rsh: new program
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@1948 ec53bebd-3082-4978-b11e-865c3cabbd6b
This commit is contained in:
Assar Westerlund
473
appl/rsh/rsh.c
Normal file
473
appl/rsh/rsh.c
Normal file
@@ -0,0 +1,473 @@
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#include "rsh_locl.h"
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RCSID("$Id$");
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/*
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*
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*/
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enum auth_method { AUTH_KRB4, AUTH_KRB5 } auth_method;
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/*
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*
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*/
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/*
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* Encryption with krb5 should probably use des-cbc-crc
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*/
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#define RSH_BUFSIZ 10240
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static krb5_context context;
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static krb5_auth_context auth_context;
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static krb5_keyblock keyblock;
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static des_key_schedule schedule;
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static des_cblock iv;
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static int no_input, do_encrypt;
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static void
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usage (void)
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{
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errx (1, "Usage: %s [-45nx] [-l user] host command", __progname);
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}
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static ssize_t
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do_read (int fd,
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void *buf,
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size_t sz)
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{
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int ret;
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if (do_encrypt) {
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if (auth_method == AUTH_KRB4) {
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return des_enc_read (fd, buf, sz, schedule, &iv);
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} else if(auth_method == AUTH_KRB5) {
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u_int32_t len, outer_len;
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int status;
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krb5_data data;
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ret = krb5_net_read (context, fd, &len, 4);
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if (ret != 4)
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return ret;
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len = ntohl(len);
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outer_len = len + 12;
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outer_len = (outer_len + 7) & ~7;
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if (outer_len > sz)
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abort ();
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ret = krb5_net_read (context, fd, buf, outer_len);
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if (ret != outer_len)
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return ret;
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status = krb5_decrypt(context, buf, outer_len,
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&keyblock, &data);
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if (status != KSUCCESS)
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errx ("%s", krb5_get_err_text (context, status));
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memcpy (buf, data.data, len);
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free (data.data);
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return len;
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} else {
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abort ();
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}
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} else
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return read (fd, buf, sz);
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}
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static ssize_t
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do_write (int fd, void *buf, size_t sz)
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{
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int ret;
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if (do_encrypt) {
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if(auth_method == AUTH_KRB4) {
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return des_enc_write (fd, buf, sz, schedule, &iv);
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} else if(auth_method == AUTH_KRB5) {
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int status;
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krb5_data data;
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u_int32_t len;
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int ret;
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status = krb5_encrypt (context,
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buf,
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sz,
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&keyblock,
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&data);
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if (status != KSUCCESS)
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errx (1, "%s", krb5_get_err_text(context, status));
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len = htonl(sz);
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ret = krb5_net_write (context, fd, &len, 4);
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if (ret != 4)
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return ret;
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ret = krb5_net_write (context, fd, data.data, data.length);
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if (ret != data.length)
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return ret;
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free (data.data);
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return sz;
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} else {
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abort();
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}
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} else
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return write (fd, buf, sz);
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}
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static int
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loop (int s, int errsock)
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{
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struct fd_set real_readset;
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int count = 0;
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FD_ZERO(&real_readset);
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FD_SET(s, &real_readset);
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FD_SET(errsock, &real_readset);
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if(!no_input)
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FD_SET(STDIN_FILENO, &real_readset);
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for (;;) {
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int ret;
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struct fd_set readset;
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char buf[RSH_BUFSIZ];
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readset = real_readset;
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ret = select (max(s, errsock) + 1, &readset, NULL, NULL, NULL);
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if (ret < 0)
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if (errno == EINTR)
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continue;
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else
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err (1, "select");
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if (FD_ISSET(s, &readset)) {
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ret = do_read (s, buf, sizeof(buf));
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if (ret < 0)
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err (1, "read");
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else if (ret == 0) {
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close (s);
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FD_CLR(s, &real_readset);
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if (++count == 2)
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return 0;
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} else
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krb_net_write (STDOUT_FILENO, buf, ret);
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}
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if (FD_ISSET(errsock, &readset)) {
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ret = do_read (errsock, buf, sizeof(buf));
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if (ret < 0)
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err (1, "read");
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else if (ret == 0) {
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close (errsock);
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FD_CLR(errsock, &real_readset);
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if (++count == 2)
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return 0;
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} else
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krb_net_write (STDERR_FILENO, buf, ret);
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}
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if (FD_ISSET(STDIN_FILENO, &readset)) {
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ret = read (STDIN_FILENO, buf, sizeof(buf));
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if (ret < 0)
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err (1, "read");
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else if (ret == 0)
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return 0;
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else
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do_write (s, buf, ret);
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}
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}
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}
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static void
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send_krb4_auth(int s, struct sockaddr_in thisaddr,
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struct sockaddr_in thataddr,
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char *hostname,
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char *remote_user,
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char *local_user,
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size_t cmd_len,
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char *cmd)
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{
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KTEXT_ST text;
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CREDENTIALS cred;
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MSG_DAT msg;
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int status;
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size_t len;
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status = krb_sendauth (do_encrypt ? KOPT_DO_MUTUAL : 0,
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s, &text, "rcmd",
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hostname, krb_realmofhost (hostname),
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getpid(), &msg, &cred, schedule,
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&thisaddr, &thataddr, "KCMDV0.1");
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if (status != KSUCCESS)
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errx ("%s: %s", hostname, krb_get_err_text(status));
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memcpy (iv, cred.session, sizeof(iv));
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len = strlen(remote_user) + 1;
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if (krb_net_write (s, remote_user, len) != len)
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err (1, "write");
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if (krb_net_write (s, cmd, cmd_len) != cmd_len)
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err (1, "write");
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free (cmd);
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}
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static void
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send_krb5_auth(int s, struct sockaddr_in thisaddr,
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struct sockaddr_in thataddr,
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char *hostname,
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char *remote_user,
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char *local_user,
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size_t cmd_len,
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char *cmd)
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{
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krb5_principal server;
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krb5_data cksum_data;
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krb5_ccache ccache;
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des_cblock key;
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char *buf;
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int status;
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size_t len;
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krb5_init_context(&context);
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krb5_cc_default (context, &ccache);
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status = krb5_sname_to_principal(context,
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hostname,
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"host",
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KRB5_NT_SRV_INST,
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&server);
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if (status)
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errx ("%s: %s", hostname, krb5_get_err_text(context, status));
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len = 6 + 3 + cmd_len + strlen(local_user);
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buf = malloc (len);
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snprintf (buf, len, "%u:%s%s%s", ntohs(thataddr.sin_port),
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do_encrypt ? "-x " : "",
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cmd, local_user);
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cksum_data.data = buf;
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cksum_data.length = strlen (buf);
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status = krb5_sendauth (context,
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&auth_context,
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&s,
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"KCMDV0.1",
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NULL,
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server,
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do_encrypt ? AP_OPTS_MUTUAL_REQUIRED : 0,
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&cksum_data,
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NULL,
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ccache,
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NULL,
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NULL,
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NULL);
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if (status)
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errx ("%s: %s", hostname, krb5_get_err_text(context, status));
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free (buf);
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keyblock = auth_context->key;
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len = strlen(local_user) + 1;
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if (krb_net_write (s, local_user, len) != len)
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err (1, "write");
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if (do_encrypt && krb_net_write (s, "-x ", 3) != 3)
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err (1, "write");
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if (krb_net_write (s, cmd, cmd_len) != cmd_len)
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err (1, "write");
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free (cmd);
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len = strlen(remote_user) + 1;
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if (krb_net_write (s, remote_user, len) != len)
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err (1, "write");
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{
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/* Empty forwarding info */
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u_int32_t zero = 0;
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write (s, &zero, 4);
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}
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}
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static int
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proto (int s, char *hostname, char *local_user, char *remote_user,
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char *cmd, size_t cmd_len)
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{
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struct sockaddr_in erraddr;
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int errsock, errsock2;
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char buf[BUFSIZ];
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char *p;
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size_t len;
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char reply;
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struct sockaddr_in thisaddr, thataddr;
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int addrlen;
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int ret;
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addrlen = sizeof(thisaddr);
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if (getsockname (s, (struct sockaddr *)&thisaddr, &addrlen) < 0
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|| addrlen != sizeof(thisaddr)) {
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err (1, "getsockname(%s)", hostname);
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}
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addrlen = sizeof(thataddr);
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if (getpeername (s, (struct sockaddr *)&thataddr, &addrlen) < 0
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|| addrlen != sizeof(thataddr)) {
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err (1, "getpeername(%s)", hostname);
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}
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errsock = socket (AF_INET, SOCK_STREAM, 0);
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if (errsock < 0)
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err (1, "socket");
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memset (&erraddr, 0, sizeof(erraddr));
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erraddr.sin_family = AF_INET;
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erraddr.sin_addr.s_addr = INADDR_ANY;
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if (bind (errsock, (struct sockaddr *)&erraddr, sizeof(erraddr)) < 0)
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err (1, "bind");
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addrlen = sizeof(erraddr);
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if (getsockname (errsock, (struct sockaddr *)&erraddr, &addrlen) < 0)
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err (1, "getsockname");
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if (listen (errsock, 1) < 0)
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err (1, "listen");
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p = buf;
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snprintf (p, sizeof(buf), "%u", ntohs(erraddr.sin_port));
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len = strlen(buf) + 1;
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if(krb_net_write (s, buf, len) != len)
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err (1, "write");
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errsock2 = accept (errsock, NULL, NULL);
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if (errsock2 < 0)
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err (1, "accept");
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close (errsock);
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if (auth_method == AUTH_KRB4)
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send_krb4_auth (s, thisaddr, thataddr,
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hostname, remote_user, local_user,
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cmd_len, cmd);
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else if(auth_method == AUTH_KRB5)
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send_krb5_auth (s, thisaddr, thataddr,
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hostname, remote_user, local_user,
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cmd_len, cmd);
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else
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abort ();
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if (krb_net_read (s, &reply, 1) != 1)
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err (1, "read");
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if (reply != 0) {
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warnx ("Error from rshd at %s:", hostname);
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while ((ret = read (s, buf, sizeof(buf))) > 0)
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write (STDOUT_FILENO, buf, ret);
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return 1;
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}
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return loop (s, errsock2);
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}
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static size_t
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construct_command (char **res, int argc, char **argv)
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{
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int i;
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size_t len = 0;
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char *tmp;
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for (i = 0; i < argc; ++i)
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len += strlen(argv[i]) + 1;
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tmp = malloc (len);
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if (tmp == NULL)
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errx (1, "malloc %u failed", len);
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*tmp = '\0';
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for (i = 0; i < argc - 1; ++i) {
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strcat (tmp, argv[i]);
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strcat (tmp, " ");
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}
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strcat (tmp, argv[argc-1]);
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*res = tmp;
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return len;
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}
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static int
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doit (char *hostname, char *remote_user, int argc, char **argv)
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{
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struct hostent *hostent;
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struct in_addr **h;
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struct passwd *pwd;
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char *cmd;
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size_t cmd_len;
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int port;
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pwd = getpwuid (getuid());
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if (pwd == NULL)
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errx (1, "who are you?");
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cmd_len = construct_command(&cmd, argc, argv);
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if (do_encrypt)
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port = k_getportbyname ("ekshell", "tcp", htons(545));
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else
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port = k_getportbyname ("kshell", "tcp", htons(544));
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hostent = gethostbyname (hostname);
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if (hostent == NULL)
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errx (1, "gethostbyname '%s' failed: %s",
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hostname,
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hstrerror(h_errno));
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for (h = (struct in_addr **)hostent->h_addr_list;
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*h != NULL;
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++h) {
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struct sockaddr_in addr;
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int s;
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memset (&addr, 0, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = port;
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addr.sin_addr = **h;
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s = socket (AF_INET, SOCK_STREAM, 0);
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if (s < 0)
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err (1, "socket");
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if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
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warn ("connect(%s)", hostname);
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close (s);
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continue;
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}
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return proto (s, hostname, pwd->pw_name,
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remote_user ? remote_user : pwd->pw_name,
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cmd, cmd_len);
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}
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return 1;
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}
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/*
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* rsh host command
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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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int c;
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char *remote_user = NULL;
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set_progname (argv[0]);
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if (argc < 3)
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usage ();
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auth_method = AUTH_KRB5;
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while ((c = getopt(argc, argv, "45l:nx")) != EOF) {
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switch (c) {
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case '4':
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auth_method = AUTH_KRB4;
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break;
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case '5':
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auth_method = AUTH_KRB5;
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break;
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case 'l':
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remote_user = optarg;
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break;
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case 'n':
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no_input = 1;
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break;
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case 'x':
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do_encrypt = 1;
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break;
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default:
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usage ();
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break;
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}
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}
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return doit (argv[optind], remote_user,
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argc - optind - 1, argv + optind + 1);
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}
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