Cygwin terminal fails to start after win update

Cygwin terminal fails to start after win update

[Michael Moats]

Hello. Loaded cygwin a few weeks ago, but after windows 10 update, 
mintty term fails to start.

Versions:
cygwin 3.1.6-1

OS Name    Microsoft Windows 10 Home
Version    10.0.19041 Build 19041

When problem first noticed:
Error: Could not fork child process: Resource temporarily unavailable (-1).
DLL rebasing may be required; see 'rebaseall / rebase --help'.
(and terminal allows no typing)

When attempt is made to add dll, bash and some other individual 
exceptions to firewall ASLR settings, Mintty starts & shell commands 
such as echo and pwd will work, but commands from /bin (i.e. ls, ln, 
grep, vi, cat, which) return nothing. Maybe more exceptions needed, but 
which ones?

To get cygwin working a usual, these gross windows defender firewall 
changes were made:

Windows Security
     App & browser control
         Exploit protection

Force randomization for images (Mandatory ASLR)
     Force relocation of images not compiled with /DYNAMICBASE
-> Off by default     [Mintty working]
-> On by default    [Mintyy not working]

Randomize memory allocations (Bottom-up ASLR)
     Randomize locations for virtual memory allocations.
-> Off by default     [Mintyy working]
-> On by default    [Mintyy not working]

High-entropy ASLR
     Increase variability when using Randomize memory allocations 
(Bottom-up ASLR)
-> Off by default     [Mintty working]
-> On by default    [Mintty not working]

When Cyg/Mintty is working with above gross changes:
     $ cd /usr

     $ ln -s /bin /usr/bin

     $ ls -i | grep bin
     1125899907459844 bin/
     562949954038681 sbin/

     $ cd ..

     $ ls -i | grep bin
     1125899907459844 bin/
     562949954038681 sbin/

     $ ps -ef | grep -i min
        XXXXX     649       1 ?        13:18:14 /usr/bin/mintty

Thanks in advance!!

-- Michael Moats

Re: Cygwin terminal fails to start after win update

[Ken Brown]

On 9/2/2020 3:32 PM, Michael Moats wrote:
> Hello. Loaded cygwin a few weeks ago, but after windows 10 update, mintty term 
> fails to start.
> 
> Versions:
> cygwin 3.1.6-1
> 
> OS Name    Microsoft Windows 10 Home
> Version    10.0.19041 Build 19041
> 
> When problem first noticed:
> Error: Could not fork child process: Resource temporarily unavailable (-1).
> DLL rebasing may be required; see 'rebaseall / rebase --help'.
> (and terminal allows no typing)
> 
> When attempt is made to add dll, bash and some other individual exceptions to 
> firewall ASLR settings, Mintty starts & shell commands such as echo and pwd will 
> work, but commands from /bin (i.e. ls, ln, grep, vi, cat, which) return nothing. 
> Maybe more exceptions needed, but which ones?
> 
> To get cygwin working a usual, these gross windows defender firewall changes 
> were made:
> 
> Windows Security
>      App & browser control
>          Exploit protection
> 
> Force randomization for images (Mandatory ASLR)
>      Force relocation of images not compiled with /DYNAMICBASE
> -> Off by default     [Mintty working]
> -> On by default    [Mintyy not working]
> 
> Randomize memory allocations (Bottom-up ASLR)
>      Randomize locations for virtual memory allocations.
> -> Off by default     [Mintyy working]
> -> On by default    [Mintyy not working]
> 
> High-entropy ASLR
>      Increase variability when using Randomize memory allocations (Bottom-up ASLR)
> -> Off by default     [Mintty working]
> -> On by default    [Mintty not working]
> 
> When Cyg/Mintty is working with above gross changes:
>      $ cd /usr
> 
>      $ ln -s /bin /usr/bin
> 
>      $ ls -i | grep bin
>      1125899907459844 bin/
>      562949954038681 sbin/
> 
>      $ cd ..
> 
>      $ ls -i | grep bin
>      1125899907459844 bin/
>      562949954038681 sbin/
> 
>      $ ps -ef | grep -i min
>         XXXXX     649       1 ?        13:18:14 /usr/bin/mintty
> 
> Thanks in advance!!

There was a recent discussion about this issue here:

   https://sourceware.org/pipermail/cygwin/2020-August/245973.html