From: fredrik Date: Sun, 26 Nov 2006 05:25:03 +0000 (+0000) Subject: Initial check-in. X-Git-Url: http://git.dolda2000.com/gitweb/?a=commitdiff_plain;h=efb71cce9b77ec188987c80e7456d5f874737ab7;p=utils.git Initial check-in. git-svn-id: svn+ssh://svn.dolda2000.com/srv/svn/repos/src/utils@773 959494ce-11ee-0310-bf91-de5d638817bd --- diff --git a/userinit2.c b/userinit2.c new file mode 100644 index 0000000..c27d548 --- /dev/null +++ b/userinit2.c @@ -0,0 +1,257 @@ +/* + * userinit2 - Launch programs as user during boot (Kerberized v2) + * Copyright (C) 2006 Fredrik Tolf (fredrik@dolda2000.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +*/ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +krb5_context ctx; +static int credsfwd; +static int credsrnw; + +static int parsetime(char *ts) +{ + char *p; + int unit; + + p = ts + strlen(ts) - 1; + unit = 1; + if(*p == 'm') + unit = 60; + else if(*p == 'h') + unit = 3600; + else if(*p == 'd') + unit = 86400; + return(atoi(ts) * unit); +} + +static void getcreds(struct passwd *pw, krb5_keytab kt, krb5_principal prn) +{ + int ret, fd; + krb5_get_init_creds_opt o; + krb5_creds c; + krb5_ccache cc; + char buf[1024], *ccnm, *fnm; + + krb5_get_init_creds_opt_init(&o); + krb5_get_init_creds_opt_set_forwardable(&o, credsfwd); + krb5_get_init_creds_opt_set_renew_life(&o, credsrnw); + if((ret = krb5_get_init_creds_keytab(ctx, &c, prn, kt, 0, NULL, &o)) != 0) { + fprintf(stderr, "userinit2: could not get krb credentials: %s\n", error_message(ret)); + exit(1); + } + ccnm = buf + sprintf(buf, "KRB5CCNAME="); + fnm = ccnm + sprintf(ccnm, "FILE:"); + sprintf(fnm, "/tmp/krb5cc_ui_%i_XXXXXX", pw->pw_uid); + if((fd = mkstemp(fnm)) < 0) { + fprintf(stderr, "userinit2: could not ccache file: %s", strerror(errno)); + exit(1); + } + close(fd); + if((ret = krb5_cc_resolve(ctx, ccnm, &cc)) != 0) { + fprintf(stderr, "userinit2: could not resolve ccache %s: %s", ccnm, error_message(ret)); + unlink(fnm); + exit(1); + } + if((ret = krb5_cc_initialize(ctx, cc, prn)) != 0) { + fprintf(stderr, "userinit2: could not initialize ccache: %s", error_message(ret)); + unlink(fnm); + exit(1); + } + if((ret = krb5_cc_store_cred(ctx, cc, &c)) != 0) { + fprintf(stderr, "userinit2: could not store TGT: %s", error_message(ret)); + unlink(fnm); + exit(1); + } + putenv(strdup(buf)); + krb5_cc_close(ctx, cc); + krb5_free_cred_contents(ctx, &c); + if(chown(fnm, pw->pw_uid, pw->pw_gid)) { + fprintf(stderr, "userinit2: could not chown ccache file: %s", strerror(errno)); + unlink(fnm); + exit(1); + } +} + +static void dologin(struct passwd *pw) +{ + char ebuf[1024]; + + if(chdir(pw->pw_dir)) { + fprintf(stderr, "userinit2: could not chdir to home directory %s: %s\n", pw->pw_dir, strerror(errno)); + exit(1); + } + if(snprintf(ebuf, sizeof(ebuf), "HOME=%s", pw->pw_dir) < sizeof(ebuf)) + putenv(strdup(ebuf)); + if(snprintf(ebuf, sizeof(ebuf), "SHELL=%s", pw->pw_shell) < sizeof(ebuf)) + putenv(strdup(ebuf)); + if(snprintf(ebuf, sizeof(ebuf), "USER=%s", pw->pw_name) < sizeof(ebuf)) + putenv(strdup(ebuf)); + if(snprintf(ebuf, sizeof(ebuf), "LOGNAME=%s", pw->pw_name) < sizeof(ebuf)) + putenv(strdup(ebuf)); + if(snprintf(ebuf, sizeof(ebuf), "PATH=%s/bin:/usr/local/bin:/bin:/usr/bin", pw->pw_dir) < sizeof(ebuf)) + putenv(strdup(ebuf)); +} + +static void dodir(void) +{ + DIR *dir; + struct dirent *de; + struct stat sb; + + if((dir = opendir(".")) == NULL) { + fprintf(stderr, "userinit2: couldn't open cwd (%s)!\n", strerror(errno)); + exit(1); + } + while((de = readdir(dir)) != NULL) { + if(de->d_name[0] == '.') + continue; + if(access(de->d_name, X_OK)) + continue; + if(stat(de->d_name, &sb)) + continue; + if(!S_ISREG(sb.st_mode)) + continue; + if(!fork()) { + setpgrp(); + execl(de->d_name, de->d_name, NULL); + exit(127); + } + } + closedir(dir); +} + +static void runstuff(struct passwd *pw) +{ + int i, fd1, fd2; + char buf[1024]; + + if(chdir(".userinit")) + return; + for(i = 3; i < FD_SETSIZE; i++) + close(i); + if((fd1 = open("/dev/null", O_RDWR)) < 0) { + fprintf(stderr, "userinit2: /dev/null: %s\n", strerror(errno)); + exit(1); + } + if((fd2 = open("stderr", O_WRONLY | O_CREAT | O_APPEND, 0666)) < 0) { + fprintf(stderr, "userinit2: stderr: %s\n", strerror(errno)); + exit(1); + } + dup2(fd1, 0); + dup2(fd1, 1); + dup2(fd2, 2); + close(fd1); + close(fd2); + setsid(); + dodir(); + if(gethostname(buf, sizeof(buf))) + return; + if(chdir(buf)) + return; + dodir(); +} + +int main(int argc, char **argv) +{ + int ret, c; + krb5_keytab kt; + krb5_kt_cursor ktc; + krb5_keytab_entry kte; + struct passwd *pw; + + while((c = getopt(argc, argv, "hfr:")) >= 0) { + switch(c) { + case 'f': + credsfwd = 1; + break; + case 'r': + credsrnw = parsetime(optarg); + break; + default: + fprintf(stderr, "usage: userinit2 [-hf] [-r renewlife]\n"); + exit((c == 'h')?0:1); + } + } + if((ret = krb5_init_context(&ctx)) != 0) { + fprintf(stderr, "userinit2: could not get krb context: %s\n", error_message(ret)); + exit(1); + } + if((ret = krb5_kt_default(ctx, &kt)) != 0) { + fprintf(stderr, "userinit2: could not get keytab: %s\n", error_message(ret)); + exit(1); + } + if((ret = krb5_kt_start_seq_get(ctx, kt, &ktc)) != 0) { + fprintf(stderr, "userinit2: could not iterate keytab: %s\n", error_message(ret)); + exit(1); + } + while(krb5_kt_next_entry(ctx, kt, &kte, &ktc) == 0) { + do { + if((kte.principal->length >= 2) && !strcmp(kte.principal->data[1].data, "userinit")) { + if((pw = getpwnam(kte.principal->data[0].data)) == NULL) + break; + if(!(ret = fork())) { + getcreds(pw, kt, kte.principal); + if(getuid() == 0) { + if(initgroups(pw->pw_name, pw->pw_gid)) { + fprintf(stderr, "userinit2: initgroups: %s\n", strerror(errno)); + exit(1); + } + if(setgid(pw->pw_gid)) { + fprintf(stderr, "userinit2: setgid: %s\n", strerror(errno)); + exit(1); + } + if(setuid(pw->pw_uid)) { + fprintf(stderr, "userinit2: setuid: %s\n", strerror(errno)); + exit(1); + } + } else { + if(pw->pw_uid != getuid()) + break; + } + dologin(pw); + runstuff(pw); + exit(0); + } + if(ret < 0) { + fprintf(stderr, "userinit2: fork: %s\n", strerror(errno)); + exit(1); + } + } + } while(0); + krb5_free_keytab_entry_contents(ctx, &kte); + } + krb5_kt_end_seq_get(ctx, kt, &ktc); + krb5_kt_close(ctx, kt); + return(0); +} + +/* + * Local Variables: + * compile-command: "gcc -Wall -g -o userinit2 userinit2.c -lkrb5" + * End: + */