pcsc-lite  2.0.3
auth.c
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1 /*
2  * MUSCLE SmartCard Development ( https://pcsclite.apdu.fr/ )
3  *
4  * Copyright (C) 2013 Red Hat
5  *
6  * All rights reserved.
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  *
14  * 2. Redistributions in binary form must reproduce the above copyright
15  * notice, this list of conditions and the following disclaimer in the
16  * documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
25  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
26  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
28  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
29  * DAMAGE.
30  *
31  * Author: Nikos Mavrogiannopoulos <nmav@redhat.com>
32  */
33 
42 #include "config.h"
43 #define _GNU_SOURCE
44 #include <sys/types.h>
45 #include <sys/socket.h>
46 #include <sys/ioctl.h>
47 #include <sys/un.h>
48 #include <stdio.h>
49 #include "debuglog.h"
50 #include "auth.h"
51 
52 #include <errno.h>
53 
54 #if defined(HAVE_POLKIT) && defined(SO_PEERCRED)
55 
56 #include <polkit/polkit.h>
57 #include <stdbool.h>
58 
59 extern bool disable_polkit;
60 
61 /* Returns non zero when the client is authorized */
62 unsigned IsClientAuthorized(int socket, const char* action, const char* reader)
63 {
64  struct ucred cr;
65  socklen_t cr_len;
66  int ret;
67  PolkitSubject *subject;
68  PolkitAuthority *authority;
69  PolkitAuthorizationResult *result;
70  PolkitDetails *details;
71  GError *error = NULL;
72  char action_name[128];
73 
74  if (disable_polkit)
75  return 1;
76 
77  snprintf(action_name, sizeof(action_name), "org.debian.pcsc-lite.%s", action);
78 
79  cr_len = sizeof(cr);
80  ret = getsockopt(socket, SOL_SOCKET, SO_PEERCRED, &cr, &cr_len);
81  if (ret == -1)
82  {
83  int e = errno;
84  Log2(PCSC_LOG_CRITICAL,
85  "Error obtaining client process credentials: %s", strerror(e));
86  return 0;
87  }
88 
89  authority = polkit_authority_get_sync(NULL, &error);
90  if (authority == NULL)
91  {
92  Log2(PCSC_LOG_CRITICAL, "polkit_authority_get_sync failed: %s",
93  error->message);
94  g_error_free(error);
95  return 0;
96  }
97 
98  subject = polkit_unix_process_new_for_owner(cr.pid, 0, cr.uid);
99  if (subject == NULL)
100  {
101  Log1(PCSC_LOG_CRITICAL, "polkit_unix_process_new_for_owner failed");
102  ret = 0;
103  goto cleanup1;
104  }
105 
106  details = polkit_details_new();
107  if (details == NULL)
108  {
109  Log1(PCSC_LOG_CRITICAL, "polkit_details_new failed");
110  ret = 0;
111  goto cleanup0;
112  }
113 
114  if (reader != NULL)
115  polkit_details_insert(details, "reader", reader);
116 
117  result = polkit_authority_check_authorization_sync(authority, subject,
118  action_name, details,
119  POLKIT_CHECK_AUTHORIZATION_FLAGS_ALLOW_USER_INTERACTION,
120  NULL,
121  &error);
122 
123  if (result == NULL)
124  {
125  Log2(PCSC_LOG_CRITICAL, "Error in authorization: %s", error->message);
126  g_error_free(error);
127  ret = 0;
128  }
129  else
130  {
131  if (polkit_authorization_result_get_is_authorized(result))
132  {
133  ret = 1;
134  }
135  else
136  {
137  ret = 0;
138  }
139  }
140 
141  if (ret == 0)
142  {
143  Log4(PCSC_LOG_CRITICAL,
144  "Process %u (user: %u) is NOT authorized for action: %s",
145  (unsigned)cr.pid, (unsigned)cr.uid, action);
146  }
147 
148  if (result)
149  g_object_unref(result);
150 
151  g_object_unref(subject);
152 cleanup0:
153  g_object_unref(details);
154 cleanup1:
155  g_object_unref(authority);
156 
157  return ret;
158 }
159 
160 #else
161 
162 unsigned IsClientAuthorized(int socket, const char* action, const char* reader)
163 {
164  (void)socket;
165  (void)action;
166  (void)reader;
167 
168  return 1;
169 }
170 
171 #endif
This handles debugging.