1 /* $OpenBSD: getgrouplist.c,v 1.31 2024/11/04 21:49:26 jca Exp $ */ 2 /* 3 * Copyright (c) 2008 Ingo Schwarze <schwarze@usta.de> 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 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 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * get credential 34 */ 35 #include <sys/types.h> 36 #include <sys/limits.h> 37 #include <string.h> 38 #include <unistd.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <grp.h> 42 #include <pwd.h> 43 #include <errno.h> 44 45 #include <rpc/rpc.h> 46 #include <rpcsvc/yp.h> 47 #include <rpcsvc/ypclnt.h> 48 49 #ifdef YP 50 #define _PATH_NETID "/etc/netid" 51 #define MAXLINELENGTH 1024 52 53 static int _parse_netid(char*, uid_t, gid_t*, int*, int); 54 static int _read_netid(const char *, uid_t, gid_t*, int*, int); 55 56 /* 57 * Parse one string of the form "uid:gid[,gid[,...]]". 58 * If the uid matches, add the groups to the group list and return 1. 59 * If the uid does not match, return 0. 60 */ 61 static int 62 _parse_netid(char *netid, uid_t uid, gid_t *groups, int *ngroups, 63 int maxgroups) 64 { 65 const char *errstr = NULL; 66 char *start, *p; 67 uid_t tuid; 68 gid_t gid; 69 int i; 70 71 /* Check the uid. */ 72 p = strchr(netid, ':'); 73 if (!p) 74 return (0); 75 *p++ = '\0'; 76 tuid = (uid_t)strtonum(netid, 0, UID_MAX, &errstr); 77 if (errstr || tuid != uid) 78 return (0); 79 80 /* Loop over the gids. */ 81 while (p && *p) { 82 start = p; 83 p = strchr(start, ','); 84 if (p) 85 *p++ = '\0'; 86 gid = (gid_t)strtonum(start, 0, GID_MAX, &errstr); 87 if (errstr) 88 continue; 89 90 /* Skip this group if it is already in the list. */ 91 for (i = 0; i < maxgroups && i < *ngroups; i++) 92 if (groups[i] == gid) 93 break; 94 95 /* Try to add this new group to the list. */ 96 if (i == *ngroups) { 97 if (*ngroups >= maxgroups) 98 (*ngroups)++; 99 else 100 groups[(*ngroups)++] = gid; 101 } 102 } 103 return (1); 104 } 105 106 /* 107 * Search /etc/netid for a particular uid and process that line. 108 * See _parse_netid for details, including return values. 109 */ 110 static int 111 _read_netid(const char *key, uid_t uid, gid_t *groups, int *ngroups, 112 int maxgroups) 113 { 114 FILE *fp; 115 char line[MAXLINELENGTH], *p; 116 int found = 0; 117 118 fp = fopen(_PATH_NETID, "re"); 119 if (!fp) 120 return (0); 121 while (!found && fgets(line, sizeof(line), fp)) { 122 p = strchr(line, '\n'); 123 if (p) 124 *p = '\0'; 125 else { /* Skip lines that are too long. */ 126 int ch; 127 while ((ch = getc_unlocked(fp)) != '\n' && ch != EOF) 128 ; 129 continue; 130 } 131 p = strchr(line, ' '); 132 if (!p) 133 continue; 134 *p++ = '\0'; 135 if (strcmp(line, key)) 136 continue; 137 found = _parse_netid(p, uid, groups, ngroups, maxgroups); 138 } 139 (void)fclose(fp); 140 return (found); 141 } 142 #endif /* YP */ 143 144 int 145 getgrouplist(const char *uname, gid_t agroup, gid_t *groups, int *grpcnt) 146 { 147 int i, ngroups = 0, maxgroups = *grpcnt, bail; 148 int needyp = 0, foundyp = 0; 149 int *skipyp = &foundyp; 150 extern struct group *_getgrent_yp(int *); 151 struct group *grp; 152 153 /* 154 * install primary group 155 */ 156 if (ngroups >= maxgroups) 157 ngroups++; 158 else 159 groups[ngroups++] = agroup; 160 161 /* 162 * Scan the group file to find additional groups. 163 */ 164 setgrent(); 165 while ((grp = _getgrent_yp(skipyp)) || foundyp) { 166 if (foundyp) { 167 if (foundyp > 0) 168 needyp = 1; 169 else 170 skipyp = NULL; 171 foundyp = 0; 172 continue; 173 } 174 if (grp->gr_gid == agroup) 175 continue; 176 for (bail = 0, i = 0; bail == 0 && i < maxgroups && 177 i < ngroups; i++) { 178 if (groups[i] == grp->gr_gid) 179 bail = 1; 180 } 181 if (bail) 182 continue; 183 for (i = 0; grp->gr_mem[i]; i++) { 184 if (!strcmp(grp->gr_mem[i], uname)) { 185 if (ngroups >= maxgroups) 186 ngroups++; 187 else 188 groups[ngroups++] = grp->gr_gid; 189 break; 190 } 191 } 192 } 193 194 #ifdef YP 195 /* 196 * If we were told that there is a YP marker, look at netid data. 197 */ 198 if (skipyp && needyp) { 199 char buf[MAXLINELENGTH], *ypdata = NULL, *key; 200 static char *__ypdomain; 201 struct passwd pwstore; 202 int ypdatalen; 203 204 /* Construct the netid key to look up. */ 205 if (getpwnam_r(uname, &pwstore, buf, sizeof buf, NULL) || 206 (!__ypdomain && yp_get_default_domain(&__ypdomain))) 207 goto out; 208 i = asprintf(&key, "unix.%u@%s", pwstore.pw_uid, __ypdomain); 209 if (i == -1) 210 goto out; 211 212 /* First scan the static netid file. */ 213 if (_read_netid(key, pwstore.pw_uid, groups, &ngroups, 214 maxgroups)) { 215 free(key); 216 goto out; 217 } 218 219 /* Only access YP when there is no static entry. */ 220 if (!yp_match(__ypdomain, "netid.byname", key, 221 (int)strlen(key), &ypdata, &ypdatalen)) 222 _parse_netid(ypdata, pwstore.pw_uid, groups, &ngroups, 223 maxgroups); 224 225 free(key); 226 free(ypdata); 227 } 228 #endif /* YP */ 229 230 out: 231 endgrent(); 232 *grpcnt = ngroups; 233 return (ngroups > maxgroups ? -1 : 0); 234 } 235 DEF_WEAK(getgrouplist); 236