GENFS_CAN_ACCESS(9) | Kernel Developer's Manual | GENFS_CAN_ACCESS(9) |
genfs_can_access
—
#include <miscfs/genfs/genfs.h>
int
genfs_can_access
(vnode_t *vp,
kauth_cred_t cred, uid_t
file_uid, gid_t file_gid, mode_t
file_mode, struct acl *acl,
accmode_t accmode);
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
() 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 genfs_can_access
()
selects a component of the file permission bits based on comparing the
passed credential, file owner, and file group. If the credential's effective
UID matches the file owner, then the owner component of the permission bits
is selected. If the UID does not match, then the credential's effective GID,
followed by additional groups, are compared with the file group—if
there is a match, then the group component of the permission bits is
selected. If neither the credential UID or GIDs match the passed file owner
and group, then the other component of the permission bits is selected.
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.
genfs_can_access
() will return 0 on success, or a
non-zero error value on failure.
vaccess
() were written by Robert
Watson.
January 17, 2022 | NetBSD 10.0 |