getauthattr, getauthnam, free_authattr, setauthattr, endauthattr, chkauthattr, chkauthattr_ucred - get authorization entry
#include <auth_attr.h>
authattr_t *getauthattr( void);
authattr_t *getauthnam( const char *name);
void free_authattr( authattr_t *auth);
void setauthattr( void);
void endauthattr( void);
int chkauthattr( const char *authname, const char * username);
int chkauthattr_ucred( const char *authname, const char * username, ucred_t ucred);
The getauthattr() and getauthnam() functions each return an auth_attr(5) entry. Entries can come from any of the sources specified in the nsswitch.conf(5) file.
The getauthattr() function enumerates auth_attr entries. The getauthnam() function searches for an auth_attr entry with a given authorization name name. Successive calls to these functions return either successive auth_attr entries or NULL.
The internal representation of an auth_attr entry is an authattr_t structure defined in <auth_attr.h > with the following members:
char *name; /* name of the authorization */ char *res1; /* reserved for future use */ char *res2; /* reserved for future use */ char *short_desc; /* short description */ char *long_desc; /* long description */ kva_t *attr; /* array of key-value pair attributes */
The setauthattr() function “rewinds” to the beginning of the enumeration of auth_attr entries. Calls to getauthnam() can leave the enumeration in an indeterminate state. Therefore, setauthattr() should be called before the first call to getauthattr().
The endauthattr() function may be called to indicate that auth_attr processing is complete; the system may then close any open auth_attr file, deallocate storage, and so forth.
The chkauthattr() function verifies whether or not a user has a given authorization. It first reads the user_attr(5) database and returns 1 if it finds a match for the given authorization. If it does not find a match in user_attr, chkauthattr () reads the prof_attr(5) database using the list of profiles assigned to the user and checks if any of the profiles assigned to the user has the given authorization.
For each user, there are two sets of profiles, an authenticated set and an unauthenticated set. Authorizations in the authenticated set or always effective, but those in the unauthenticated set only become effective after a successful response to an authentication challenge. Such challenges are automatically issued when the user executes a command matching an entry in the authenticated profiles set. See pfexec(1).
When chkauthattr() finds a profile called “Stop”, further profiles are ignored, the authorizations and profiles mentioned in /etc/security/policy.conf are ignored and it returns 0. If it does not find a match in the user's profiles, chkauthattr() reads the AUTHS_GRANTED key in the /etc/security/policy.conf file and returns 1 if it finds a match for the given authorization. If chkauthattr () does not find a match and the username is the name of the “console user”, defined as the owner of /dev/console , it first reads the CONSOLE_USER key in /etc/security/policy.conf and returns 1 if the given authorization is in any of the profiles specified in the CONSOLE_USER keyword, then reads the PROFS_GRANTED key in /etc/security/policy.conf and returns 1 if the given authorization is in any profiles specified with the PROFS_GRANTED keyword. The chkauthattr() function returns 0 if it does not find a match in any of the three sources or if the user does not exist.
The chkauthattr_ucred() function is identical to the chkauthattr() function, except for its interpretation of authorizations specified in the authenticated profiles set. In determining whether the authenticated profiles are effective, it uses the ucred pointer instead of the process flags of the calling process. This function should be used for local services that run on behalf of clients. The ucred of the client can be obtained by getpeerucred(3C) or door_ucred(3C).
The <auth_list.h> header file contains manifest constants for most of the defined authorizations. It is provided as a programming convenience to minimize typing errors and to allow tools such as cscope(1) and other source browsers to quickly identify where a particular authorization is checked.
Authorization names consist of a hierarchical set of dot (.)-separated words, called the predicate, and an optional object qualifier preceded by a slash character (/). Authorizations listed in user_attr and prof_attr may contain an asterisk (*) following the final dot in the predicate to indicate a wildcard. The reserved word grant, used for delegating authorizations, is not matched by *. Object qualifiers may use the fnmatch syntax to match multiple objects based on the provided pattern. The pattern is evaluated with the FNM_PATHNAME and FNM_LEADING_DIR flags. For more information, see the fnmatch(7) man page.
A user is considered to have been assigned an authorization if all of the following are true:
The authorization name matches exactly any authorization assigned in the user_attr or prof_attr databases (authorization names are case-sensitive).
The predicate of authname matches the predicate of an authorization completely, or the predicate does not end in grant and matches up to the * if present.
The authorization name suffix is not the key word grant and the authorization name matches any authorization up to the asterisk (*) character assigned in the user_attr or prof_attr databases.
If the authorization includes an object qualifier, then authname must include the same object qualifier.
The examples in the following table illustrate the conditions under which a user is assigned an authorization.
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The free_authattr() function releases memory allocated by the getauthnam() and getauthattr () functions.
The getauthattr() function returns a pointer to an authattr_t if it successfully enumerates an entry; otherwise it returns NULL, indicating the end of the enumeration.
The getauthnam() function returns a pointer to an authattr_t if it successfully locates the requested entry; otherwise it returns NULL.
The chkauthattr() function returns 1 if the user is authorized and 0 if the user does not exist or is not authorized.
The getauthattr() and getauthnam() functions both allocate memory for the pointers they return. This memory should be deallocated with the free_authattr() call.
Individual attributes in the attr structure can be referred to by calling the kva_match(3C) function.
Because the list of legal keys is likely to expand, code must be written to ignore unknown key-value pairs without error.
configuration file lookup information for the name service switch
extended user attributes
authorization attributes
policy definitions
profile information
See attributes(7) for descriptions of the following attributes:
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getexecattr(3C), getprofattr(3C), getuserattr(3C), auth_attr(5), nsswitch.conf(5), prof_attr(5), user_attr(5), attributes(7), rbac(7), fnmatch(7)