qga/commands-posix-ssh.c

   1  /*
   2   * This work is licensed under the terms of the GNU GPL, version 2 or later.
   3   * See the COPYING file in the top-level directory.
   4   */
   5 #include "qemu/osdep.h"
   6
   7 #include <glib-unix.h>
   8 #include <glib/gstdio.h>
   9 #include <locale.h>
  10 #include <pwd.h>
  11
  12 #include "qapi/error.h"
  13 #include "qga-qapi-commands.h"
  14
  15 #ifdef QGA_BUILD_UNIT_TEST
  16 static struct passwd *
  17 test_get_passwd_entry(const gchar *user_name, GError **error)
  18 {
  19     struct passwd *p;
  20     int ret;
  21
  22     if (!user_name || g_strcmp0(user_name, g_get_user_name())) {
  23         g_set_error(error, G_UNIX_ERROR, 0, "Invalid user name");
  24         return NULL;
  25     }
  26
  27     p = g_new0(struct passwd, 1);
  28     p->pw_dir = (char *)g_get_home_dir();
  29     p->pw_uid = geteuid();
  30     p->pw_gid = getegid();
  31
  32     ret = g_mkdir_with_parents(p->pw_dir, 0700);
  33     g_assert(ret == 0);
  34
  35     return p;
  36 }
  37
  38 #define g_unix_get_passwd_entry_qemu(username, err) \
  39    test_get_passwd_entry(username, err)
  40 #endif
  41
  42 static struct passwd *
  43 get_passwd_entry(const char *username, Error **errp)
  44 {
  45     g_autoptr(GError) err = NULL;
  46     struct passwd *p;
  47
  48     p = g_unix_get_passwd_entry_qemu(username, &err);
  49     if (p == NULL) {
  50         error_setg(errp, "failed to lookup user '%s': %s",
  51                    username, err->message);
  52         return NULL;
  53     }
  54
  55     return p;
  56 }
  57
  58 static bool
  59 mkdir_for_user(const char *path, const struct passwd *p,
  60                mode_t mode, Error **errp)
  61 {
  62     if (g_mkdir(path, mode) == -1) {
  63         error_setg(errp, "failed to create directory '%s': %s",
  64                    path, g_strerror(errno));
  65         return false;
  66     }
  67
  68     if (chown(path, p->pw_uid, p->pw_gid) == -1) {
  69         error_setg(errp, "failed to set ownership of directory '%s': %s",
  70                    path, g_strerror(errno));
  71         return false;
  72     }
  73
  74     if (chmod(path, mode) == -1) {
  75         error_setg(errp, "failed to set permissions of directory '%s': %s",
  76                    path, g_strerror(errno));
  77         return false;
  78     }
  79
  80     return true;
  81 }
  82
  83 static bool
  84 check_openssh_pub_key(const char *key, Error **errp)
  85 {
  86     /* simple sanity-check, we may want more? */
  87     if (!key || key[0] == '#' || strchr(key, '\n')) {
  88         error_setg(errp, "invalid OpenSSH public key: '%s'", key);
  89         return false;
  90     }
  91
  92     return true;
  93 }
  94
  95 static bool
  96 check_openssh_pub_keys(strList *keys, size_t *nkeys, Error **errp)
  97 {
  98     size_t n = 0;
  99     strList *k;
 100
 101     for (k = keys; k != NULL; k = k->next) {
 102         if (!check_openssh_pub_key(k->value, errp)) {
 103             return false;
 104         }
 105         n++;
 106     }
 107
 108     if (nkeys) {
 109         *nkeys = n;
 110     }
 111     return true;
 112 }
 113
 114 static bool
 115 write_authkeys(const char *path, const GStrv keys,
 116                const struct passwd *p, Error **errp)
 117 {
 118     g_autofree char *contents = NULL;
 119     g_autoptr(GError) err = NULL;
 120
 121     contents = g_strjoinv("\n", keys);
 122     if (!g_file_set_contents(path, contents, -1, &err)) {
 123         error_setg(errp, "failed to write to '%s': %s", path, err->message);
 124         return false;
 125     }
 126
 127     if (chown(path, p->pw_uid, p->pw_gid) == -1) {
 128         error_setg(errp, "failed to set ownership of directory '%s': %s",
 129                    path, g_strerror(errno));
 130         return false;
 131     }
 132
 133     if (chmod(path, 0600) == -1) {
 134         error_setg(errp, "failed to set permissions of '%s': %s",
 135                    path, g_strerror(errno));
 136         return false;
 137     }
 138
 139     return true;
 140 }
 141
 142 static GStrv
 143 read_authkeys(const char *path, Error **errp)
 144 {
 145     g_autoptr(GError) err = NULL;
 146     g_autofree char *contents = NULL;
 147
 148     if (!g_file_get_contents(path, &contents, NULL, &err)) {
 149         error_setg(errp, "failed to read '%s': %s", path, err->message);
 150         return NULL;
 151     }
 152
 153     return g_strsplit(contents, "\n", -1);
 154
 155 }
 156
 157 void
 158 qmp_guest_ssh_add_authorized_keys(const char *username, strList *keys,
 159                                   bool has_reset, bool reset,
 160                                   Error **errp)
 161 {
 162     g_autofree struct passwd *p = NULL;
 163     g_autofree char *ssh_path = NULL;
 164     g_autofree char *authkeys_path = NULL;
 165     g_auto(GStrv) authkeys = NULL;
 166     strList *k;
 167     size_t nkeys, nauthkeys;
 168
 169     reset = has_reset && reset;
 170
 171     if (!check_openssh_pub_keys(keys, &nkeys, errp)) {
 172         return;
 173     }
 174
 175     p = get_passwd_entry(username, errp);
 176     if (p == NULL) {
 177         return;
 178     }
 179
 180     ssh_path = g_build_filename(p->pw_dir, ".ssh", NULL);
 181     authkeys_path = g_build_filename(ssh_path, "authorized_keys", NULL);
 182
 183     if (!reset) {
 184         authkeys = read_authkeys(authkeys_path, NULL);
 185     }
 186     if (authkeys == NULL) {
 187         if (!g_file_test(ssh_path, G_FILE_TEST_IS_DIR) &&
 188             !mkdir_for_user(ssh_path, p, 0700, errp)) {
 189             return;
 190         }
 191     }
 192
 193     nauthkeys = authkeys ? g_strv_length(authkeys) : 0;
 194     authkeys = g_realloc_n(authkeys, nauthkeys + nkeys + 1, sizeof(char *));
 195     memset(authkeys + nauthkeys, 0, (nkeys + 1) * sizeof(char *));
 196
 197     for (k = keys; k != NULL; k = k->next) {
 198         if (g_strv_contains((const gchar * const *)authkeys, k->value)) {
 199             continue;
 200         }
 201         authkeys[nauthkeys++] = g_strdup(k->value);
 202     }
 203
 204     write_authkeys(authkeys_path, authkeys, p, errp);
 205 }
 206
 207 void
 208 qmp_guest_ssh_remove_authorized_keys(const char *username, strList *keys,
 209                                      Error **errp)
 210 {
 211     g_autofree struct passwd *p = NULL;
 212     g_autofree char *authkeys_path = NULL;
 213     g_autofree GStrv new_keys = NULL; /* do not own the strings */
 214     g_auto(GStrv) authkeys = NULL;
 215     GStrv a;
 216     size_t nkeys = 0;
 217
 218     if (!check_openssh_pub_keys(keys, NULL, errp)) {
 219         return;
 220     }
 221
 222     p = get_passwd_entry(username, errp);
 223     if (p == NULL) {
 224         return;
 225     }
 226
 227     authkeys_path = g_build_filename(p->pw_dir, ".ssh",
 228                                      "authorized_keys", NULL);
 229     if (!g_file_test(authkeys_path, G_FILE_TEST_EXISTS)) {
 230         return;
 231     }
 232     authkeys = read_authkeys(authkeys_path, errp);
 233     if (authkeys == NULL) {
 234         return;
 235     }
 236
 237     new_keys = g_new0(char *, g_strv_length(authkeys) + 1);
 238     for (a = authkeys; *a != NULL; a++) {
 239         strList *k;
 240
 241         for (k = keys; k != NULL; k = k->next) {
 242             if (g_str_equal(k->value, *a)) {
 243                 break;
 244             }
 245         }
 246         if (k != NULL) {
 247             continue;
 248         }
 249
 250         new_keys[nkeys++] = *a;
 251     }
 252
 253     write_authkeys(authkeys_path, new_keys, p, errp);
 254 }
 255
 256 GuestAuthorizedKeys *
 257 qmp_guest_ssh_get_authorized_keys(const char *username, Error **errp)
 258 {
 259     g_autofree struct passwd *p = NULL;
 260     g_autofree char *authkeys_path = NULL;
 261     g_auto(GStrv) authkeys = NULL;
 262     g_autoptr(GuestAuthorizedKeys) ret = NULL;
 263     int i;
 264
 265     p = get_passwd_entry(username, errp);
 266     if (p == NULL) {
 267         return NULL;
 268     }
 269
 270     authkeys_path = g_build_filename(p->pw_dir, ".ssh",
 271                                      "authorized_keys", NULL);
 272     authkeys = read_authkeys(authkeys_path, errp);
 273     if (authkeys == NULL) {
 274         return NULL;
 275     }
 276
 277     ret = g_new0(GuestAuthorizedKeys, 1);
 278     for (i = 0; authkeys[i] != NULL; i++) {
 279         g_strstrip(authkeys[i]);
 280         if (!authkeys[i][0] || authkeys[i][0] == '#') {
 281             continue;
 282         }
 283
 284         QAPI_LIST_PREPEND(ret->keys, g_strdup(authkeys[i]));
 285     }
 286
 287     return g_steal_pointer(&ret);
 288 }
 289
 290 #ifdef QGA_BUILD_UNIT_TEST
 291 #if GLIB_CHECK_VERSION(2, 60, 0)
 292 static const strList test_key2 = {
 293     .value = (char *)"algo key2 comments"
 294 };
 295
 296 static const strList test_key1_2 = {
 297     .value = (char *)"algo key1 comments",
 298     .next = (strList *)&test_key2,
 299 };
 300
 301 static char *
 302 test_get_authorized_keys_path(void)
 303 {
 304     return g_build_filename(g_get_home_dir(), ".ssh", "authorized_keys", NULL);
 305 }
 306
 307 static void
 308 test_authorized_keys_set(const char *contents)
 309 {
 310     g_autoptr(GError) err = NULL;
 311     g_autofree char *path = NULL;
 312     int ret;
 313
 314     path = g_build_filename(g_get_home_dir(), ".ssh", NULL);
 315     ret = g_mkdir_with_parents(path, 0700);
 316     g_assert(ret == 0);
 317     g_free(path);
 318
 319     path = test_get_authorized_keys_path();
 320     g_file_set_contents(path, contents, -1, &err);
 321     g_assert(err == NULL);
 322 }
 323
 324 static void
 325 test_authorized_keys_equal(const char *expected)
 326 {
 327     g_autoptr(GError) err = NULL;
 328     g_autofree char *path = NULL;
 329     g_autofree char *contents = NULL;
 330
 331     path = test_get_authorized_keys_path();
 332     g_file_get_contents(path, &contents, NULL, &err);
 333     g_assert(err == NULL);
 334
 335     g_assert(g_strcmp0(contents, expected) == 0);
 336 }
 337
 338 static void
 339 test_invalid_user(void)
 340 {
 341     Error *err = NULL;
 342
 343     qmp_guest_ssh_add_authorized_keys("", NULL, FALSE, FALSE, &err);
 344     error_free_or_abort(&err);
 345
 346     qmp_guest_ssh_remove_authorized_keys("", NULL, &err);
 347     error_free_or_abort(&err);
 348 }
 349
 350 static void
 351 test_invalid_key(void)
 352 {
 353     strList key = {
 354         .value = (char *)"not a valid\nkey"
 355     };
 356     Error *err = NULL;
 357
 358     qmp_guest_ssh_add_authorized_keys(g_get_user_name(), &key,
 359                                       FALSE, FALSE, &err);
 360     error_free_or_abort(&err);
 361
 362     qmp_guest_ssh_remove_authorized_keys(g_get_user_name(), &key, &err);
 363     error_free_or_abort(&err);
 364 }
 365
 366 static void
 367 test_add_keys(void)
 368 {
 369     Error *err = NULL;
 370
 371     qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
 372                                       (strList *)&test_key2,
 373                                       FALSE, FALSE,
 374                                       &err);
 375     g_assert(err == NULL);
 376
 377     test_authorized_keys_equal("algo key2 comments");
 378
 379     qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
 380                                       (strList *)&test_key1_2,
 381                                       FALSE, FALSE,
 382                                       &err);
 383     g_assert(err == NULL);
 384
 385     /*  key2 came first, and shouldn't be duplicated */
 386     test_authorized_keys_equal("algo key2 comments\n"
 387                                "algo key1 comments");
 388 }
 389
 390 static void
 391 test_add_reset_keys(void)
 392 {
 393     Error *err = NULL;
 394
 395     qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
 396                                       (strList *)&test_key1_2,
 397                                       FALSE, FALSE,
 398                                       &err);
 399     g_assert(err == NULL);
 400
 401     /* reset with key2 only */
 402     test_authorized_keys_equal("algo key1 comments\n"
 403                                "algo key2 comments");
 404
 405     qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
 406                                       (strList *)&test_key2,
 407                                       TRUE, TRUE,
 408                                       &err);
 409     g_assert(err == NULL);
 410
 411     test_authorized_keys_equal("algo key2 comments");
 412
 413     /* empty should clear file */
 414     qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
 415                                       (strList *)NULL,
 416                                       TRUE, TRUE,
 417                                       &err);
 418     g_assert(err == NULL);
 419
 420     test_authorized_keys_equal("");
 421 }
 422
 423 static void
 424 test_remove_keys(void)
 425 {
 426     Error *err = NULL;
 427     static const char *authkeys =
 428         "algo key1 comments\n"
 429         /* originally duplicated */
 430         "algo key1 comments\n"
 431         "# a commented line\n"
 432         "algo some-key another\n";
 433
 434     test_authorized_keys_set(authkeys);
 435     qmp_guest_ssh_remove_authorized_keys(g_get_user_name(),
 436                                          (strList *)&test_key2, &err);
 437     g_assert(err == NULL);
 438     test_authorized_keys_equal(authkeys);
 439
 440     qmp_guest_ssh_remove_authorized_keys(g_get_user_name(),
 441                                          (strList *)&test_key1_2, &err);
 442     g_assert(err == NULL);
 443     test_authorized_keys_equal("# a commented line\n"
 444                                "algo some-key another\n");
 445 }
 446
 447 static void
 448 test_get_keys(void)
 449 {
 450     Error *err = NULL;
 451     static const char *authkeys =
 452         "algo key1 comments\n"
 453         "# a commented line\n"
 454         "algo some-key another\n";
 455     g_autoptr(GuestAuthorizedKeys) ret = NULL;
 456     strList *k;
 457     size_t len = 0;
 458
 459     test_authorized_keys_set(authkeys);
 460
 461     ret = qmp_guest_ssh_get_authorized_keys(g_get_user_name(), &err);
 462     g_assert(err == NULL);
 463
 464     for (len = 0, k = ret->keys; k != NULL; k = k->next) {
 465         g_assert(g_str_has_prefix(k->value, "algo "));
 466         len++;
 467     }
 468
 469     g_assert(len == 2);
 470 }
 471
 472 int main(int argc, char *argv[])
 473 {
 474     setlocale(LC_ALL, "");
 475
 476     g_test_init(&argc, &argv, G_TEST_OPTION_ISOLATE_DIRS, NULL);
 477
 478     g_test_add_func("/qga/ssh/invalid_user", test_invalid_user);
 479     g_test_add_func("/qga/ssh/invalid_key", test_invalid_key);
 480     g_test_add_func("/qga/ssh/add_keys", test_add_keys);
 481     g_test_add_func("/qga/ssh/add_reset_keys", test_add_reset_keys);
 482     g_test_add_func("/qga/ssh/remove_keys", test_remove_keys);
 483     g_test_add_func("/qga/ssh/get_keys", test_get_keys);
 484
 485     return g_test_run();
 486 }
 487 #else
 488 int main(int argc, char *argv[])
 489 {
 490     g_test_message("test skipped, needs glib >= 2.60");
 491     return 0;
 492 }
 493 #endif /* GLIB_2_60 */
 494 #endif /* BUILD_UNIT_TEST */