet-stream" (20 bytes)

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