2 * Copyright (c) 1989 - 1993, Julianne Frances Haugh
3 * Copyright (c) 1996 - 1999, Marek Michałkiewicz
4 * Copyright (c) 2003 - 2005, Tomasz Kłoczko
5 * Copyright (c) 2007 - 2008, Nicolas François
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9 * modification, are permitted provided that the following conditions
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37 #include <sys/types.h>
39 #include "prototypes.h"
43 * valid - compare encrypted passwords
45 * Valid() compares the DES encrypted password from the password file
46 * against the password which the user has entered after it has been
47 * encrypted using the same salt as the original. Entries which do
48 * not have a password file entry have a NULL pw_name field and this
49 * is used to indicate that a dummy salt must be used to encrypt the
52 bool valid (const char *password, const struct passwd *ent)
54 const char *encrypted;
58 * Start with blank or empty password entries. Always encrypt
59 * a password if no such user exists. Only if the ID exists and
60 * the password is really empty do you return quickly. This
61 * routine is meant to waste CPU time.
64 if ((NULL != ent->pw_name) && ('\0' == ent->pw_passwd[0])) {
65 if ('\0' == password[0]) {
66 return true; /* user entered nothing */
68 return false; /* user entered something! */
73 * If there is no entry then we need a salt to use.
76 if ((NULL == ent->pw_name) || ('\0' == ent->pw_passwd[0])) {
79 salt = ent->pw_passwd;
83 * Now, perform the encryption using the salt from before on
84 * the users input. Since we always encrypt the string, it
85 * should be very difficult to determine if the user exists by
86 * looking at execution time.
89 encrypted = pw_encrypt (password, salt);
92 * One last time we must deal with there being no password file
93 * entry for the user. We use the pw_name == NULL idiom to
94 * cause non-existent users to not be validated.
97 if ( (NULL != ent->pw_name)
98 && (strcmp (encrypted, ent->pw_passwd) == 0)) {