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checkpassword-ng

Uniform password checking interface for applications git clone https://anongit.hacktivis.me/git/checkpassword-ng.git/

chkpw.c (1778B)

    

  1. // checkpassword-ng: Uniform password checking interface for applications
  2. // Copyright © 2021 checkpassword-ng Authors <https://hacktivis.me/git/checkpassword-ng>
  3. // SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
  5. #define _POSIX_C_SOURCE 200809L
  7. #include "chkpw.h"
  9. #include <assert.h> /* assert */
  10. #include <errno.h>  /* errno */
  11. #include <pwd.h>    /* getpwnam */
  12. #include <stdio.h>  /* sprintf() */
  13. #include <string.h> /* strerror, strcmp */
  14. #include <unistd.h> /* crypt, sleep */
  15. #ifdef __GLIBC__
  16. // GNU's Not POSIX
  17. #include <crypt.h>
  18. #endif
  19. #ifdef __linux__
  20. // I love linux extensions (no)
  21. #include <shadow.h> /* getspnam */
  22. #endif
  24. char strerror_buf[1024];
  26. struct chkpw_extra
  27. {
  28. 	// intentionally left blank
  29. } chkpw_extra;
  31. static void
  32. safe_strerror(char *desc, int errnum)
  33. {
  34. 	char *err = strerror(errnum);
  36. 	snprintf(strerror_buf, 1024, "%s: %s", desc, err);
  37. }
  39. char *
  40. chkpw(const char *username, const char *password, struct chkpw_extra *chkpw_extra)
  41. {
  42. 	(void)chkpw_extra;
  43. 	char *pw_hash = "";
  45. 	struct passwd *pwent = getpwnam(username);
  46. 	if(!pwent)
  47. 	{
  48. 		safe_strerror("getpwnam", errno);
  49. 		return strerror_buf;
  50. 	}
  52. 	assert(pwent->pw_passwd);
  53. 	pw_hash = pwent->pw_passwd;
  55. 	if(strcmp(pw_hash, "") == 0)
  56. 	{
  57. 		return CHKPW_EMPTY;
  58. 	}
  60. 	if(strcmp(pw_hash, "x") == 0)
  61. 	{
  62. #ifdef __linux__
  63. 		struct spwd *swent = getspnam(username);
  64. 		if(!swent)
  65. 		{
  66. 			safe_strerror("getspnam", errno);
  67. 			return strerror_buf;
  68. 		}
  69. 		pw_hash = swent->sp_pwdp;
  70. #else /* __linux__ */
  71. 		return "Invalid password entry";
  72. #endif
  73. 	}
  75. 	char *chk_hash = crypt(password, pw_hash);
  76. 	if(chk_hash == NULL)
  77. 	{
  78. 		safe_strerror("crypt", errno);
  79. 		return strerror_buf;
  80. 	}
  82. 	if(strcmp(chk_hash, pw_hash) == 0)
  83. 	{
  84. 		return CHKPW_VALID;
  85. 	}
  86. 	else
  87. 	{
  88. 		sleep(2);
  89. 		return CHKPW_INVALID;
  90. 	}
  92. 	assert(1);
  93. }