openvpn/plugin/auth-pam/pamdl.c

   1 #if DLOPEN_PAM
   2 /*
   3  * If you want to dynamically load libpam using dlopen() or something,
   4  * then dlopen( ' this shared object ' ); It takes care of exporting
   5  * the right symbols to any modules loaded by libpam.
   6  *
   7  * Modified by JY for use with openvpn-pam-auth
   8  */
   9
  10 #include <stdio.h>
  11 #include <dlfcn.h>
  12 #include <security/pam_appl.h>
  13 #include <security/_pam_macros.h>
  14
  15 #include "pamdl.h"
  16
  17 static void *libpam_h = NULL;
  18
  19 #define RESOLVE_PAM_FUNCTION(x, y, z, err) \
  20     { \
  21         union { const void *tpointer; y (*fn) z ; } fptr; \
  22         fptr.tpointer = dlsym(libpam_h, #x); real_##x = fptr.fn; \
  23         if (real_##x == NULL) { \
  24             fprintf (stderr, "PAMDL: unable to resolve '%s': %s\n", #x, dlerror()); \
  25             return err; \
  26         } \
  27     }
  28
  29 int
  30 dlopen_pam (const char *so)
  31 {
  32   if (libpam_h == NULL)
  33     {
  34       libpam_h = dlopen(so, RTLD_GLOBAL|RTLD_NOW);
  35     }
  36   return libpam_h != NULL;
  37 }
  38
  39 void
  40 dlclose_pam (void)
  41 {
  42   if (libpam_h != NULL)
  43     {
  44       dlclose(libpam_h);
  45       libpam_h = NULL;
  46     }
  47 }
  48
  49 int pam_start(const char *service_name, const char *user,
  50               const struct pam_conv *pam_conversation,
  51               pam_handle_t **pamh)
  52 {
  53     int (*real_pam_start)(const char *, const char *,
  54                                  const struct pam_conv *,
  55                                  pam_handle_t **);
  56     RESOLVE_PAM_FUNCTION(pam_start, int, (const char *, const char *,
  57                                           const struct pam_conv *,
  58                                           pam_handle_t **), PAM_ABORT);
  59     return real_pam_start(service_name, user, pam_conversation, pamh);
  60 }
  61
  62 int pam_end(pam_handle_t *pamh, int pam_status)
  63 {
  64     int (*real_pam_end)(pam_handle_t *, int);
  65     RESOLVE_PAM_FUNCTION(pam_end, int, (pam_handle_t *, int), PAM_ABORT);
  66     return real_pam_end(pamh, pam_status);
  67 }
  68
  69 int pam_set_item(pam_handle_t *pamh, int item_type, const void *item)
  70 {
  71     int (*real_pam_set_item)(pam_handle_t *, int, const void *);
  72     RESOLVE_PAM_FUNCTION(pam_set_item, int,
  73                          (pam_handle_t *, int, const void *), PAM_ABORT);
  74     return real_pam_set_item(pamh, item_type, item);
  75 }
  76
  77 int pam_get_item(const pam_handle_t *pamh, int item_type, const void **item)
  78 {
  79     int (*real_pam_get_item)(const pam_handle_t *, int, const void **);
  80     RESOLVE_PAM_FUNCTION(pam_get_item, int,
  81                          (const pam_handle_t *, int, const void **),
  82                          PAM_ABORT);
  83     return real_pam_get_item(pamh, item_type, item);
  84 }
  85
  86 int pam_fail_delay(pam_handle_t *pamh, unsigned int musec_delay)
  87 {
  88     int (*real_pam_fail_delay)(pam_handle_t *, unsigned int);
  89     RESOLVE_PAM_FUNCTION(pam_fail_delay, int, (pam_handle_t *, unsigned int),
  90                          PAM_ABORT);
  91     return real_pam_fail_delay(pamh, musec_delay);
  92 }
  93
  94 typedef const char * const_char_pointer;
  95
  96 const_char_pointer pam_strerror(pam_handle_t *pamh, int errnum)
  97 {
  98     const_char_pointer (*real_pam_strerror)(pam_handle_t *, int);
  99     RESOLVE_PAM_FUNCTION(pam_strerror, const_char_pointer,
 100                          (pam_handle_t *, int), NULL);
 101     return real_pam_strerror(pamh, errnum);
 102 }
 103
 104 int pam_putenv(pam_handle_t *pamh, const char *name_value)
 105 {
 106     int (*real_pam_putenv)(pam_handle_t *, const char *);
 107     RESOLVE_PAM_FUNCTION(pam_putenv, int, (pam_handle_t *, const char *),
 108                          PAM_ABORT);
 109     return real_pam_putenv(pamh, name_value);
 110 }
 111
 112 const_char_pointer pam_getenv(pam_handle_t *pamh, const char *name)
 113 {
 114     const_char_pointer (*real_pam_getenv)(pam_handle_t *, const char *);
 115     RESOLVE_PAM_FUNCTION(pam_getenv, const_char_pointer,
 116                          (pam_handle_t *, const char *), NULL);
 117     return real_pam_getenv(pamh, name);
 118 }
 119
 120 typedef char ** char_ppointer;
 121 char_ppointer pam_getenvlist(pam_handle_t *pamh)
 122 {
 123     char_ppointer (*real_pam_getenvlist)(pam_handle_t *);
 124     RESOLVE_PAM_FUNCTION(pam_getenvlist, char_ppointer, (pam_handle_t *),
 125                          NULL);
 126     return real_pam_getenvlist(pamh);
 127 }
 128
 129 /* Authentication management */
 130
 131 int pam_authenticate(pam_handle_t *pamh, int flags)
 132 {
 133     int (*real_pam_authenticate)(pam_handle_t *, int);
 134     RESOLVE_PAM_FUNCTION(pam_authenticate, int, (pam_handle_t *, int),
 135                          PAM_ABORT);
 136     return real_pam_authenticate(pamh, flags);
 137 }
 138
 139 int pam_setcred(pam_handle_t *pamh, int flags)
 140 {
 141     int (*real_pam_setcred)(pam_handle_t *, int);
 142     RESOLVE_PAM_FUNCTION(pam_setcred, int, (pam_handle_t *, int), PAM_ABORT);
 143     return real_pam_setcred(pamh, flags);
 144 }
 145
 146 /* Account Management API's */
 147
 148 int pam_acct_mgmt(pam_handle_t *pamh, int flags)
 149 {
 150     int (*real_pam_acct_mgmt)(pam_handle_t *, int);
 151     RESOLVE_PAM_FUNCTION(pam_acct_mgmt, int, (pam_handle_t *, int), PAM_ABORT);
 152     return real_pam_acct_mgmt(pamh, flags);
 153 }
 154
 155 /* Session Management API's */
 156
 157 int pam_open_session(pam_handle_t *pamh, int flags)
 158 {
 159     int (*real_pam_open_session)(pam_handle_t *, int);
 160     RESOLVE_PAM_FUNCTION(pam_open_session, int, (pam_handle_t *, int),
 161                          PAM_ABORT);
 162     return real_pam_open_session(pamh, flags);
 163 }
 164
 165 int pam_close_session(pam_handle_t *pamh, int flags)
 166 {
 167     int (*real_pam_close_session)(pam_handle_t *, int);
 168     RESOLVE_PAM_FUNCTION(pam_close_session, int, (pam_handle_t *, int),
 169                          PAM_ABORT);
 170     return real_pam_close_session(pamh, flags);
 171 }
 172
 173 /* Password Management API's */
 174
 175 int pam_chauthtok(pam_handle_t *pamh, int flags)
 176 {
 177     int (*real_pam_chauthtok)(pam_handle_t *, int);
 178     RESOLVE_PAM_FUNCTION(pam_chauthtok, int, (pam_handle_t *, int), PAM_ABORT);
 179     return real_pam_chauthtok(pamh, flags);
 180 }
 181 #endif