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Full Discussion: Shadow Passwords
Top Forums Programming Shadow Passwords Post 302091275 by blowtorch on Saturday 30th of September 2006 09:56:16 PM
Old 09-30-2006
What library function are you using to get the passwd entries? Don't just read them using fgets or something. Use getpwent to iteratively read the entire file. getpwent returns a structure that holds the different fields. The second field in that is pw_passwd which holds the user's encrypted passwd.

To determine whether your system is using shadow files or is a trusted system, all you should do is verify that the pw_passwd string is not 13 chars or longer. If it is then you can use the trusted system calls to get the shadow entries. If not, you can use the current pw_passwd string as it does hold the encrypted password for the user.
 

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pwck(1M)																  pwck(1M)

NAME
pwck, grpck - password/group file checkers SYNOPSIS
[password [shadow]] [password] [file] DESCRIPTION
scans fields in the password and shadow files and reports any inconsistencies to standard error. The checks include validation of the num- ber of fields, login name, user ID, group ID, and whether the login directory and optional program exist. In addition, if the root entry shows a program, it can only be one of: or The default password file is The default shadow file is For additional verification, use to check consistency between entries in the password and shadow files. verifies all entries in the group file and reports any inconsistencies to standard error. This verification includes a check of the number of fields, group name, group ID, and whether all login names appear in the password file. The default group file is Options recognizes the following options: Check inconsistencies with the Protected Password database. It calls Check encrypted password lengths that are greater than 8 characters. DIAGNOSTICS
Group entries in with no login names are flagged. WARNINGS
Successful password file validation is not sufficient for proper system operation. To help maintain consistency with other system data- bases, editing of the password file with is discouraged. HP recommends that you use or to edit HP-UX 11i Version 3 is the last release to support trusted systems functionality. DEPENDENCIES
NFS and check only the local password, shadow and group files. The Network Information Service database is not checked. AUTHOR
was developed by AT&T and HP. FILES
SEE ALSO
authck(1M), pwconv(1M), vipw(1M), group(4), passwd(4), shadow(4). STANDARDS CONFORMANCE
pwck(1M)
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