[tor-dev] Latest state of the guard algorithm proposal (prop259) (April 2016)

[Fan Jiang]

Hi,

Just some update,
We fixed this chosen_by_version SIGSEGV error,
And Tania is working on removing XXX comments.

Will keep u updated when we close more issues.

Cheers,
Fan

On Fri, Apr 22, 2016 at 9:14 AM, George Kadianakis <desnacked at riseup.net>
wrote:

> Fan Jiang <fanjiang at thoughtworks.com> writes:
>
> > [ text/plain ]
> > 2016年4月22日 上午4:54，"George Kadianakis" <desnacked at riseup.net>写道：
> >>
> >> Fan Jiang <fanjiang at thoughtworks.com> writes:
> >>
> >> > [ text/plain ]
> >> > On Thu, Apr 21, 2016 at 4:32 AM, George Kadianakis <
> desnacked at riseup.net
> >>
> >> > wrote:
> >> >
> >> > <snip>
> >
> > It seems like we come to a point that most of prop259 can be stable for a
> > while, we are going to do some cleanup in this implementation and spec. I
> > think next week we can ask more people to review, does that sounds OK?
> >
>
> Sounds good!
>
> > BTW, About your segmentfault I couldn't reproduce, maybe related with
> your
> > torrc/state file?
>
> I think it's some sort of dangling pointer error. e->chosen_by_version
> seems to
> be referring to a corrupted memory address.
>
> Not sure if it's caused by my state file, but in general the prop259 branch
> should work well with any old state file without crashing.
>
> Here is some gdb output from the segfault:
>
> ---
> Apr 22 17:08:21.161 [notice] Tor v0.2.8.1-alpha-dev (git-d7ed996b2aba9f10)
> running on Linux with Libevent 2.0.21-stable, OpenSSL 1.0.1k and Zlib 1.2.8.
> Apr 22 17:08:21.161 [notice] Tor can't help you if you use it wrong! Learn
> how to be safe at https://www.torproject.org/download/download#warning
> Apr 22 17:08:21.161 [notice] This version is not a stable Tor release.
> Expect more bugs than usual.
> Apr 22 17:08:21.161 [notice] Read configuration file
> "/home/f/Computers/tor/mytor/../confs/prop259".
> Apr 22 17:08:21.164 [notice] Opening Socks listener on 127.0.0.1:9999
>
> Program received signal SIGSEGV, Segmentation fault.
> __strchr_sse2 () at ../sysdeps/x86_64/multiarch/../strchr.S:32
> 32      ../sysdeps/x86_64/multiarch/../strchr.S: No such file or directory.
> (gdb) up
> #1  0x000055555567eb25 in guards_update_state (next=0x5555559c3f40,
> next at entry=0x5555559c35e8, guards=guards at entry=0x5555559c4620,
>     config_name=config_name at entry=0x55555570c3be "UsedGuard") at
> src/or/prop259.c:1155
> 1155                !strchr(e->chosen_by_version, ' ')) {
> (gdb) p/x e
> $1 = 0x5555559c42d0
> (gdb) p/x e->chosen_by_version
> $2 = 0x4137323000000000
> (gdb) x/s chosen_by_version
> No symbol "chosen_by_version" in current context.
> (gdb) x/s e->chosen_by_version
> 0x4137323000000000:     <error: Cannot access memory at address
> 0x4137323000000000>
> ---
>
> and here is my state file in case it matters:
>
> ---
> EntryGuard jaures4 5CF8AFA5E4B0BB88942A44A3F3AAE08C3BDFD60B DirCache
> EntryGuardAddedBy 5CF8AFA5E4B0BB88942A44A3F3AAE08C3BDFD60B 0.2.5.12
> 2016-01-11 02:54:36
> EntryGuard SGGSUK4 38F423A4320380FFE32DB60B72E7457CD6E3F096 DirCache
> EntryGuardAddedBy 38F423A4320380FFE32DB60B72E7457CD6E3F096 0.2.5.12
> 2016-01-25 08:20:31
> EntryGuard aTomicRelayFR1 25EF027A85BAA044048AD1D635AF8583DB88C08F DirCache
> EntryGuardAddedBy 25EF027A85BAA044048AD1D635AF8583DB88C08F 0.2.5.12
> 2016-02-06 01:04:20
> TorVersion Tor 0.2.5.12 (git-3731dd5c3071dcba)
> LastWritten 2016-02-07 18:18:11
> ---
>



-- 
____


Fan Jiang 蒋帆
Amateur Code Chef
Thoughtworks, Inc.
mobile +86-150-9189-3714
skype fan at torchz.net
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