1 | /* |
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2 | * nonlocal-group.c |
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3 | * group database for nss_nonlocal proxy |
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4 | * |
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5 | * Copyright © 2007–2010 Anders Kaseorg <andersk@mit.edu> and Tim |
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6 | * Abbott <tabbott@mit.edu> |
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7 | * |
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8 | * This file is part of nss_nonlocal. |
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9 | * |
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10 | * nss_nonlocal is free software; you can redistribute it and/or |
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11 | * modify it under the terms of the GNU Lesser General Public License |
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12 | * as published by the Free Software Foundation; either version 2.1 of |
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13 | * the License, or (at your option) any later version. |
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14 | * |
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15 | * nss_nonlocal is distributed in the hope that it will be useful, but |
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16 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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18 | * Lesser General Public License for more details. |
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19 | * |
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20 | * You should have received a copy of the GNU Lesser General Public |
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21 | * License along with nss_nonlocal; if not, write to the Free Software |
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22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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23 | * 02110-1301 USA |
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24 | */ |
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25 | |
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26 | #define _GNU_SOURCE |
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27 | #include <sys/types.h> |
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28 | #include <unistd.h> |
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29 | #include <stdlib.h> |
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30 | #include <stdint.h> |
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31 | #include <string.h> |
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32 | #include <dlfcn.h> |
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33 | #include <stdio.h> |
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34 | #include <syslog.h> |
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35 | #include <errno.h> |
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36 | #include <pwd.h> |
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37 | #include <grp.h> |
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38 | #include <nss.h> |
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39 | #include "nsswitch-internal.h" |
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40 | #include "nonlocal.h" |
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41 | |
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42 | /* |
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43 | * If the MAGIC_NONLOCAL_GROUPNAME local group exists, then nonlocal |
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44 | * users will be automatically added to it. Furthermore, if a local |
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45 | * user is added to this group, then that user will inherit any |
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46 | * nonlocal gids from a nonlocal user of the same name, as |
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47 | * supplementary gids. |
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48 | */ |
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49 | #define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users" |
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50 | |
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51 | /* |
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52 | * If the MAGIC_LOCAL_GROUPNAME local group exists, then local users |
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53 | * will be automatically added to it. |
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54 | */ |
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55 | #define MAGIC_LOCAL_GROUPNAME "nss-local-users" |
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56 | |
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57 | /* |
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58 | * If the MAGIC_NONLOCAL_USERNAME local user is added to a local |
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59 | * group, then the local group will inherit the nonlocal membership of |
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60 | * a group of the same gid. |
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61 | */ |
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62 | #define MAGIC_NONLOCAL_USERNAME "nss-nonlocal-users" |
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63 | |
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64 | |
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65 | enum nss_status |
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66 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, |
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67 | char *buffer, size_t buflen, int *errnop); |
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68 | |
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69 | enum nss_status |
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70 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, |
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71 | char *buffer, size_t buflen, int *errnop); |
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72 | |
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73 | |
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74 | static service_user *__nss_group_nonlocal_database; |
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75 | |
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76 | static int |
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77 | internal_function |
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78 | __nss_group_nonlocal_lookup(service_user **ni, const char *fct_name, |
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79 | void **fctp) |
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80 | { |
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81 | if (__nss_group_nonlocal_database == NULL |
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82 | && __nss_database_lookup("group_nonlocal", NULL, NULL, |
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83 | &__nss_group_nonlocal_database) < 0) |
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84 | return -1; |
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85 | |
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86 | *ni = __nss_group_nonlocal_database; |
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87 | |
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88 | *fctp = __nss_lookup_function(*ni, fct_name); |
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89 | return 0; |
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90 | } |
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91 | |
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92 | |
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93 | enum nss_status |
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94 | check_nonlocal_gid(const char *user, const char *group, gid_t gid, int *errnop) |
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95 | { |
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96 | enum nss_status status; |
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97 | struct group gbuf; |
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98 | char *buf; |
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99 | size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); |
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100 | const struct walk_nss w = { |
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101 | .lookup = &__nss_group_lookup, .fct_name = "getgrgid_r", |
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102 | .status = &status, .errnop = errnop, .buf = &buf, .buflen = &buflen |
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103 | }; |
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104 | const __typeof__(&_nss_nonlocal_getgrgid_r) self = &_nss_nonlocal_getgrgid_r; |
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105 | #define args (gid, &gbuf, buf, buflen, errnop) |
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106 | #include "walk_nss.h" |
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107 | #undef args |
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108 | |
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109 | if (status == NSS_STATUS_TRYAGAIN) |
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110 | return status; |
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111 | else if (status != NSS_STATUS_SUCCESS) |
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112 | return NSS_STATUS_SUCCESS; |
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113 | |
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114 | if (group == NULL || strcmp(gbuf.gr_name, group) == 0) { |
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115 | char *const *mem; |
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116 | for (mem = gbuf.gr_mem; *mem != NULL; mem++) |
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117 | if (strcmp(*mem, MAGIC_NONLOCAL_USERNAME) == 0) { |
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118 | status = check_nonlocal_user(*mem, errnop); |
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119 | if (status == NSS_STATUS_TRYAGAIN) { |
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120 | free(buf); |
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121 | return status; |
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122 | } else if (status == NSS_STATUS_NOTFOUND) { |
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123 | free(buf); |
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124 | return NSS_STATUS_SUCCESS; |
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125 | } |
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126 | break; |
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127 | } |
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128 | } |
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129 | |
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130 | syslog(LOG_DEBUG, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); |
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131 | free(buf); |
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132 | return NSS_STATUS_NOTFOUND; |
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133 | } |
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134 | |
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135 | enum nss_status |
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136 | check_nonlocal_group(const char *user, struct group *grp, int *errnop) |
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137 | { |
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138 | enum nss_status status = NSS_STATUS_SUCCESS; |
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139 | int old_errno = errno; |
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140 | char *end; |
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141 | unsigned long gid; |
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142 | |
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143 | errno = 0; |
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144 | gid = strtoul(grp->gr_name, &end, 10); |
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145 | if (errno == 0 && *end == '\0' && (gid_t)gid == gid) { |
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146 | errno = old_errno; |
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147 | status = check_nonlocal_gid(user, grp->gr_name, gid, errnop); |
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148 | } else |
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149 | errno = old_errno; |
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150 | if (status != NSS_STATUS_SUCCESS) |
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151 | return status; |
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152 | |
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153 | return check_nonlocal_gid(user, grp->gr_name, grp->gr_gid, errnop); |
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154 | } |
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155 | |
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156 | enum nss_status |
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157 | get_local_group(const char *name, struct group *grp, char **buffer, int *errnop) |
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158 | { |
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159 | enum nss_status status; |
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160 | size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX); |
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161 | const struct walk_nss w = { |
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162 | .lookup = &__nss_group_lookup, .fct_name = "getgrnam_r", |
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163 | .status = &status, .errnop = errnop, .buf = buffer, .buflen = &buflen |
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164 | }; |
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165 | const __typeof__(&_nss_nonlocal_getgrnam_r) self = &_nss_nonlocal_getgrnam_r; |
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166 | #define args (name, grp, *buffer, buflen, errnop) |
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167 | #include "walk_nss.h" |
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168 | #undef args |
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169 | return status; |
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170 | } |
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171 | |
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172 | static service_user *grent_startp, *grent_nip; |
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173 | static void *grent_fct_start; |
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174 | static union { |
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175 | enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, |
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176 | int *errnop); |
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177 | void *ptr; |
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178 | } grent_fct; |
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179 | static const char *grent_fct_name = "getgrent_r"; |
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180 | |
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181 | enum nss_status |
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182 | _nss_nonlocal_setgrent(int stayopen) |
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183 | { |
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184 | enum nss_status status; |
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185 | const struct walk_nss w = { |
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186 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "setgrent", |
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187 | .status = &status |
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188 | }; |
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189 | const __typeof__(&_nss_nonlocal_setgrent) self = NULL; |
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190 | #define args (stayopen) |
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191 | #include "walk_nss.h" |
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192 | #undef args |
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193 | if (status != NSS_STATUS_SUCCESS) |
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194 | return status; |
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195 | |
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196 | if (grent_fct_start == NULL) |
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197 | __nss_group_nonlocal_lookup(&grent_startp, grent_fct_name, |
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198 | &grent_fct_start); |
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199 | grent_nip = grent_startp; |
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200 | grent_fct.ptr = grent_fct_start; |
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201 | return NSS_STATUS_SUCCESS; |
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202 | } |
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203 | |
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204 | enum nss_status |
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205 | _nss_nonlocal_endgrent(void) |
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206 | { |
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207 | enum nss_status status; |
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208 | const struct walk_nss w = { |
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209 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "endgrent", |
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210 | .status = &status |
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211 | }; |
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212 | const __typeof__(&_nss_nonlocal_endgrent) self = NULL; |
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213 | |
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214 | grent_nip = NULL; |
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215 | |
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216 | #define args () |
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217 | #include "walk_nss.h" |
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218 | #undef args |
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219 | return status; |
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220 | } |
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221 | |
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222 | enum nss_status |
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223 | _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, |
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224 | int *errnop) |
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225 | { |
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226 | enum nss_status status; |
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227 | |
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228 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); |
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229 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') |
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230 | return NSS_STATUS_UNAVAIL; |
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231 | |
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232 | if (grent_nip == NULL) { |
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233 | status = _nss_nonlocal_setgrent(0); |
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234 | if (status != NSS_STATUS_SUCCESS) |
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235 | return status; |
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236 | } |
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237 | do { |
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238 | if (grent_fct.ptr == NULL) |
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239 | status = NSS_STATUS_UNAVAIL; |
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240 | else { |
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241 | int nonlocal_errno; |
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242 | do |
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243 | status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); |
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244 | while (status == NSS_STATUS_SUCCESS && |
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245 | check_nonlocal_group("(unknown)", grp, &nonlocal_errno) != NSS_STATUS_SUCCESS); |
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246 | } |
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247 | if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) |
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248 | return status; |
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249 | |
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250 | if (status == NSS_STATUS_SUCCESS) |
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251 | return NSS_STATUS_SUCCESS; |
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252 | } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); |
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253 | |
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254 | grent_nip = NULL; |
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255 | return NSS_STATUS_NOTFOUND; |
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256 | } |
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257 | |
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258 | |
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259 | enum nss_status |
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260 | _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, |
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261 | char *buffer, size_t buflen, int *errnop) |
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262 | { |
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263 | enum nss_status status; |
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264 | const struct walk_nss w = { |
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265 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrnam_r", |
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266 | .status = &status, .errnop = errnop |
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267 | }; |
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268 | const __typeof__(&_nss_nonlocal_getgrnam_r) self = NULL; |
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269 | |
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270 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); |
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271 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') |
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272 | return NSS_STATUS_UNAVAIL; |
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273 | |
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274 | #define args (name, grp, buffer, buflen, errnop) |
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275 | #include "walk_nss.h" |
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276 | #undef args |
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277 | if (status != NSS_STATUS_SUCCESS) |
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278 | return status; |
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279 | |
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280 | if (strcmp(name, grp->gr_name) != 0) { |
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281 | syslog(LOG_ERR, "nss_nonlocal: discarding group %s from lookup for group %s\n", grp->gr_name, name); |
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282 | return NSS_STATUS_NOTFOUND; |
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283 | } |
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284 | |
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285 | return check_nonlocal_group(name, grp, errnop); |
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286 | } |
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287 | |
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288 | enum nss_status |
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289 | _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, |
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290 | char *buffer, size_t buflen, int *errnop) |
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291 | { |
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292 | enum nss_status status; |
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293 | const struct walk_nss w = { |
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294 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "getgrgid_r", |
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295 | .status = &status, .errnop = errnop |
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296 | }; |
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297 | const __typeof__(&_nss_nonlocal_getgrgid_r) self = NULL; |
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298 | |
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299 | char *nonlocal_ignore = getenv(NONLOCAL_IGNORE_ENV); |
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300 | if (nonlocal_ignore != NULL && nonlocal_ignore[0] != '\0') |
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301 | return NSS_STATUS_UNAVAIL; |
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302 | |
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303 | #define args (gid, grp, buffer, buflen, errnop) |
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304 | #include "walk_nss.h" |
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305 | #undef args |
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306 | if (status != NSS_STATUS_SUCCESS) |
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307 | return status; |
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308 | |
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309 | if (gid != grp->gr_gid) { |
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310 | syslog(LOG_ERR, "nss_nonlocal: discarding gid %d from lookup for gid %d\n", grp->gr_gid, gid); |
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311 | return NSS_STATUS_NOTFOUND; |
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312 | } |
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313 | |
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314 | return check_nonlocal_group(grp->gr_name, grp, errnop); |
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315 | } |
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316 | |
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317 | static bool |
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318 | add_group(gid_t group, long int *start, long int *size, gid_t **groupsp, |
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319 | long int limit, int *errnop, enum nss_status *status) |
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320 | { |
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321 | int i, old_errno = errno; |
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322 | for (i = 0; i < *start; ++i) |
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323 | if ((*groupsp)[i] == group) |
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324 | return true; |
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325 | if (*start + 1 > *size) { |
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326 | gid_t *newgroups; |
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327 | long int newsize = 2 * *size; |
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328 | if (limit > 0) { |
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329 | if (*size >= limit) { |
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330 | *status = NSS_STATUS_SUCCESS; |
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331 | return false; |
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332 | } |
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333 | if (newsize > limit) |
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334 | newsize = limit; |
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335 | } |
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336 | newgroups = realloc(*groupsp, newsize * sizeof((*groupsp)[0])); |
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337 | errno = old_errno; |
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338 | if (newgroups == NULL) { |
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339 | *errnop = ENOMEM; |
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340 | *status = NSS_STATUS_TRYAGAIN; |
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341 | return false; |
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342 | } |
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343 | *groupsp = newgroups; |
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344 | *size = newsize; |
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345 | } |
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346 | (*groupsp)[(*start)++] = group; |
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347 | return true; |
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348 | } |
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349 | |
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350 | enum nss_status |
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351 | _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, |
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352 | long int *size, gid_t **groupsp, long int limit, |
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353 | int *errnop) |
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354 | { |
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355 | enum nss_status status; |
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356 | const struct walk_nss w = { |
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357 | .lookup = &__nss_group_nonlocal_lookup, .fct_name = "initgroups_dyn", |
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358 | .status = &status, .errnop = errnop |
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359 | }; |
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360 | const __typeof__(&_nss_nonlocal_initgroups_dyn) self = NULL; |
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361 | |
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362 | struct group local_users_group, nonlocal_users_group; |
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363 | bool is_nonlocal = true; |
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364 | char *buffer; |
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365 | int in, out, i; |
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366 | |
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367 | /* Check that the user is a nonlocal user, or a member of the |
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368 | * MAGIC_NONLOCAL_GROUPNAME group, before adding any groups. */ |
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369 | status = check_nonlocal_user(user, errnop); |
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370 | if (status == NSS_STATUS_TRYAGAIN) { |
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371 | return status; |
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372 | } else if (status != NSS_STATUS_SUCCESS) { |
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373 | is_nonlocal = false; |
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374 | |
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375 | status = get_local_group(MAGIC_LOCAL_GROUPNAME, |
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376 | &local_users_group, &buffer, errnop); |
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377 | if (status == NSS_STATUS_SUCCESS) { |
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378 | free(buffer); |
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379 | if (!add_group(local_users_group.gr_gid, start, size, groupsp, |
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380 | limit, errnop, &status)) |
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381 | return status; |
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382 | } else if (status == NSS_STATUS_TRYAGAIN) { |
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383 | return status; |
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384 | } else { |
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385 | syslog(LOG_WARNING, |
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386 | "nss_nonlocal: Group %s does not exist locally!", |
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387 | MAGIC_LOCAL_GROUPNAME); |
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388 | } |
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389 | } |
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390 | |
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391 | status = get_local_group(MAGIC_NONLOCAL_GROUPNAME, |
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392 | &nonlocal_users_group, &buffer, errnop); |
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393 | if (status == NSS_STATUS_SUCCESS) { |
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394 | free(buffer); |
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395 | if (is_nonlocal) { |
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396 | if (!add_group(nonlocal_users_group.gr_gid, start, size, groupsp, |
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397 | limit, errnop, &status)) |
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398 | return status; |
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399 | } else { |
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400 | int i; |
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401 | for (i = 0; i < *start; ++i) { |
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402 | if ((*groupsp)[i] == nonlocal_users_group.gr_gid) { |
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403 | is_nonlocal = true; |
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404 | break; |
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405 | } |
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406 | } |
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407 | |
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408 | if (is_nonlocal) { |
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409 | struct passwd pwbuf; |
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410 | char *buf; |
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411 | int nonlocal_errno = *errnop; |
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412 | status = get_nonlocal_passwd(user, &pwbuf, &buf, errnop); |
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413 | |
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414 | if (status == NSS_STATUS_SUCCESS) { |
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415 | nonlocal_errno = *errnop; |
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416 | status = check_nonlocal_gid(user, NULL, pwbuf.pw_gid, |
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417 | &nonlocal_errno); |
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418 | free(buf); |
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419 | } |
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420 | |
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421 | if (status == NSS_STATUS_SUCCESS) { |
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422 | if (!add_group(pwbuf.pw_gid, start, size, groupsp, limit, |
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423 | errnop, &status)) |
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424 | return status; |
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425 | } else if (status == NSS_STATUS_TRYAGAIN) { |
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426 | *errnop = nonlocal_errno; |
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427 | return status; |
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428 | } |
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429 | } |
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430 | } |
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431 | } else if (status == NSS_STATUS_TRYAGAIN) { |
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432 | if (is_nonlocal) |
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433 | return status; |
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434 | } else { |
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435 | syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", |
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436 | MAGIC_NONLOCAL_GROUPNAME); |
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437 | } |
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438 | |
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439 | if (!is_nonlocal) |
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440 | return NSS_STATUS_SUCCESS; |
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441 | |
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442 | in = out = *start; |
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443 | |
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444 | #define args (user, group, start, size, groupsp, limit, errnop) |
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445 | #include "walk_nss.h" |
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446 | #undef args |
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447 | if (status != NSS_STATUS_SUCCESS) |
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448 | return status; |
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449 | |
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450 | for (; in < *start; ++in) { |
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451 | int nonlocal_errno = *errnop; |
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452 | |
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453 | for (i = 0; i < out; ++i) |
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454 | if ((*groupsp)[i] == (*groupsp)[in]) |
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455 | break; |
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456 | if (i < out) |
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457 | continue; |
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458 | |
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459 | status = check_nonlocal_gid(user, NULL, (*groupsp)[in], |
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460 | &nonlocal_errno); |
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461 | if (status == NSS_STATUS_SUCCESS) { |
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462 | (*groupsp)[out++] = (*groupsp)[in]; |
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463 | } else if (status == NSS_STATUS_TRYAGAIN) { |
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464 | *start = out; |
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465 | *errnop = nonlocal_errno; |
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466 | return status; |
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467 | } |
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468 | } |
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469 | |
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470 | *start = out; |
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471 | return NSS_STATUS_SUCCESS; |
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472 | } |
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