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Re: No way to use ssh ~/.ssh/config with "noacl" option




On 11/4/2017 7:37 AM, Corinna Vinschen wrote:
On Nov  4 05:47, Matt D. wrote:
I mount with "noacl" as I don't need ACLs for my purposes and prefer to
leave everything up to Windows permissions.

The problem with this is that ssh insists that ~/.ssh/config be less
permissive. But this file is bound to --rw-r--r-- for this option.

Would it be appropriate to request ssh to ignore this requirement when
"noacl" present on the mounted volume?

Yes, in theory.  However, this shouldn't be necessary.

Ssh already has code to check extrem perms only in "acl" mounted
directories, but it does not have this extra check for config files,
basically because it was never necessary:

If you use noacl, your file perms are faked to always be 644, or
444 if the DOS R/O bit is set, or 755/555 if executable/directory.
Additionally all files are faked as if they are owned by your own
account.

Ssh checks the config file like this:

   if (((sb.st_uid != 0 && sb.st_uid != getuid()) ||
       (sb.st_mode & 022) != 0))
	  fatal("Bad owner or permissions on %s", filename);

Which means, 0644 permissions are perfectly fine.  As are 755 perms
for the ~/.ssh and ~ dirs.

I just mounted my home dir "noacl".  The perms are as expected:

   $ ls -ld . .ssh .ssh/config .ssh/id_local
   drwxr-xr-x 1 corinna vinschen    0 Nov  4 12:27 .
   drwxr-xr-x 1 corinna vinschen    0 Mar 14  2017 .ssh
   -rw-r--r-- 1 corinna vinschen  703 Jan 19  2017 .ssh/config
   -rw-r--r-- 1 corinna vinschen 7329 Jan 12  2017 .ssh/id_local

Note especially the too open perms in case of the private keyfile
"id_local".  Still, I can ssh into one of my other machines just fine.

How come this doesn't work for you?


Corinna


I don't know why it doesn't work for me other than the reported error. I am trying to use ssh combined with git. My .ssh permissions are:

$ls -ld . .ssh .ssh/config .ssh/github
drwxr-xr-x 1 Matthew D'Onofrio None    0 Nov  4 06:42 .
drwxr-xr-x 1 Matthew D'Onofrio None    0 Nov  4 04:51 .ssh
-rw-r--r-- 1 Matthew D'Onofrio None   80 Nov  4 04:51 .ssh/config
-rw-r--r-- 1 Matthew D'Onofrio None 3243 Nov  3 10:53 .ssh/github

I removed the noacl option in fstab, re-ran Cygwin setup, set .ssh/config to 600 and ssh was happy. I then reverted back to noacl and the problem returned.

I'm in the process of trying to build openssh with cygpath for debugging but this is my first time building anything from Cygwin or using cygports so it's taking some time.


Matt D.

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