UUCP on macOS / *BSD

[Kevin Lee]

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.
> 
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> -- 
> Grant. . . .
> unix || die
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> 
> -- 
> Grant. . . .
> unix || die