mdw@git.distorted.org.uk Git - tripe/blob - priv/priv.h

   1 /* -*-c-*-
   2  *
   3  * Privilege separation definitions
   4  *
   5  * (c) 2008 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Trivial IP Encryption (TrIPE).
  11  *
  12  * TrIPE is free software: you can redistribute it and/or modify it under
  13  * the terms of the GNU General Public License as published by the Free
  14  * Software Foundation; either version 3 of the License, or (at your
  15  * option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  24  */
  25
  26 #ifndef PRIV_H
  27 #define PRIV_H
  28
  29 #ifdef __cplusplus
  30   extern "C" {
  31 #endif
  32
  33 /*----- Header files ------------------------------------------------------*/
  34
  35 #include "config.h"
  36
  37 #include <errno.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #include <sys/types.h>
  43 #include <unistd.h>
  44 #include <fcntl.h>
  45
  46 #include <sys/socket.h>
  47 #include <sys/un.h>
  48
  49 #include <mLib/dstr.h>
  50 #include <mLib/fdpass.h>
  51 #include <mLib/quis.h>
  52 #include <mLib/report.h>
  53 #include <mLib/trace.h>
  54
  55 #include "util.h"
  56
  57 #undef sun
  58
  59 /*----- Protocol ----------------------------------------------------------*/
  60
  61 /* --- Notes --- *
  62  *
  63  * The protocol is synchronous.  The socket is not marked as nonblocking;
  64  * instead we just trust the helper to respond in good time; this is
  65  * reasonable since it's not doing anything complicated.  The helper is
  66  * completely trusted.
  67  *
  68  * The protocol works like this.  Messages begin with a request code which is
  69  * a single @unsigned int@.  The server sends a request @PS_TUNRQ@ to the
  70  * helper, followed by a strin naming the tunnel driver of interest.  The
  71  * server responds with a sequence of @PS_TRACE@ and/or @PS_WARN@ messages,
  72  * followed by either a @PS_TUNFD@ carrying a file descriptor, or a
  73  * @PS_TUNERR@ followed by an integer @errno@ code.
  74  *
  75  * Simple data items are sent as native representations.  A string is sent as
  76  * a @size_t@ giving the string's length in bytes followed by that many
  77  * characters.  There is no padding for alignment.
  78  *
  79  * If all else fails, the helper process will just quit.
  80  */
  81
  82 enum {
  83   PS_TUNRQ,                             /* Request (string) */
  84   PS_TUNFD,                             /* Tunnel descriptor (nothing) */
  85   PS_TUNERR,                            /* Error (@int errno@) */
  86 #ifndef NTRACE
  87   PS_TRACE,                             /* Trace (@unsigned mask@, string) */
  88 #endif
  89   PS_WARN,                              /* Warning (string) */
  90 };
  91
  92 /*----- Tracing definitions -----------------------------------------------*/
  93
  94 #define T_PRIVSEP 512u
  95
  96 /*----- Global variables --------------------------------------------------*/
  97
  98 extern int pc_fd;                       /* File descriptor for comms */
  99
 100 /*----- Functions provided ------------------------------------------------*/
 101
 102 #define COMM_TYPES(_)                                                   \
 103   _(err, int)                                                           \
 104   _(uint, unsigned int)                                                 \
 105   _(sz, size_t)
 106
 107 /* --- @pc_put@ --- *
 108  *
 109  * Arguments:   @const void *p@ = pointer to buffer
 110  *              @size_t sz@ = size of the buffer
 111  *
 112  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 113  *
 114  * Use:         Writes a buffer, handling short writes and other bogosity.
 115  */
 116
 117 extern int pc_put(const void */*p*/, size_t /*sz*/);
 118
 119 /* --- @pc_puterr@, @pc_putuint@, @pc_putsz@ --- *
 120  *
 121  * Arguments:   @int err@ = error number to write
 122  *              @uint u@ = unsigned integer to write
 123  *              @size_t sz@ = size to write
 124  *
 125  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 126  *
 127  * Use:         Sends an error/integer/size.
 128  */
 129
 130 #define DECL(abbr, type) extern int pc_put##abbr(type /*x*/);
 131 COMM_TYPES(DECL)
 132 #undef DECL
 133
 134 /* --- @pc_putstring@ --- *
 135  *
 136  * Arguments:   @const char *s@ = pointer to string to write
 137  *
 138  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 139  *
 140  * Use:         Sends a string.
 141  */
 142
 143 extern int pc_putstring(const char */*s*/);
 144
 145 /* --- @pc_get@ --- *
 146  *
 147  * Arguments:   @void *p@ = pointer to buffer
 148  *              @size_t sz@ = size of the buffer
 149  *
 150  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 151  *
 152  * Use:         Receives a buffer, handling short reads and other bogosity.
 153  */
 154
 155 extern int pc_get(void */*p*/, size_t /*sz*/);
 156
 157 /* --- @pc_geterr@, @pc_getuint@, @pc_getsz@ --- *
 158  *
 159  * Arguments:   @int *err@ = where to put the error number
 160  *              @uint *u@ = where to put the unsigned integer
 161  *              @size_t *sz@ = where to put the size
 162  *
 163  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 164  *
 165  * Use:         Receives an error/integer/size.
 166  */
 167
 168 #define DECL(abbr, type) extern int pc_get##abbr(type */*x*/);
 169 COMM_TYPES(DECL)
 170 #undef DECL
 171
 172 /* --- @pc_getstring@ --- *
 173  *
 174  * Arguments:   @dstr *d@ = where to put the string
 175  *
 176  * Returns:     Zero on success, @-1@ on error (and @errno@ set).
 177  *
 178  * Use:         Receives a string.
 179  */
 180
 181 extern int pc_getstring(dstr */*d*/);
 182
 183 /*----- That's all, folks -------------------------------------------------*/
 184
 185 #ifdef __cplusplus
 186   }
 187 #endif
 188
 189 #endif