windows/winnps.c

   1 /*
   2  * Windows support module which deals with being a named-pipe server.
   3  */
   4
   5 #include <stdio.h>
   6 #include <assert.h>
   7
   8 #define DEFINE_PLUG_METHOD_MACROS
   9 #include "tree234.h"
  10 #include "putty.h"
  11 #include "network.h"
  12 #include "proxy.h"
  13 #include "ssh.h"
  14
  15 #if !defined NO_SECURITY
  16
  17 #include "winsecur.h"
  18
  19 Socket make_handle_socket(HANDLE send_H, HANDLE recv_H, Plug plug,
  20                           int overlapped);
  21
  22 typedef struct Socket_named_pipe_server_tag *Named_Pipe_Server_Socket;
  23 struct Socket_named_pipe_server_tag {
  24     const struct socket_function_table *fn;
  25     /* the above variable absolutely *must* be the first in this structure */
  26
  27     /* Parameters for (repeated) creation of named pipe objects */
  28     PSECURITY_DESCRIPTOR psd;
  29     PACL acl;
  30     char *pipename;
  31
  32     /* The current named pipe object + attempt to connect to it */
  33     HANDLE pipehandle;
  34     OVERLAPPED connect_ovl;
  35
  36     /* PuTTY Socket machinery */
  37     Plug plug;
  38     char *error;
  39 };
  40
  41 static Plug sk_namedpipeserver_plug(Socket s, Plug p)
  42 {
  43     Named_Pipe_Server_Socket ps = (Named_Pipe_Server_Socket) s;
  44     Plug ret = ps->plug;
  45     if (p)
  46         ps->plug = p;
  47     return ret;
  48 }
  49
  50 static void sk_namedpipeserver_close(Socket s)
  51 {
  52     Named_Pipe_Server_Socket ps = (Named_Pipe_Server_Socket) s;
  53
  54     CloseHandle(ps->pipehandle);
  55     CloseHandle(ps->connect_ovl.hEvent);
  56     sfree(ps->error);
  57     sfree(ps->pipename);
  58     if (ps->acl)
  59         LocalFree(ps->acl);
  60     if (ps->psd)
  61         LocalFree(ps->psd);
  62     sfree(ps);
  63 }
  64
  65 static const char *sk_namedpipeserver_socket_error(Socket s)
  66 {
  67     Named_Pipe_Server_Socket ps = (Named_Pipe_Server_Socket) s;
  68     return ps->error;
  69 }
  70
  71 static int create_named_pipe(Named_Pipe_Server_Socket ps, int first_instance)
  72 {
  73     SECURITY_ATTRIBUTES sa;
  74
  75     memset(&sa, 0, sizeof(sa));
  76     sa.nLength = sizeof(sa);
  77     sa.lpSecurityDescriptor = ps->psd;
  78     sa.bInheritHandle = FALSE;
  79
  80     ps->pipehandle = CreateNamedPipe
  81         (/* lpName */
  82          ps->pipename,
  83
  84          /* dwOpenMode */
  85          PIPE_ACCESS_DUPLEX |
  86          FILE_FLAG_OVERLAPPED |
  87          (first_instance ? FILE_FLAG_FIRST_PIPE_INSTANCE : 0),
  88
  89          /* dwPipeMode */
  90          PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT
  91 #ifdef PIPE_REJECT_REMOTE_CLIENTS
  92          | PIPE_REJECT_REMOTE_CLIENTS
  93 #endif
  94          ,
  95
  96          /* nMaxInstances */
  97          PIPE_UNLIMITED_INSTANCES,
  98
  99          /* nOutBufferSize, nInBufferSize */
 100          4096, 4096,     /* FIXME: think harder about buffer sizes? */
 101
 102          /* nDefaultTimeOut */
 103          0 /* default timeout */,
 104
 105          /* lpSecurityAttributes */
 106          &sa);
 107
 108     return ps->pipehandle != INVALID_HANDLE_VALUE;
 109 }
 110
 111 static Socket named_pipe_accept(accept_ctx_t ctx, Plug plug)
 112 {
 113     HANDLE conn = (HANDLE)ctx.p;
 114
 115     return make_handle_socket(conn, conn, plug, TRUE);
 116 }
 117
 118 /*
 119  * Dummy SockAddr type which just holds a named pipe address. Only
 120  * used for calling plug_log from named_pipe_accept_loop() here.
 121  */
 122 SockAddr sk_namedpipe_addr(const char *pipename);
 123
 124 static void named_pipe_accept_loop(Named_Pipe_Server_Socket ps,
 125                                    int got_one_already)
 126 {
 127     while (1) {
 128         int error;
 129         char *errmsg;
 130
 131         if (got_one_already) {
 132             /* If we were called with a connection already waiting,
 133              * skip this step. */
 134             got_one_already = FALSE;
 135             error = 0;
 136         } else {
 137             /*
 138              * Call ConnectNamedPipe, which might succeed or might
 139              * tell us that an overlapped operation is in progress and
 140              * we should wait for our event object.
 141              */
 142             if (ConnectNamedPipe(ps->pipehandle, &ps->connect_ovl))
 143                 error = 0;
 144             else
 145                 error = GetLastError();
 146
 147             if (error == ERROR_IO_PENDING)
 148                 return;
 149         }
 150
 151         if (error == 0 || error == ERROR_PIPE_CONNECTED) {
 152             /*
 153              * We've successfully retrieved an incoming connection, so
 154              * ps->pipehandle now refers to that connection. So
 155              * convert that handle into a separate connection-type
 156              * Socket, and create a fresh one to be the new listening
 157              * pipe.
 158              */
 159             HANDLE conn = ps->pipehandle;
 160             accept_ctx_t actx;
 161
 162             actx.p = (void *)conn;
 163             if (plug_accepting(ps->plug, named_pipe_accept, actx)) {
 164                 /*
 165                  * If the plug didn't want the connection, might as
 166                  * well close this handle.
 167                  */
 168                 CloseHandle(conn);
 169             }
 170
 171             if (!create_named_pipe(ps, FALSE)) {
 172                 error = GetLastError();
 173             } else {
 174                 /*
 175                  * Go round again to see if more connections can be
 176                  * got, or to begin waiting on the event object.
 177                  */
 178                 continue;
 179             }
 180         }
 181
 182         errmsg = dupprintf("Error while listening to named pipe: %s",
 183                            win_strerror(error));
 184         plug_log(ps->plug, 1, sk_namedpipe_addr(ps->pipename), 0,
 185                  errmsg, error);
 186         sfree(errmsg);
 187         break;
 188     }
 189 }
 190
 191 static void named_pipe_connect_callback(void *vps)
 192 {
 193     Named_Pipe_Server_Socket ps = (Named_Pipe_Server_Socket)vps;
 194     named_pipe_accept_loop(ps, TRUE);
 195 }
 196
 197 Socket new_named_pipe_listener(const char *pipename, Plug plug)
 198 {
 199     /*
 200      * This socket type is only used for listening, so it should never
 201      * be asked to write or flush or set_frozen.
 202      */
 203     static const struct socket_function_table socket_fn_table = {
 204         sk_namedpipeserver_plug,
 205         sk_namedpipeserver_close,
 206         NULL /* write */,
 207         NULL /* write_oob */,
 208         NULL /* write_eof */,
 209         NULL /* flush */,
 210         NULL /* set_frozen */,
 211         sk_namedpipeserver_socket_error
 212     };
 213
 214     Named_Pipe_Server_Socket ret;
 215
 216     ret = snew(struct Socket_named_pipe_server_tag);
 217     ret->fn = &socket_fn_table;
 218     ret->plug = plug;
 219     ret->error = NULL;
 220     ret->psd = NULL;
 221     ret->pipename = dupstr(pipename);
 222     ret->acl = NULL;
 223
 224     assert(strncmp(pipename, "\\\\.\\pipe\\", 9) == 0);
 225     assert(strchr(pipename + 9, '\\') == NULL);
 226
 227     if (!make_private_security_descriptor(GENERIC_READ | GENERIC_WRITE,
 228                                           &ret->psd, &ret->acl, &ret->error)) {
 229         goto cleanup;
 230     }
 231
 232     if (!create_named_pipe(ret, TRUE)) {
 233         ret->error = dupprintf("unable to create named pipe '%s': %s",
 234                                pipename, win_strerror(GetLastError()));
 235         goto cleanup;
 236     }
 237
 238     memset(&ret->connect_ovl, 0, sizeof(ret->connect_ovl));
 239     ret->connect_ovl.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
 240     handle_add_foreign_event(ret->connect_ovl.hEvent,
 241                              named_pipe_connect_callback, ret);
 242     named_pipe_accept_loop(ret, FALSE);
 243
 244   cleanup:
 245     return (Socket) ret;
 246 }
 247
 248 #endif /* !defined NO_SECURITY */