Generating Client Principal Names

Servers need to be able to operate on a client's principal name -- for example, to compare a client's principal name to an access control list, or look up a UNIX credential for that client, if such a credential exists. Such principal names are kept in the form of a rpc_gss_principal_t structure pointer. (See the rpcsec_gss(3N) man page for more on rpc_gss_principal_t.) If a server wants to compare a principal name it has received with the name of a known entity, it needs to be able to generate a principal name in that form.

The rpc_gss_get_principal_name() call takes as input several parameters that uniquely identify an individual on a network, and generates a principal name as a rpc_gss_principal_t structure pointer:

Example 4-32 rpc_gss_get_principal_name()

rpc_gss_principal_t *principal;

rpc_gss_get_principal_name(principal, mechanism, name, node, domain);
. . .

The arguments to rpc_gss_get_principal_name() are as follows:

• principal is a pointer to the rpc_gss_principal_t structure to be set.

• mechanism is the security mechanism being used (remember, the principal name being generated is mechanism-dependent).

• name is an individual or service name, such as joeh or nfs, or even the name of a user-defined application.

• node might be, for example, a UNIX machine name.

• domain might be, for example, a DNS, NIS, or NIS+ domain name, or a Kerberos realm.

Each security mechanism requires different identifying parameters. For example, Kerberos V5 requires a user name and, only optionally, qualified node and domain names (in Kerberos terms, host and realm names).

For more information, see the rpc_gss_get_principal_name(3N) man page.