KEYRING-AUTH(2)KEYRING-AUTH(2)NAME
keyring: auth, readauthinfo, writeauthinfo - authenticate a connection
SYNOPSIS
include "keyring.m";
keyring := load Keyring Keyring->PATH;
auth: fn(fd: ref Sys->FD, info: ref Authinfo, setid: int)
: (string, array of byte);
readauthinfo: fn(filename: string): ref Authinfo;
writeauthinfo: fn(filename: string, info: ref Authinfo): int;
DESCRIPTION
Auth performs mutual authentication over a network connection, usually
between a client and a server. The function is symmetric: each party
runs it on their end of the connection. Info holds the public key of a
certifying authority (PKca), the private key of the user (SKu), the
public key (PKu) of the user signed by the certifying authority
(CERTu), and Diffie-Hellman parameters (alpha, p).
Auth returns a string and a byte array. If the byte array is nil then
the authentication has failed and the string is an error message. If
the byte array is non-nil, it represents a secret shared by the two
communicating parties, and the string names the party at the other end
of the connection.
If the authentication is successful and setid is non-zero then auth
attempts to write the name of the party at the other end of the connec‐
tion into /dev/user (see cons(3)); no error is generated if that does
not succeed. If the authentication is not successful and setid is non-
zero, auth writes the name nobody into /dev/user.
The authentication protocol is based on the Station-to-Station proto‐
col. In the following, the parties are labelled 0 and 1. Sig0(x) is x
signed with 0's private key.
0 → 1 alpha**r0 mod p, CERTu0, PKu0
1 → 0 alpha**r1 mod p, CERTu1, PKu1
0 → 1 sig0(alpha**r0 mod p, alpha**r1 mod p)
1 → 0 sig1(alpha**r0 mod p, alpha**r1 mod p)
At this point both 0 and 1 share the secret alpha**(r0*r1) which is
returned in the byte array. Amongst other things, it can be the secret
to digest or encrypt a conversation (see security-ssl(2)).
Readauthinfo reads a representation of an Authinfo from a file. It
returns nil if there is a read error or a conversion error; it returns
a reference to the Authinfo otherwise.
Writeauthinfo writes a representation of info to a file. It returns -1
if the write operation fails, 0 otherwise.
FILES
/usr/user/keyring
The conventional directory for storing Authinfo files
/usr/user/keyring/default
The key file normally used by server programs
/usr/user/keyring/net!server
The key file normally used by clients for a given server
SOURCE
/libinterp/keyring.c
KEYRING-AUTH(2)
