+/* $OpenBSD: auth-rhosts.c,v 1.43 2008/06/13 14:18:51 dtucker Exp $ */
/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * Rhosts authentication. This file contains code to check whether to admit
+ * the login based on rhosts authentication. This file also processes
+ * /etc/hosts.equiv.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose. Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ */
-auth-rhosts.c
-
-Author: Tatu Ylonen <ylo@cs.hut.fi>
-
-Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- All rights reserved
-
-Created: Fri Mar 17 05:12:18 1995 ylo
-
-Rhosts authentication. This file contains code to check whether to admit
-the login based on rhosts authentication. This file also processes
-/etc/hosts.equiv.
+#include "includes.h"
-*/
+#include <sys/types.h>
+#include <sys/stat.h>
-#include "includes.h"
-RCSID("$Id$");
+#ifdef HAVE_NETGROUP_H
+# include <netgroup.h>
+#endif
+#include <pwd.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdarg.h>
+#include <fcntl.h>
+#include <unistd.h>
#include "packet.h"
-#include "ssh.h"
-#include "xmalloc.h"
+#include "buffer.h"
#include "uidswap.h"
+#include "pathnames.h"
+#include "log.h"
+#include "servconf.h"
+#include "canohost.h"
+#include "key.h"
+#include "hostfile.h"
+#include "auth.h"
+#include "misc.h"
+
+/* import */
+extern ServerOptions options;
+extern int use_privsep;
-/* This function processes an rhosts-style file (.rhosts, .shosts, or
- /etc/hosts.equiv). This returns true if authentication can be granted
- based on the file, and returns zero otherwise. */
-
-int check_rhosts_file(const char *filename, const char *hostname,
- const char *ipaddr, const char *client_user,
- const char *server_user)
+/*
+ * This function processes an rhosts-style file (.rhosts, .shosts, or
+ * /etc/hosts.equiv). This returns true if authentication can be granted
+ * based on the file, and returns zero otherwise.
+ */
+
+static int
+check_rhosts_file(const char *filename, const char *hostname,
+ const char *ipaddr, const char *client_user,
+ const char *server_user)
{
- FILE *f;
- char buf[1024]; /* Must not be larger than host, user, dummy below. */
-
- /* Open the .rhosts file. */
- f = fopen(filename, "r");
- if (!f)
- return 0; /* Cannot read the .rhosts - deny access. */
-
- /* Go through the file, checking every entry. */
- while (fgets(buf, sizeof(buf), f))
- {
- /* All three must be at least as big as buf to avoid overflows. */
- char hostbuf[1024], userbuf[1024], dummy[1024], *host, *user, *cp;
- int negated;
-
- for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
- ;
- if (*cp == '#' || *cp == '\n' || !*cp)
- continue;
-
- /* NO_PLUS is supported at least on OSF/1. We skip it (we don't ever
- support the plus syntax). */
- if (strncmp(cp, "NO_PLUS", 7) == 0)
- continue;
-
- /* This should be safe because each buffer is as big as the whole
- string, and thus cannot be overwritten. */
- switch (sscanf(buf, "%s %s %s", hostbuf, userbuf, dummy))
- {
- case 0:
- packet_send_debug("Found empty line in %.100s.", filename);
- continue; /* Empty line? */
- case 1:
- /* Host name only. */
- strlcpy(userbuf, server_user, sizeof(userbuf));
- break;
- case 2:
- /* Got both host and user name. */
- break;
- case 3:
- packet_send_debug("Found garbage in %.100s.", filename);
- continue; /* Extra garbage */
- default:
- continue; /* Weird... */
+ FILE *f;
+ char buf[1024]; /* Must not be larger than host, user, dummy below. */
+ int fd;
+ struct stat st;
+
+ /* Open the .rhosts file, deny if unreadable */
+ if ((fd = open(filename, O_RDONLY|O_NONBLOCK)) == -1)
+ return 0;
+ if (fstat(fd, &st) == -1) {
+ close(fd);
+ return 0;
}
-
- host = hostbuf;
- user = userbuf;
- negated = 0;
-
- /* Process negated host names, or positive netgroups. */
- if (host[0] == '-')
- {
- negated = 1;
- host++;
+ if (!S_ISREG(st.st_mode)) {
+ logit("User %s hosts file %s is not a regular file",
+ server_user, filename);
+ close(fd);
+ return 0;
}
- else
- if (host[0] == '+')
- host++;
-
- if (user[0] == '-')
- {
- negated = 1;
- user++;
+ unset_nonblock(fd);
+ if ((f = fdopen(fd, "r")) == NULL) {
+ close(fd);
+ return 0;
}
- else
- if (user[0] == '+')
- user++;
-
- /* Check for empty host/user names (particularly '+'). */
- if (!host[0] || !user[0])
- {
- /* We come here if either was '+' or '-'. */
- packet_send_debug("Ignoring wild host/user names in %.100s.",
+ while (fgets(buf, sizeof(buf), f)) {
+ /* All three must be at least as big as buf to avoid overflows. */
+ char hostbuf[1024], userbuf[1024], dummy[1024], *host, *user, *cp;
+ int negated;
+
+ for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
+ ;
+ if (*cp == '#' || *cp == '\n' || !*cp)
+ continue;
+
+ /*
+ * NO_PLUS is supported at least on OSF/1. We skip it (we
+ * don't ever support the plus syntax).
+ */
+ if (strncmp(cp, "NO_PLUS", 7) == 0)
+ continue;
+
+ /*
+ * This should be safe because each buffer is as big as the
+ * whole string, and thus cannot be overwritten.
+ */
+ switch (sscanf(buf, "%1023s %1023s %1023s", hostbuf, userbuf,
+ dummy)) {
+ case 0:
+ auth_debug_add("Found empty line in %.100s.", filename);
+ continue;
+ case 1:
+ /* Host name only. */
+ strlcpy(userbuf, server_user, sizeof(userbuf));
+ break;
+ case 2:
+ /* Got both host and user name. */
+ break;
+ case 3:
+ auth_debug_add("Found garbage in %.100s.", filename);
+ continue;
+ default:
+ /* Weird... */
+ continue;
+ }
+
+ host = hostbuf;
+ user = userbuf;
+ negated = 0;
+
+ /* Process negated host names, or positive netgroups. */
+ if (host[0] == '-') {
+ negated = 1;
+ host++;
+ } else if (host[0] == '+')
+ host++;
+
+ if (user[0] == '-') {
+ negated = 1;
+ user++;
+ } else if (user[0] == '+')
+ user++;
+
+ /* Check for empty host/user names (particularly '+'). */
+ if (!host[0] || !user[0]) {
+ /* We come here if either was '+' or '-'. */
+ auth_debug_add("Ignoring wild host/user names in %.100s.",
filename);
- continue;
- }
-
- /* Verify that host name matches. */
- if (host[0] == '@')
- {
- if (!innetgr(host + 1, hostname, NULL, NULL) &&
- !innetgr(host + 1, ipaddr, NULL, NULL))
- continue;
- }
- else
- if (strcasecmp(host, hostname) && strcmp(host, ipaddr) != 0)
- continue; /* Different hostname. */
-
- /* Verify that user name matches. */
- if (user[0] == '@')
- {
- if (!innetgr(user + 1, NULL, client_user, NULL))
- continue;
- }
- else
- if (strcmp(user, client_user) != 0)
- continue; /* Different username. */
-
- /* Found the user and host. */
- fclose(f);
-
- /* If the entry was negated, deny access. */
- if (negated)
- {
- packet_send_debug("Matched negative entry in %.100s.",
+ continue;
+ }
+ /* Verify that host name matches. */
+ if (host[0] == '@') {
+ if (!innetgr(host + 1, hostname, NULL, NULL) &&
+ !innetgr(host + 1, ipaddr, NULL, NULL))
+ continue;
+ } else if (strcasecmp(host, hostname) && strcmp(host, ipaddr) != 0)
+ continue; /* Different hostname. */
+
+ /* Verify that user name matches. */
+ if (user[0] == '@') {
+ if (!innetgr(user + 1, NULL, client_user, NULL))
+ continue;
+ } else if (strcmp(user, client_user) != 0)
+ continue; /* Different username. */
+
+ /* Found the user and host. */
+ fclose(f);
+
+ /* If the entry was negated, deny access. */
+ if (negated) {
+ auth_debug_add("Matched negative entry in %.100s.",
filename);
- return 0;
+ return 0;
+ }
+ /* Accept authentication. */
+ return 1;
}
- /* Accept authentication. */
- return 1;
- }
-
- /* Authentication using this file denied. */
- fclose(f);
- return 0;
+ /* Authentication using this file denied. */
+ fclose(f);
+ return 0;
}
-/* Tries to authenticate the user using the .shosts or .rhosts file.
- Returns true if authentication succeeds. If ignore_rhosts is
- true, only /etc/hosts.equiv will be considered (.rhosts and .shosts
- are ignored). */
+/*
+ * Tries to authenticate the user using the .shosts or .rhosts file. Returns
+ * true if authentication succeeds. If ignore_rhosts is true, only
+ * /etc/hosts.equiv will be considered (.rhosts and .shosts are ignored).
+ */
-int auth_rhosts(struct passwd *pw, const char *client_user,
- int ignore_rhosts, int strict_modes)
+int
+auth_rhosts(struct passwd *pw, const char *client_user)
{
- char buf[1024];
- const char *hostname, *ipaddr;
- int port;
- struct stat st;
- static const char *rhosts_files[] = { ".shosts", ".rhosts", NULL };
- unsigned int rhosts_file_index;
-
- /* Quick check: if the user has no .shosts or .rhosts files, return failure
- immediately without doing costly lookups from name servers. */
- /* Switch to the user's uid. */
- temporarily_use_uid(pw->pw_uid);
- for (rhosts_file_index = 0; rhosts_files[rhosts_file_index];
- rhosts_file_index++)
- {
- /* Check users .rhosts or .shosts. */
- snprintf(buf, sizeof buf, "%.500s/%.100s",
- pw->pw_dir, rhosts_files[rhosts_file_index]);
- if (stat(buf, &st) >= 0)
- break;
- }
- /* Switch back to privileged uid. */
- restore_uid();
-
- if (!rhosts_files[rhosts_file_index] && stat("/etc/hosts.equiv", &st) < 0 &&
- stat(SSH_HOSTS_EQUIV, &st) < 0)
- return 0; /* The user has no .shosts or .rhosts file and there are no
- system-wide files. */
-
- /* Get the name, address, and port of the remote host. */
- hostname = get_canonical_hostname();
- ipaddr = get_remote_ipaddr();
- port = get_remote_port();
-
- /* Check that the connection comes from a privileged port.
- Rhosts authentication only makes sense for priviledged programs.
- Of course, if the intruder has root access on his local machine,
- he can connect from any port. So do not use .rhosts
- authentication from machines that you do not trust. */
- if (port >= IPPORT_RESERVED ||
- port < IPPORT_RESERVED / 2)
- {
- log("Connection from %.100s from nonpriviledged port %d",
- hostname, port);
- packet_send_debug("Your ssh client is not running as root.");
- return 0;
- }
-
- /* If not logging in as superuser, try /etc/hosts.equiv and shosts.equiv. */
- if (pw->pw_uid != 0)
- {
- if (check_rhosts_file("/etc/hosts.equiv", hostname, ipaddr, client_user,
- pw->pw_name))
- {
- packet_send_debug("Accepted for %.100s [%.100s] by /etc/hosts.equiv.",
+ const char *hostname, *ipaddr;
+
+ hostname = get_canonical_hostname(options.use_dns);
+ ipaddr = get_remote_ipaddr();
+ return auth_rhosts2(pw, client_user, hostname, ipaddr);
+}
+
+static int
+auth_rhosts2_raw(struct passwd *pw, const char *client_user, const char *hostname,
+ const char *ipaddr)
+{
+ char buf[1024];
+ struct stat st;
+ static const char *rhosts_files[] = {".shosts", ".rhosts", NULL};
+ u_int rhosts_file_index;
+
+ debug2("auth_rhosts2: clientuser %s hostname %s ipaddr %s",
+ client_user, hostname, ipaddr);
+
+ /* Switch to the user's uid. */
+ temporarily_use_uid(pw);
+ /*
+ * Quick check: if the user has no .shosts or .rhosts files, return
+ * failure immediately without doing costly lookups from name
+ * servers.
+ */
+ for (rhosts_file_index = 0; rhosts_files[rhosts_file_index];
+ rhosts_file_index++) {
+ /* Check users .rhosts or .shosts. */
+ snprintf(buf, sizeof buf, "%.500s/%.100s",
+ pw->pw_dir, rhosts_files[rhosts_file_index]);
+ if (stat(buf, &st) >= 0)
+ break;
+ }
+ /* Switch back to privileged uid. */
+ restore_uid();
+
+ /* Deny if The user has no .shosts or .rhosts file and there are no system-wide files. */
+ if (!rhosts_files[rhosts_file_index] &&
+ stat(_PATH_RHOSTS_EQUIV, &st) < 0 &&
+ stat(_PATH_SSH_HOSTS_EQUIV, &st) < 0)
+ return 0;
+
+ /* If not logging in as superuser, try /etc/hosts.equiv and shosts.equiv. */
+ if (pw->pw_uid != 0) {
+ if (check_rhosts_file(_PATH_RHOSTS_EQUIV, hostname, ipaddr,
+ client_user, pw->pw_name)) {
+ auth_debug_add("Accepted for %.100s [%.100s] by /etc/hosts.equiv.",
hostname, ipaddr);
- return 1;
+ return 1;
+ }
+ if (check_rhosts_file(_PATH_SSH_HOSTS_EQUIV, hostname, ipaddr,
+ client_user, pw->pw_name)) {
+ auth_debug_add("Accepted for %.100s [%.100s] by %.100s.",
+ hostname, ipaddr, _PATH_SSH_HOSTS_EQUIV);
+ return 1;
+ }
}
- if (check_rhosts_file(SSH_HOSTS_EQUIV, hostname, ipaddr, client_user,
- pw->pw_name))
- {
- packet_send_debug("Accepted for %.100s [%.100s] by %.100s.",
- hostname, ipaddr, SSH_HOSTS_EQUIV);
- return 1;
+ /*
+ * Check that the home directory is owned by root or the user, and is
+ * not group or world writable.
+ */
+ if (stat(pw->pw_dir, &st) < 0) {
+ logit("Rhosts authentication refused for %.100s: "
+ "no home directory %.200s", pw->pw_name, pw->pw_dir);
+ auth_debug_add("Rhosts authentication refused for %.100s: "
+ "no home directory %.200s", pw->pw_name, pw->pw_dir);
+ return 0;
}
- }
-
- /* Check that the home directory is owned by root or the user, and is not
- group or world writable. */
- if (stat(pw->pw_dir, &st) < 0)
- {
- log("Rhosts authentication refused for %.100: no home directory %.200s",
- pw->pw_name, pw->pw_dir);
- packet_send_debug("Rhosts authentication refused for %.100: no home directory %.200s",
- pw->pw_name, pw->pw_dir);
- return 0;
- }
- if (strict_modes &&
- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
- (st.st_mode & 022) != 0))
- {
- log("Rhosts authentication refused for %.100s: bad ownership or modes for home directory.",
- pw->pw_name);
- packet_send_debug("Rhosts authentication refused for %.100s: bad ownership or modes for home directory.",
- pw->pw_name);
- return 0;
- }
-
- /* Check all .rhosts files (currently .shosts and .rhosts). */
- /* Temporarily use the user's uid. */
- temporarily_use_uid(pw->pw_uid);
- for (rhosts_file_index = 0; rhosts_files[rhosts_file_index];
- rhosts_file_index++)
- {
- /* Check users .rhosts or .shosts. */
- snprintf(buf, sizeof buf, "%.500s/%.100s",
- pw->pw_dir, rhosts_files[rhosts_file_index]);
- if (stat(buf, &st) < 0)
- continue; /* No such file. */
-
- /* Make sure that the file is either owned by the user or by root,
- and make sure it is not writable by anyone but the owner. This is
- to help avoid novices accidentally allowing access to their account
- by anyone. */
- if (strict_modes &&
- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
- (st.st_mode & 022) != 0))
- {
- log("Rhosts authentication refused for %.100s: bad modes for %.200s",
- pw->pw_name, buf);
- packet_send_debug("Bad file modes for %.200s", buf);
- continue;
+ if (options.strict_modes &&
+ ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+ (st.st_mode & 022) != 0)) {
+ logit("Rhosts authentication refused for %.100s: "
+ "bad ownership or modes for home directory.", pw->pw_name);
+ auth_debug_add("Rhosts authentication refused for %.100s: "
+ "bad ownership or modes for home directory.", pw->pw_name);
+ return 0;
}
-
- /* Check if we have been configured to ignore .rhosts and .shosts
- files. */
- if (ignore_rhosts)
- {
- packet_send_debug("Server has been configured to ignore %.100s.",
+ /* Temporarily use the user's uid. */
+ temporarily_use_uid(pw);
+
+ /* Check all .rhosts files (currently .shosts and .rhosts). */
+ for (rhosts_file_index = 0; rhosts_files[rhosts_file_index];
+ rhosts_file_index++) {
+ /* Check users .rhosts or .shosts. */
+ snprintf(buf, sizeof buf, "%.500s/%.100s",
+ pw->pw_dir, rhosts_files[rhosts_file_index]);
+ if (stat(buf, &st) < 0)
+ continue;
+
+ /*
+ * Make sure that the file is either owned by the user or by
+ * root, and make sure it is not writable by anyone but the
+ * owner. This is to help avoid novices accidentally
+ * allowing access to their account by anyone.
+ */
+ if (options.strict_modes &&
+ ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+ (st.st_mode & 022) != 0)) {
+ logit("Rhosts authentication refused for %.100s: bad modes for %.200s",
+ pw->pw_name, buf);
+ auth_debug_add("Bad file modes for %.200s", buf);
+ continue;
+ }
+ /* Check if we have been configured to ignore .rhosts and .shosts files. */
+ if (options.ignore_rhosts) {
+ auth_debug_add("Server has been configured to ignore %.100s.",
rhosts_files[rhosts_file_index]);
- continue;
- }
-
- /* Check if authentication is permitted by the file. */
- if (check_rhosts_file(buf, hostname, ipaddr, client_user, pw->pw_name))
- {
- packet_send_debug("Accepted by %.100s.",
+ continue;
+ }
+ /* Check if authentication is permitted by the file. */
+ if (check_rhosts_file(buf, hostname, ipaddr, client_user, pw->pw_name)) {
+ auth_debug_add("Accepted by %.100s.",
rhosts_files[rhosts_file_index]);
- /* Restore the privileged uid. */
- restore_uid();
- return 1;
+ /* Restore the privileged uid. */
+ restore_uid();
+ auth_debug_add("Accepted host %s ip %s client_user %s server_user %s",
+ hostname, ipaddr, client_user, pw->pw_name);
+ return 1;
+ }
}
- }
- /* Rhosts authentication denied. */
- /* Restore the privileged uid. */
- restore_uid();
- return 0;
+ /* Restore the privileged uid. */
+ restore_uid();
+ return 0;
+}
+
+int
+auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname,
+ const char *ipaddr)
+{
+ int ret;
+
+ auth_debug_reset();
+ ret = auth_rhosts2_raw(pw, client_user, hostname, ipaddr);
+ if (!use_privsep)
+ auth_debug_send();
+ return ret;
}
andersk / openssh.git / blobdiff