From: Corinna Vinschen <corinna-cygwin@cygwin.com>
To: cygwin@cygwin.com
Subject: Re: Fork issue on W10 WOW
Date: Mon, 09 Jul 2018 12:37:00 -0000 [thread overview]
Message-ID: <20180709123739.GB27673@calimero.vinschen.de> (raw)
In-Reply-To: <87e94b8c-13d0-928e-957d-c32b15b8a962@gmail.com>
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On Jul 9 13:37, Marco Atzeri wrote:
> Am 7/9/2018 um 11:03 AM schrieb Corinna Vinschen:
> > On Jul 8 18:03, Marco Atzeri wrote:
> > > Am 30.06.2018 um 22:47 schrieb Ken Brown:
> > > > On 6/30/2018 11:52 AM, Marco Atzeri wrote:
> > > >
> > > > I've never had this problem with my own 32bit installation on W10, but I
> > > > just reproduced it by doing a new installation with your list of
> > > > packages. Have you tried just installing a minimal list of packages
> > > > that you need for building the packages you maintain?
> > > >
> > >
> > > On a fresh minimal installation the problem can arise again
> > >
> > > $ cygcheck -cd |wc -l
> > > 245
> > >
> > > as the first system shared libs are lower than the rebase
> > > DefaultBaseAddress=0x070000000
> > >
> > > 6F810000-6F811000 r--p /cygdrive/c/Windows/System32/wow64.dll
> > > 6F811000-6F844000 r-xp /cygdrive/c/Windows/System32/wow64.dll
> > >
> > > I think that rebase should consider different rebase
> > > base address for W10.
> > >
> > > Using DefaultBaseAddress=0x06F000000 seems fine
> > > for the time being
> >
> > I can do that in the rebaseall script (I have a matching patch locally),
> > but it looks like a race we can't win in the long run. 240 Megs less
> > space is a lot given the number of DLLs in the distro.
>
> I know, but until we try to support the 32bit version, we need a
> way to handle it.
>
> > To make matters worse, I just checked my local 32 bit W10 and it turns
> > out that various Windows DLLs loaded by default (even in a simple tcsh)
> > are at even lower addresses, e.g.
> >
> > 6B690000-6B6A3000 /mnt/c/Windows/System32/netapi32.dll
>
> I suspect it is due the their 64bit base address
netapi32.dll is 32 bit. And it's a 32 bit OS, not WOW64...
> $ objdump -x /cygdrive/c/Windows/System32/wow64.dll|grep ImageBase
> ImageBase 000000006b000000
>
> $ objdump -x /cygdrive/c/Windows/System32/wow64win.dll |grep ImageBase
> ImageBase 000000006b180000
>
> It is like they put the 64bit System 32 over 0x6b000000 (maybe)
0x6b000000? In your previous mail you wrote 0x6f000000.
> and the WoW64 over 0x70000000
I don't think there's a rule. On my 64 bit W10 system:
76E60000-76ED8000 /mnt/c/Windows/System32/wow64win.dll
76EE0000-76EEA000 /mnt/c/Windows/System32/wow64cpu.dll
76EF0000-76F42000 /mnt/c/Windows/System32/wow64.dll
Of course you can rebase the wow64 DLLs, it's just unclear if that
helps, given Windows uses different DLL addresses for their system DLLs
after each reboot.
> But I guess that ALSR can play around that numbers.
> There is still a way to disable ALSR?
ASLR is disabled by default on Cygwin executables. Unless it can't
be disabled anymore for certain (system?) DLLs.
Corinna
--
Corinna Vinschen Please, send mails regarding Cygwin to
Cygwin Maintainer cygwin AT cygwin DOT com
Red Hat
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next prev parent reply other threads:[~2018-07-09 12:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-30 17:33 Marco Atzeri
[not found] ` <c1505248-8d03-c0b6-37ca-9c6eed2100e9@cornell.edu>
2018-07-01 8:51 ` Marco Atzeri
2018-07-08 16:03 ` Marco Atzeri
2018-07-09 9:03 ` Corinna Vinschen
2018-07-09 11:37 ` Marco Atzeri
2018-07-09 12:37 ` Corinna Vinschen [this message]
2018-07-10 5:33 ` Marco Atzeri
2018-07-12 12:34 ` marco atzeri
2018-07-14 12:46 ` Corinna Vinschen
2018-07-14 14:31 ` Marco Atzeri
2018-07-14 17:58 ` Achim Gratz
2018-07-14 19:03 ` Marco Atzeri
2018-07-14 22:41 ` Achim Gratz
2018-07-15 2:12 ` Brian Inglis
2018-07-15 9:18 ` Marco Atzeri
2018-07-15 13:25 ` Achim Gratz
2018-07-15 19:33 ` Brian Inglis
2018-07-15 23:01 ` David Stacey
2018-07-16 18:58 ` Marco Atzeri
2018-07-16 1:06 ` Andrey Repin
2018-07-17 18:34 ` Marco Atzeri
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