diff options
author | Damien Miller <djm@mindrot.org> | 2000-04-01 11:09:21 +1000 |
---|---|---|
committer | Damien Miller <djm@mindrot.org> | 2000-04-01 11:09:21 +1000 |
commit | b38eff8e4ff901df9cf1113a9f14d64c3565a401 (patch) | |
tree | 9a856898f15f7760ed95c5d47789a6f954b4ad2f /sshd.c | |
parent | 450a7a1ff40fe7c2d84c93b83cf2df53445d807d (diff) |
- Big OpenBSD CVS update (mainly beginnings of SSH2 infrastructure)
- [auth.c session.c sshd.c auth.h]
split sshd.c -> auth.c session.c sshd.c plus cleanup and goto-removal
- [bufaux.c bufaux.h]
support ssh2 bignums
- [channels.c channels.h clientloop.c sshd.c nchan.c nchan.h packet.c]
[readconf.c ssh.c ssh.h serverloop.c]
replace big switch() with function tables (prepare for ssh2)
- [ssh2.h]
ssh2 message type codes
- [sshd.8]
reorder Xr to avoid cutting
- [serverloop.c]
close(fdin) if fdin != fdout, shutdown otherwise, ok theo@
- [channels.c]
missing close
allow bigger packets
- [cipher.c cipher.h]
support ssh2 ciphers
- [compress.c]
cleanup, less code
- [dispatch.c dispatch.h]
function tables for different message types
- [log-server.c]
do not log() if debuggin to stderr
rename a cpp symbol, to avoid param.h collision
- [mpaux.c]
KNF
- [nchan.c]
sync w/ channels.c
Diffstat (limited to 'sshd.c')
-rw-r--r-- | sshd.c | 1855 |
1 files changed, 110 insertions, 1745 deletions
@@ -11,19 +11,37 @@ | |||
11 | */ | 11 | */ |
12 | 12 | ||
13 | #include "includes.h" | 13 | #include "includes.h" |
14 | RCSID("$OpenBSD: sshd.c,v 1.94 2000/03/23 22:15:34 markus Exp $"); | 14 | RCSID("$OpenBSD: sshd.c,v 1.96 2000/03/28 21:15:45 markus Exp $"); |
15 | 15 | ||
16 | #include "xmalloc.h" | 16 | #include "xmalloc.h" |
17 | #include "rsa.h" | 17 | #include "rsa.h" |
18 | #include "ssh.h" | 18 | #include "ssh.h" |
19 | #include "pty.h" | 19 | #include "pty.h" |
20 | #include "packet.h" | 20 | #include "packet.h" |
21 | #include "buffer.h" | ||
22 | #include "cipher.h" | 21 | #include "cipher.h" |
23 | #include "mpaux.h" | 22 | #include "mpaux.h" |
24 | #include "servconf.h" | 23 | #include "servconf.h" |
25 | #include "uidswap.h" | 24 | #include "uidswap.h" |
26 | #include "compat.h" | 25 | #include "compat.h" |
26 | #include "buffer.h" | ||
27 | |||
28 | #ifdef HAVE_OPENSSL | ||
29 | # include <openssl/dh.h> | ||
30 | # include <openssl/bn.h> | ||
31 | # include <openssl/hmac.h> | ||
32 | # include <openssl/dsa.h> | ||
33 | # include <openssl/rsa.h> | ||
34 | #endif | ||
35 | #ifdef HAVE_SSL | ||
36 | # include <ssl/dh.h> | ||
37 | # include <ssl/bn.h> | ||
38 | # include <ssl/hmac.h> | ||
39 | # include <ssl/dsa.h> | ||
40 | # include <ssl/rsa.h> | ||
41 | #endif | ||
42 | #include "key.h" | ||
43 | |||
44 | #include "auth.h" | ||
27 | 45 | ||
28 | #ifdef LIBWRAP | 46 | #ifdef LIBWRAP |
29 | #include <tcpd.h> | 47 | #include <tcpd.h> |
@@ -36,9 +54,6 @@ int deny_severity = LOG_WARNING; | |||
36 | #define O_NOCTTY 0 | 54 | #define O_NOCTTY 0 |
37 | #endif | 55 | #endif |
38 | 56 | ||
39 | /* Local Xauthority file. */ | ||
40 | static char *xauthfile = NULL; | ||
41 | |||
42 | /* Server configuration options. */ | 57 | /* Server configuration options. */ |
43 | ServerOptions options; | 58 | ServerOptions options; |
44 | 59 | ||
@@ -88,21 +103,7 @@ int num_listen_socks = 0; | |||
88 | * sshd will skip the version-number exchange | 103 | * sshd will skip the version-number exchange |
89 | */ | 104 | */ |
90 | char *client_version_string = NULL; | 105 | char *client_version_string = NULL; |
91 | 106 | char *server_version_string = NULL; | |
92 | /* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ | ||
93 | int no_port_forwarding_flag = 0; | ||
94 | int no_agent_forwarding_flag = 0; | ||
95 | int no_x11_forwarding_flag = 0; | ||
96 | int no_pty_flag = 0; | ||
97 | |||
98 | /* RSA authentication "command=" option. */ | ||
99 | char *forced_command = NULL; | ||
100 | |||
101 | /* RSA authentication "environment=" options. */ | ||
102 | struct envstring *custom_environment = NULL; | ||
103 | |||
104 | /* Session id for the current session. */ | ||
105 | unsigned char session_id[16]; | ||
106 | 107 | ||
107 | /* | 108 | /* |
108 | * Any really sensitive data in the application is contained in this | 109 | * Any really sensitive data in the application is contained in this |
@@ -130,43 +131,11 @@ int received_sighup = 0; | |||
130 | the private key. */ | 131 | the private key. */ |
131 | RSA *public_key; | 132 | RSA *public_key; |
132 | 133 | ||
133 | /* Prototypes for various functions defined later in this file. */ | 134 | /* session identifier, used by RSA-auth */ |
134 | void do_ssh_kex(); | 135 | unsigned char session_id[16]; |
135 | void do_authentication(); | ||
136 | void do_authloop(struct passwd * pw); | ||
137 | void do_fake_authloop(char *user); | ||
138 | void do_authenticated(struct passwd * pw); | ||
139 | void do_exec_pty(const char *command, int ptyfd, int ttyfd, | ||
140 | const char *ttyname, struct passwd * pw, const char *term, | ||
141 | const char *display, const char *auth_proto, | ||
142 | const char *auth_data); | ||
143 | void do_exec_no_pty(const char *command, struct passwd * pw, | ||
144 | const char *display, const char *auth_proto, | ||
145 | const char *auth_data); | ||
146 | void do_child(const char *command, struct passwd * pw, const char *term, | ||
147 | const char *display, const char *auth_proto, | ||
148 | const char *auth_data, const char *ttyname); | ||
149 | 136 | ||
150 | /* | 137 | /* Prototypes for various functions defined later in this file. */ |
151 | * Remove local Xauthority file. | 138 | void do_ssh1_kex(); |
152 | */ | ||
153 | void | ||
154 | xauthfile_cleanup_proc(void *ignore) | ||
155 | { | ||
156 | debug("xauthfile_cleanup_proc called"); | ||
157 | |||
158 | if (xauthfile != NULL) { | ||
159 | char *p; | ||
160 | unlink(xauthfile); | ||
161 | p = strrchr(xauthfile, '/'); | ||
162 | if (p != NULL) { | ||
163 | *p = '\0'; | ||
164 | rmdir(xauthfile); | ||
165 | } | ||
166 | xfree(xauthfile); | ||
167 | xauthfile = NULL; | ||
168 | } | ||
169 | } | ||
170 | 139 | ||
171 | /* | 140 | /* |
172 | * Close all listening sockets | 141 | * Close all listening sockets |
@@ -250,35 +219,6 @@ grace_alarm_handler(int sig) | |||
250 | } | 219 | } |
251 | 220 | ||
252 | /* | 221 | /* |
253 | * convert ssh auth msg type into description | ||
254 | */ | ||
255 | char * | ||
256 | get_authname(int type) | ||
257 | { | ||
258 | static char buf[1024]; | ||
259 | switch (type) { | ||
260 | case SSH_CMSG_AUTH_PASSWORD: | ||
261 | return "password"; | ||
262 | case SSH_CMSG_AUTH_RSA: | ||
263 | return "rsa"; | ||
264 | case SSH_CMSG_AUTH_RHOSTS_RSA: | ||
265 | return "rhosts-rsa"; | ||
266 | case SSH_CMSG_AUTH_RHOSTS: | ||
267 | return "rhosts"; | ||
268 | #ifdef KRB4 | ||
269 | case SSH_CMSG_AUTH_KERBEROS: | ||
270 | return "kerberos"; | ||
271 | #endif | ||
272 | #ifdef SKEY | ||
273 | case SSH_CMSG_AUTH_TIS_RESPONSE: | ||
274 | return "s/key"; | ||
275 | #endif | ||
276 | } | ||
277 | snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); | ||
278 | return buf; | ||
279 | } | ||
280 | |||
281 | /* | ||
282 | * Signal handler for the key regeneration alarm. Note that this | 222 | * Signal handler for the key regeneration alarm. Note that this |
283 | * alarm only occurs in the daemon waiting for connections, and it does not | 223 | * alarm only occurs in the daemon waiting for connections, and it does not |
284 | * do anything with the private key or random state before forking. | 224 | * do anything with the private key or random state before forking. |
@@ -315,6 +255,88 @@ key_regeneration_alarm(int sig) | |||
315 | errno = save_errno; | 255 | errno = save_errno; |
316 | } | 256 | } |
317 | 257 | ||
258 | void | ||
259 | sshd_exchange_identification(int sock_in, int sock_out) | ||
260 | { | ||
261 | int i; | ||
262 | int remote_major, remote_minor; | ||
263 | char *s; | ||
264 | char buf[256]; /* Must not be larger than remote_version. */ | ||
265 | char remote_version[256]; /* Must be at least as big as buf. */ | ||
266 | |||
267 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | ||
268 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); | ||
269 | server_version_string = xstrdup(buf); | ||
270 | |||
271 | if (client_version_string == NULL) { | ||
272 | /* Send our protocol version identification. */ | ||
273 | if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) | ||
274 | != strlen(server_version_string)) { | ||
275 | log("Could not write ident string to %s.", get_remote_ipaddr()); | ||
276 | fatal_cleanup(); | ||
277 | } | ||
278 | |||
279 | /* Read other side\'s version identification. */ | ||
280 | for (i = 0; i < sizeof(buf) - 1; i++) { | ||
281 | if (read(sock_in, &buf[i], 1) != 1) { | ||
282 | log("Did not receive ident string from %s.", get_remote_ipaddr()); | ||
283 | fatal_cleanup(); | ||
284 | } | ||
285 | if (buf[i] == '\r') { | ||
286 | buf[i] = '\n'; | ||
287 | buf[i + 1] = 0; | ||
288 | continue; | ||
289 | /*break; XXX eat \r */ | ||
290 | } | ||
291 | if (buf[i] == '\n') { | ||
292 | /* buf[i] == '\n' */ | ||
293 | buf[i + 1] = 0; | ||
294 | break; | ||
295 | } | ||
296 | } | ||
297 | buf[sizeof(buf) - 1] = 0; | ||
298 | client_version_string = xstrdup(buf); | ||
299 | } | ||
300 | |||
301 | /* | ||
302 | * Check that the versions match. In future this might accept | ||
303 | * several versions and set appropriate flags to handle them. | ||
304 | */ | ||
305 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | ||
306 | &remote_major, &remote_minor, remote_version) != 3) { | ||
307 | s = "Protocol mismatch.\n"; | ||
308 | (void) atomicio(write, sock_out, s, strlen(s)); | ||
309 | close(sock_in); | ||
310 | close(sock_out); | ||
311 | log("Bad protocol version identification '%.100s' from %s", | ||
312 | client_version_string, get_remote_ipaddr()); | ||
313 | fatal_cleanup(); | ||
314 | } | ||
315 | debug("Client protocol version %d.%d; client software version %.100s", | ||
316 | remote_major, remote_minor, remote_version); | ||
317 | |||
318 | switch(remote_major) { | ||
319 | case 1: | ||
320 | if (remote_minor < 3) { | ||
321 | packet_disconnect("Your ssh version is too old and" | ||
322 | "is no longer supported. Please install a newer version."); | ||
323 | } else if (remote_minor == 3) { | ||
324 | /* note that this disables agent-forwarding */ | ||
325 | enable_compat13(); | ||
326 | } | ||
327 | break; | ||
328 | default: | ||
329 | s = "Protocol major versions differ.\n"; | ||
330 | (void) atomicio(write, sock_out, s, strlen(s)); | ||
331 | close(sock_in); | ||
332 | close(sock_out); | ||
333 | log("Protocol major versions differ for %s: %d vs. %d", | ||
334 | get_remote_ipaddr(), PROTOCOL_MAJOR, remote_major); | ||
335 | fatal_cleanup(); | ||
336 | break; | ||
337 | } | ||
338 | } | ||
339 | |||
318 | /* | 340 | /* |
319 | * Main program for the daemon. | 341 | * Main program for the daemon. |
320 | */ | 342 | */ |
@@ -325,12 +347,9 @@ main(int ac, char **av) | |||
325 | extern int optind; | 347 | extern int optind; |
326 | int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1; | 348 | int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1; |
327 | socklen_t fromlen; | 349 | socklen_t fromlen; |
328 | int remote_major, remote_minor; | ||
329 | int silentrsa = 0; | 350 | int silentrsa = 0; |
330 | fd_set *fdset; | 351 | fd_set *fdset; |
331 | struct sockaddr_storage from; | 352 | struct sockaddr_storage from; |
332 | char buf[100]; /* Must not be larger than remote_version. */ | ||
333 | char remote_version[100]; /* Must be at least as big as buf. */ | ||
334 | const char *remote_ip; | 353 | const char *remote_ip; |
335 | int remote_port; | 354 | int remote_port; |
336 | char *comment; | 355 | char *comment; |
@@ -794,73 +813,7 @@ main(int ac, char **av) | |||
794 | if (!debug_flag) | 813 | if (!debug_flag) |
795 | alarm(options.login_grace_time); | 814 | alarm(options.login_grace_time); |
796 | 815 | ||
797 | if (client_version_string != NULL) { | 816 | sshd_exchange_identification(sock_in, sock_out); |
798 | /* we are exec'ed by sshd2, so skip exchange of protocol version */ | ||
799 | strlcpy(buf, client_version_string, sizeof(buf)); | ||
800 | } else { | ||
801 | /* Send our protocol version identification. */ | ||
802 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | ||
803 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); | ||
804 | if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) { | ||
805 | log("Could not write ident string to %s.", remote_ip); | ||
806 | fatal_cleanup(); | ||
807 | } | ||
808 | |||
809 | /* Read other side\'s version identification. */ | ||
810 | for (i = 0; i < sizeof(buf) - 1; i++) { | ||
811 | if (read(sock_in, &buf[i], 1) != 1) { | ||
812 | log("Did not receive ident string from %s.", remote_ip); | ||
813 | fatal_cleanup(); | ||
814 | } | ||
815 | if (buf[i] == '\r') { | ||
816 | buf[i] = '\n'; | ||
817 | buf[i + 1] = 0; | ||
818 | break; | ||
819 | } | ||
820 | if (buf[i] == '\n') { | ||
821 | /* buf[i] == '\n' */ | ||
822 | buf[i + 1] = 0; | ||
823 | break; | ||
824 | } | ||
825 | } | ||
826 | buf[sizeof(buf) - 1] = 0; | ||
827 | } | ||
828 | |||
829 | /* | ||
830 | * Check that the versions match. In future this might accept | ||
831 | * several versions and set appropriate flags to handle them. | ||
832 | */ | ||
833 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, | ||
834 | remote_version) != 3) { | ||
835 | char *s = "Protocol mismatch.\n"; | ||
836 | |||
837 | (void) atomicio(write, sock_out, s, strlen(s)); | ||
838 | close(sock_in); | ||
839 | close(sock_out); | ||
840 | log("Bad protocol version identification '%.100s' from %s", | ||
841 | buf, remote_ip); | ||
842 | fatal_cleanup(); | ||
843 | } | ||
844 | debug("Client protocol version %d.%d; client software version %.100s", | ||
845 | remote_major, remote_minor, remote_version); | ||
846 | if (remote_major != PROTOCOL_MAJOR) { | ||
847 | char *s = "Protocol major versions differ.\n"; | ||
848 | |||
849 | (void) atomicio(write, sock_out, s, strlen(s)); | ||
850 | close(sock_in); | ||
851 | close(sock_out); | ||
852 | log("Protocol major versions differ for %s: %d vs. %d", | ||
853 | remote_ip, PROTOCOL_MAJOR, remote_major); | ||
854 | fatal_cleanup(); | ||
855 | } | ||
856 | /* Check that the client has sufficiently high software version. */ | ||
857 | if (remote_major == 1 && remote_minor < 3) | ||
858 | packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); | ||
859 | |||
860 | if (remote_major == 1 && remote_minor == 3) { | ||
861 | /* note that this disables agent-forwarding */ | ||
862 | enable_compat13(); | ||
863 | } | ||
864 | /* | 817 | /* |
865 | * Check that the connection comes from a privileged port. Rhosts- | 818 | * Check that the connection comes from a privileged port. Rhosts- |
866 | * and Rhosts-RSA-Authentication only make sense from priviledged | 819 | * and Rhosts-RSA-Authentication only make sense from priviledged |
@@ -884,8 +837,7 @@ main(int ac, char **av) | |||
884 | packet_set_nonblocking(); | 837 | packet_set_nonblocking(); |
885 | 838 | ||
886 | /* perform the key exchange */ | 839 | /* perform the key exchange */ |
887 | do_ssh_kex(); | 840 | do_ssh1_kex(); |
888 | |||
889 | /* authenticate user and start session */ | 841 | /* authenticate user and start session */ |
890 | do_authentication(); | 842 | do_authentication(); |
891 | 843 | ||
@@ -895,10 +847,6 @@ main(int ac, char **av) | |||
895 | (void) dest_tkt(); | 847 | (void) dest_tkt(); |
896 | #endif /* KRB4 */ | 848 | #endif /* KRB4 */ |
897 | 849 | ||
898 | /* Cleanup user's local Xauthority file. */ | ||
899 | if (xauthfile) | ||
900 | xauthfile_cleanup_proc(NULL); | ||
901 | |||
902 | /* The connection has been terminated. */ | 850 | /* The connection has been terminated. */ |
903 | verbose("Closing connection to %.100s", remote_ip); | 851 | verbose("Closing connection to %.100s", remote_ip); |
904 | 852 | ||
@@ -914,7 +862,7 @@ main(int ac, char **av) | |||
914 | * SSH1 key exchange | 862 | * SSH1 key exchange |
915 | */ | 863 | */ |
916 | void | 864 | void |
917 | do_ssh_kex() | 865 | do_ssh1_kex() |
918 | { | 866 | { |
919 | int i, len; | 867 | int i, len; |
920 | int plen, slen; | 868 | int plen, slen; |
@@ -1101,1586 +1049,3 @@ do_ssh_kex() | |||
1101 | packet_send(); | 1049 | packet_send(); |
1102 | packet_write_wait(); | 1050 | packet_write_wait(); |
1103 | } | 1051 | } |
1104 | |||
1105 | |||
1106 | /* | ||
1107 | * Check if the user is allowed to log in via ssh. If user is listed in | ||
1108 | * DenyUsers or user's primary group is listed in DenyGroups, false will | ||
1109 | * be returned. If AllowUsers isn't empty and user isn't listed there, or | ||
1110 | * if AllowGroups isn't empty and user isn't listed there, false will be | ||
1111 | * returned. | ||
1112 | * If the user's shell is not executable, false will be returned. | ||
1113 | * Otherwise true is returned. | ||
1114 | */ | ||
1115 | static int | ||
1116 | allowed_user(struct passwd * pw) | ||
1117 | { | ||
1118 | struct stat st; | ||
1119 | struct group *grp; | ||
1120 | int i; | ||
1121 | #ifdef WITH_AIXAUTHENTICATE | ||
1122 | char *loginmsg; | ||
1123 | #endif /* WITH_AIXAUTHENTICATE */ | ||
1124 | |||
1125 | /* Shouldn't be called if pw is NULL, but better safe than sorry... */ | ||
1126 | if (!pw) | ||
1127 | return 0; | ||
1128 | |||
1129 | /* deny if shell does not exists or is not executable */ | ||
1130 | if (stat(pw->pw_shell, &st) != 0) | ||
1131 | return 0; | ||
1132 | if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) | ||
1133 | return 0; | ||
1134 | |||
1135 | /* Return false if user is listed in DenyUsers */ | ||
1136 | if (options.num_deny_users > 0) { | ||
1137 | if (!pw->pw_name) | ||
1138 | return 0; | ||
1139 | for (i = 0; i < options.num_deny_users; i++) | ||
1140 | if (match_pattern(pw->pw_name, options.deny_users[i])) | ||
1141 | return 0; | ||
1142 | } | ||
1143 | /* Return false if AllowUsers isn't empty and user isn't listed there */ | ||
1144 | if (options.num_allow_users > 0) { | ||
1145 | if (!pw->pw_name) | ||
1146 | return 0; | ||
1147 | for (i = 0; i < options.num_allow_users; i++) | ||
1148 | if (match_pattern(pw->pw_name, options.allow_users[i])) | ||
1149 | break; | ||
1150 | /* i < options.num_allow_users iff we break for loop */ | ||
1151 | if (i >= options.num_allow_users) | ||
1152 | return 0; | ||
1153 | } | ||
1154 | /* Get the primary group name if we need it. Return false if it fails */ | ||
1155 | if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { | ||
1156 | grp = getgrgid(pw->pw_gid); | ||
1157 | if (!grp) | ||
1158 | return 0; | ||
1159 | |||
1160 | /* Return false if user's group is listed in DenyGroups */ | ||
1161 | if (options.num_deny_groups > 0) { | ||
1162 | if (!grp->gr_name) | ||
1163 | return 0; | ||
1164 | for (i = 0; i < options.num_deny_groups; i++) | ||
1165 | if (match_pattern(grp->gr_name, options.deny_groups[i])) | ||
1166 | return 0; | ||
1167 | } | ||
1168 | /* | ||
1169 | * Return false if AllowGroups isn't empty and user's group | ||
1170 | * isn't listed there | ||
1171 | */ | ||
1172 | if (options.num_allow_groups > 0) { | ||
1173 | if (!grp->gr_name) | ||
1174 | return 0; | ||
1175 | for (i = 0; i < options.num_allow_groups; i++) | ||
1176 | if (match_pattern(grp->gr_name, options.allow_groups[i])) | ||
1177 | break; | ||
1178 | /* i < options.num_allow_groups iff we break for | ||
1179 | loop */ | ||
1180 | if (i >= options.num_allow_groups) | ||
1181 | return 0; | ||
1182 | } | ||
1183 | } | ||
1184 | |||
1185 | #ifdef WITH_AIXAUTHENTICATE | ||
1186 | if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0) | ||
1187 | return 0; | ||
1188 | #endif /* WITH_AIXAUTHENTICATE */ | ||
1189 | |||
1190 | /* We found no reason not to let this user try to log on... */ | ||
1191 | return 1; | ||
1192 | } | ||
1193 | |||
1194 | /* | ||
1195 | * Performs authentication of an incoming connection. Session key has already | ||
1196 | * been exchanged and encryption is enabled. | ||
1197 | */ | ||
1198 | void | ||
1199 | do_authentication() | ||
1200 | { | ||
1201 | struct passwd *pw, pwcopy; | ||
1202 | int plen; | ||
1203 | unsigned int ulen; | ||
1204 | char *user; | ||
1205 | |||
1206 | /* Get the name of the user that we wish to log in as. */ | ||
1207 | packet_read_expect(&plen, SSH_CMSG_USER); | ||
1208 | |||
1209 | /* Get the user name. */ | ||
1210 | user = packet_get_string(&ulen); | ||
1211 | packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); | ||
1212 | |||
1213 | setproctitle("%s", user); | ||
1214 | |||
1215 | #ifdef WITH_AIXAUTHENTICATE | ||
1216 | char *loginmsg; | ||
1217 | #endif /* WITH_AIXAUTHENTICATE */ | ||
1218 | |||
1219 | #ifdef AFS | ||
1220 | /* If machine has AFS, set process authentication group. */ | ||
1221 | if (k_hasafs()) { | ||
1222 | k_setpag(); | ||
1223 | k_unlog(); | ||
1224 | } | ||
1225 | #endif /* AFS */ | ||
1226 | |||
1227 | /* Verify that the user is a valid user. */ | ||
1228 | pw = getpwnam(user); | ||
1229 | if (!pw || !allowed_user(pw)) | ||
1230 | do_fake_authloop(user); | ||
1231 | xfree(user); | ||
1232 | |||
1233 | /* Take a copy of the returned structure. */ | ||
1234 | memset(&pwcopy, 0, sizeof(pwcopy)); | ||
1235 | pwcopy.pw_name = xstrdup(pw->pw_name); | ||
1236 | pwcopy.pw_passwd = xstrdup(pw->pw_passwd); | ||
1237 | pwcopy.pw_uid = pw->pw_uid; | ||
1238 | pwcopy.pw_gid = pw->pw_gid; | ||
1239 | pwcopy.pw_dir = xstrdup(pw->pw_dir); | ||
1240 | pwcopy.pw_shell = xstrdup(pw->pw_shell); | ||
1241 | pw = &pwcopy; | ||
1242 | |||
1243 | #ifdef USE_PAM | ||
1244 | start_pam(pw); | ||
1245 | #endif | ||
1246 | |||
1247 | /* | ||
1248 | * If we are not running as root, the user must have the same uid as | ||
1249 | * the server. | ||
1250 | */ | ||
1251 | if (getuid() != 0 && pw->pw_uid != getuid()) | ||
1252 | packet_disconnect("Cannot change user when server not running as root."); | ||
1253 | |||
1254 | debug("Attempting authentication for %.100s.", pw->pw_name); | ||
1255 | |||
1256 | /* If the user has no password, accept authentication immediately. */ | ||
1257 | if (options.password_authentication && | ||
1258 | #ifdef KRB4 | ||
1259 | (!options.kerberos_authentication || options.kerberos_or_local_passwd) && | ||
1260 | #endif /* KRB4 */ | ||
1261 | #ifdef USE_PAM | ||
1262 | auth_pam_password(pw, "")) { | ||
1263 | #else /* USE_PAM */ | ||
1264 | auth_password(pw, "")) { | ||
1265 | #endif /* USE_PAM */ | ||
1266 | /* Authentication with empty password succeeded. */ | ||
1267 | log("Login for user %s from %.100s, accepted without authentication.", | ||
1268 | pw->pw_name, get_remote_ipaddr()); | ||
1269 | } else { | ||
1270 | /* Loop until the user has been authenticated or the | ||
1271 | connection is closed, do_authloop() returns only if | ||
1272 | authentication is successfull */ | ||
1273 | do_authloop(pw); | ||
1274 | } | ||
1275 | |||
1276 | /* The user has been authenticated and accepted. */ | ||
1277 | #ifdef WITH_AIXAUTHENTICATE | ||
1278 | loginsuccess(user,get_canonical_hostname(),"ssh",&loginmsg); | ||
1279 | #endif /* WITH_AIXAUTHENTICATE */ | ||
1280 | packet_start(SSH_SMSG_SUCCESS); | ||
1281 | packet_send(); | ||
1282 | packet_write_wait(); | ||
1283 | |||
1284 | /* Perform session preparation. */ | ||
1285 | do_authenticated(pw); | ||
1286 | } | ||
1287 | |||
1288 | #define AUTH_FAIL_MAX 6 | ||
1289 | #define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) | ||
1290 | #define AUTH_FAIL_MSG "Too many authentication failures for %.100s" | ||
1291 | |||
1292 | /* | ||
1293 | * read packets and try to authenticate local user *pw. | ||
1294 | * return if authentication is successfull | ||
1295 | */ | ||
1296 | void | ||
1297 | do_authloop(struct passwd * pw) | ||
1298 | { | ||
1299 | int attempt = 0; | ||
1300 | unsigned int bits; | ||
1301 | RSA *client_host_key; | ||
1302 | BIGNUM *n; | ||
1303 | char *client_user = NULL, *password = NULL; | ||
1304 | char user[1024]; | ||
1305 | unsigned int dlen; | ||
1306 | int plen, nlen, elen; | ||
1307 | unsigned int ulen; | ||
1308 | int type = 0; | ||
1309 | void (*authlog) (const char *fmt,...) = verbose; | ||
1310 | |||
1311 | /* Indicate that authentication is needed. */ | ||
1312 | packet_start(SSH_SMSG_FAILURE); | ||
1313 | packet_send(); | ||
1314 | packet_write_wait(); | ||
1315 | |||
1316 | for (attempt = 1;; attempt++) { | ||
1317 | int authenticated = 0; | ||
1318 | strlcpy(user, "", sizeof user); | ||
1319 | |||
1320 | /* Get a packet from the client. */ | ||
1321 | type = packet_read(&plen); | ||
1322 | |||
1323 | /* Process the packet. */ | ||
1324 | switch (type) { | ||
1325 | #ifdef AFS | ||
1326 | case SSH_CMSG_HAVE_KERBEROS_TGT: | ||
1327 | if (!options.kerberos_tgt_passing) { | ||
1328 | /* packet_get_all(); */ | ||
1329 | verbose("Kerberos tgt passing disabled."); | ||
1330 | break; | ||
1331 | } else { | ||
1332 | /* Accept Kerberos tgt. */ | ||
1333 | char *tgt = packet_get_string(&dlen); | ||
1334 | packet_integrity_check(plen, 4 + dlen, type); | ||
1335 | if (!auth_kerberos_tgt(pw, tgt)) | ||
1336 | verbose("Kerberos tgt REFUSED for %s", pw->pw_name); | ||
1337 | xfree(tgt); | ||
1338 | } | ||
1339 | continue; | ||
1340 | |||
1341 | case SSH_CMSG_HAVE_AFS_TOKEN: | ||
1342 | if (!options.afs_token_passing || !k_hasafs()) { | ||
1343 | /* packet_get_all(); */ | ||
1344 | verbose("AFS token passing disabled."); | ||
1345 | break; | ||
1346 | } else { | ||
1347 | /* Accept AFS token. */ | ||
1348 | char *token_string = packet_get_string(&dlen); | ||
1349 | packet_integrity_check(plen, 4 + dlen, type); | ||
1350 | if (!auth_afs_token(pw, token_string)) | ||
1351 | verbose("AFS token REFUSED for %s", pw->pw_name); | ||
1352 | xfree(token_string); | ||
1353 | } | ||
1354 | continue; | ||
1355 | #endif /* AFS */ | ||
1356 | #ifdef KRB4 | ||
1357 | case SSH_CMSG_AUTH_KERBEROS: | ||
1358 | if (!options.kerberos_authentication) { | ||
1359 | /* packet_get_all(); */ | ||
1360 | verbose("Kerberos authentication disabled."); | ||
1361 | break; | ||
1362 | } else { | ||
1363 | /* Try Kerberos v4 authentication. */ | ||
1364 | KTEXT_ST auth; | ||
1365 | char *tkt_user = NULL; | ||
1366 | char *kdata = packet_get_string((unsigned int *) &auth.length); | ||
1367 | packet_integrity_check(plen, 4 + auth.length, type); | ||
1368 | |||
1369 | if (auth.length < MAX_KTXT_LEN) | ||
1370 | memcpy(auth.dat, kdata, auth.length); | ||
1371 | xfree(kdata); | ||
1372 | |||
1373 | authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); | ||
1374 | |||
1375 | if (authenticated) { | ||
1376 | snprintf(user, sizeof user, " tktuser %s", tkt_user); | ||
1377 | xfree(tkt_user); | ||
1378 | } | ||
1379 | } | ||
1380 | break; | ||
1381 | #endif /* KRB4 */ | ||
1382 | |||
1383 | case SSH_CMSG_AUTH_RHOSTS: | ||
1384 | if (!options.rhosts_authentication) { | ||
1385 | verbose("Rhosts authentication disabled."); | ||
1386 | break; | ||
1387 | } | ||
1388 | /* | ||
1389 | * Get client user name. Note that we just have to | ||
1390 | * trust the client; this is one reason why rhosts | ||
1391 | * authentication is insecure. (Another is | ||
1392 | * IP-spoofing on a local network.) | ||
1393 | */ | ||
1394 | client_user = packet_get_string(&ulen); | ||
1395 | packet_integrity_check(plen, 4 + ulen, type); | ||
1396 | |||
1397 | /* Try to authenticate using /etc/hosts.equiv and | ||
1398 | .rhosts. */ | ||
1399 | authenticated = auth_rhosts(pw, client_user); | ||
1400 | |||
1401 | snprintf(user, sizeof user, " ruser %s", client_user); | ||
1402 | break; | ||
1403 | |||
1404 | case SSH_CMSG_AUTH_RHOSTS_RSA: | ||
1405 | if (!options.rhosts_rsa_authentication) { | ||
1406 | verbose("Rhosts with RSA authentication disabled."); | ||
1407 | break; | ||
1408 | } | ||
1409 | /* | ||
1410 | * Get client user name. Note that we just have to | ||
1411 | * trust the client; root on the client machine can | ||
1412 | * claim to be any user. | ||
1413 | */ | ||
1414 | client_user = packet_get_string(&ulen); | ||
1415 | |||
1416 | /* Get the client host key. */ | ||
1417 | client_host_key = RSA_new(); | ||
1418 | if (client_host_key == NULL) | ||
1419 | fatal("RSA_new failed"); | ||
1420 | client_host_key->e = BN_new(); | ||
1421 | client_host_key->n = BN_new(); | ||
1422 | if (client_host_key->e == NULL || client_host_key->n == NULL) | ||
1423 | fatal("BN_new failed"); | ||
1424 | bits = packet_get_int(); | ||
1425 | packet_get_bignum(client_host_key->e, &elen); | ||
1426 | packet_get_bignum(client_host_key->n, &nlen); | ||
1427 | |||
1428 | if (bits != BN_num_bits(client_host_key->n)) | ||
1429 | error("Warning: keysize mismatch for client_host_key: " | ||
1430 | "actual %d, announced %d", BN_num_bits(client_host_key->n), bits); | ||
1431 | packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); | ||
1432 | |||
1433 | authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); | ||
1434 | RSA_free(client_host_key); | ||
1435 | |||
1436 | snprintf(user, sizeof user, " ruser %s", client_user); | ||
1437 | break; | ||
1438 | |||
1439 | case SSH_CMSG_AUTH_RSA: | ||
1440 | if (!options.rsa_authentication) { | ||
1441 | verbose("RSA authentication disabled."); | ||
1442 | break; | ||
1443 | } | ||
1444 | /* RSA authentication requested. */ | ||
1445 | n = BN_new(); | ||
1446 | packet_get_bignum(n, &nlen); | ||
1447 | packet_integrity_check(plen, nlen, type); | ||
1448 | authenticated = auth_rsa(pw, n); | ||
1449 | BN_clear_free(n); | ||
1450 | break; | ||
1451 | |||
1452 | case SSH_CMSG_AUTH_PASSWORD: | ||
1453 | if (!options.password_authentication) { | ||
1454 | verbose("Password authentication disabled."); | ||
1455 | break; | ||
1456 | } | ||
1457 | /* | ||
1458 | * Read user password. It is in plain text, but was | ||
1459 | * transmitted over the encrypted channel so it is | ||
1460 | * not visible to an outside observer. | ||
1461 | */ | ||
1462 | password = packet_get_string(&dlen); | ||
1463 | packet_integrity_check(plen, 4 + dlen, type); | ||
1464 | |||
1465 | #ifdef USE_PAM | ||
1466 | /* Do PAM auth with password */ | ||
1467 | authenticated = auth_pam_password(pw, password); | ||
1468 | #else /* USE_PAM */ | ||
1469 | /* Try authentication with the password. */ | ||
1470 | authenticated = auth_password(pw, password); | ||
1471 | #endif /* USE_PAM */ | ||
1472 | memset(password, 0, strlen(password)); | ||
1473 | xfree(password); | ||
1474 | break; | ||
1475 | |||
1476 | #ifdef SKEY | ||
1477 | case SSH_CMSG_AUTH_TIS: | ||
1478 | debug("rcvd SSH_CMSG_AUTH_TIS"); | ||
1479 | if (options.skey_authentication == 1) { | ||
1480 | char *skeyinfo = skey_keyinfo(pw->pw_name); | ||
1481 | if (skeyinfo == NULL) { | ||
1482 | debug("generating fake skeyinfo for %.100s.", pw->pw_name); | ||
1483 | skeyinfo = skey_fake_keyinfo(pw->pw_name); | ||
1484 | } | ||
1485 | if (skeyinfo != NULL) { | ||
1486 | /* we send our s/key- in tis-challenge messages */ | ||
1487 | debug("sending challenge '%s'", skeyinfo); | ||
1488 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | ||
1489 | packet_put_string(skeyinfo, strlen(skeyinfo)); | ||
1490 | packet_send(); | ||
1491 | packet_write_wait(); | ||
1492 | continue; | ||
1493 | } | ||
1494 | } | ||
1495 | break; | ||
1496 | case SSH_CMSG_AUTH_TIS_RESPONSE: | ||
1497 | debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); | ||
1498 | if (options.skey_authentication == 1) { | ||
1499 | char *response = packet_get_string(&dlen); | ||
1500 | debug("skey response == '%s'", response); | ||
1501 | packet_integrity_check(plen, 4 + dlen, type); | ||
1502 | authenticated = (skey_haskey(pw->pw_name) == 0 && | ||
1503 | skey_passcheck(pw->pw_name, response) != -1); | ||
1504 | xfree(response); | ||
1505 | } | ||
1506 | break; | ||
1507 | #else | ||
1508 | case SSH_CMSG_AUTH_TIS: | ||
1509 | /* TIS Authentication is unsupported */ | ||
1510 | log("TIS authentication unsupported."); | ||
1511 | break; | ||
1512 | #endif | ||
1513 | |||
1514 | default: | ||
1515 | /* | ||
1516 | * Any unknown messages will be ignored (and failure | ||
1517 | * returned) during authentication. | ||
1518 | */ | ||
1519 | log("Unknown message during authentication: type %d", type); | ||
1520 | break; | ||
1521 | } | ||
1522 | |||
1523 | /* | ||
1524 | * Check if the user is logging in as root and root logins | ||
1525 | * are disallowed. | ||
1526 | * Note that root login is allowed for forced commands. | ||
1527 | */ | ||
1528 | if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) { | ||
1529 | if (forced_command) { | ||
1530 | log("Root login accepted for forced command."); | ||
1531 | } else { | ||
1532 | authenticated = 0; | ||
1533 | log("ROOT LOGIN REFUSED FROM %.200s", | ||
1534 | get_canonical_hostname()); | ||
1535 | } | ||
1536 | } | ||
1537 | |||
1538 | /* Raise logging level */ | ||
1539 | if (authenticated || | ||
1540 | attempt == AUTH_FAIL_LOG || | ||
1541 | type == SSH_CMSG_AUTH_PASSWORD) | ||
1542 | authlog = log; | ||
1543 | |||
1544 | authlog("%s %s for %.200s from %.200s port %d%s", | ||
1545 | authenticated ? "Accepted" : "Failed", | ||
1546 | get_authname(type), | ||
1547 | pw->pw_uid == 0 ? "ROOT" : pw->pw_name, | ||
1548 | get_remote_ipaddr(), | ||
1549 | get_remote_port(), | ||
1550 | user); | ||
1551 | |||
1552 | #ifdef USE_PAM | ||
1553 | if (authenticated) { | ||
1554 | if (!do_pam_account(pw->pw_name, client_user)) { | ||
1555 | if (client_user != NULL) { | ||
1556 | xfree(client_user); | ||
1557 | client_user = NULL; | ||
1558 | } | ||
1559 | do_fake_authloop(pw->pw_name); | ||
1560 | } | ||
1561 | return; | ||
1562 | } | ||
1563 | #else /* USE_PAM */ | ||
1564 | if (authenticated) { | ||
1565 | return; | ||
1566 | } | ||
1567 | #endif /* USE_PAM */ | ||
1568 | |||
1569 | if (client_user != NULL) { | ||
1570 | xfree(client_user); | ||
1571 | client_user = NULL; | ||
1572 | } | ||
1573 | |||
1574 | if (attempt > AUTH_FAIL_MAX) | ||
1575 | packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); | ||
1576 | |||
1577 | /* Send a message indicating that the authentication attempt failed. */ | ||
1578 | packet_start(SSH_SMSG_FAILURE); | ||
1579 | packet_send(); | ||
1580 | packet_write_wait(); | ||
1581 | } | ||
1582 | } | ||
1583 | |||
1584 | /* | ||
1585 | * The user does not exist or access is denied, | ||
1586 | * but fake indication that authentication is needed. | ||
1587 | */ | ||
1588 | void | ||
1589 | do_fake_authloop(char *user) | ||
1590 | { | ||
1591 | int attempt = 0; | ||
1592 | |||
1593 | log("Faking authloop for illegal user %.200s from %.200s port %d", | ||
1594 | user, | ||
1595 | get_remote_ipaddr(), | ||
1596 | get_remote_port()); | ||
1597 | |||
1598 | /* Indicate that authentication is needed. */ | ||
1599 | packet_start(SSH_SMSG_FAILURE); | ||
1600 | packet_send(); | ||
1601 | packet_write_wait(); | ||
1602 | |||
1603 | /* | ||
1604 | * Keep reading packets, and always respond with a failure. This is | ||
1605 | * to avoid disclosing whether such a user really exists. | ||
1606 | */ | ||
1607 | for (attempt = 1;; attempt++) { | ||
1608 | /* Read a packet. This will not return if the client disconnects. */ | ||
1609 | int plen; | ||
1610 | #ifndef SKEY | ||
1611 | (void)packet_read(&plen); | ||
1612 | #else /* SKEY */ | ||
1613 | int type = packet_read(&plen); | ||
1614 | unsigned int dlen; | ||
1615 | char *password, *skeyinfo; | ||
1616 | /* Try to send a fake s/key challenge. */ | ||
1617 | if (options.skey_authentication == 1 && | ||
1618 | (skeyinfo = skey_fake_keyinfo(user)) != NULL) { | ||
1619 | password = NULL; | ||
1620 | if (type == SSH_CMSG_AUTH_TIS) { | ||
1621 | packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); | ||
1622 | packet_put_string(skeyinfo, strlen(skeyinfo)); | ||
1623 | packet_send(); | ||
1624 | packet_write_wait(); | ||
1625 | continue; | ||
1626 | } else if (type == SSH_CMSG_AUTH_PASSWORD && | ||
1627 | options.password_authentication && | ||
1628 | (password = packet_get_string(&dlen)) != NULL && | ||
1629 | dlen == 5 && | ||
1630 | strncasecmp(password, "s/key", 5) == 0 ) { | ||
1631 | packet_send_debug(skeyinfo); | ||
1632 | } | ||
1633 | if (password != NULL) | ||
1634 | xfree(password); | ||
1635 | } | ||
1636 | #endif | ||
1637 | if (attempt > AUTH_FAIL_MAX) | ||
1638 | packet_disconnect(AUTH_FAIL_MSG, user); | ||
1639 | |||
1640 | /* | ||
1641 | * Send failure. This should be indistinguishable from a | ||
1642 | * failed authentication. | ||
1643 | */ | ||
1644 | packet_start(SSH_SMSG_FAILURE); | ||
1645 | packet_send(); | ||
1646 | packet_write_wait(); | ||
1647 | #ifdef WITH_AIXAUTHENTICATE | ||
1648 | if (strncmp(get_authname(type),"password", | ||
1649 | strlen(get_authname(type))) == 0) | ||
1650 | loginfailed(pw->pw_name,get_canonical_hostname(),"ssh"); | ||
1651 | #endif /* WITH_AIXAUTHENTICATE */ | ||
1652 | } | ||
1653 | /* NOTREACHED */ | ||
1654 | abort(); | ||
1655 | } | ||
1656 | |||
1657 | struct pty_cleanup_context { | ||
1658 | const char *ttyname; | ||
1659 | int pid; | ||
1660 | }; | ||
1661 | |||
1662 | /* | ||
1663 | * Function to perform cleanup if we get aborted abnormally (e.g., due to a | ||
1664 | * dropped connection). | ||
1665 | */ | ||
1666 | void | ||
1667 | pty_cleanup_proc(void *context) | ||
1668 | { | ||
1669 | struct pty_cleanup_context *cu = context; | ||
1670 | |||
1671 | debug("pty_cleanup_proc called"); | ||
1672 | |||
1673 | /* Record that the user has logged out. */ | ||
1674 | record_logout(cu->pid, cu->ttyname); | ||
1675 | |||
1676 | /* Release the pseudo-tty. */ | ||
1677 | pty_release(cu->ttyname); | ||
1678 | } | ||
1679 | |||
1680 | /* simple cleanup: chown tty slave back to root */ | ||
1681 | static void | ||
1682 | pty_release_proc(void *tty) | ||
1683 | { | ||
1684 | char *ttyname = tty; | ||
1685 | pty_release(ttyname); | ||
1686 | } | ||
1687 | |||
1688 | /* | ||
1689 | * Prepares for an interactive session. This is called after the user has | ||
1690 | * been successfully authenticated. During this message exchange, pseudo | ||
1691 | * terminals are allocated, X11, TCP/IP, and authentication agent forwardings | ||
1692 | * are requested, etc. | ||
1693 | */ | ||
1694 | void | ||
1695 | do_authenticated(struct passwd * pw) | ||
1696 | { | ||
1697 | int type; | ||
1698 | int compression_level = 0, enable_compression_after_reply = 0; | ||
1699 | int have_pty = 0, ptyfd = -1, ttyfd = -1; | ||
1700 | int row, col, xpixel, ypixel, screen; | ||
1701 | char ttyname[64]; | ||
1702 | char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL; | ||
1703 | int plen; | ||
1704 | unsigned int dlen; | ||
1705 | int n_bytes; | ||
1706 | |||
1707 | /* | ||
1708 | * Cancel the alarm we set to limit the time taken for | ||
1709 | * authentication. | ||
1710 | */ | ||
1711 | alarm(0); | ||
1712 | |||
1713 | /* | ||
1714 | * Inform the channel mechanism that we are the server side and that | ||
1715 | * the client may request to connect to any port at all. (The user | ||
1716 | * could do it anyway, and we wouldn\'t know what is permitted except | ||
1717 | * by the client telling us, so we can equally well trust the client | ||
1718 | * not to request anything bogus.) | ||
1719 | */ | ||
1720 | if (!no_port_forwarding_flag) | ||
1721 | channel_permit_all_opens(); | ||
1722 | |||
1723 | /* | ||
1724 | * We stay in this loop until the client requests to execute a shell | ||
1725 | * or a command. | ||
1726 | */ | ||
1727 | while (1) { | ||
1728 | |||
1729 | /* Get a packet from the client. */ | ||
1730 | type = packet_read(&plen); | ||
1731 | |||
1732 | /* Process the packet. */ | ||
1733 | switch (type) { | ||
1734 | case SSH_CMSG_REQUEST_COMPRESSION: | ||
1735 | packet_integrity_check(plen, 4, type); | ||
1736 | compression_level = packet_get_int(); | ||
1737 | if (compression_level < 1 || compression_level > 9) { | ||
1738 | packet_send_debug("Received illegal compression level %d.", | ||
1739 | compression_level); | ||
1740 | goto fail; | ||
1741 | } | ||
1742 | /* Enable compression after we have responded with SUCCESS. */ | ||
1743 | enable_compression_after_reply = 1; | ||
1744 | break; | ||
1745 | |||
1746 | case SSH_CMSG_REQUEST_PTY: | ||
1747 | if (no_pty_flag) { | ||
1748 | debug("Allocating a pty not permitted for this authentication."); | ||
1749 | goto fail; | ||
1750 | } | ||
1751 | if (have_pty) | ||
1752 | packet_disconnect("Protocol error: you already have a pty."); | ||
1753 | |||
1754 | debug("Allocating pty."); | ||
1755 | |||
1756 | /* Allocate a pty and open it. */ | ||
1757 | if (!pty_allocate(&ptyfd, &ttyfd, ttyname, | ||
1758 | sizeof(ttyname))) { | ||
1759 | error("Failed to allocate pty."); | ||
1760 | goto fail; | ||
1761 | } | ||
1762 | fatal_add_cleanup(pty_release_proc, (void *)ttyname); | ||
1763 | pty_setowner(pw, ttyname); | ||
1764 | |||
1765 | /* Get TERM from the packet. Note that the value may be of arbitrary length. */ | ||
1766 | term = packet_get_string(&dlen); | ||
1767 | packet_integrity_check(dlen, strlen(term), type); | ||
1768 | |||
1769 | /* Remaining bytes */ | ||
1770 | n_bytes = plen - (4 + dlen + 4 * 4); | ||
1771 | |||
1772 | if (strcmp(term, "") == 0) { | ||
1773 | xfree(term); | ||
1774 | term = NULL; | ||
1775 | } | ||
1776 | |||
1777 | /* Get window size from the packet. */ | ||
1778 | row = packet_get_int(); | ||
1779 | col = packet_get_int(); | ||
1780 | xpixel = packet_get_int(); | ||
1781 | ypixel = packet_get_int(); | ||
1782 | pty_change_window_size(ptyfd, row, col, xpixel, ypixel); | ||
1783 | |||
1784 | /* Get tty modes from the packet. */ | ||
1785 | tty_parse_modes(ttyfd, &n_bytes); | ||
1786 | packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); | ||
1787 | |||
1788 | /* Indicate that we now have a pty. */ | ||
1789 | have_pty = 1; | ||
1790 | break; | ||
1791 | |||
1792 | case SSH_CMSG_X11_REQUEST_FORWARDING: | ||
1793 | if (!options.x11_forwarding) { | ||
1794 | packet_send_debug("X11 forwarding disabled in server configuration file."); | ||
1795 | goto fail; | ||
1796 | } | ||
1797 | #ifdef XAUTH_PATH | ||
1798 | if (no_x11_forwarding_flag) { | ||
1799 | packet_send_debug("X11 forwarding not permitted for this authentication."); | ||
1800 | goto fail; | ||
1801 | } | ||
1802 | debug("Received request for X11 forwarding with auth spoofing."); | ||
1803 | if (display) | ||
1804 | packet_disconnect("Protocol error: X11 display already set."); | ||
1805 | { | ||
1806 | unsigned int proto_len, data_len; | ||
1807 | proto = packet_get_string(&proto_len); | ||
1808 | data = packet_get_string(&data_len); | ||
1809 | packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); | ||
1810 | } | ||
1811 | if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) | ||
1812 | screen = packet_get_int(); | ||
1813 | else | ||
1814 | screen = 0; | ||
1815 | display = x11_create_display_inet(screen, options.x11_display_offset); | ||
1816 | if (!display) | ||
1817 | goto fail; | ||
1818 | |||
1819 | /* Setup to always have a local .Xauthority. */ | ||
1820 | xauthfile = xmalloc(MAXPATHLEN); | ||
1821 | strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); | ||
1822 | temporarily_use_uid(pw->pw_uid); | ||
1823 | if (mkdtemp(xauthfile) == NULL) { | ||
1824 | restore_uid(); | ||
1825 | error("private X11 dir: mkdtemp %s failed: %s", | ||
1826 | xauthfile, strerror(errno)); | ||
1827 | xfree(xauthfile); | ||
1828 | xauthfile = NULL; | ||
1829 | goto fail; | ||
1830 | } | ||
1831 | strlcat(xauthfile, "/cookies", MAXPATHLEN); | ||
1832 | open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600); | ||
1833 | restore_uid(); | ||
1834 | fatal_add_cleanup(xauthfile_cleanup_proc, NULL); | ||
1835 | break; | ||
1836 | #else /* XAUTH_PATH */ | ||
1837 | packet_send_debug("No xauth program; cannot forward with spoofing."); | ||
1838 | goto fail; | ||
1839 | #endif /* XAUTH_PATH */ | ||
1840 | |||
1841 | case SSH_CMSG_AGENT_REQUEST_FORWARDING: | ||
1842 | if (no_agent_forwarding_flag || compat13) { | ||
1843 | debug("Authentication agent forwarding not permitted for this authentication."); | ||
1844 | goto fail; | ||
1845 | } | ||
1846 | debug("Received authentication agent forwarding request."); | ||
1847 | auth_input_request_forwarding(pw); | ||
1848 | break; | ||
1849 | |||
1850 | case SSH_CMSG_PORT_FORWARD_REQUEST: | ||
1851 | if (no_port_forwarding_flag) { | ||
1852 | debug("Port forwarding not permitted for this authentication."); | ||
1853 | goto fail; | ||
1854 | } | ||
1855 | debug("Received TCP/IP port forwarding request."); | ||
1856 | channel_input_port_forward_request(pw->pw_uid == 0); | ||
1857 | break; | ||
1858 | |||
1859 | case SSH_CMSG_MAX_PACKET_SIZE: | ||
1860 | if (packet_set_maxsize(packet_get_int()) < 0) | ||
1861 | goto fail; | ||
1862 | break; | ||
1863 | |||
1864 | case SSH_CMSG_EXEC_SHELL: | ||
1865 | /* Set interactive/non-interactive mode. */ | ||
1866 | packet_set_interactive(have_pty || display != NULL, | ||
1867 | options.keepalives); | ||
1868 | |||
1869 | if (forced_command != NULL) | ||
1870 | goto do_forced_command; | ||
1871 | debug("Forking shell."); | ||
1872 | packet_integrity_check(plen, 0, type); | ||
1873 | if (have_pty) | ||
1874 | do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | ||
1875 | else | ||
1876 | do_exec_no_pty(NULL, pw, display, proto, data); | ||
1877 | return; | ||
1878 | |||
1879 | case SSH_CMSG_EXEC_CMD: | ||
1880 | /* Set interactive/non-interactive mode. */ | ||
1881 | packet_set_interactive(have_pty || display != NULL, | ||
1882 | options.keepalives); | ||
1883 | |||
1884 | if (forced_command != NULL) | ||
1885 | goto do_forced_command; | ||
1886 | /* Get command from the packet. */ | ||
1887 | { | ||
1888 | unsigned int dlen; | ||
1889 | command = packet_get_string(&dlen); | ||
1890 | debug("Executing command '%.500s'", command); | ||
1891 | packet_integrity_check(plen, 4 + dlen, type); | ||
1892 | } | ||
1893 | if (have_pty) | ||
1894 | do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | ||
1895 | else | ||
1896 | do_exec_no_pty(command, pw, display, proto, data); | ||
1897 | xfree(command); | ||
1898 | return; | ||
1899 | |||
1900 | default: | ||
1901 | /* | ||
1902 | * Any unknown messages in this phase are ignored, | ||
1903 | * and a failure message is returned. | ||
1904 | */ | ||
1905 | log("Unknown packet type received after authentication: %d", type); | ||
1906 | goto fail; | ||
1907 | } | ||
1908 | |||
1909 | /* The request was successfully processed. */ | ||
1910 | packet_start(SSH_SMSG_SUCCESS); | ||
1911 | packet_send(); | ||
1912 | packet_write_wait(); | ||
1913 | |||
1914 | /* Enable compression now that we have replied if appropriate. */ | ||
1915 | if (enable_compression_after_reply) { | ||
1916 | enable_compression_after_reply = 0; | ||
1917 | packet_start_compression(compression_level); | ||
1918 | } | ||
1919 | continue; | ||
1920 | |||
1921 | fail: | ||
1922 | /* The request failed. */ | ||
1923 | packet_start(SSH_SMSG_FAILURE); | ||
1924 | packet_send(); | ||
1925 | packet_write_wait(); | ||
1926 | continue; | ||
1927 | |||
1928 | do_forced_command: | ||
1929 | /* | ||
1930 | * There is a forced command specified for this login. | ||
1931 | * Execute it. | ||
1932 | */ | ||
1933 | debug("Executing forced command: %.900s", forced_command); | ||
1934 | if (have_pty) | ||
1935 | do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); | ||
1936 | else | ||
1937 | do_exec_no_pty(forced_command, pw, display, proto, data); | ||
1938 | return; | ||
1939 | } | ||
1940 | } | ||
1941 | |||
1942 | /* | ||
1943 | * This is called to fork and execute a command when we have no tty. This | ||
1944 | * will call do_child from the child, and server_loop from the parent after | ||
1945 | * setting up file descriptors and such. | ||
1946 | */ | ||
1947 | void | ||
1948 | do_exec_no_pty(const char *command, struct passwd * pw, | ||
1949 | const char *display, const char *auth_proto, | ||
1950 | const char *auth_data) | ||
1951 | { | ||
1952 | int pid; | ||
1953 | |||
1954 | #ifdef USE_PIPES | ||
1955 | int pin[2], pout[2], perr[2]; | ||
1956 | /* Allocate pipes for communicating with the program. */ | ||
1957 | if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) | ||
1958 | packet_disconnect("Could not create pipes: %.100s", | ||
1959 | strerror(errno)); | ||
1960 | #else /* USE_PIPES */ | ||
1961 | int inout[2], err[2]; | ||
1962 | /* Uses socket pairs to communicate with the program. */ | ||
1963 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || | ||
1964 | socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) | ||
1965 | packet_disconnect("Could not create socket pairs: %.100s", | ||
1966 | strerror(errno)); | ||
1967 | #endif /* USE_PIPES */ | ||
1968 | |||
1969 | setproctitle("%s@notty", pw->pw_name); | ||
1970 | |||
1971 | #ifdef USE_PAM | ||
1972 | do_pam_setcred(); | ||
1973 | #endif /* USE_PAM */ | ||
1974 | |||
1975 | /* Fork the child. */ | ||
1976 | if ((pid = fork()) == 0) { | ||
1977 | /* Child. Reinitialize the log since the pid has changed. */ | ||
1978 | log_init(av0, options.log_level, options.log_facility, log_stderr); | ||
1979 | |||
1980 | /* | ||
1981 | * Create a new session and process group since the 4.4BSD | ||
1982 | * setlogin() affects the entire process group. | ||
1983 | */ | ||
1984 | if (setsid() < 0) | ||
1985 | error("setsid failed: %.100s", strerror(errno)); | ||
1986 | |||
1987 | #ifdef USE_PIPES | ||
1988 | /* | ||
1989 | * Redirect stdin. We close the parent side of the socket | ||
1990 | * pair, and make the child side the standard input. | ||
1991 | */ | ||
1992 | close(pin[1]); | ||
1993 | if (dup2(pin[0], 0) < 0) | ||
1994 | perror("dup2 stdin"); | ||
1995 | close(pin[0]); | ||
1996 | |||
1997 | /* Redirect stdout. */ | ||
1998 | close(pout[0]); | ||
1999 | if (dup2(pout[1], 1) < 0) | ||
2000 | perror("dup2 stdout"); | ||
2001 | close(pout[1]); | ||
2002 | |||
2003 | /* Redirect stderr. */ | ||
2004 | close(perr[0]); | ||
2005 | if (dup2(perr[1], 2) < 0) | ||
2006 | perror("dup2 stderr"); | ||
2007 | close(perr[1]); | ||
2008 | #else /* USE_PIPES */ | ||
2009 | /* | ||
2010 | * Redirect stdin, stdout, and stderr. Stdin and stdout will | ||
2011 | * use the same socket, as some programs (particularly rdist) | ||
2012 | * seem to depend on it. | ||
2013 | */ | ||
2014 | close(inout[1]); | ||
2015 | close(err[1]); | ||
2016 | if (dup2(inout[0], 0) < 0) /* stdin */ | ||
2017 | perror("dup2 stdin"); | ||
2018 | if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ | ||
2019 | perror("dup2 stdout"); | ||
2020 | if (dup2(err[0], 2) < 0) /* stderr */ | ||
2021 | perror("dup2 stderr"); | ||
2022 | #endif /* USE_PIPES */ | ||
2023 | |||
2024 | /* Do processing for the child (exec command etc). */ | ||
2025 | do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); | ||
2026 | /* NOTREACHED */ | ||
2027 | } | ||
2028 | if (pid < 0) | ||
2029 | packet_disconnect("fork failed: %.100s", strerror(errno)); | ||
2030 | #ifdef USE_PIPES | ||
2031 | /* We are the parent. Close the child sides of the pipes. */ | ||
2032 | close(pin[0]); | ||
2033 | close(pout[1]); | ||
2034 | close(perr[1]); | ||
2035 | |||
2036 | /* Enter the interactive session. */ | ||
2037 | server_loop(pid, pin[1], pout[0], perr[0]); | ||
2038 | /* server_loop has closed pin[1], pout[1], and perr[1]. */ | ||
2039 | #else /* USE_PIPES */ | ||
2040 | /* We are the parent. Close the child sides of the socket pairs. */ | ||
2041 | close(inout[0]); | ||
2042 | close(err[0]); | ||
2043 | |||
2044 | /* | ||
2045 | * Enter the interactive session. Note: server_loop must be able to | ||
2046 | * handle the case that fdin and fdout are the same. | ||
2047 | */ | ||
2048 | server_loop(pid, inout[1], inout[1], err[1]); | ||
2049 | /* server_loop has closed inout[1] and err[1]. */ | ||
2050 | #endif /* USE_PIPES */ | ||
2051 | } | ||
2052 | |||
2053 | /* | ||
2054 | * This is called to fork and execute a command when we have a tty. This | ||
2055 | * will call do_child from the child, and server_loop from the parent after | ||
2056 | * setting up file descriptors, controlling tty, updating wtmp, utmp, | ||
2057 | * lastlog, and other such operations. | ||
2058 | */ | ||
2059 | void | ||
2060 | do_exec_pty(const char *command, int ptyfd, int ttyfd, | ||
2061 | const char *ttyname, struct passwd * pw, const char *term, | ||
2062 | const char *display, const char *auth_proto, | ||
2063 | const char *auth_data) | ||
2064 | { | ||
2065 | int pid, fdout; | ||
2066 | int ptymaster; | ||
2067 | const char *hostname; | ||
2068 | time_t last_login_time; | ||
2069 | char buf[100], *time_string; | ||
2070 | FILE *f; | ||
2071 | char line[256]; | ||
2072 | struct stat st; | ||
2073 | int quiet_login; | ||
2074 | struct sockaddr_storage from; | ||
2075 | socklen_t fromlen; | ||
2076 | struct pty_cleanup_context cleanup_context; | ||
2077 | |||
2078 | /* Get remote host name. */ | ||
2079 | hostname = get_canonical_hostname(); | ||
2080 | |||
2081 | /* | ||
2082 | * Get the time when the user last logged in. Buf will be set to | ||
2083 | * contain the hostname the last login was from. | ||
2084 | */ | ||
2085 | if (!options.use_login) { | ||
2086 | last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, | ||
2087 | buf, sizeof(buf)); | ||
2088 | } | ||
2089 | setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); | ||
2090 | |||
2091 | #ifdef USE_PAM | ||
2092 | do_pam_session(pw->pw_name, ttyname); | ||
2093 | do_pam_setcred(); | ||
2094 | #endif /* USE_PAM */ | ||
2095 | |||
2096 | /* Fork the child. */ | ||
2097 | if ((pid = fork()) == 0) { | ||
2098 | pid = getpid(); | ||
2099 | |||
2100 | /* Child. Reinitialize the log because the pid has | ||
2101 | changed. */ | ||
2102 | log_init(av0, options.log_level, options.log_facility, log_stderr); | ||
2103 | |||
2104 | /* Close the master side of the pseudo tty. */ | ||
2105 | close(ptyfd); | ||
2106 | |||
2107 | /* Make the pseudo tty our controlling tty. */ | ||
2108 | pty_make_controlling_tty(&ttyfd, ttyname); | ||
2109 | |||
2110 | /* Redirect stdin from the pseudo tty. */ | ||
2111 | if (dup2(ttyfd, fileno(stdin)) < 0) | ||
2112 | error("dup2 stdin failed: %.100s", strerror(errno)); | ||
2113 | |||
2114 | /* Redirect stdout to the pseudo tty. */ | ||
2115 | if (dup2(ttyfd, fileno(stdout)) < 0) | ||
2116 | error("dup2 stdin failed: %.100s", strerror(errno)); | ||
2117 | |||
2118 | /* Redirect stderr to the pseudo tty. */ | ||
2119 | if (dup2(ttyfd, fileno(stderr)) < 0) | ||
2120 | error("dup2 stdin failed: %.100s", strerror(errno)); | ||
2121 | |||
2122 | /* Close the extra descriptor for the pseudo tty. */ | ||
2123 | close(ttyfd); | ||
2124 | |||
2125 | /* | ||
2126 | * Get IP address of client. This is needed because we want | ||
2127 | * to record where the user logged in from. If the | ||
2128 | * connection is not a socket, let the ip address be 0.0.0.0. | ||
2129 | */ | ||
2130 | memset(&from, 0, sizeof(from)); | ||
2131 | if (packet_get_connection_in() == packet_get_connection_out()) { | ||
2132 | fromlen = sizeof(from); | ||
2133 | if (getpeername(packet_get_connection_in(), | ||
2134 | (struct sockaddr *) & from, &fromlen) < 0) { | ||
2135 | debug("getpeername: %.100s", strerror(errno)); | ||
2136 | fatal_cleanup(); | ||
2137 | } | ||
2138 | } | ||
2139 | /* Record that there was a login on that terminal. */ | ||
2140 | record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, | ||
2141 | (struct sockaddr *)&from); | ||
2142 | |||
2143 | /* Check if .hushlogin exists. */ | ||
2144 | snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); | ||
2145 | quiet_login = stat(line, &st) >= 0; | ||
2146 | |||
2147 | #ifdef USE_PAM | ||
2148 | if (!quiet_login) | ||
2149 | print_pam_messages(); | ||
2150 | #endif /* USE_PAM */ | ||
2151 | |||
2152 | /* | ||
2153 | * If the user has logged in before, display the time of last | ||
2154 | * login. However, don't display anything extra if a command | ||
2155 | * has been specified (so that ssh can be used to execute | ||
2156 | * commands on a remote machine without users knowing they | ||
2157 | * are going to another machine). Login(1) will do this for | ||
2158 | * us as well, so check if login(1) is used | ||
2159 | */ | ||
2160 | if (command == NULL && last_login_time != 0 && !quiet_login && | ||
2161 | !options.use_login) { | ||
2162 | /* Convert the date to a string. */ | ||
2163 | time_string = ctime(&last_login_time); | ||
2164 | /* Remove the trailing newline. */ | ||
2165 | if (strchr(time_string, '\n')) | ||
2166 | *strchr(time_string, '\n') = 0; | ||
2167 | /* Display the last login time. Host if displayed | ||
2168 | if known. */ | ||
2169 | if (strcmp(buf, "") == 0) | ||
2170 | printf("Last login: %s\r\n", time_string); | ||
2171 | else | ||
2172 | printf("Last login: %s from %s\r\n", time_string, buf); | ||
2173 | } | ||
2174 | /* | ||
2175 | * Print /etc/motd unless a command was specified or printing | ||
2176 | * it was disabled in server options or login(1) will be | ||
2177 | * used. Note that some machines appear to print it in | ||
2178 | * /etc/profile or similar. | ||
2179 | */ | ||
2180 | if (command == NULL && options.print_motd && !quiet_login && | ||
2181 | !options.use_login) { | ||
2182 | /* Print /etc/motd if it exists. */ | ||
2183 | f = fopen("/etc/motd", "r"); | ||
2184 | if (f) { | ||
2185 | while (fgets(line, sizeof(line), f)) | ||
2186 | fputs(line, stdout); | ||
2187 | fclose(f); | ||
2188 | } | ||
2189 | } | ||
2190 | /* Do common processing for the child, such as execing the command. */ | ||
2191 | do_child(command, pw, term, display, auth_proto, auth_data, ttyname); | ||
2192 | /* NOTREACHED */ | ||
2193 | } | ||
2194 | if (pid < 0) | ||
2195 | packet_disconnect("fork failed: %.100s", strerror(errno)); | ||
2196 | /* Parent. Close the slave side of the pseudo tty. */ | ||
2197 | close(ttyfd); | ||
2198 | |||
2199 | /* | ||
2200 | * Add a cleanup function to clear the utmp entry and record logout | ||
2201 | * time in case we call fatal() (e.g., the connection gets closed). | ||
2202 | */ | ||
2203 | cleanup_context.pid = pid; | ||
2204 | cleanup_context.ttyname = ttyname; | ||
2205 | fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | ||
2206 | fatal_remove_cleanup(pty_release_proc, (void *) ttyname); | ||
2207 | |||
2208 | /* | ||
2209 | * Create another descriptor of the pty master side for use as the | ||
2210 | * standard input. We could use the original descriptor, but this | ||
2211 | * simplifies code in server_loop. The descriptor is bidirectional. | ||
2212 | */ | ||
2213 | fdout = dup(ptyfd); | ||
2214 | if (fdout < 0) | ||
2215 | packet_disconnect("dup #1 failed: %.100s", strerror(errno)); | ||
2216 | |||
2217 | /* we keep a reference to the pty master */ | ||
2218 | ptymaster = dup(ptyfd); | ||
2219 | if (ptymaster < 0) | ||
2220 | packet_disconnect("dup #2 failed: %.100s", strerror(errno)); | ||
2221 | |||
2222 | /* Enter interactive session. */ | ||
2223 | server_loop(pid, ptyfd, fdout, -1); | ||
2224 | /* server_loop _has_ closed ptyfd and fdout. */ | ||
2225 | |||
2226 | /* Cancel the cleanup function. */ | ||
2227 | fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); | ||
2228 | |||
2229 | /* Record that the user has logged out. */ | ||
2230 | record_logout(pid, ttyname); | ||
2231 | |||
2232 | /* Release the pseudo-tty. */ | ||
2233 | pty_release(ttyname); | ||
2234 | |||
2235 | /* | ||
2236 | * Close the server side of the socket pairs. We must do this after | ||
2237 | * the pty cleanup, so that another process doesn't get this pty | ||
2238 | * while we're still cleaning up. | ||
2239 | */ | ||
2240 | if (close(ptymaster) < 0) | ||
2241 | error("close(ptymaster): %s", strerror(errno)); | ||
2242 | } | ||
2243 | |||
2244 | /* | ||
2245 | * Sets the value of the given variable in the environment. If the variable | ||
2246 | * already exists, its value is overriden. | ||
2247 | */ | ||
2248 | void | ||
2249 | child_set_env(char ***envp, unsigned int *envsizep, const char *name, | ||
2250 | const char *value) | ||
2251 | { | ||
2252 | unsigned int i, namelen; | ||
2253 | char **env; | ||
2254 | |||
2255 | /* | ||
2256 | * Find the slot where the value should be stored. If the variable | ||
2257 | * already exists, we reuse the slot; otherwise we append a new slot | ||
2258 | * at the end of the array, expanding if necessary. | ||
2259 | */ | ||
2260 | env = *envp; | ||
2261 | namelen = strlen(name); | ||
2262 | for (i = 0; env[i]; i++) | ||
2263 | if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') | ||
2264 | break; | ||
2265 | if (env[i]) { | ||
2266 | /* Reuse the slot. */ | ||
2267 | xfree(env[i]); | ||
2268 | } else { | ||
2269 | /* New variable. Expand if necessary. */ | ||
2270 | if (i >= (*envsizep) - 1) { | ||
2271 | (*envsizep) += 50; | ||
2272 | env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); | ||
2273 | } | ||
2274 | /* Need to set the NULL pointer at end of array beyond the new slot. */ | ||
2275 | env[i + 1] = NULL; | ||
2276 | } | ||
2277 | |||
2278 | /* Allocate space and format the variable in the appropriate slot. */ | ||
2279 | env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); | ||
2280 | snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); | ||
2281 | } | ||
2282 | |||
2283 | /* | ||
2284 | * Reads environment variables from the given file and adds/overrides them | ||
2285 | * into the environment. If the file does not exist, this does nothing. | ||
2286 | * Otherwise, it must consist of empty lines, comments (line starts with '#') | ||
2287 | * and assignments of the form name=value. No other forms are allowed. | ||
2288 | */ | ||
2289 | void | ||
2290 | read_environment_file(char ***env, unsigned int *envsize, | ||
2291 | const char *filename) | ||
2292 | { | ||
2293 | FILE *f; | ||
2294 | char buf[4096]; | ||
2295 | char *cp, *value; | ||
2296 | |||
2297 | f = fopen(filename, "r"); | ||
2298 | if (!f) | ||
2299 | return; | ||
2300 | |||
2301 | while (fgets(buf, sizeof(buf), f)) { | ||
2302 | for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) | ||
2303 | ; | ||
2304 | if (!*cp || *cp == '#' || *cp == '\n') | ||
2305 | continue; | ||
2306 | if (strchr(cp, '\n')) | ||
2307 | *strchr(cp, '\n') = '\0'; | ||
2308 | value = strchr(cp, '='); | ||
2309 | if (value == NULL) { | ||
2310 | fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); | ||
2311 | continue; | ||
2312 | } | ||
2313 | /* Replace the equals sign by nul, and advance value to the value string. */ | ||
2314 | *value = '\0'; | ||
2315 | value++; | ||
2316 | child_set_env(env, envsize, cp, value); | ||
2317 | } | ||
2318 | fclose(f); | ||
2319 | } | ||
2320 | |||
2321 | #ifdef USE_PAM | ||
2322 | /* | ||
2323 | * Sets any environment variables which have been specified by PAM | ||
2324 | */ | ||
2325 | void do_pam_environment(char ***env, int *envsize) | ||
2326 | { | ||
2327 | char *equals, var_name[512], var_val[512]; | ||
2328 | char **pam_env; | ||
2329 | int i; | ||
2330 | |||
2331 | if ((pam_env = fetch_pam_environment()) == NULL) | ||
2332 | return; | ||
2333 | |||
2334 | for(i = 0; pam_env[i] != NULL; i++) { | ||
2335 | if ((equals = strstr(pam_env[i], "=")) == NULL) | ||
2336 | continue; | ||
2337 | |||
2338 | if (strlen(pam_env[i]) < (sizeof(var_name) - 1)) | ||
2339 | { | ||
2340 | memset(var_name, '\0', sizeof(var_name)); | ||
2341 | memset(var_val, '\0', sizeof(var_val)); | ||
2342 | |||
2343 | strncpy(var_name, pam_env[i], equals - pam_env[i]); | ||
2344 | strcpy(var_val, equals + 1); | ||
2345 | |||
2346 | debug("PAM environment: %s=%s", var_name, var_val); | ||
2347 | |||
2348 | child_set_env(env, envsize, var_name, var_val); | ||
2349 | } | ||
2350 | } | ||
2351 | } | ||
2352 | #endif /* USE_PAM */ | ||
2353 | |||
2354 | /* | ||
2355 | * Performs common processing for the child, such as setting up the | ||
2356 | * environment, closing extra file descriptors, setting the user and group | ||
2357 | * ids, and executing the command or shell. | ||
2358 | */ | ||
2359 | void | ||
2360 | do_child(const char *command, struct passwd * pw, const char *term, | ||
2361 | const char *display, const char *auth_proto, | ||
2362 | const char *auth_data, const char *ttyname) | ||
2363 | { | ||
2364 | const char *shell, *cp = NULL; | ||
2365 | char buf[256]; | ||
2366 | FILE *f; | ||
2367 | unsigned int envsize, i; | ||
2368 | char **env; | ||
2369 | extern char **environ; | ||
2370 | struct stat st; | ||
2371 | char *argv[10]; | ||
2372 | |||
2373 | #ifndef USE_PAM /* pam_nologin handles this */ | ||
2374 | /* Check /etc/nologin. */ | ||
2375 | f = fopen("/etc/nologin", "r"); | ||
2376 | if (f) { | ||
2377 | /* /etc/nologin exists. Print its contents and exit. */ | ||
2378 | while (fgets(buf, sizeof(buf), f)) | ||
2379 | fputs(buf, stderr); | ||
2380 | fclose(f); | ||
2381 | if (pw->pw_uid != 0) | ||
2382 | exit(254); | ||
2383 | } | ||
2384 | #endif /* USE_PAM */ | ||
2385 | |||
2386 | /* Set login name in the kernel. */ | ||
2387 | if (setlogin(pw->pw_name) < 0) | ||
2388 | error("setlogin failed: %s", strerror(errno)); | ||
2389 | |||
2390 | /* Set uid, gid, and groups. */ | ||
2391 | /* Login(1) does this as well, and it needs uid 0 for the "-h" | ||
2392 | switch, so we let login(1) to this for us. */ | ||
2393 | if (!options.use_login) { | ||
2394 | if (getuid() == 0 || geteuid() == 0) { | ||
2395 | if (setgid(pw->pw_gid) < 0) { | ||
2396 | perror("setgid"); | ||
2397 | exit(1); | ||
2398 | } | ||
2399 | /* Initialize the group list. */ | ||
2400 | if (initgroups(pw->pw_name, pw->pw_gid) < 0) { | ||
2401 | perror("initgroups"); | ||
2402 | exit(1); | ||
2403 | } | ||
2404 | endgrent(); | ||
2405 | |||
2406 | /* Permanently switch to the desired uid. */ | ||
2407 | permanently_set_uid(pw->pw_uid); | ||
2408 | } | ||
2409 | if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) | ||
2410 | fatal("Failed to set uids to %d.", (int) pw->pw_uid); | ||
2411 | } | ||
2412 | /* | ||
2413 | * Get the shell from the password data. An empty shell field is | ||
2414 | * legal, and means /bin/sh. | ||
2415 | */ | ||
2416 | shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; | ||
2417 | |||
2418 | #ifdef AFS | ||
2419 | /* Try to get AFS tokens for the local cell. */ | ||
2420 | if (k_hasafs()) { | ||
2421 | char cell[64]; | ||
2422 | |||
2423 | if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) | ||
2424 | krb_afslog(cell, 0); | ||
2425 | |||
2426 | krb_afslog(0, 0); | ||
2427 | } | ||
2428 | #endif /* AFS */ | ||
2429 | |||
2430 | /* Initialize the environment. */ | ||
2431 | envsize = 100; | ||
2432 | env = xmalloc(envsize * sizeof(char *)); | ||
2433 | env[0] = NULL; | ||
2434 | |||
2435 | if (!options.use_login) { | ||
2436 | /* Set basic environment. */ | ||
2437 | child_set_env(&env, &envsize, "USER", pw->pw_name); | ||
2438 | child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); | ||
2439 | child_set_env(&env, &envsize, "HOME", pw->pw_dir); | ||
2440 | child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); | ||
2441 | |||
2442 | snprintf(buf, sizeof buf, "%.200s/%.50s", | ||
2443 | _PATH_MAILDIR, pw->pw_name); | ||
2444 | child_set_env(&env, &envsize, "MAIL", buf); | ||
2445 | |||
2446 | /* Normal systems set SHELL by default. */ | ||
2447 | child_set_env(&env, &envsize, "SHELL", shell); | ||
2448 | } | ||
2449 | if (getenv("TZ")) | ||
2450 | child_set_env(&env, &envsize, "TZ", getenv("TZ")); | ||
2451 | |||
2452 | /* Set custom environment options from RSA authentication. */ | ||
2453 | while (custom_environment) { | ||
2454 | struct envstring *ce = custom_environment; | ||
2455 | char *s = ce->s; | ||
2456 | int i; | ||
2457 | for (i = 0; s[i] != '=' && s[i]; i++); | ||
2458 | if (s[i] == '=') { | ||
2459 | s[i] = 0; | ||
2460 | child_set_env(&env, &envsize, s, s + i + 1); | ||
2461 | } | ||
2462 | custom_environment = ce->next; | ||
2463 | xfree(ce->s); | ||
2464 | xfree(ce); | ||
2465 | } | ||
2466 | |||
2467 | snprintf(buf, sizeof buf, "%.50s %d %d", | ||
2468 | get_remote_ipaddr(), get_remote_port(), get_local_port()); | ||
2469 | child_set_env(&env, &envsize, "SSH_CLIENT", buf); | ||
2470 | |||
2471 | if (ttyname) | ||
2472 | child_set_env(&env, &envsize, "SSH_TTY", ttyname); | ||
2473 | if (term) | ||
2474 | child_set_env(&env, &envsize, "TERM", term); | ||
2475 | if (display) | ||
2476 | child_set_env(&env, &envsize, "DISPLAY", display); | ||
2477 | |||
2478 | #ifdef _AIX | ||
2479 | { | ||
2480 | char *authstate,*krb5cc; | ||
2481 | |||
2482 | if ((authstate = getenv("AUTHSTATE")) != NULL) | ||
2483 | child_set_env(&env,&envsize,"AUTHSTATE",authstate); | ||
2484 | |||
2485 | if ((krb5cc = getenv("KRB5CCNAME")) != NULL) | ||
2486 | child_set_env(&env,&envsize,"KRB5CCNAME",krb5cc); | ||
2487 | } | ||
2488 | #endif | ||
2489 | |||
2490 | #ifdef KRB4 | ||
2491 | { | ||
2492 | extern char *ticket; | ||
2493 | |||
2494 | if (ticket) | ||
2495 | child_set_env(&env, &envsize, "KRBTKFILE", ticket); | ||
2496 | } | ||
2497 | #endif /* KRB4 */ | ||
2498 | |||
2499 | #ifdef USE_PAM | ||
2500 | /* Pull in any environment variables that may have been set by PAM. */ | ||
2501 | do_pam_environment(&env, &envsize); | ||
2502 | #endif /* USE_PAM */ | ||
2503 | |||
2504 | if (xauthfile) | ||
2505 | child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); | ||
2506 | |||
2507 | if (auth_get_socket_name() != NULL) | ||
2508 | child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, | ||
2509 | auth_get_socket_name()); | ||
2510 | |||
2511 | read_environment_file(&env,&envsize,"/etc/environment"); | ||
2512 | |||
2513 | /* read $HOME/.ssh/environment. */ | ||
2514 | if (!options.use_login) { | ||
2515 | snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); | ||
2516 | read_environment_file(&env, &envsize, buf); | ||
2517 | } | ||
2518 | if (debug_flag) { | ||
2519 | /* dump the environment */ | ||
2520 | fprintf(stderr, "Environment:\n"); | ||
2521 | for (i = 0; env[i]; i++) | ||
2522 | fprintf(stderr, " %.200s\n", env[i]); | ||
2523 | } | ||
2524 | /* | ||
2525 | * Close the connection descriptors; note that this is the child, and | ||
2526 | * the server will still have the socket open, and it is important | ||
2527 | * that we do not shutdown it. Note that the descriptors cannot be | ||
2528 | * closed before building the environment, as we call | ||
2529 | * get_remote_ipaddr there. | ||
2530 | */ | ||
2531 | if (packet_get_connection_in() == packet_get_connection_out()) | ||
2532 | close(packet_get_connection_in()); | ||
2533 | else { | ||
2534 | close(packet_get_connection_in()); | ||
2535 | close(packet_get_connection_out()); | ||
2536 | } | ||
2537 | /* | ||
2538 | * Close all descriptors related to channels. They will still remain | ||
2539 | * open in the parent. | ||
2540 | */ | ||
2541 | /* XXX better use close-on-exec? -markus */ | ||
2542 | channel_close_all(); | ||
2543 | |||
2544 | /* | ||
2545 | * Close any extra file descriptors. Note that there may still be | ||
2546 | * descriptors left by system functions. They will be closed later. | ||
2547 | */ | ||
2548 | endpwent(); | ||
2549 | |||
2550 | /* | ||
2551 | * Close any extra open file descriptors so that we don\'t have them | ||
2552 | * hanging around in clients. Note that we want to do this after | ||
2553 | * initgroups, because at least on Solaris 2.3 it leaves file | ||
2554 | * descriptors open. | ||
2555 | */ | ||
2556 | for (i = 3; i < 64; i++) | ||
2557 | close(i); | ||
2558 | |||
2559 | /* Change current directory to the user\'s home directory. */ | ||
2560 | if (chdir(pw->pw_dir) < 0) | ||
2561 | fprintf(stderr, "Could not chdir to home directory %s: %s\n", | ||
2562 | pw->pw_dir, strerror(errno)); | ||
2563 | |||
2564 | /* | ||
2565 | * Must take new environment into use so that .ssh/rc, /etc/sshrc and | ||
2566 | * xauth are run in the proper environment. | ||
2567 | */ | ||
2568 | environ = env; | ||
2569 | |||
2570 | /* | ||
2571 | * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first | ||
2572 | * in this order). | ||
2573 | */ | ||
2574 | if (!options.use_login) { | ||
2575 | if (stat(SSH_USER_RC, &st) >= 0) { | ||
2576 | if (debug_flag) | ||
2577 | fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); | ||
2578 | |||
2579 | f = popen("/bin/sh " SSH_USER_RC, "w"); | ||
2580 | if (f) { | ||
2581 | if (auth_proto != NULL && auth_data != NULL) | ||
2582 | fprintf(f, "%s %s\n", auth_proto, auth_data); | ||
2583 | pclose(f); | ||
2584 | } else | ||
2585 | fprintf(stderr, "Could not run %s\n", SSH_USER_RC); | ||
2586 | } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { | ||
2587 | if (debug_flag) | ||
2588 | fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); | ||
2589 | |||
2590 | f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); | ||
2591 | if (f) { | ||
2592 | if (auth_proto != NULL && auth_data != NULL) | ||
2593 | fprintf(f, "%s %s\n", auth_proto, auth_data); | ||
2594 | pclose(f); | ||
2595 | } else | ||
2596 | fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); | ||
2597 | } | ||
2598 | #ifdef XAUTH_PATH | ||
2599 | else { | ||
2600 | /* Add authority data to .Xauthority if appropriate. */ | ||
2601 | if (auth_proto != NULL && auth_data != NULL) { | ||
2602 | if (debug_flag) | ||
2603 | fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", | ||
2604 | XAUTH_PATH, display, auth_proto, auth_data); | ||
2605 | |||
2606 | f = popen(XAUTH_PATH " -q -", "w"); | ||
2607 | if (f) { | ||
2608 | fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); | ||
2609 | pclose(f); | ||
2610 | } else | ||
2611 | fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); | ||
2612 | } | ||
2613 | } | ||
2614 | #endif /* XAUTH_PATH */ | ||
2615 | |||
2616 | /* Get the last component of the shell name. */ | ||
2617 | cp = strrchr(shell, '/'); | ||
2618 | if (cp) | ||
2619 | cp++; | ||
2620 | else | ||
2621 | cp = shell; | ||
2622 | } | ||
2623 | /* | ||
2624 | * If we have no command, execute the shell. In this case, the shell | ||
2625 | * name to be passed in argv[0] is preceded by '-' to indicate that | ||
2626 | * this is a login shell. | ||
2627 | */ | ||
2628 | if (!command) { | ||
2629 | if (!options.use_login) { | ||
2630 | char buf[256]; | ||
2631 | |||
2632 | /* | ||
2633 | * Check for mail if we have a tty and it was enabled | ||
2634 | * in server options. | ||
2635 | */ | ||
2636 | if (ttyname && options.check_mail) { | ||
2637 | char *mailbox; | ||
2638 | struct stat mailstat; | ||
2639 | mailbox = getenv("MAIL"); | ||
2640 | if (mailbox != NULL) { | ||
2641 | if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) | ||
2642 | printf("No mail.\n"); | ||
2643 | else if (mailstat.st_mtime < mailstat.st_atime) | ||
2644 | printf("You have mail.\n"); | ||
2645 | else | ||
2646 | printf("You have new mail.\n"); | ||
2647 | } | ||
2648 | } | ||
2649 | /* Start the shell. Set initial character to '-'. */ | ||
2650 | buf[0] = '-'; | ||
2651 | strncpy(buf + 1, cp, sizeof(buf) - 1); | ||
2652 | buf[sizeof(buf) - 1] = 0; | ||
2653 | |||
2654 | /* Execute the shell. */ | ||
2655 | argv[0] = buf; | ||
2656 | argv[1] = NULL; | ||
2657 | execve(shell, argv, env); | ||
2658 | |||
2659 | /* Executing the shell failed. */ | ||
2660 | perror(shell); | ||
2661 | exit(1); | ||
2662 | |||
2663 | } else { | ||
2664 | /* Launch login(1). */ | ||
2665 | |||
2666 | execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(), | ||
2667 | "-p", "-f", "--", pw->pw_name, NULL); | ||
2668 | |||
2669 | /* Login couldn't be executed, die. */ | ||
2670 | |||
2671 | perror("login"); | ||
2672 | exit(1); | ||
2673 | } | ||
2674 | } | ||
2675 | /* | ||
2676 | * Execute the command using the user's shell. This uses the -c | ||
2677 | * option to execute the command. | ||
2678 | */ | ||
2679 | argv[0] = (char *) cp; | ||
2680 | argv[1] = "-c"; | ||
2681 | argv[2] = (char *) command; | ||
2682 | argv[3] = NULL; | ||
2683 | execve(shell, argv, env); | ||
2684 | perror(shell); | ||
2685 | exit(1); | ||
2686 | } | ||