code.delx.au - pulseaudio/blob - polyp/caps.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2 of the License,
   9   or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <assert.h>
  27 #include <unistd.h>
  28 #include <errno.h>
  29 #include <string.h>
  30
  31 #ifdef HAVE_SYS_CAPABILITY_H
  32 #include <sys/capability.h>
  33 #endif
  34
  35 #include "log.h"
  36 #include "caps.h"
  37
  38 /* Drop root rights when called SUID root */
  39 void pa_drop_root(void) {
  40     uid_t uid = getuid();
  41
  42     if (uid == 0 || geteuid() != 0)
  43         return;
  44
  45     pa_log(__FILE__": dropping root rights.\n");
  46
  47     setreuid(uid, uid);
  48 /*    setuid(uid);
  49     seteuid(uid);*/
  50 }
  51
  52 #ifdef HAVE_SYS_CAPABILITY_H
  53
  54 /* Limit capabilities set to CAPSYS_NICE */
  55 int pa_limit_caps(void) {
  56     int r = -1;
  57     cap_t caps;
  58     cap_value_t nice_cap = CAP_SYS_NICE;
  59
  60     caps = cap_init();
  61     assert(caps);
  62
  63     cap_clear(caps);
  64
  65     cap_set_flag(caps, CAP_EFFECTIVE, 1, &nice_cap, CAP_SET);
  66     cap_set_flag(caps, CAP_PERMITTED, 1, &nice_cap, CAP_SET);
  67
  68     if (cap_set_proc(caps) < 0)
  69         goto fail;
  70
  71     pa_log(__FILE__": dropped capabilities successfully.\n");
  72
  73     r = 0;
  74
  75 fail:
  76     cap_free (caps);
  77
  78     return r;
  79 }
  80
  81 /* Drop all capabilities, effectively becoming a normal user */
  82 int pa_drop_caps(void) {
  83     cap_t caps;
  84     int r = -1;
  85
  86     caps = cap_init();
  87     assert(caps);
  88
  89     cap_clear(caps);
  90
  91     if (cap_set_proc(caps) < 0) {
  92         pa_log(__FILE__": failed to drop capabilities: %s\n", strerror(errno));
  93         goto fail;
  94     }
  95
  96     r = 0;
  97
  98 fail:
  99     cap_free (caps);
 100
 101     return r;
 102 }
 103
 104 #else
 105
 106 /* NOOPs in case capabilities are not available. */
 107 int pa_limit_caps(void) {
 108     return 0;
 109 }
 110
 111 int pa_drop_caps(void) {
 112     pa_drop_root();
 113     return 0;
 114 }
 115
 116 #endif
 117