NAME¶
vaccess_acl_posix1e
—
generate a POSIX.1e ACL access control decision using
vnode parameters
SYNOPSIS¶
#include
<sys/param.h>
#include
<sys/vnode.h>
#include
<sys/acl.h>
int
vaccess_acl_posix1e
(
enum
vtype type,
uid_t file_uid,
gid_t file_gid,
struct acl *acl,
accmode_t accmode,
struct ucred *cred,
int *privused);
DESCRIPTION¶
This call implements the logic for the
UNIX
discretionary file security model with POSIX.1e ACL extensions. It accepts the
vnodes type
type, owning UID
file_uid, owning GID
file_gid, access ACL for the file
acl, desired access mode
accmode, requesting credential
cred, and an optional call-by-reference
int pointer returning whether or not
privilege was required for successful evaluation of the call; the
privused pointer may be set to
NULL
by the caller in order not to be
informed of privilege information, or it may point to an integer that will be
set to 1 if privilege is used, and 0 otherwise.
This call is intended to support implementations of
VOP_ACCESS(9), which will use their own access
methods to retrieve the vnode properties, and then invoke
vaccess_acl_posix1e
() in order to perform
the actual check. Implementations of
VOP_ACCESS(9) may choose to implement additional
security mechanisms whose results will be composed with the return value.
The algorithm used by
vaccess_acl_posix1e
()
is based on the POSIX.1e ACL evaluation algorithm. The algorithm selects a
matching entry from the access ACL, which may
then be composed with an available ACL mask entry, providing
UNIX security compatibility.
Once appropriate protections are selected for the current credential, the
requested access mode, in combination with the vnode type, will be compared
with the discretionary rights available for the credential. If the rights
granted by discretionary protections are insufficient, then super-user
privilege, if available for the credential, will also be considered.
RETURN VALUES¶
vaccess_acl_posix1e
() will return 0 on
success, or a non-zero error value on failure.
ERRORS¶
- [
EACCES
]
- Permission denied. An attempt was made to access a file in a way forbidden
by its file access permissions.
- [
EPERM
]
- Operation not permitted. An attempt was made to perform an operation
limited to processes with appropriate privileges or to the owner of a file
or other resource.
SEE ALSO¶
vaccess(9),
vnode(9),
VOP_ACCESS(9)
AUTHORS¶
This manual page and the current implementation of
vaccess_acl_posix1e
() were written by
Robert Watson.
BUGS¶
This manual page should include a full description of the POSIX.1e ACL
evaluation algorithm, or cross reference another page that does.