lib/uid_wrapper/uid_wrapper.c

   1 /*
   2    Copyright (C) Andrew Tridgell 2009
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #ifdef _SAMBA_BUILD_
  19
  20 #define UID_WRAPPER_NOT_REPLACE
  21 #include "../replace/replace.h"
  22 #include <talloc.h>
  23 #include "system/passwd.h"
  24
  25 #else /* _SAMBA_BUILD_ */
  26
  27 #error uid_wrapper_only_supported_in_samba_yet
  28
  29 #endif
  30
  31 #ifndef _PUBLIC_
  32 #define _PUBLIC_
  33 #endif
  34
  35 /*
  36   we keep the virtualised euid/egid/groups information here
  37  */
  38 static struct {
  39         bool initialised;
  40         bool enabled;
  41         uid_t euid;
  42         gid_t egid;
  43         unsigned ngroups;
  44         gid_t *groups;
  45 } uwrap;
  46
  47 static void uwrap_init(void)
  48 {
  49         if (uwrap.initialised) return;
  50         uwrap.initialised = true;
  51         if (getenv("UID_WRAPPER")) {
  52                 uwrap.enabled = true;
  53                 /* put us in one group */
  54                 uwrap.ngroups = 1;
  55                 uwrap.groups = talloc_array(talloc_autofree_context(), gid_t, 1);
  56                 uwrap.groups[0] = 0;
  57         }
  58 }
  59
  60 #undef uwrap_enabled
  61 _PUBLIC_ int uwrap_enabled(void)
  62 {
  63         uwrap_init();
  64         return uwrap.enabled?1:0;
  65 }
  66
  67 _PUBLIC_ int uwrap_seteuid(uid_t euid)
  68 {
  69         uwrap_init();
  70         if (!uwrap.enabled) {
  71                 return seteuid(euid);
  72         }
  73         /* assume for now that the ruid stays as root */
  74         uwrap.euid = euid;
  75         return 0;
  76 }
  77
  78 _PUBLIC_ uid_t uwrap_geteuid(void)
  79 {
  80         uwrap_init();
  81         if (!uwrap.enabled) {
  82                 return geteuid();
  83         }
  84         return uwrap.euid;
  85 }
  86
  87 _PUBLIC_ int uwrap_setegid(gid_t egid)
  88 {
  89         uwrap_init();
  90         if (!uwrap.enabled) {
  91                 return setegid(egid);
  92         }
  93         /* assume for now that the ruid stays as root */
  94         uwrap.egid = egid;
  95         return 0;
  96 }
  97
  98 _PUBLIC_ uid_t uwrap_getegid(void)
  99 {
 100         uwrap_init();
 101         if (!uwrap.enabled) {
 102                 return getegid();
 103         }
 104         return uwrap.egid;
 105 }
 106
 107 _PUBLIC_ int uwrap_setgroups(size_t size, const gid_t *list)
 108 {
 109         uwrap_init();
 110         if (!uwrap.enabled) {
 111                 return setgroups(size, list);
 112         }
 113
 114         talloc_free(uwrap.groups);
 115         uwrap.ngroups = 0;
 116         uwrap.groups = NULL;
 117
 118         if (size != 0) {
 119                 uwrap.groups = talloc_array(talloc_autofree_context(), gid_t, size);
 120                 if (uwrap.groups == NULL) {
 121                         errno = ENOMEM;
 122                         return -1;
 123                 }
 124                 memcpy(uwrap.groups, list, size*sizeof(gid_t));
 125                 uwrap.ngroups = size;
 126         }
 127         return 0;
 128 }
 129
 130 _PUBLIC_ int uwrap_getgroups(int size, gid_t *list)
 131 {
 132         uwrap_init();
 133         if (!uwrap.enabled) {
 134                 return getgroups(size, list);
 135         }
 136
 137         if (size > uwrap.ngroups) {
 138                 size = uwrap.ngroups;
 139         }
 140         if (size == 0) {
 141                 return uwrap.ngroups;
 142         }
 143         if (size < uwrap.ngroups) {
 144                 errno = EINVAL;
 145                 return -1;
 146         }
 147         memcpy(list, uwrap.groups, size*sizeof(gid_t));
 148         return uwrap.ngroups;
 149 }
 150
 151 _PUBLIC_ uid_t uwrap_getuid(void)
 152 {
 153         uwrap_init();
 154         if (!uwrap.enabled) {
 155                 return getuid();
 156         }
 157         /* we don't simulate ruid changing */
 158         return 0;
 159 }
 160
 161 _PUBLIC_ gid_t uwrap_getgid(void)
 162 {
 163         uwrap_init();
 164         if (!uwrap.enabled) {
 165                 return getgid();
 166         }
 167         /* we don't simulate rgid changing */
 168         return 0;
 169 }