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correct_password.c 2.9 KB

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
  4. * All rights reserved.
  5. *
  6. * Redistribution and use in source and binary forms, with or without
  7. * modification, are permitted provided that the following conditions
  8. * are met:
  9. * 1. Redistributions of source code must retain the above copyright
  10. * notice, this list of conditions and the following disclaimer.
  11. * 2. Redistributions in binary form must reproduce the above copyright
  12. * notice, this list of conditions and the following disclaimer in the
  13. * documentation and/or other materials provided with the distribution.
  14. * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
  15. * may be used to endorse or promote products derived from this software
  16. * without specific prior written permission.
  17. *
  18. * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
  19. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21. * ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
  22. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28. * SUCH DAMAGE.
  29. */
  30. #include "libbb.h"
  31. /* Ask the user for a password.
  32. * Return 1 if the user gives the correct password for entry PW,
  33. * 0 if not. Return 1 without asking if PW has an empty password.
  34. *
  35. * NULL pw means "just fake it for login with bad username" */
  36. int FAST_FUNC correct_password(const struct passwd *pw)
  37. {
  38. char *unencrypted, *encrypted;
  39. const char *correct;
  40. int r;
  41. #if ENABLE_FEATURE_SHADOWPASSWDS
  42. /* Using _r function to avoid pulling in static buffers */
  43. struct spwd spw;
  44. char buffer[256];
  45. #endif
  46. /* fake salt. crypt() can choke otherwise. */
  47. correct = "aa";
  48. if (!pw) {
  49. /* "aa" will never match */
  50. goto fake_it;
  51. }
  52. correct = pw->pw_passwd;
  53. #if ENABLE_FEATURE_SHADOWPASSWDS
  54. if ((correct[0] == 'x' || correct[0] == '*') && !correct[1]) {
  55. /* getspnam_r may return 0 yet set result to NULL.
  56. * At least glibc 2.4 does this. Be extra paranoid here. */
  57. struct spwd *result = NULL;
  58. r = getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result);
  59. correct = (r || !result) ? "aa" : result->sp_pwdp;
  60. }
  61. #endif
  62. if (!correct[0]) /* empty password field? */
  63. return 1;
  64. fake_it:
  65. unencrypted = bb_ask_stdin("Password: ");
  66. if (!unencrypted) {
  67. return 0;
  68. }
  69. encrypted = pw_encrypt(unencrypted, correct, 1);
  70. r = (strcmp(encrypted, correct) == 0);
  71. free(encrypted);
  72. memset(unencrypted, 0, strlen(unencrypted));
  73. return r;
  74. }