root/src/vfs/sftpfs/config_parser.c

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DEFINITIONS

This source file includes following definitions.
  1. sftpfs_ssh_config_entity_free
  2. sftpfs_correct_file_name
  3. sftpfs_fill_config_entity_from_string
  4. sftpfs_fill_config_entity_from_config
  5. sftpfs_get_config_entity
  6. sftpfs_fill_connection_data_from_config
  7. sftpfs_init_config_variables_patterns
  8. sftpfs_deinit_config_variables_patterns

   1 /* Virtual File System: SFTP file system.
   2    The SSH config parser
   3 
   4    Copyright (C) 2011-2019
   5    Free Software Foundation, Inc.
   6 
   7    Written by:
   8    Ilia Maslakov <il.smind@gmail.com>, 2011
   9    Slava Zanko <slavazanko@gmail.com>, 2011, 2012, 2013
  10 
  11    This file is part of the Midnight Commander.
  12 
  13    The Midnight Commander is free software: you can redistribute it
  14    and/or modify it under the terms of the GNU General Public License as
  15    published by the Free Software Foundation, either version 3 of the License,
  16    or (at your option) any later version.
  17 
  18    The Midnight Commander is distributed in the hope that it will be useful,
  19    but WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21    GNU General Public License for more details.
  22 
  23    You should have received a copy of the GNU General Public License
  24    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  25  */
  26 
  27 #include <config.h>
  28 #include <errno.h>
  29 #include <stddef.h>
  30 #include <stdlib.h>             /* atoi() */
  31 
  32 #include "lib/global.h"
  33 
  34 #include "lib/search.h"
  35 #include "lib/util.h"           /* tilde_expand() */
  36 #include "lib/vfs/utilvfs.h"
  37 
  38 #include "internal.h"
  39 
  40 /*** global variables ****************************************************************************/
  41 
  42 /*** file scope macro definitions ****************************************************************/
  43 
  44 #define SFTP_DEFAULT_PORT 22
  45 
  46 #ifndef SFTPFS_SSH_CONFIG
  47 #define SFTPFS_SSH_CONFIG "~/.ssh/config"
  48 #endif
  49 
  50 /*** file scope type declarations ****************************************************************/
  51 
  52 typedef struct
  53 {
  54     char *real_host;            /* host DNS name or ip address */
  55     int port;                   /* port for connect to host */
  56     char *user;                 /* the user to log in as */
  57     gboolean password_auth;     /* FALSE - no passwords allowed (default TRUE) */
  58     gboolean identities_only;   /* TRUE - no ssh agent (default FALSE) */
  59     gboolean pubkey_auth;       /* FALSE - disable public key authentication (default TRUE) */
  60     char *identity_file;        /* A file from which the user's DSA, ECDSA or DSA authentication identity is read. */
  61 } sftpfs_ssh_config_entity_t;
  62 
  63 enum config_var_type
  64 {
  65     STRING,
  66     INTEGER,
  67     BOOLEAN,
  68     FILENAME
  69 };
  70 
  71 /*** file scope variables ************************************************************************/
  72 
  73 /* *INDENT-OFF* */
  74 static struct
  75 {
  76     const char *pattern;
  77     mc_search_t *pattern_regexp;
  78     enum config_var_type type;
  79     size_t offset;
  80 } config_variables[] =
  81 {
  82     {"^\\s*User\\s+(.*)$", NULL, STRING, offsetof (sftpfs_ssh_config_entity_t, user)},
  83     {"^\\s*HostName\\s+(.*)$", NULL, STRING, offsetof (sftpfs_ssh_config_entity_t, real_host)},
  84     {"^\\s*IdentitiesOnly\\s+(.*)$", NULL, BOOLEAN, offsetof (sftpfs_ssh_config_entity_t, identities_only)},
  85     {"^\\s*IdentityFile\\s+(.*)$", NULL, FILENAME, offsetof (sftpfs_ssh_config_entity_t, identity_file)},
  86     {"^\\s*Port\\s+(.*)$", NULL, INTEGER, offsetof (sftpfs_ssh_config_entity_t, port)},
  87     {"^\\s*PasswordAuthentication\\s+(.*)$", NULL, BOOLEAN, offsetof (sftpfs_ssh_config_entity_t, password_auth)},
  88     {"^\\s*PubkeyAuthentication\\s+(.*)$", NULL, STRING, offsetof (sftpfs_ssh_config_entity_t, pubkey_auth)},
  89     {NULL, NULL, 0, 0}
  90 };
  91 /* *INDENT-ON* */
  92 
  93 /* --------------------------------------------------------------------------------------------- */
  94 /*** file scope functions ************************************************************************/
  95 /* --------------------------------------------------------------------------------------------- */
  96 /**
  97  * Free one config entity.
  98  *
  99  * @param config_entity config entity structure
 100  */
 101 
 102 static void
 103 sftpfs_ssh_config_entity_free (sftpfs_ssh_config_entity_t * config_entity)
     /* [previous][next][first][last][top][bottom][index][help]  */
 104 {
 105     g_free (config_entity->real_host);
 106     g_free (config_entity->user);
 107     g_free (config_entity->identity_file);
 108     g_free (config_entity);
 109 }
 110 
 111 /* --------------------------------------------------------------------------------------------- */
 112 /**
 113  * Transform tilda (~) to full home dirname.
 114  *
 115  * @param filename file name with tilda
 116  * @return newly allocated file name with full home dirname
 117  */
 118 
 119 static char *
 120 sftpfs_correct_file_name (const char *filename)
     /* [previous][next][first][last][top][bottom][index][help]  */
 121 {
 122     vfs_path_t *vpath;
 123     char *ret_value;
 124 
 125     ret_value = tilde_expand (filename);
 126     vpath = vfs_path_from_str (ret_value);
 127     g_free (ret_value);
 128     ret_value = g_strdup (vfs_path_as_str (vpath));
 129     vfs_path_free (vpath);
 130     return ret_value;
 131 }
 132 
 133 /* --------------------------------------------------------------------------------------------- */
 134 
 135 #define POINTER_TO_STRUCTURE_MEMBER(type)  \
 136     ((type) ((char *) config_entity + (size_t) config_variables[i].offset))
 137 
 138 /**
 139  * Parse string and filling one config entity by parsed data.
 140  *
 141  * @param config_entity config entity structure
 142  * @param buffer        string for parce
 143  */
 144 
 145 static void
 146 sftpfs_fill_config_entity_from_string (sftpfs_ssh_config_entity_t * config_entity, char *buffer)
     /* [previous][next][first][last][top][bottom][index][help]  */
 147 {
 148     int i;
 149 
 150     for (i = 0; config_variables[i].pattern != NULL; i++)
 151     {
 152         if (mc_search_run (config_variables[i].pattern_regexp, buffer, 0, strlen (buffer), NULL))
 153         {
 154             int value_offset;
 155             char *value;
 156 
 157             int *pointer_int;
 158             char **pointer_str;
 159             gboolean *pointer_bool;
 160 
 161             /* Calculate start of value in string */
 162             value_offset = mc_search_getstart_result_by_num (config_variables[i].pattern_regexp, 1);
 163             value = &buffer[value_offset];
 164 
 165             switch (config_variables[i].type)
 166             {
 167             case STRING:
 168                 pointer_str = POINTER_TO_STRUCTURE_MEMBER (char **);
 169                 *pointer_str = g_strdup (value);
 170                 break;
 171             case FILENAME:
 172                 pointer_str = POINTER_TO_STRUCTURE_MEMBER (char **);
 173                 *pointer_str = sftpfs_correct_file_name (value);
 174                 break;
 175             case INTEGER:
 176                 pointer_int = POINTER_TO_STRUCTURE_MEMBER (int *);
 177                 *pointer_int = atoi (value);
 178                 break;
 179             case BOOLEAN:
 180                 pointer_bool = POINTER_TO_STRUCTURE_MEMBER (gboolean *);
 181                 *pointer_bool = strcasecmp (value, "True") == 0;
 182                 break;
 183             default:
 184                 continue;
 185             }
 186             return;
 187         }
 188     }
 189 }
 190 
 191 #undef POINTER_TO_STRUCTURE_MEMBER
 192 
 193 /* --------------------------------------------------------------------------------------------- */
 194 /**
 195  * Fill one config entity from config file.
 196  *
 197  * @param ssh_config_handler file descriptor for the ssh config file
 198  * @param config_entity      config entity structure
 199  * @param vpath_element      path element with host data (hostname, port)
 200  * @param mcerror            pointer to the error handler
 201  * @return TRUE if config entity was filled successfully, FALSE otherwise
 202  */
 203 
 204 static gboolean
 205 sftpfs_fill_config_entity_from_config (FILE * ssh_config_handler,
     /* [previous][next][first][last][top][bottom][index][help]  */
 206                                        sftpfs_ssh_config_entity_t * config_entity,
 207                                        const vfs_path_element_t * vpath_element, GError ** mcerror)
 208 {
 209     char buffer[BUF_MEDIUM];
 210     gboolean host_block_hit = FALSE;
 211     gboolean pattern_block_hit = FALSE;
 212     mc_search_t *host_regexp;
 213     gboolean ok = TRUE;
 214 
 215     mc_return_val_if_error (mcerror, FALSE);
 216 
 217     host_regexp = mc_search_new ("^\\s*host\\s+(.*)$", DEFAULT_CHARSET);
 218     host_regexp->search_type = MC_SEARCH_T_REGEX;
 219     host_regexp->is_case_sensitive = FALSE;
 220 
 221     while (TRUE)
 222     {
 223         char *cr;
 224 
 225         if (fgets (buffer, sizeof (buffer), ssh_config_handler) == NULL)
 226         {
 227             int e;
 228 
 229             e = errno;
 230 
 231             if (!feof (ssh_config_handler))
 232             {
 233                 mc_propagate_error (mcerror, e,
 234                                     _("sftp: an error occurred while reading %s: %s"),
 235                                     SFTPFS_SSH_CONFIG, strerror (e));
 236                 ok = FALSE;
 237                 goto done;
 238             }
 239 
 240             break;
 241         }
 242 
 243         cr = strrchr (buffer, '\n');
 244         if (cr != NULL)
 245             *cr = '\0';
 246 
 247         if (mc_search_run (host_regexp, buffer, 0, strlen (buffer), NULL))
 248         {
 249             const char *host_pattern;
 250             int host_pattern_offset;
 251 
 252             /* if previous host block exactly describe our connection */
 253             if (host_block_hit)
 254                 goto done;
 255 
 256             host_pattern_offset = mc_search_getstart_result_by_num (host_regexp, 1);
 257             host_pattern = &buffer[host_pattern_offset];
 258             if (strcmp (host_pattern, vpath_element->host) == 0)
 259             {
 260                 /* current host block describe our connection */
 261                 host_block_hit = TRUE;
 262             }
 263             else
 264             {
 265                 mc_search_t *pattern_regexp;
 266 
 267                 pattern_regexp = mc_search_new (host_pattern, DEFAULT_CHARSET);
 268                 pattern_regexp->search_type = MC_SEARCH_T_GLOB;
 269                 pattern_regexp->is_case_sensitive = FALSE;
 270                 pattern_regexp->is_entire_line = TRUE;
 271                 pattern_block_hit =
 272                     mc_search_run (pattern_regexp, vpath_element->host, 0,
 273                                    strlen (vpath_element->host), NULL);
 274                 mc_search_free (pattern_regexp);
 275             }
 276         }
 277         else if (pattern_block_hit || host_block_hit)
 278         {
 279             sftpfs_fill_config_entity_from_string (config_entity, buffer);
 280         }
 281     }
 282 
 283   done:
 284     mc_search_free (host_regexp);
 285     return ok;
 286 }
 287 
 288 /* --------------------------------------------------------------------------------------------- */
 289 /**
 290  * Open the ssh config file and fill config entity.
 291  *
 292  * @param vpath_element path element with host data (hostname, port)
 293  * @param mcerror       pointer to the error handler
 294  * @return newly allocated config entity structure
 295  */
 296 
 297 static sftpfs_ssh_config_entity_t *
 298 sftpfs_get_config_entity (const vfs_path_element_t * vpath_element, GError ** mcerror)
     /* [previous][next][first][last][top][bottom][index][help]  */
 299 {
 300     sftpfs_ssh_config_entity_t *config_entity;
 301     FILE *ssh_config_handler;
 302     char *config_filename;
 303 
 304     mc_return_val_if_error (mcerror, FALSE);
 305 
 306     config_entity = g_new0 (sftpfs_ssh_config_entity_t, 1);
 307     config_entity->password_auth = TRUE;
 308     config_entity->identities_only = FALSE;
 309     config_entity->pubkey_auth = TRUE;
 310     config_entity->port = SFTP_DEFAULT_PORT;
 311 
 312     config_filename = sftpfs_correct_file_name (SFTPFS_SSH_CONFIG);
 313     ssh_config_handler = fopen (config_filename, "r");
 314     g_free (config_filename);
 315 
 316     if (ssh_config_handler != NULL)
 317     {
 318         gboolean ok;
 319 
 320         ok = sftpfs_fill_config_entity_from_config
 321             (ssh_config_handler, config_entity, vpath_element, mcerror);
 322         fclose (ssh_config_handler);
 323 
 324         if (!ok)
 325         {
 326             sftpfs_ssh_config_entity_free (config_entity);
 327             return NULL;
 328         }
 329     }
 330 
 331     if (config_entity->user == NULL)
 332     {
 333         config_entity->user = vfs_get_local_username ();
 334         if (config_entity->user == NULL)
 335         {
 336             sftpfs_ssh_config_entity_free (config_entity);
 337             config_entity = NULL;
 338             mc_propagate_error (mcerror, EPERM, "%s", _("sftp: Unable to get current user name."));
 339         }
 340     }
 341     return config_entity;
 342 }
 343 
 344 /* --------------------------------------------------------------------------------------------- */
 345 /*** public functions ****************************************************************************/
 346 /* --------------------------------------------------------------------------------------------- */
 347 /**
 348  * Reads data from the ssh config file related to connection.
 349  *
 350  * @param super connection data
 351  * @param error pointer to the error handler
 352  */
 353 
 354 void
 355 sftpfs_fill_connection_data_from_config (struct vfs_s_super *super, GError ** mcerror)
     /* [previous][next][first][last][top][bottom][index][help]  */
 356 {
 357     sftpfs_super_t *sftpfs_super = SFTP_SUPER (super);
 358     sftpfs_ssh_config_entity_t *config_entity;
 359 
 360     mc_return_if_error (mcerror);
 361 
 362     config_entity = sftpfs_get_config_entity (super->path_element, mcerror);
 363     if (config_entity == NULL)
 364         return;
 365 
 366     sftpfs_super->config_auth_type = (config_entity->pubkey_auth) ? PUBKEY : 0;
 367     sftpfs_super->config_auth_type |= (config_entity->identities_only) ? 0 : AGENT;
 368     sftpfs_super->config_auth_type |= (config_entity->password_auth) ? PASSWORD : 0;
 369 
 370     if (super->path_element->port == 0)
 371         super->path_element->port = config_entity->port;
 372 
 373     if (super->path_element->user == NULL)
 374         super->path_element->user = g_strdup (config_entity->user);
 375 
 376     if (config_entity->real_host != NULL)
 377     {
 378         g_free (super->path_element->host);
 379         super->path_element->host = g_strdup (config_entity->real_host);
 380     }
 381 
 382     if (config_entity->identity_file != NULL)
 383     {
 384         sftpfs_super->privkey = g_strdup (config_entity->identity_file);
 385         sftpfs_super->pubkey = g_strdup_printf ("%s.pub", config_entity->identity_file);
 386     }
 387 
 388     sftpfs_ssh_config_entity_free (config_entity);
 389 }
 390 
 391 /* --------------------------------------------------------------------------------------------- */
 392 /**
 393  * Initialize the SSH config parser.
 394  */
 395 
 396 void
 397 sftpfs_init_config_variables_patterns (void)
     /* [previous][next][first][last][top][bottom][index][help]  */
 398 {
 399     int i;
 400 
 401     for (i = 0; config_variables[i].pattern != NULL; i++)
 402     {
 403         config_variables[i].pattern_regexp =
 404             mc_search_new (config_variables[i].pattern, DEFAULT_CHARSET);
 405         config_variables[i].pattern_regexp->search_type = MC_SEARCH_T_REGEX;
 406         config_variables[i].pattern_regexp->is_case_sensitive = FALSE;
 407     }
 408 }
 409 
 410 /* --------------------------------------------------------------------------------------------- */
 411 /**
 412  * Deinitialize the SSH config parser.
 413  */
 414 
 415 void
 416 sftpfs_deinit_config_variables_patterns (void)
     /* [previous][next][first][last][top][bottom][index][help]  */
 417 {
 418     int i;
 419 
 420     for (i = 0; config_variables[i].pattern != NULL; i++)
 421     {
 422         mc_search_free (config_variables[i].pattern_regexp);
 423         config_variables[i].pattern_regexp = NULL;
 424     }
 425 }
 426 
 427 /* --------------------------------------------------------------------------------------------- */

/* [previous][next][first][last][top][bottom][index][help]  */