src/security-srv/server/security-server-cookie.c

   1 /*
   2  *  security-server
   3  *  Copyright (c) 2000 - 2011 Samsung Electronics Co., Ltd All Rights Reserved
   4  *
   5  *  Contact: Bumjin Im <bj.im@samsung.com>
   6  *
   7  *  Licensed under the Apache License, Version 2.0 (the "License");
   8  *  you may not use this file except in compliance with the License.
   9  *  You may obtain a copy of the License at
  10  *
  11  *      http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  *  Unless required by applicable law or agreed to in writing, software
  14  *  distributed under the License is distributed on an "AS IS" BASIS,
  15  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  *  See the License for the specific language governing permissions and
  17  *  limitations under the License
  18  *
  19  */
  20
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <sys/stat.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <string.h>
  27 #include <sys/types.h>
  28 #include <fcntl.h>
  29 #include <sys/smack.h>
  30
  31 #include "security-server-cookie.h"
  32
  33 /* Delete useless cookie item *
  34  * then connect prev and next */
  35 int free_cookie_item(cookie_list *cookie)
  36 {
  37         if(cookie->path != NULL)
  38                 free(cookie->path);
  39         if(cookie->permissions != NULL)
  40                 free(cookie->permissions);
  41         if(cookie->smack_label != NULL)
  42                 free(cookie->smack_label);
  43         if(cookie->prev != NULL)
  44                 cookie->prev->next = cookie->next;
  45         if(cookie->next != NULL)
  46                 cookie->next->prev = cookie->prev;
  47         free(cookie);
  48         cookie = NULL;
  49         return 0;
  50 }
  51
  52 /* Cut the link of the current cookie item and connect previous link and next line *
  53  * That is remove a cookie item *
  54  * Returns next cookie item  if exist, NULL for no more cookie item */
  55 cookie_list *delete_cookie_item(cookie_list *cookie)
  56 {
  57         cookie_list *retval = NULL;
  58         if(cookie == NULL)
  59         {
  60                 SEC_SVR_DBG("%s", "Cannot delete null cookie");
  61                 return retval;
  62         }
  63
  64         /* Reconnect cookie item */
  65         if(cookie->next != NULL)
  66         {
  67                 cookie->prev->next = cookie->next;
  68                 cookie->next->prev = cookie->prev;
  69                 retval = cookie->next;
  70         }
  71         else
  72         {
  73                 cookie->prev->next = NULL;
  74         }
  75
  76         free_cookie_item(cookie);
  77         return retval;
  78 }
  79
  80 cookie_list * garbage_collection(cookie_list *cookie)
  81 {
  82         char path[17];
  83         cookie_list *retval = NULL;
  84         struct stat statbuf;
  85         int ret;
  86
  87         while(cookie != NULL)
  88         {
  89                 /* Skip default cookie */
  90                 if(cookie->pid ==0)
  91                         return cookie;
  92
  93                 /* Try to find the PID directory from proc fs */
  94                 snprintf(path, sizeof(path), "/proc/%d", cookie->pid);
  95                 path[16] = 0;
  96                 ret = stat(path, &statbuf);
  97                 if(ret != 0)
  98                 {
  99                         /* If it's not exist, delete the cookie */
 100                         if(errno == ENOENT)
 101                         {
 102                                 SEC_SVR_DBG("Garbage found. PID:%d, deleting...", cookie->pid);
 103                                 cookie = delete_cookie_item(cookie);
 104                                 continue;
 105                         }
 106                         else
 107                         {
 108                                 /* Some error occurred */
 109                                 SEC_SVR_DBG("Error occurred on stat: errno = %d", errno);
 110                                 return cookie;
 111                         }
 112                 }
 113                 else
 114                 {
 115                         /* This is not a garbage. returning */
 116                         return cookie;
 117                 }
 118         }
 119         return retval;
 120 }
 121
 122 /* Search existing cookie from the cookie list for the client process *
 123  * At the same time, it collects garbage cookie which PID is no longer exist and delete them */
 124 cookie_list *search_existing_cookie(int pid, const cookie_list *c_list)
 125 {
 126         cookie_list *current =(cookie_list *)c_list, *cookie = NULL;
 127         char *cmdline = NULL, *debug_cmdline = NULL;
 128
 129         /* Search from the list */
 130         while(current != NULL)
 131         {
 132                 /* print_cookie(current);*/
 133                 current = garbage_collection(current);
 134                 if(current == NULL)
 135                         break;
 136
 137                 /* PID must be same */
 138                 if(current->pid == pid)
 139                 {
 140                         /* Found cookie for the pid. Check the cookie is reused by dirrent executable */
 141                         /* Check the path of the process */
 142                         cmdline = (char*)read_cmdline_from_proc(pid);
 143                         if(cmdline == NULL)
 144                         {
 145                                 SEC_SVR_DBG("%s", "cannot read cmdline");
 146                                 return NULL;
 147                         }
 148                         /* Check the path is different */
 149                         if(strncmp(cmdline, current->path, current->path_len) != 0 || strlen(cmdline) != current->path_len)
 150                         {
 151                                 SEC_SVR_DBG("pid [%d] has been reused by %s. deleting the old cookie.", pid, cmdline);
 152                                 debug_cmdline = malloc(current->path_len + 1);
 153                                 if(debug_cmdline == NULL)
 154                                 {
 155                                         SEC_SVR_DBG("%s", "out of memory error");
 156                                         free(cmdline);
 157                                         return NULL;
 158                                 }
 159                                 strncpy(debug_cmdline, current->path, current->path_len);
 160                                 debug_cmdline[current->path_len] = 0;
 161                                 SEC_SVR_DBG("[%s] --> [%s]", cmdline, debug_cmdline);
 162                                 if(debug_cmdline != NULL)
 163                                 {
 164                                         free(debug_cmdline);
 165                                         debug_cmdline = NULL;
 166                                 }
 167                                 /* Okay. delete current cookie */
 168                                 current = delete_cookie_item(current);
 169                                 if(cmdline != NULL)
 170                                 {
 171                                         free(cmdline);
 172                                         cmdline = NULL;
 173                                 }
 174                                 continue;
 175                         }
 176                         else
 177                         {
 178                                 SEC_SVR_DBG("%s", "cookie found");
 179                                 cookie = current;
 180                         }
 181
 182                         if(cmdline != NULL)
 183                         {
 184                                 free(cmdline);
 185                                 cmdline = NULL;
 186                         }
 187                 }
 188                 current = current->next;
 189         }
 190         return cookie;
 191 }
 192
 193 /* Search existing cookie from the cookie list for matching pid *
 194  * Default cookie (meaning PID 0) is not allowed in here */
 195 cookie_list *search_cookie_from_pid(cookie_list *c_list, int pid)
 196 {
 197         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 198
 199         /* Search from the list */
 200         while(current != NULL)
 201         {
 202                 /* print_cookie(current);*/
 203                 /* PID must be same */
 204                 current = garbage_collection(current);
 205                 if(current == NULL)
 206                         break;
 207
 208                 if(current->pid == pid)
 209                 {
 210                         SEC_SVR_DBG("%s", "cookie has been found");
 211                         retval = current;
 212                         goto finish;
 213                 }
 214                 current = current->next;
 215         }
 216 finish:
 217         return retval;
 218 }
 219
 220 /* Search existing cookie from the cookie list for matching cookie and privilege */
 221 /* If privilege is 0, just search cookie exists or not */
 222 cookie_list *search_cookie(const cookie_list *c_list, const unsigned char *cookie, int privilege)
 223 {
 224         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 225         int i;
 226
 227         /* Search from the list */
 228         while(current != NULL)
 229         {
 230                 /* print_cookie(current);*/
 231                 /* PID must be same */
 232                 current = garbage_collection(current);
 233                 if(current == NULL)
 234                         break;
 235
 236                 if(memcmp(current->cookie, cookie, SECURITY_SERVER_COOKIE_LEN) == 0)
 237                 {
 238                         SEC_SVR_DBG("%s", "cookie has been found");
 239
 240                         /* default cookie is for root process which is pid is set to 0 */
 241                         if(current->pid == 0 || privilege == 0)
 242                         {
 243                                 retval = current;
 244                                 goto finish;
 245                         }
 246                         else
 247                         {
 248                                 for(i=0 ; i < current->permission_len ; i++)
 249                                 {
 250                                         if(privilege == current->permissions[i])
 251                                         {
 252                                                 SEC_SVR_DBG("Found privilege %d", privilege);
 253                                                 retval = current;
 254                                                 goto finish;
 255                                         }
 256                                 }
 257                         }
 258                 }
 259                 current = current->next;
 260         }
 261 finish:
 262         return retval;
 263 }
 264
 265
 266 cookie_list *search_cookie_new(const cookie_list *c_list,
 267                                const unsigned char *cookie,
 268                                const char *object,
 269                                const char *access_rights)
 270 {
 271         cookie_list *current = (cookie_list *)c_list, *retval = NULL;
 272         int ret;
 273         int i;
 274
 275         /* Search from the list */
 276         while(current != NULL)
 277         {
 278                 /* print_cookie(current);*/
 279                 /* PID must be same */
 280                 current = garbage_collection(current);
 281                 if(current == NULL)
 282                         break;
 283
 284                 if(memcmp(current->cookie, cookie, SECURITY_SERVER_COOKIE_LEN) == 0)
 285                 {
 286                         SEC_SVR_DBG("%s", "cookie has been found");
 287
 288                                 ret = smack_have_access(current->smack_label, object, access_rights);
 289           SEC_SVR_DBG("smack_have_access, subject >%s< object >%s< access >%s< ===> %d",
 290                     current->smack_label, object, access_rights, ret);
 291                                 if (ret == 1)
 292                                 {
 293                                         retval = current;
 294                                         goto finish;
 295                                 }
 296                 }
 297                 current = current->next;
 298         }
 299 finish:
 300         return retval;
 301 }
 302
 303
 304 /* Generage a random stream value of size to cookie *
 305  * by reading /dev/uranddom file */
 306 int generate_random_cookie(unsigned char *cookie, int size)
 307 {
 308         int fd, ret;
 309
 310     if (cookie == NULL) {
 311         SEC_SVR_DBG("%s", "Null pointer passed to function");
 312         return SECURITY_SERVER_ERROR_UNKNOWN;
 313     }
 314         fd = open("/dev/urandom", O_RDONLY);
 315         if(fd < 0)
 316         {
 317                 SEC_SVR_DBG("%s", "Cannot open /dev/urandom");
 318                 return SECURITY_SERVER_ERROR_FILE_OPERATION;
 319         }
 320         ret = read(fd, cookie, size);
 321         if(ret < size)
 322         {
 323                 SEC_SVR_DBG("Cannot read /dev/urandom: %d", ret);
 324                 ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 325                 goto error;
 326         }
 327         close(fd);
 328         ret = SECURITY_SERVER_SUCCESS;
 329 error:
 330         if(fd >= 0)
 331                 close(fd);
 332         return ret;
 333 }
 334
 335 /* Create a cookie item from PID */
 336 cookie_list *create_cookie_item(int pid, int sockfd, cookie_list *c_list)
 337 {
 338         int ret, tempint;
 339         cookie_list *added = NULL, *current = NULL;
 340         char path[24], *cmdline = NULL;
 341         char *buf = NULL, inputed, *tempptr = NULL;
 342         char delim[] = ": ", *token = NULL;
 343         int *permissions = NULL, perm_num = 1, cnt, i, *tempperm = NULL;
 344         char *smack_label = NULL;
 345         FILE *fp = NULL;
 346
 347         current = search_existing_cookie(pid, c_list);
 348         if(current != NULL)
 349         {
 350                 /* There is a cookie for this process already */
 351                 added = current;
 352                 SEC_SVR_DBG("%s", "Existing cookie found");
 353                 goto error;
 354         }
 355
 356         /* Read command line of the PID from proc fs */
 357         cmdline = (char *)read_cmdline_from_proc(pid);
 358         if(cmdline == NULL)
 359         {
 360                 SEC_SVR_DBG("Error on reading /proc/%d/cmdline", pid);
 361                 goto error;
 362         }
 363
 364         /*
 365          * modified by security part
 366          *  - get gid from /etc/group
 367          */
 368         /* Read group info of the PID from proc fs - /proc/[PID]/status */
 369         snprintf(path, sizeof(path), "/proc/%d/status", pid);
 370         fp = fopen(path, "r");
 371
 372         /* Find the line which starts with 'Groups:' */
 373         i = 0;
 374
 375         while(1)
 376         {
 377                 buf = (char*)malloc(sizeof(char) * 128);
 378                 if(buf == NULL)
 379                 {
 380                         SEC_SVR_DBG("%s", "Error on malloc()");
 381                         goto error;
 382                 }
 383                 memset(buf, 0x00, 128);
 384                 cnt = 128;
 385
 386                 /* get one line from /proc/[PID]/status */
 387                 while(1)
 388                 {
 389                         tempint = fgetc(fp);
 390                         inputed = (char)tempint;
 391                         if(tempint == EOF)
 392                                 goto out_of_while;
 393                         else if(inputed == '\n')
 394                         {
 395                                 buf[i] = '\0';
 396                                 break;
 397                         }
 398                         else if((i == cnt) && (inputed != '\n'))
 399                         {
 400                                 tempptr = (char*)realloc(buf, sizeof(char) * (i + 128));
 401                                 if(tempptr == NULL)
 402                                 {
 403                                         SEC_SVR_DBG("%s", "Error on realloc()");
 404                                         goto error;
 405                                 }
 406                                 buf = tempptr;
 407                                 buf[i++] = inputed;
 408                                 cnt = i + 128;
 409                         }
 410                         else
 411                                 buf[i++] = inputed;
 412                 }
 413                 i = 0;
 414
 415                 /* find 'Groups:' */
 416                 if(strncmp(buf, "Groups:", 7) == 0)
 417                 {
 418                         /* get gid from the line and insert to 'permissions' array */
 419                         token = strtok(buf, delim); // first string is "Groups"
 420                         while((token = strtok(NULL, delim)))
 421                         {
 422                                 tempperm = realloc(permissions, sizeof(int) * perm_num);
 423                                 if(tempperm == NULL)
 424                                 {
 425                                         SEC_SVR_DBG("%s", "Error on realloc()");
 426                                         goto error;
 427                                 }
 428                                 permissions = tempperm;
 429                                 errno = 0;
 430                                 permissions[perm_num - 1] = strtoul(token, 0, 10);
 431                                 if (errno != 0)
 432                                 {
 433                                         SEC_SVR_DBG("cannot change string to integer [%s]", token);
 434                                         ret = SECURITY_SERVER_ERROR_SERVER_ERROR;
 435                                         goto error;
 436                                 }
 437                                 perm_num++;
 438                         }
 439                         perm_num--;
 440
 441                         /* goto out of while loop */
 442                         break;
 443                 }
 444                 if(buf != NULL)
 445                 {
 446                         free(buf);
 447                         buf = NULL;
 448                 }
 449         }
 450 out_of_while:
 451
 452         /* Each group ID is stored in each line of the file */
 453 //      while(fgets(permline, sizeof(permline), fp) != NULL)
 454 //      {
 455 //              permissions = realloc(permissions, sizeof(int) * perm_num);
 456 //              if(permissions == NULL)
 457 //              {
 458 //                      SEC_SVR_DBG("%s", "Error on realloc()");
 459 //                      goto error;
 460 //              }
 461 //              permissions[perm_num -1] = strtoul(permline, 0, 10);
 462 //              perm_num++;
 463 //      }
 464 //      perm_num--;
 465         /*
 466          * modifying end
 467          */
 468
 469         /* Go to last cookie from the list */
 470         current = c_list;
 471         while(current->next != NULL)
 472         {
 473                 current = current->next;
 474         }
 475
 476         /* Create a new one and assign values */
 477         added = malloc(sizeof(cookie_list));
 478         if(added == NULL)
 479                 goto error;
 480
 481         ret = generate_random_cookie(added->cookie, SECURITY_SERVER_COOKIE_LEN);
 482         if(ret != SECURITY_SERVER_SUCCESS)
 483         {
 484                 SEC_SVR_DBG("Error on making random cookie: %d", ret);
 485                 free(added);
 486                 added = NULL;
 487                 goto error;
 488         }
 489
 490 #ifdef SMACK_ENABLED
 491         /* Check SMACK label */
 492         ret = smack_new_label_from_socket(sockfd, &smack_label);
 493         if (ret != 0)
 494         {
 495                 SEC_SVR_DBG("Error checking peer label: %d", ret);
 496                 free(added);
 497                 added = NULL;
 498                 goto error;
 499         }
 500 #endif
 501
 502         added->path_len = strlen(cmdline);
 503         added->path = calloc(1, strlen(cmdline));
 504         memcpy(added->path, cmdline, strlen(cmdline));
 505
 506         added->permission_len = perm_num;
 507         added->pid = pid;
 508         added->permissions = permissions;
 509 #ifdef SMACK_ENABLED
 510         added->smack_label = smack_label;
 511 #endif
 512         added->prev = current;
 513         current->next = added;
 514         added->next = NULL;
 515
 516 error:
 517         if(cmdline != NULL)
 518                 free(cmdline);
 519         if(fp != NULL)
 520                 fclose(fp);
 521         if(buf != NULL)
 522                 free(buf);
 523
 524         if(added == NULL && permissions != NULL)
 525                 free(permissions);
 526
 527         return added;
 528 }
 529
 530 /* Check stored default cookie, if it's not exist make a new one and store it */
 531 int check_stored_cookie(unsigned char *cookie, int size)
 532 {
 533         int fd, ret;
 534
 535         /* First, check the default cookie is stored */
 536         fd = open(SECURITY_SERVER_DEFAULT_COOKIE_PATH, O_RDONLY);
 537         if(fd < 0)
 538         {
 539                 if(errno != ENOENT)
 540                 {
 541                         SEC_SVR_DBG("Cannot open default cookie. errno=%d", errno);
 542                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 543                         unlink(SECURITY_SERVER_DEFAULT_COOKIE_PATH);
 544                 }
 545
 546                 ret = generate_random_cookie(cookie, size);
 547
 548                 /* Save cookie to disk */
 549                 fd = open(SECURITY_SERVER_DEFAULT_COOKIE_PATH, O_WRONLY | O_CREAT, 0600);
 550                 if (fd < 0)
 551                 {
 552                         SEC_SVR_DBG("Cannot open default cookie errno=%d", errno);
 553                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 554                         goto error;
 555                 }
 556                 ret = write(fd, cookie, size);
 557                 if(ret < size)
 558                 {
 559                         SEC_SVR_DBG("%s", "Cannot save default cookie");
 560                         ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 561                         goto error;
 562                 }
 563
 564                 close(fd);
 565                 return SECURITY_SERVER_SUCCESS;
 566         }
 567
 568         ret = read (fd, cookie, size);
 569         if(ret < size)
 570         {
 571                 SEC_SVR_DBG("Cannot read default cookie errno=%d", errno);
 572                 ret = SECURITY_SERVER_ERROR_FILE_OPERATION;
 573                 goto error;
 574         }
 575         ret = SECURITY_SERVER_SUCCESS;
 576
 577 error:
 578         if(fd >= 0)
 579                 close(fd);
 580         return ret;
 581 }
 582 /* Create a cookie item from PID */
 583
 584 /* Create a default cookie when security server is executed *
 585  * Default cookie is for root processes that needs cookie */
 586 cookie_list *create_default_cookie(void)
 587 {
 588         cookie_list *first = NULL;
 589         int ret;
 590
 591         first = malloc(sizeof(cookie_list));
 592
 593         ret = check_stored_cookie(first->cookie, SECURITY_SERVER_COOKIE_LEN);
 594         if(ret != SECURITY_SERVER_SUCCESS)
 595         {
 596                 SEC_SVR_DBG("Error on making random cookie: %d", ret);
 597                 free(first);
 598                 return NULL;
 599         }
 600
 601         first->path_len = 0;
 602         first->permission_len = 0;
 603         first->pid = 0;
 604         first->path = NULL;
 605         first->permissions = NULL;
 606         first->smack_label = NULL;
 607         first->prev = NULL;
 608         first->next = NULL;
 609         return first;
 610 }