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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:54:37 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 14:54:37 +0000 |
commit | 97c26c1924b076ef23ebe4381558e8aa025712b2 (patch) | |
tree | 109724175f07436696f51b14b5abbd3f4d704d6d /libmisc/valid.c | |
parent | Initial commit. (diff) | |
download | shadow-e5df02f9b4d325b0ac1812e1456ba966566da242.tar.xz shadow-e5df02f9b4d325b0ac1812e1456ba966566da242.zip |
Adding upstream version 1:4.13+dfsg1.upstream/1%4.13+dfsg1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'libmisc/valid.c')
-rw-r--r-- | libmisc/valid.c | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/libmisc/valid.c b/libmisc/valid.c new file mode 100644 index 0000000..326635f --- /dev/null +++ b/libmisc/valid.c @@ -0,0 +1,82 @@ +/* + * SPDX-FileCopyrightText: 1989 - 1993, Julianne Frances Haugh + * SPDX-FileCopyrightText: 1996 - 1999, Marek Michałkiewicz + * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko + * SPDX-FileCopyrightText: 2007 - 2008, Nicolas François + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include <config.h> + +#ident "$Id$" + +#include <sys/types.h> +#include <stdio.h> +#include "prototypes.h" +#include "defines.h" +#include <pwd.h> +/* + * valid - compare encrypted passwords + * + * Valid() compares the DES encrypted password from the password file + * against the password which the user has entered after it has been + * encrypted using the same salt as the original. Entries which do + * not have a password file entry have a NULL pw_name field and this + * is used to indicate that a dummy salt must be used to encrypt the + * password anyway. + */ +bool valid (const char *password, const struct passwd *ent) +{ + const char *encrypted; + /*@observer@*/const char *salt; + + /* + * Start with blank or empty password entries. Always encrypt + * a password if no such user exists. Only if the ID exists and + * the password is really empty do you return quickly. This + * routine is meant to waste CPU time. + */ + + if ((NULL != ent->pw_name) && ('\0' == ent->pw_passwd[0])) { + if ('\0' == password[0]) { + return true; /* user entered nothing */ + } else { + return false; /* user entered something! */ + } + } + + /* + * If there is no entry then we need a salt to use. + */ + + if ((NULL == ent->pw_name) || ('\0' == ent->pw_passwd[0])) { + salt = "xx"; + } else { + salt = ent->pw_passwd; + } + + /* + * Now, perform the encryption using the salt from before on + * the users input. Since we always encrypt the string, it + * should be very difficult to determine if the user exists by + * looking at execution time. + */ + + encrypted = pw_encrypt (password, salt); + + /* + * One last time we must deal with there being no password file + * entry for the user. We use the pw_name == NULL idiom to + * cause non-existent users to not be validated. + */ + + if ( (NULL != ent->pw_name) + && (NULL != encrypted) + && (strcmp (encrypted, ent->pw_passwd) == 0)) { + return true; + } else { + return false; + } +} + |