| 1 | /* |
| 2 | * uxproxy.c: Unix implementation of platform_new_connection(), |
| 3 | * supporting an OpenSSH-like proxy command. |
| 4 | */ |
| 5 | |
| 6 | #include <stdio.h> |
| 7 | #include <assert.h> |
| 8 | #include <errno.h> |
| 9 | #include <unistd.h> |
| 10 | #include <fcntl.h> |
| 11 | |
| 12 | #define DEFINE_PLUG_METHOD_MACROS |
| 13 | #include "tree234.h" |
| 14 | #include "putty.h" |
| 15 | #include "network.h" |
| 16 | #include "proxy.h" |
| 17 | |
| 18 | typedef struct Socket_localproxy_tag * Local_Proxy_Socket; |
| 19 | |
| 20 | struct Socket_localproxy_tag { |
| 21 | const struct socket_function_table *fn; |
| 22 | /* the above variable absolutely *must* be the first in this structure */ |
| 23 | |
| 24 | int to_cmd, from_cmd; /* fds */ |
| 25 | |
| 26 | char *error; |
| 27 | |
| 28 | Plug plug; |
| 29 | |
| 30 | bufchain pending_output_data; |
| 31 | bufchain pending_input_data; |
| 32 | |
| 33 | void *privptr; |
| 34 | }; |
| 35 | |
| 36 | static int localproxy_select_result(int fd, int event); |
| 37 | |
| 38 | /* |
| 39 | * Trees to look up the pipe fds in. |
| 40 | */ |
| 41 | static tree234 *localproxy_by_fromfd, *localproxy_by_tofd; |
| 42 | static int localproxy_fromfd_cmp(void *av, void *bv) |
| 43 | { |
| 44 | Local_Proxy_Socket a = (Local_Proxy_Socket)av; |
| 45 | Local_Proxy_Socket b = (Local_Proxy_Socket)bv; |
| 46 | if (a->from_cmd < b->from_cmd) |
| 47 | return -1; |
| 48 | if (a->from_cmd > b->from_cmd) |
| 49 | return +1; |
| 50 | return 0; |
| 51 | } |
| 52 | static int localproxy_fromfd_find(void *av, void *bv) |
| 53 | { |
| 54 | int a = *(int *)av; |
| 55 | Local_Proxy_Socket b = (Local_Proxy_Socket)bv; |
| 56 | if (a < b->from_cmd) |
| 57 | return -1; |
| 58 | if (a > b->from_cmd) |
| 59 | return +1; |
| 60 | return 0; |
| 61 | } |
| 62 | static int localproxy_tofd_cmp(void *av, void *bv) |
| 63 | { |
| 64 | Local_Proxy_Socket a = (Local_Proxy_Socket)av; |
| 65 | Local_Proxy_Socket b = (Local_Proxy_Socket)bv; |
| 66 | if (a->to_cmd < b->to_cmd) |
| 67 | return -1; |
| 68 | if (a->to_cmd > b->to_cmd) |
| 69 | return +1; |
| 70 | return 0; |
| 71 | } |
| 72 | static int localproxy_tofd_find(void *av, void *bv) |
| 73 | { |
| 74 | int a = *(int *)av; |
| 75 | Local_Proxy_Socket b = (Local_Proxy_Socket)bv; |
| 76 | if (a < b->to_cmd) |
| 77 | return -1; |
| 78 | if (a > b->to_cmd) |
| 79 | return +1; |
| 80 | return 0; |
| 81 | } |
| 82 | |
| 83 | /* basic proxy socket functions */ |
| 84 | |
| 85 | static Plug sk_localproxy_plug (Socket s, Plug p) |
| 86 | { |
| 87 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 88 | Plug ret = ps->plug; |
| 89 | if (p) |
| 90 | ps->plug = p; |
| 91 | return ret; |
| 92 | } |
| 93 | |
| 94 | static void sk_localproxy_close (Socket s) |
| 95 | { |
| 96 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 97 | |
| 98 | del234(localproxy_by_fromfd, ps); |
| 99 | del234(localproxy_by_tofd, ps); |
| 100 | |
| 101 | uxsel_del(ps->to_cmd); |
| 102 | uxsel_del(ps->from_cmd); |
| 103 | close(ps->to_cmd); |
| 104 | close(ps->from_cmd); |
| 105 | |
| 106 | sfree(ps); |
| 107 | } |
| 108 | |
| 109 | static int localproxy_try_send(Local_Proxy_Socket ps) |
| 110 | { |
| 111 | int sent = 0; |
| 112 | |
| 113 | while (bufchain_size(&ps->pending_output_data) > 0) { |
| 114 | void *data; |
| 115 | int len, ret; |
| 116 | |
| 117 | bufchain_prefix(&ps->pending_output_data, &data, &len); |
| 118 | ret = write(ps->to_cmd, data, len); |
| 119 | if (ret < 0 && errno != EWOULDBLOCK) { |
| 120 | /* We're inside the Unix frontend here, so we know |
| 121 | * that the frontend handle is unnecessary. */ |
| 122 | logevent(NULL, strerror(errno)); |
| 123 | fatalbox("%s", strerror(errno)); |
| 124 | } else if (ret <= 0) { |
| 125 | break; |
| 126 | } else { |
| 127 | bufchain_consume(&ps->pending_output_data, ret); |
| 128 | sent += ret; |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | if (bufchain_size(&ps->pending_output_data) == 0) |
| 133 | uxsel_del(ps->to_cmd); |
| 134 | else |
| 135 | uxsel_set(ps->to_cmd, 2, localproxy_select_result); |
| 136 | |
| 137 | return sent; |
| 138 | } |
| 139 | |
| 140 | static int sk_localproxy_write (Socket s, const char *data, int len) |
| 141 | { |
| 142 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 143 | |
| 144 | bufchain_add(&ps->pending_output_data, data, len); |
| 145 | |
| 146 | localproxy_try_send(ps); |
| 147 | |
| 148 | return bufchain_size(&ps->pending_output_data); |
| 149 | } |
| 150 | |
| 151 | static int sk_localproxy_write_oob (Socket s, const char *data, int len) |
| 152 | { |
| 153 | /* |
| 154 | * oob data is treated as inband; nasty, but nothing really |
| 155 | * better we can do |
| 156 | */ |
| 157 | return sk_localproxy_write(s, data, len); |
| 158 | } |
| 159 | |
| 160 | static void sk_localproxy_flush (Socket s) |
| 161 | { |
| 162 | /* Local_Proxy_Socket ps = (Local_Proxy_Socket) s; */ |
| 163 | /* do nothing */ |
| 164 | } |
| 165 | |
| 166 | static void sk_localproxy_set_private_ptr (Socket s, void *ptr) |
| 167 | { |
| 168 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 169 | ps->privptr = ptr; |
| 170 | } |
| 171 | |
| 172 | static void * sk_localproxy_get_private_ptr (Socket s) |
| 173 | { |
| 174 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 175 | return ps->privptr; |
| 176 | } |
| 177 | |
| 178 | static void sk_localproxy_set_frozen (Socket s, int is_frozen) |
| 179 | { |
| 180 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 181 | |
| 182 | if (is_frozen) |
| 183 | uxsel_del(ps->from_cmd); |
| 184 | else |
| 185 | uxsel_set(ps->from_cmd, 1, localproxy_select_result); |
| 186 | } |
| 187 | |
| 188 | static const char * sk_localproxy_socket_error (Socket s) |
| 189 | { |
| 190 | Local_Proxy_Socket ps = (Local_Proxy_Socket) s; |
| 191 | return ps->error; |
| 192 | } |
| 193 | |
| 194 | static int localproxy_select_result(int fd, int event) |
| 195 | { |
| 196 | Local_Proxy_Socket s; |
| 197 | char buf[20480]; |
| 198 | int ret; |
| 199 | |
| 200 | if (!(s = find234(localproxy_by_fromfd, &fd, localproxy_fromfd_find)) && |
| 201 | !(s = find234(localproxy_by_tofd, &fd, localproxy_tofd_find)) ) |
| 202 | return 1; /* boggle */ |
| 203 | |
| 204 | if (event == 1) { |
| 205 | assert(fd == s->from_cmd); |
| 206 | ret = read(fd, buf, sizeof(buf)); |
| 207 | if (ret < 0) { |
| 208 | return plug_closing(s->plug, strerror(errno), errno, 0); |
| 209 | } else if (ret == 0) { |
| 210 | return plug_closing(s->plug, NULL, 0, 0); |
| 211 | } else { |
| 212 | return plug_receive(s->plug, 1, buf, ret); |
| 213 | } |
| 214 | } else if (event == 2) { |
| 215 | assert(fd == s->to_cmd); |
| 216 | if (localproxy_try_send(s)) |
| 217 | plug_sent(s->plug, bufchain_size(&s->pending_output_data)); |
| 218 | return 1; |
| 219 | } |
| 220 | |
| 221 | return 1; |
| 222 | } |
| 223 | |
| 224 | Socket platform_new_connection(SockAddr addr, char *hostname, |
| 225 | int port, int privport, |
| 226 | int oobinline, int nodelay, int keepalive, |
| 227 | Plug plug, const Config *cfg) |
| 228 | { |
| 229 | char *cmd; |
| 230 | |
| 231 | static const struct socket_function_table socket_fn_table = { |
| 232 | sk_localproxy_plug, |
| 233 | sk_localproxy_close, |
| 234 | sk_localproxy_write, |
| 235 | sk_localproxy_write_oob, |
| 236 | sk_localproxy_flush, |
| 237 | sk_localproxy_set_private_ptr, |
| 238 | sk_localproxy_get_private_ptr, |
| 239 | sk_localproxy_set_frozen, |
| 240 | sk_localproxy_socket_error |
| 241 | }; |
| 242 | |
| 243 | Local_Proxy_Socket ret; |
| 244 | int to_cmd_pipe[2], from_cmd_pipe[2], pid; |
| 245 | |
| 246 | if (cfg->proxy_type != PROXY_CMD) |
| 247 | return NULL; |
| 248 | |
| 249 | cmd = format_telnet_command(addr, port, cfg); |
| 250 | |
| 251 | ret = snew(struct Socket_localproxy_tag); |
| 252 | ret->fn = &socket_fn_table; |
| 253 | ret->plug = plug; |
| 254 | ret->error = NULL; |
| 255 | |
| 256 | bufchain_init(&ret->pending_input_data); |
| 257 | bufchain_init(&ret->pending_output_data); |
| 258 | |
| 259 | /* |
| 260 | * Create the pipes to the proxy command, and spawn the proxy |
| 261 | * command process. |
| 262 | */ |
| 263 | if (pipe(to_cmd_pipe) < 0 || |
| 264 | pipe(from_cmd_pipe) < 0) { |
| 265 | ret->error = dupprintf("pipe: %s", strerror(errno)); |
| 266 | return (Socket)ret; |
| 267 | } |
| 268 | |
| 269 | pid = fork(); |
| 270 | |
| 271 | if (pid < 0) { |
| 272 | ret->error = dupprintf("fork: %s", strerror(errno)); |
| 273 | return (Socket)ret; |
| 274 | } else if (pid == 0) { |
| 275 | int i; |
| 276 | close(0); |
| 277 | close(1); |
| 278 | dup2(to_cmd_pipe[0], 0); |
| 279 | dup2(from_cmd_pipe[1], 1); |
| 280 | for (i = 3; i < 127; i++) |
| 281 | close(i); |
| 282 | fcntl(0, F_SETFD, 0); |
| 283 | fcntl(1, F_SETFD, 0); |
| 284 | execl("/bin/sh", "sh", "-c", cmd, NULL); |
| 285 | _exit(255); |
| 286 | } |
| 287 | |
| 288 | close(to_cmd_pipe[0]); |
| 289 | close(from_cmd_pipe[1]); |
| 290 | |
| 291 | ret->to_cmd = to_cmd_pipe[1]; |
| 292 | ret->from_cmd = from_cmd_pipe[0]; |
| 293 | |
| 294 | if (!localproxy_by_fromfd) |
| 295 | localproxy_by_fromfd = newtree234(localproxy_fromfd_cmp); |
| 296 | if (!localproxy_by_tofd) |
| 297 | localproxy_by_tofd = newtree234(localproxy_tofd_cmp); |
| 298 | |
| 299 | add234(localproxy_by_fromfd, ret); |
| 300 | add234(localproxy_by_tofd, ret); |
| 301 | |
| 302 | uxsel_set(ret->from_cmd, 1, localproxy_select_result); |
| 303 | |
| 304 | /* We are responsible for this and don't need it any more */ |
| 305 | sk_addr_free(addr); |
| 306 | |
| 307 | return (Socket) ret; |
| 308 | } |