KRB5_PRINCIPAL(3)

KRB5_PRINCIPAL(3) | Library Functions Manual | KRB5_PRINCIPAL(3)

# NAME

`krb5_get_default_principal`, `krb5_principal`, `krb5_build_principal`, `krb5_build_principal_ext`, `krb5_build_principal_va`, `krb5_build_principal_va_ext`, `krb5_copy_principal`, `krb5_free_principal`, `krb5_make_principal`, `krb5_parse_name`, `krb5_parse_name_flags`, `krb5_parse_nametype`, `krb5_princ_set_realm`, `krb5_principal_compare`, `krb5_principal_compare_any_realm`, `krb5_principal_get_comp_string`, `krb5_principal_get_realm`, `krb5_principal_get_type`, `krb5_principal_match`, `krb5_principal_set_type`, `krb5_realm_compare`, `krb5_sname_to_principal`, `krb5_sock_to_principal`, `krb5_unparse_name`, `krb5_unparse_name_flags`, `krb5_unparse_name_fixed`, `krb5_unparse_name_fixed_flags`, `krb5_unparse_name_fixed_short`, `krb5_unparse_name_short` —
Kerberos 5 principal handling functions

# LIBRARY

Kerberos 5 Library (libkrb5, -lkrb5)

# SYNOPSIS

`#include <krb5/krb5.h>`

`krb5_principal`;
void
`krb5_free_principal`(krb5_context context, krb5_principal principal);

krb5_error_code
`krb5_parse_name`(krb5_context context, const char *name, krb5_principal *principal);

krb5_error_code
`krb5_parse_name_flags`(krb5_context context, const char *name, int flags, krb5_principal *principal);

krb5_error_code
`krb5_unparse_name`(krb5_context context, krb5_const_principal principal, char **name);

krb5_error_code
`krb5_unparse_name_flags`(krb5_context context, krb5_const_principal principal, int flags, char **name);

krb5_error_code
`krb5_unparse_name_fixed`(krb5_context context, krb5_const_principal principal, char *name, size_t len);

krb5_error_code
`krb5_unparse_name_fixed_flags`(krb5_context context, krb5_const_principal principal, int flags, char *name, size_t len);

krb5_error_code
`krb5_unparse_name_short`(krb5_context context, krb5_const_principal principal, char **name);

krb5_error_code
`krb5_unparse_name_fixed_short`(krb5_context context, krb5_const_principal principal, char *name, size_t len);

void
`krb5_princ_set_realm`(krb5_context context, krb5_principal principal, krb5_realm *realm);

krb5_error_code
`krb5_build_principal`(krb5_context context, krb5_principal *principal, int rlen, krb5_const_realm realm, ...);

krb5_error_code
`krb5_build_principal_va`(krb5_context context, krb5_principal *principal, int rlen, krb5_const_realm realm, va_list ap);

krb5_error_code
`krb5_build_principal_ext`(krb5_context context, krb5_principal *principal, int rlen, krb5_const_realm realm, ...);

krb5_error_code
`krb5_build_principal_va_ext`(krb5_context context, krb5_principal *principal, int rlen, krb5_const_realm realm, va_list ap);

krb5_error_code
`krb5_make_principal`(krb5_context context, krb5_principal *principal, krb5_const_realm realm, ...);

krb5_error_code
`krb5_copy_principal`(krb5_context context, krb5_const_principal inprinc, krb5_principal *outprinc);

krb5_boolean
`krb5_principal_compare`(krb5_context context, krb5_const_principal princ1, krb5_const_principal princ2);

krb5_boolean
`krb5_principal_compare_any_realm`(krb5_context context, krb5_const_principal princ1, krb5_const_principal princ2);

const char *
`krb5_principal_get_comp_string`(krb5_context context, krb5_const_principal principal, unsigned int component);

const char *
`krb5_principal_get_realm`(krb5_context context, krb5_const_principal principal);

int
`krb5_principal_get_type`(krb5_context context, krb5_const_principal principal);

krb5_boolean
`krb5_principal_match`(krb5_context context, krb5_const_principal principal, krb5_const_principal pattern);

void
`krb5_principal_set_type`(krb5_context context, krb5_principal principal, int type);

krb5_boolean
`krb5_realm_compare`(krb5_context context, krb5_const_principal princ1, krb5_const_principal princ2);

krb5_error_code
`krb5_sname_to_principal`(krb5_context context, const char *hostname, const char *sname, int32_t type, krb5_principal *ret_princ);

krb5_error_code
`krb5_sock_to_principal`(krb5_context context, int socket, const char *sname, int32_t type, krb5_principal *principal);

krb5_error_code
`krb5_get_default_principal`(krb5_context context, krb5_principal *princ);

krb5_error_code
`krb5_parse_nametype`(krb5_context context, const char *str, int32_t *type);

# DESCRIPTION

`krb5_principal` holds the name of a user or service in Kerberos.

A principal has two parts, a `PrincipalName` and a `realm`. The PrincipalName consists of one or more components. In printed form, the components are separated by /. The PrincipalName also has a name-type.

Examples of a principal are `nisse/root@EXAMPLE.COM` and `host/datan.kth.se@KTH.SE`. `krb5_parse_name`() and `krb5_parse_name_flags`() passes a principal name in name to the kerberos principal structure. `krb5_parse_name_flags`() takes an extra flags argument the following flags can be passed in

`KRB5_PRINCIPAL_PARSE_NO_REALM`
  requires the input string to be without a realm, and no realm is stored in the principal return argument.
`KRB5_PRINCIPAL_PARSE_REQUIRE_REALM`
  requires the input string to with a realm.

`krb5_unparse_name`() and `krb5_unparse_name_flags`() prints the principal princ to the string name. name should be freed with free(3). To the flags argument the following flags can be passed in

`KRB5_PRINCIPAL_UNPARSE_SHORT`
  no realm if the realm is one of the local realms.
`KRB5_PRINCIPAL_UNPARSE_NO_REALM`
  never include any realm in the principal name.
`KRB5_PRINCIPAL_UNPARSE_DISPLAY`
  don't quote

On failure name is set to `NULL`. `krb5_unparse_name_fixed`() and `krb5_unparse_name_fixed_flags`() behaves just like `krb5_unparse`(), but instead unparses the principal into a fixed size buffer.

`krb5_unparse_name_short`() just returns the principal without the realm if the principal is in the default realm. If the principal isn't, the full name is returned. `krb5_unparse_name_fixed_short`() works just like `krb5_unparse_name_short`() but on a fixed size buffer.

`krb5_build_principal`() builds a principal from the realm realm that has the length rlen. The following arguments form the components of the principal. The list of components is terminated with `NULL`.

`krb5_build_principal_va`() works like `krb5_build_principal`() using vargs.

`krb5_build_principal_ext`() and `krb5_build_principal_va_ext`() take a list of length-value pairs, the list is terminated with a zero length.

`krb5_make_principal`() works the same way as `krb5_build_principal`(), except it figures out the length of the realm itself.

`krb5_copy_principal`() makes a copy of a principal. The copy needs to be freed with `krb5_free_principal`().

`krb5_principal_compare`() compares the two principals, including realm of the principals and returns `TRUE` if they are the same and `FALSE` if not.

`krb5_principal_compare_any_realm`() works the same way as `krb5_principal_compare`() but doesn't compare the realm component of the principal.

`krb5_realm_compare`() compares the realms of the two principals and returns `TRUE` is they are the same, and `FALSE` if not.

`krb5_principal_match`() matches a principal against a pattern. The pattern is a globbing expression, where each component (separated by /) is matched against the corresponding component of the principal.

The `krb5_principal_get_realm`() and `krb5_principal_get_comp_string`() functions return parts of the principal, either the realm or a specific component. Both functions return string pointers to data inside the principal, so they are valid only as long as the principal exists.

The component argument to `krb5_principal_get_comp_string`() is the index of the component to return, from zero to the total number of components minus one. If the index is out of range `NULL` is returned.

`krb5_principal_get_realm`() and `krb5_principal_get_comp_string`() are replacements for `krb5_princ_component`() and related macros, described as internal in the MIT API specification. Unlike the macros, these functions return strings, not `krb5_data`. A reason to return `krb5_data` was that it was believed that principal components could contain binary data, but this belief was unfounded, and it has been decided that principal components are infact UTF8, so it's safe to use zero terminated strings.

It's generally not necessary to look at the components of a principal.

`krb5_principal_get_type`() and `krb5_principal_set_type`() get and sets the name type for a principal. Name type handling is tricky and not often needed, don't use this unless you know what you do.

`krb5_sname_to_principal`() and `krb5_sock_to_principal`() are for easy creation of “service” principals that can, for instance, be used to lookup a key in a keytab. For both functions the sname parameter will be used for the first component of the created principal. If sname is `NULL`, “host” will be used instead.

`krb5_sname_to_principal`() will use the passed hostname for the second component. If type is `KRB5_NT_SRV_HST` this name will be looked up with `gethostbyname`(). If hostname is `NULL`, the local hostname will be used.

`krb5_sock_to_principal`() will use the “sockname” of the passed socket, which should be a bound `AF_INET` or `AF_INET6` socket. There must be a mapping between the address and “sockname”. The function may try to resolve the name in DNS.

`krb5_get_default_principal`() tries to find out what's a reasonable default principal by looking at the environment it is running in.

`krb5_parse_nametype`() parses and returns the name type integer value in type. On failure the function returns an error code and set the error string.

# SEE ALSO

krb5_config(3), krb5.conf(5)

# BUGS

You can not have a NUL in a component in some of the variable argument functions above. Until someone can give a good example of where it would be a good idea to have NUL's in a component, this will not be fixed.

May 1, 2006 | NetBSD 10.1