On 25/08/2022 17:52, Adam Dinwoodie wrote:
On Wed, Aug 24, 2022 at 08:46:10PM +0000, Brian Cowan via Cygwin wrote:
>>Does the Cygwin setup program do internal sanity checks on startup?
Not as such. And if it did, the behaviour when the fails should be to
say those checks have failed, rather than crash apparently randomly...
Why would I ask that question? Because I have a host running a
hodgepodge of company-mandated security software, and -- only on that
host -- the Cygwin setup tool crashes...
Oddities:
1. The crash generates 3 dump files when I use procdump, which is odd
since I "normally" only get 2 identical dumps from procdump.
2. A Websense ForcePoint DLP DLL is loaded in the process space,
apparently through DLL injection.
3. There seem to be 3 threads started, only one of which is the setup
program's "main" function. I had to get that out of a Process Monitor
log since the dump files are largely content free.
4. The crash is unique to the setup program. Nothing else appears to
fail.
The crash is an "illegal instruction" dump, which of course doesn't
make a lot of sense... This could be one of the other security
packages/policies on this host being "helpful."
I need ammunition to take to my internal Mordak's so I can update
Cygwin... Sure I can use WSL, but not for everything.
This sounds like classic "BLODA": applications that interfere with how
Cygwin provides *nix compatibility. There's more info in the FAQs at
https://cygwin.com/faq/faq.html#faq.using.bloda, but in short it seems
very likely that this problem is caused by some security software
running on this system.
This does indeed sound like interference by some other software.
But the setup program is not a Cygwin executable (it's not linked with
the cygwin DLL because (i) it's not present before setup has installed
it, and (ii) updating that DLL from setup while setup is using is
problematic...
Note that the Cygwin setup executable as distributed is packed with UPX,
which could very well interfere with the expectations of a poorly
written injected DLL.
(You can reverse that compression by running 'upx -d' on the setup
executable)
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