3 * Privilege separation communication protocol
5 * (c) 2008 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Trivial IP Encryption (TrIPE).
12 * TrIPE is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * TrIPE is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
32 /*----- Static variables --------------------------------------------------*/
34 static pid_t kid
= -1;
36 /*----- Fetching a tunnel file descriptor ---------------------------------*/
38 /* --- @ps_tunfd@ --- *
40 * Arguments: @const tunnel_ops *tops@ = pointer to tunnel operations
41 * @char **ifn@ = where to put the interface name
43 * Returns: The file descriptor, or @-1@ on error.
45 * Use: Fetches a file descriptor for a tunnel driver.
48 int ps_tunfd(const tunnel_ops
*tops
, char **ifn
)
56 a_warn("PRIVSEP", "helper-died", A_END
);
60 "privsep: requesting descriptor for %s tunnel",
62 if (pc_putuint(PS_TUNRQ
) || pc_putstring(tops
->name
)) {
63 a_warn("PRIVSEP", "helper-write-error", "?ERRNO", A_END
);
67 n
= fdpass_recv(pc_fd
, &fd
, &code
, sizeof(code
));
68 if (n
< 0) goto readlose
;
69 if (n
< sizeof(code
)) {
70 a_warn("PRIVSEP", "helper-short-read", A_END
);
76 a_warn("PRIVSEP", "no-fd-from-helper", A_END
);
79 if (pc_getstring(&d
)) { close(fd
); goto readlose
; }
80 *ifn
= xstrdup(d
.buf
);
82 "privsep: received winning descriptor for %s",
86 if (pc_geterr(&errno
)) goto readlose
;
87 T( trace(T_PRIVSEP
, "privsep: helper lost: %s", strerror(errno
)); )
92 if (pc_getuint(&code
) || pc_getstring(&d
)) goto readlose
;
93 trace(code
, "%s", d
.buf
);
98 if (pc_getstring(&d
)) goto readlose
;
99 a_warn("*%s", d
.buf
, A_END
);
103 a_warn("PRIVSEP", "unknown-response-code", "%u", code
, A_END
);
112 a_warn("PRIVSEP", "helper-read-error", "?ERRNO", A_END
);
120 /*----- Main code ---------------------------------------------------------*/
124 * Arguments: @int sig@ = signal number (always @SIGCHLD@; ignored)
128 * Use: Notices and reports child process death.
131 static void reap(int sig
)
137 k
= waitpid(-1, &st
, WNOHANG
);
143 a_warn("SERVER", "waitpid-error", "?ERRNO", A_END
);
152 a_warn("PRIVSEP", "child-exited", "%d", WEXITSTATUS(st
), A_END
);
153 else if (WIFSIGNALED(st
))
154 a_warn("PRIVSEP", "child-killed", "%d", WTERMSIG(st
), A_END
);
156 a_warn("PRIVSEP", "child-died", "%d", st
, A_END
);
162 /* --- @ps_split@ --- *
164 * Arguments: @int detachp@ = whether to detach the child from its terminal
168 * Use: Separates off the privileged tunnel-opening service from the
169 * rest of the server.
172 void ps_split(int detachp
)
179 if (socketpair(PF_UNIX
, SOCK_STREAM
, 0, fd
)) {
181 "failed to create socket pair for privilege separation: %s",
184 helper
= getenv("TRIPE_PRIVHELPER");
185 if (!helper
) helper
= PRIVSEP_HELPER
;
186 fdflags(fd
[0], 0, 0, FD_CLOEXEC
, FD_CLOEXEC
);
187 fdflags(fd
[1], 0, 0, FD_CLOEXEC
, FD_CLOEXEC
);
188 signal(SIGCHLD
, reap
);
191 signal(SIGCHLD
, SIG_DFL
);
192 if (detachp
) detachtty();
194 md
[0].cur
= fd
[0]; md
[0].want
= STDIN_FILENO
;
195 if (mdup(md
, 1)) goto lose
;
196 execl(helper
, helper
, (char *)0);
198 fprintf(stderr
, "helper: failed to run helper: %s\n", strerror(errno
));
201 T( trace(T_PRIVSEP
, "privsep: forked child successfully"); )
206 /* --- @ps_quit@ --- *
212 * Use: Detaches from the helper process.
215 void ps_quit(void) { if (pc_fd
!= -1) close(pc_fd
); }
217 /*----- That's all, folks -------------------------------------------------*/