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Diffstat (limited to 'lib/obscure.c')
| -rw-r--r-- | lib/obscure.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/lib/obscure.c b/lib/obscure.c new file mode 100644 index 0000000..549c2a8 --- /dev/null +++ b/lib/obscure.c @@ -0,0 +1,224 @@ +/* + * SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh + * SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz + * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko + * SPDX-FileCopyrightText: 2007 - 2010, Nicolas François + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <config.h> + +#ident "$Id$" + + +#include <ctype.h> +#include <stdio.h> + +#include "alloc.h" +#include "attr.h" +#include "memzero.h" +#include "prototypes.h" +#include "defines.h" +#include "getdef.h" + +#if WITH_LIBBSD == 0 +#include "freezero.h" +#endif /* WITH_LIBBSD */ + +/* + * can't be a palindrome - like `R A D A R' or `M A D A M' + */ +static bool palindrome (MAYBE_UNUSED const char *old, const char *new) +{ + size_t i, j; + + i = strlen (new); + + for (j = 0; j < i; j++) { + if (new[i - j - 1] != new[j]) { + return false; + } + } + + return true; +} + +/* + * more than half of the characters are different ones. + */ + +static bool similar (/*@notnull@*/const char *old, /*@notnull@*/const char *new) +{ + int i, j; + + /* + * XXX - sometimes this fails when changing from a simple password + * to a really long one (MD5). For now, I just return success if + * the new password is long enough. Please feel free to suggest + * something better... --marekm + */ + if (strlen (new) >= 8) { + return false; + } + + for (i = j = 0; ('\0' != new[i]) && ('\0' != old[i]); i++) { + if (strchr (new, old[i]) != NULL) { + j++; + } + } + + if (i >= j * 2) { + return false; + } + + return true; +} + +static char *str_lower (/*@returned@*/char *string) +{ + char *cp; + + for (cp = string; '\0' != *cp; cp++) { + *cp = tolower (*cp); + } + return string; +} + +static /*@observer@*//*@null@*/const char *password_check ( + /*@notnull@*/const char *old, + /*@notnull@*/const char *new, + /*@notnull@*/MAYBE_UNUSED const struct passwd *pwdp) +{ + const char *msg = NULL; + char *oldmono, *newmono, *wrapped; + + if (strcmp (new, old) == 0) { + return _("no change"); + } + + newmono = str_lower (xstrdup (new)); + oldmono = str_lower (xstrdup (old)); + wrapped = XMALLOC(strlen(oldmono) * 2 + 1, char); + strcpy (wrapped, oldmono); + strcat (wrapped, oldmono); + + if (palindrome (oldmono, newmono)) { + msg = _("a palindrome"); + } else if (strcmp (oldmono, newmono) == 0) { + msg = _("case changes only"); + } else if (similar (oldmono, newmono)) { + msg = _("too similar"); + } else if (strstr (wrapped, newmono) != NULL) { + msg = _("rotated"); + } + strzero (newmono); + strzero (oldmono); + strzero (wrapped); + free (newmono); + free (oldmono); + free (wrapped); + + return msg; +} + +static /*@observer@*//*@null@*/const char *obscure_msg ( + /*@notnull@*/const char *old, + /*@notnull@*/const char *new, + /*@notnull@*/const struct passwd *pwdp) +{ + size_t maxlen, oldlen, newlen; + char *new1, *old1; + const char *msg; + const char *result; + + oldlen = strlen (old); + newlen = strlen (new); + + if (newlen < (size_t) getdef_num ("PASS_MIN_LEN", 0)) { + return _("too short"); + } + + /* + * Remaining checks are optional. + */ + if (!getdef_bool ("OBSCURE_CHECKS_ENAB")) { + return NULL; + } + + msg = password_check (old, new, pwdp); + if (NULL != msg) { + return msg; + } + + result = getdef_str ("ENCRYPT_METHOD"); + if (NULL == result) { + /* The traditional crypt() truncates passwords to 8 chars. It is + possible to circumvent the above checks by choosing an easy + 8-char password and adding some random characters to it... + Example: "password$%^&*123". So check it again, this time + truncated to the maximum length. Idea from npasswd. --marekm */ + + if (getdef_bool ("MD5_CRYPT_ENAB")) { + return NULL; + } + + } else { + + if ( (strcmp (result, "MD5") == 0) +#ifdef USE_SHA_CRYPT + || (strcmp (result, "SHA256") == 0) + || (strcmp (result, "SHA512") == 0) +#endif +#ifdef USE_BCRYPT + || (strcmp (result, "BCRYPT") == 0) +#endif +#ifdef USE_YESCRYPT + || (strcmp (result, "YESCRYPT") == 0) +#endif + ) { + return NULL; + } + + } + maxlen = getdef_num ("PASS_MAX_LEN", 8); + if ( (oldlen <= maxlen) + && (newlen <= maxlen)) { + return NULL; + } + + new1 = xstrdup (new); + old1 = xstrdup (old); + if (newlen > maxlen) { + new1[maxlen] = '\0'; + } + if (oldlen > maxlen) { + old1[maxlen] = '\0'; + } + + msg = password_check (old1, new1, pwdp); + + freezero (new1, newlen); + freezero (old1, oldlen); + + return msg; +} + +/* + * Obscure - see if password is obscure enough. + * + * The programmer is encouraged to add as much complexity to this + * routine as desired. Included are some of my favorite ways to + * check passwords. + */ + +bool obscure (const char *old, const char *new, const struct passwd *pwdp) +{ + const char *msg = obscure_msg (old, new, pwdp); + + if (NULL != msg) { + printf (_("Bad password: %s. "), msg); + return false; + } + return true; +} |