135 lines
3.2 KiB
C
135 lines
3.2 KiB
C
/* setgrp.c - by Michael Haardt. Set the gid if possible */
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/* Added a bit more error recovery/reporting - poe */
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/* Vesa Roukonen added code for asking password */
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/* Currently maintained at ftp://ftp.daimi.aau.dk/pub/linux/poe/ */
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/* 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
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* - added Native Language Support
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*/
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#include <unistd.h>
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#include <pwd.h>
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#include <grp.h>
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <errno.h>
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#ifdef HAVE_CRYPT_H
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#include <crypt.h>
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#endif
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#include "c.h"
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#include "pathnames.h"
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#include "nls.h"
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/* try to read password from gshadow */
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static char *
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get_gshadow_pwd(char *groupname)
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{
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char buf[BUFSIZ];
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char *pwd = NULL;
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FILE *f = fopen(_PATH_GSHADOW, "r");
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if (groupname == NULL || *groupname == '\0' || f == NULL)
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return NULL;
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while(fgets(buf, sizeof buf, f))
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{
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char *cp = strchr (buf, ':');
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if (!cp)
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continue; /* any junk in gshadow? */
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*cp = '\0';
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if (strcmp(buf, groupname) == 0)
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{
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if (cp-buf >= BUFSIZ)
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break; /* only group name on line */
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pwd = cp+1;
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if ((cp = strchr(pwd, ':')) && pwd == cp+1 )
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pwd = NULL; /* empty password */
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else if (cp)
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*cp = '\0';
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break;
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}
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}
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fclose(f);
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return pwd ? strdup(pwd) : NULL;
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}
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static int
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allow_setgid(struct passwd *pe, struct group *ge)
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{
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char **look;
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int notfound = 1;
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char *pwd, *xpwd;
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if (getuid() == 0) return TRUE; /* root may do anything */
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if (ge->gr_gid == pe->pw_gid) return TRUE; /* You can switch back to your default group */
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look = ge->gr_mem;
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while (*look && (notfound = strcmp(*look++,pe->pw_name)));
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if(!notfound) return TRUE; /* member of group => OK */
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/* Ask for password. Often there is no password in /etc/group, so
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contrary to login et al. we let an empty password mean the same
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as * in /etc/passwd */
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/* check /etc/gshadow */
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if (!(pwd = get_gshadow_pwd(ge->gr_name)))
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pwd = ge->gr_passwd;
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if(pwd && *pwd && (xpwd = getpass(_("Password: ")))) {
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if(strcmp(pwd, crypt(xpwd, pwd)) == 0)
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return TRUE; /* password accepted */
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}
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return FALSE; /* default to denial */
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}
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int
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main(int argc, char *argv[])
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{
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struct passwd *pw_entry;
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struct group *gr_entry;
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char *shell;
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setlocale(LC_ALL, "");
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bindtextdomain(PACKAGE, LOCALEDIR);
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textdomain(PACKAGE);
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if (!(pw_entry = getpwuid(getuid())))
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err(EXIT_FAILURE, _("who are you?"));
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shell = (pw_entry->pw_shell[0] ? pw_entry->pw_shell : _PATH_BSHELL);
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if (argc < 2) {
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if(setgid(pw_entry->pw_gid) < 0)
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err(EXIT_FAILURE, _("setgid failed"));
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} else {
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errno = 0;
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if (!(gr_entry = getgrnam(argv[1]))) {
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if (errno)
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err(EXIT_FAILURE, _("no such group"));
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else
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errx(EXIT_FAILURE, _("no such group")); /* No group */
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} else {
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if (allow_setgid(pw_entry, gr_entry)) {
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if (setgid(gr_entry->gr_gid) < 0)
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err(EXIT_FAILURE, _("setgid failed"));
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} else
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errx(EXIT_FAILURE, _("permission denied"));
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}
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}
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if (setuid(getuid()) < 0)
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err(EXIT_FAILURE, _("setuid failed"));
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fflush(stdout); fflush(stderr);
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execl(shell,shell,(char*)0);
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warn(_("exec %s failed"), shell);
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fflush(stderr);
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return EXIT_FAILURE;
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}
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