Re: How to check UID of process on the other side of local TCP/UDP connection

On Fri, Nov 24, 2006 at 10:11:39AM -0800, [email protected] wrote:
> I
> was also thinking about using Unix sockets for communication, but it
> seems that they also lack any mechanism for authenticating the client.

man 7 unix:
...
setsockopt(.., SO_PASSCRED, ...);
...
ANCILLARY MESSAGES
       Ancillary data is sent and received using  sendmsg(2)  and
recvmsg(2).
...
       SCM_CREDENTIALS
              Send or receive Unix credentials.  This can be used for authen-
              tication.   The  credentials are passed as a struct ucred ancil-
              lary message.

                struct ucred {
                    pid_t pid;    /* process ID of the sending process */
                    uid_t uid;    /* user ID of the sending process */
                    gid_t gid;    /* group ID of the sending process */
                };

              The credentials which the sender specifies are  checked by  the
              kernel.   A process with effective user ID 0 is allowed to spec-
              ify values that do not match its own.

> Anyways, I would prefer to stick with TCP/UDP, because this is what my
> programs use already, and  I don't really want to change everything to
> Unix sockets (unless of course Unix sockets are the only good way to
> resolve my problems). 

Or you can try parsing the output of netstat (with option -p in Linux) or
lsof (eg: lsof -i [email protected]:4015 for a connection from localhost,
port 4015).

-- 
lfr
0/0

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