PAM_UNIX_CRED(7) Standards, Environments, and Macros PAM_UNIX_CRED(7)

NAME

pam_unix_cred - PAM user credential module for UNIX

SYNOPSIS

pam_unix_cred.so.1

DESCRIPTION

The pam_unix_cred module implements pam_sm_setcred(3PAM). It provides
functions that establish user credential information. It is a module
separate from the pam_unix_auth(7) module to allow replacement of the
authentication functionality independently from the credential
functionality.


The pam_unix_cred module must always be stacked along with whatever
authentication module is used to ensure correct credential setting.


Authentication service modules must implement both
pam_sm_authenticate() and pam_sm_setcred().


pam_sm_authenticate() in this module always returns PAM_IGNORE.


pam_sm_setcred() initializes the user's project, privilege sets and
initializes or updates the user's audit context if it hasn't already
been initialized. The following flags may be set in the flags field:

PAM_ESTABLISH_CRED
PAM_REFRESH_CRED
PAM_REINITIALIZE_CRED

Initializes the user's project to the project specified in
PAM_RESOURCE, or if PAM_RESOURCE is not specified, to the user's
default project. Establishes the user's privilege sets.

If the audit context is not already initialized and auditing is
configured, these flags cause the context to be initialized to
that of the user specified in PAM_AUSER (if any) merged with the
user specified in PAM_USER and host specified in PAM_RHOST. If
PAM_RHOST is not specified, PAM_TTY specifies the local terminal
name. Attributing audit to PAM_AUSER and merging PAM_USER is
required for correctly attributing auditing when the system entry
is performed by another user that can be identified as
trustworthy.

If the audit context is already initialized, the
PAM_REINITIALIZE_CRED flag merges the current audit context with
that of the user specified in PAM_USER. PAM_REINITIALIZE_CRED is
useful when a user is assuming a new identity, as with su(8).


PAM_DELETE_CRED

This flag has no effect and always returns PAM_SUCCESS.


The following options are interpreted:

debug
Provides syslog(3C) debugging information at the LOG_DEBUG
level.


nowarn
Disables any warning messages.

ERRORS

Upon successful completion of pam_sm_setcred(), PAM_SUCCESS is
returned. The following error codes are returned upon error:

PAM_CRED_UNAVAIL
Underlying authentication service cannot retrieve
user credentials


PAM_CRED_EXPIRED
User credentials have expired


PAM_USER_UNKNOWN
User is unknown to the authentication service


PAM_CRED_ERR
Failure in setting user credentials


PAM_BUF_ERR
Memory buffer error


PAM_SYSTEM_ERR
System error


The following values are returned from pam_sm_authenticate():

PAM_IGNORE
Ignores this module regardless of the control flag

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:


+--------------------+-------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-------------------------+
|Interface Stability | Evolving |
+--------------------+-------------------------+
|MT Level | MT-Safe with exceptions |
+--------------------+-------------------------+

SEE ALSO

syslog(3C), libpam(3LIB), pam(3PAM), pam_sm_authenticate(3PAM),
pam_sm_setcred(3PAM), pam.conf(5), project(5), attributes(7),
pam_unix_auth(7), pam_unix_session(7), su(8)

NOTES

The interfaces in libpam(3LIB) are MT-Safe only if each thread within
the multi-threaded application uses its own PAM handle.


If this module is replaced, the audit context and credential may not
be correctly configured.

August 19, 2023 PAM_UNIX_CRED(7)