UUCP on macOS / *BSD

Kevin Lee 821 at 128.ca
Wed Jul 1 14:14:55 CDT 2020


Mac OS 10.15 and above had very tight controls on what can run in user space. Areas are designated off limits and blocked for security reasons.  According to apple. OS X 11 is worse. 

K. 

> On 1 Jul 2020, at 20:13, Grant Taylor via cctalk <cctalk at classiccmp.org> wrote:
> 
> On 6/28/20 6:48 PM, Grant Taylor wrote:
>> Does anyone have any experience with UUCP on macOS or *BSD systems that would be willing to help me figure something out?
> 
> I ended up getting this to work.
> 
> I don't know if it was a macOSism or a *BSDism, but the root of the problem was crossing between users via setuid / setgid in relation to OpenSSH.
> 
> Two different versions of macOS behaved differently.
> 
> macOS Yosemite 10.10.5 runs the underlying ssh pipe command as the user account that initiates the uucp / uuto / uux.
> 
> macOS Catalina 10.15.15 runs the underlying ssh pipe command as the _uucp user, NOT the account that initiates the uucp / uuto / uux.
> 
> As such, on macOS Yosemite 10.10.5, I have to have the normal user's ssh public key in the authorized_keys file on the remote system.
> 
> Conversely, on macOS Catalina 10.15.15, I have to have the _uucp user's ssh public key in the authorized_keys file on the remote system.
> 
> I don't know why macOS Yosemite 10.10.5 and macOS Catalina 10.15.15 are behaving differently, but they are.
> 
> These inconsistencies made identifying which client ssh config file -- nominally ~/.ssh/config -- was used cumbersome.
> 
> For some unknown reason, I couldn't rely on "~/" or defaults to specify the _uucp user's key (Identity) file or the known_hosts file on macOS Catalina 10.15.15, despite the fact that it was running as the _uucp user.  I ended up having to hard code the paths, as they were defaulting to the original user account that initiated the uucp / uuto / uux.
> 
> I can only surmise that something is fundamentally different between Linux and macOS in how it does things when changing user accounts via setuid & setgid as I did not have any of these problems on multiple Linux machines.  I can further surmise that something is different between macOS Yosemite 10.10.5 and macOS Catalina 10.15.15.  I don't know if this is related to System Integrity Protection or something else.
> 
> 
> 
> -- 
> Grant. . . .
> unix || die
> 
> 
> 
> 
> 
> -- 
> Grant. . . .
> unix || die



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