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KAUTH(9) Kernel Developer's Manual KAUTH(9)
NAME
kauth - kernel authorization framework
SYNOPSIS
#include <sys/kauth.h>
DESCRIPTION
kauth, or kernel authorization, is the subsystem managing all
authorization requests inside the kernel. It manages user credentials
and rights, and can be used to implement a system-wide security policy.
It allows external modules to plug-in the authorization process.
kauth introduces some new concepts, namely "scopes" and "listeners",
which will be detailed together with other useful information for kernel
developers in this document.
Types
Some kauth types include the following:
kauth_cred_t Representing credentials that can be associated with an
object. Includes user- and group-ids (real, effective,
and save) as well as group membership information.
kauth_scope_t Describes a scope.
kauth_listener_t Describes a listener.
Terminology
kauth operates in various "scopes", each scope holding a group of
"listeners".
Each listener works as a callback for when an authorization request
within the scope is made. When such a request is made, all listeners on
the scope are passed common information such as the credentials of the
request context, an identifier for the requested operation, and possibly
other information as well.
Every listener examines the passed information and returns its decision
regarding the requested operation. It can either return:
KAUTH_RESULT_ALLOW The listener allows the operation.
KAUTH_RESULT_DENY The listener denies the operation.
KAUTH_RESULT_DEFER The listener defers the decision to other listeners.
For an operation to be allowed, at least one listener has to return
KAUTH_RESULT_ALLOW while no other listener returned KAUTH_RESULT_DENY.
Scopes manage listeners that operate in the same aspect of the system.
Kernel Programming Interface
kauth exports a KPI that allows developers both of NetBSD and third-party
products to authorize requests, access and modify credentials, create and
remove scopes and listeners, and perform other miscellaneous operations
on credentials.
Authorization Requests
kauth provides a single authorization request routine, which all
authorization requests go through. This routine dispatches the request
to the listeners of the appropriate scope, together with four optional
user-data variables, and returns the augmented result.
It is declared as
int kauth_authorize_action(kauth_scope_t scope, kauth_cred_t cred,
kauth_action_t op, void *arg0, void *arg1, void *arg2, void *arg3)
An authorization request can return one of two possible values:
0 (zero) indicates success; operation is allowed.
EPERM indicates failure; operation is denied. See
errno(2).
Each scope has its own authorization wrapper, to make it easy to call
from various places by eliminating the need to specify the scope and/or
cast values. The authorization wrappers are detailed in each scope's
section.
kauth_authorize_action() has several special cases, when it will always
allow the request. These are for when the request is issued by the
kernel itself (indicated by the credentials being either NOCRED or
FSCRED), or when there was no definitive decision from any of the
listeners (i.e., it was not explicitly allowed or denied) and no security
model was loaded.
Generic Scope
The generic scope, "org.netbsd.kauth.generic", manages generic
authorization requests in the kernel.
The authorization wrapper for this scope is declared as
int kauth_authorize_generic(kauth_cred_t cred, kauth_action_t op, void
*arg0)
The following operations are available for this scope:
KAUTH_GENERIC_ISSUSER
Checks whether the credentials belong to the super-user.
Using this request is strongly discouraged and should only be
done as a temporary place-holder, as it is breaking the
separation between the interface for authorization requests from
the back-end implementation.
System Scope
The system scope, "org.netbsd.kauth.system", manages authorization
requests affecting the entire system.
The authorization wrapper for this scope is declared as
int kauth_authorize_system(kauth_cred_t cred, kauth_action_t op, enum
kauth_system_req req, void *arg1, void *arg2, void *arg3)
The following requests are available for this scope:
KAUTH_SYSTEM_ACCOUNTING
Check if enabling/disabling accounting allowed.
KAUTH_SYSTEM_CHROOT
req can be any of the following:
KAUTH_REQ_SYSTEM_CHROOT_CHROOT
Check if calling chroot(2) is allowed.
KAUTH_REQ_SYSTEM_CHROOT_FCHROOT
Check if calling fchroot(2) is allowed.
KAUTH_SYSTEM_CPU
Check CPU-manipulation access.
req can be any of the following:
KAUTH_REQ_SYSTEM_CPU_SETSTATE
Set CPU state, including setting it online or offline.
KAUTH_SYSTEM_DEBUG
This request concentrates several debugging-related operations.
KAUTH_SYSTEM_DEVMAPPER
Check if operations on the device mapper dm(4) device are
allowed.
KAUTH_SYSTEM_FILEHANDLE
Check if file handle operations allowed.
KAUTH_SYSTEM_FS_EXTATTR
Check if starting, stopping, enabling, or disabling extended
attributes is allowed. arg1 is a struct mount * of the mount-
point on which the operation is performed.
KAUTH_SYSTEM_FS_SNAPSHOT
Check if setting up a file system snapshot is allowed. arg1 is
a struct mount * of the mount-point of which the snapshot is
taken, and arg2 is a struct vnode * of the vnode where the
snapshot is expected to be.
KAUTH_SYSTEM_FS_QUOTA
Check if file system quota operations are allowed.
arg1 is a struct mount * describing the file system mount in
question. req can be one of the following:
KAUTH_REQ_SYSTEM_FS_QUOTA_GET
Check if retrieving quota information is allowed.
arg2 is a uid_t with the user-id of the user whose
quota information is to be retrieved.
KAUTH_REQ_SYSTEM_FS_QUOTA_ONOFF
Check if turning quota on/off is allowed.
KAUTH_REQ_SYSTEM_FS_QUOTA_MANAGE
Check if managing the quota by setting the quota/quota
use is allowed.
arg2 is a uid_t with the user-id of the user whose
quota/quota use is to be set.
KAUTH_REQ_SYSTEM_FS_QUOTA_NOLIMIT
Check if bypassing the quota (not enforcing it) is
allowed.
KAUTH_SYSTEM_FS_RESERVEDSPACE
Check if using the file system reserved space is allowed.
KAUTH_SYSTEM_LFS
Check if LFS-related operations are allowed. req can be one of
the following:
KAUTH_REQ_SYSTEM_LFS_MARKV
Check if calling lfs_markv(2) is allowed.
KAUTH_REQ_SYSTEM_LFS_BMAPV
Check if calling lfs_bmapv(2) is allowed.
KAUTH_REQ_SYSTEM_LFS_SEGCLEAN
Check if calling lfs_segclean(2) is allowed.
KAUTH_REQ_SYSTEM_LFS_SEGWAIT
Check if calling lfs_segwait(2) is allowed.
KAUTH_REQ_SYSTEM_LFS_FCNTL
Check if operations on LFS through fcntl(2) are
allowed.
KAUTH_SYSTEM_MAP_VA_ZERO
Check if changing the status of memory mapping of virtual
address zero is allowed.
KAUTH_SYSTEM_MODULE
Check if a module request is allowed.
arg1 is the command.
KAUTH_SYSTEM_MKNOD
Check if creating devices is allowed.
KAUTH_SYSTEM_MOUNT
Check if mount-related operations are allowed.
req can be any of the following:
KAUTH_REQ_SYSTEM_MOUNT_DEVICE
Check if mounting a device is allowed. arg1 is a
vnode_t * of the device, arg2 is a struct mount * with
the mount-point, and arg3 is a mode_t with the desired
access mode.
KAUTH_REQ_SYSTEM_MOUNT_GET
Check if retrieving information about a mount is
allowed. arg1 is a struct mount * with the mount
structure in question, arg2 is a void * with file
system specific data, if any.
KAUTH_REQ_SYSTEM_MOUNT_NEW
Check if mounting a new file system is allowed.
arg1 is the struct vnode * on which the file system is
to be mounted, arg2 is an int with the mount flags, and
arg3 is a void * with file system specific data, if
any.
KAUTH_REQ_SYSTEM_MOUNT_UNMOUNT
Checks if unmounting a file system is allowed.
arg1 is a struct mount * with the mount in question.
KAUTH_REQ_SYSTEM_MOUNT_UPDATE
Checks if updating an existing mount is allowed.
arg1 is the struct mount * of the existing mount, arg2
is an int with the new mount flags, and arg3 is a void
* with file system specific data, if any.
KAUTH_REQ_SYSTEM_MOUNT_UMAP
Check if mounting the user and group id remapping file
system. See mount_umap(8).
KAUTH_SYSTEM_MQUEUE
Check if bypassing permissions on a message queue object are
allowed. arg1 is a mqueue_t * describing the message queue.
KAUTH_SYSTEM_PSET
Check processor-set manipulation.
req can be any of the following:
KAUTH_REQ_SYSTEM_PSET_ASSIGN
Change processor-set processor assignment.
KAUTH_REQ_SYSTEM_PSET_BIND
Bind an LWP to a processor-set.
KAUTH_REQ_SYSTEM_PSET_CREATE
Create a processor-set.
KAUTH_REQ_SYSTEM_PSET_DESTROY
Destroy a processor-set.
KAUTH_SYSTEM_REBOOT
Check if rebooting is allowed.
KAUTH_SYSTEM_SETIDCORE
Check if changing coredump settings for set-id processes is
allowed.
KAUTH_SYSTEM_SEMAPHORE
Check if access to a kernel semaphore is allowed. arg1 is a
ksem_t * describing the semaphore.
KAUTH_SYSTEM_SWAPCTL
Check if privileged swapctl(2) requests are allowed.
KAUTH_SYSTEM_SYSCTL
This requests operations related to sysctl(9). req indicates
the specific request and can be one of the following:
KAUTH_REQ_SYSTEM_SYSCTL_ADD
Check if adding a sysctl(9) node is allowed.
KAUTH_REQ_SYSTEM_SYSCTL_DELETE
Check if deleting a sysctl(9) node is allowed.
KAUTH_REQ_SYSTEM_SYSCTL_DESC
Check if adding description to a sysctl(9) node is
allowed.
KAUTH_REQ_SYSTEM_SYSCTL_MODIFY
Check if modifying a sysctl(9) node variable that
doesn't have a custom sysctl helper function is
allowed.
This request might be deprecated in the future.
KAUTH_REQ_SYSTEM_SYSCTL_PRVT
Check if accessing private sysctl(9) nodes is allowed.
KAUTH_SYSTEM_SYSVIPC
Check SysV IPC related operations. req indicates the specific
request and can be one of the following:
KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS
Check if bypassing a SysV IPC object's permissions is
allowed. arg1 is a struct ipc_perm * with the object's
permissions and arg2 is a mode_t indicating the
requested access mode.
KAUTH_REQ_SYSTEM_SYSVIPC_SHM_LOCK
Check if shared memory locking is allowed.
KAUTH_REQ_SYSTEM_SYSVIPC_SHM_UNLOCK
Check if shared memory unlocking is allowed.
KAUTH_REQ_SYSTEM_SYSVIPC_MSGQ_OVERSIZE
Check if oversizing a message queue is allowed. arg1
is a msglen_t indicating the size of the message
buffer, and arg2 is a msglen_t indicating the size of
the message queue.
KAUTH_SYSTEM_TIME
This request groups time-related operations. req can be any of
the following:
KAUTH_REQ_SYSTEM_TIME_ADJTIME
Check if changing the time using adjtime(2) is allowed.
KAUTH_REQ_SYSTEM_TIME_NTPADJTIME
Check if setting the time using ntp_adjtime(2) is
allowed.
KAUTH_REQ_SYSTEM_TIME_SYSTEM
Check if changing the time (usually via
settimeofday(2)) is allowed.
arg1 is a struct timespec * with the new time, arg2 is
a struct timeval * with the delta from the current
time, arg3 is a bool indicating whether the caller is a
device context (e.g. /dev/clockctl) or not.
KAUTH_REQ_SYSTEM_TIME_RTCOFFSET
Check if changing the RTC offset is allowed.
KAUTH_REQ_SYSTEM_TIME_TIMECOUNTERS
Check if manipulating timecounters is allowed.
KAUTH_SYSTEM_VERIEXEC
Check if operations on the veriexec(8) subsystem are allowed.
req can be one of the following:
KAUTH_REQ_SYSTEM_VERIEXEC_ACCESS
Check if access to the veriexec(8) subsystem is
allowed.
KAUTH_REQ_SYSTEM_VERIEXEC_MODIFY
Check if modifications to the state of veriexec(8) are
allowed.
Process Scope
The process scope, "org.netbsd.kauth.process", manages authorization
requests related to processes in the system.
The authorization wrapper for this scope is declared as
int kauth_authorize_process(kauth_cred_t cred, kauth_action_t op, struct
proc *p, void *arg1, void *arg2, void *arg3)
The following operations are available for this scope:
KAUTH_PROCESS_KTRACE
Checks whether an object with one set of credentials can
ktrace(1) another process p, possibly with a different set of
credentials.
If arg1 is KAUTH_REQ_PROCESS_KTRACE_PERSISTENT, this checks if
persistent tracing can be done. Persistent tracing maintains
the trace across a set-user-id/set-group-id exec(3), and
normally requires privileged credentials.
KAUTH_PROCESS_PROCFS
Checks whether object with passed credentials can use procfs to
access process p.
arg1 is the struct pfsnode * for the target element in the
target process, and arg2 is the access type, which can be either
KAUTH_REQ_PROCESS_PROCFS_READ, KAUTH_REQ_PROCESS_PROCFS_RW, or
KAUTH_REQ_PROCESS_PROCFS_WRITE, indicating control, read,
read-write, or write access respectively.
KAUTH_PROCESS_PTRACE
Checks whether object with passed credentials can use ptrace(2)
to access process p.
arg1 is the ptrace(2) command.
KAUTH_PROCESS_CANSEE
Checks whether an object with one set of credentials can access
information about another process, possibly with a different set
of credentials.
arg1 indicates the class of information being viewed, and can be
either of KAUTH_REQ_PROCESS_CANSEE_ARGS,
KAUTH_REQ_PROCESS_CANSEE_ENTRY, KAUTH_REQ_PROCESS_CANSEE_ENV, or
KAUTH_REQ_PROCESS_CANSEE_OPENFILES.
KAUTH_PROCESS_SCHEDULER_GETAFFINITY
Checks whether viewing the scheduler affinity is allowed.
KAUTH_PROCESS_SCHEDULER_SETAFFINITY
Checks whether setting the scheduler affinity is allowed.
KAUTH_PROCESS_SCHEDULER_GETPARAM
Checks whether viewing the scheduler policy and parameters is
allowed.
KAUTH_PROCESS_SCHEDULER_SETPARAM
Checks whether modifying the scheduler policy and parameters is
allowed.
KAUTH_PROCESS_SIGNAL
Checks whether an object with one set of credentials can post
signals to another process.
p is the process the signal is being posted to, and arg1 is the
signal number.
KAUTH_PROCESS_CORENAME
Controls access to process corename.
arg1 can be KAUTH_REQ_PROCESS_CORENAME_GET or
KAUTH_REQ_PROCESS_CORENAME_SET, indicating access to read or
write the process' corename, respectively.
When modifying the corename, arg2 holds the new corename to be
used.
KAUTH_PROCESS_FORK
Checks if the process can fork. arg1 is an int indicating how
many processes exist on the system at the time of the check.
KAUTH_PROCESS_KEVENT_FILTER
Checks whether setting a process kevent(2) filter is allowed.
KAUTH_PROCESS_NICE
Checks whether the nice value of p can be changed to arg1.
KAUTH_PROCESS_RLIMIT
Controls access to process resource limits.
arg1 can be KAUTH_REQ_PROCESS_RLIMIT_GET or
KAUTH_REQ_PROCESS_RLIMIT_SET, indicating access to read or write
the process' resource limits, respectively, or
KAUTH_REQ_PROCESS_RLIMIT_BYPASS to check if the limit
enforcement can be bypassed.
When modifying resource limits, arg2 is the new value to be used
and arg3 indicates which resource limit is to be modified.
KAUTH_PROCESS_SETID
Check if changing the user- or group-ids, groups, or login-name
for p is allowed.
KAUTH_PROCESS_STOPFLAG
Check if setting the stop flags for exec(3), exit(3), and
fork(2) is allowed.
arg1 indicates the flag, and can be either P_STOPEXEC,
P_STOPEXIT, or P_STOPFORK respectively.
Network Scope
The network scope, "org.netbsd.kauth.network", manages networking-related
authorization requests in the kernel.
The authorization wrapper for this scope is declared as
int kauth_authorize_network(kauth_cred_t cred, kauth_action_t op, enum
kauth_network_req req, void *arg1, void *arg2, void *arg3)
The following operations are available for this scope:
KAUTH_NETWORK_ALTQ
Checks if an ALTQ operation is allowed.
req indicates the ALTQ subsystem in question, and can be one of
the following:
KAUTH_REQ_NETWORK_ALTQ_AFMAP
KAUTH_REQ_NETWORK_ALTQ_BLUE
KAUTH_REQ_NETWORK_ALTQ_CBQ
KAUTH_REQ_NETWORK_ALTQ_CDNR
KAUTH_REQ_NETWORK_ALTQ_CONF
KAUTH_REQ_NETWORK_ALTQ_FIFOQ
KAUTH_REQ_NETWORK_ALTQ_HFSC
KAUTH_REQ_NETWORK_ALTQ_JOBS
KAUTH_REQ_NETWORK_ALTQ_PRIQ
KAUTH_REQ_NETWORK_ALTQ_RED
KAUTH_REQ_NETWORK_ALTQ_RIO
KAUTH_REQ_NETWORK_ALTQ_WFQ
KAUTH_NETWORK_BIND
Checks if a bind(2) request is allowed.
req allows to indicate the type of the request to structure
listeners and callers easier. Supported request types:
KAUTH_REQ_NETWORK_BIND_PORT
Checks if binding to a non-privileged/reserved port is
allowed.
KAUTH_REQ_NETWORK_BIND_PRIVPORT
Checks if binding to a privileged/reserved port is
allowed.
KAUTH_NETWORK_FIREWALL
Checks if firewall-related operations are allowed.
req indicates the sub-action, and can be one of the following:
KAUTH_REQ_NETWORK_FIREWALL_FW
Modification of packet filtering rules.
KAUTH_REQ_NETWORK_FIREWALL_NAT
Modification of NAT rules.
KAUTH_NETWORK_INTERFACE
Checks if network interface-related operations are allowed.
arg1 is (optionally) the struct ifnet * associated with the
interface. arg2 is (optionally) an int describing the
interface-specific operation. arg3 is (optionally) a pointer to
the interface-specific request structure. req indicates the
sub-action, and can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_GET
Check if retrieving information from the device is
allowed.
KAUTH_REQ_NETWORK_INTERFACE_GETPRIV
Check if retrieving privileged information from the
device is allowed.
KAUTH_REQ_NETWORK_INTERFACE_SET
Check if setting parameters on the device is allowed.
KAUTH_REQ_NETWORK_INTERFACE_SETPRIV
Check if setting privileged parameters on the device is
allowed.
KAUTH_REQ_NETWORK_INTERFACE_FIRMWARE
Check if manipulating the firmware on a network
interface device is allowed.
Note that unless the struct ifnet * for the interface was passed
in arg1, there's no way to tell what structure arg3 is.
KAUTH_NETWORK_INTERFACE_BRIDGE
Check if operations performed on the bridge(4) network interface
are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_BRIDGE_GETPRIV
Check if getting privileges parameters is allowed.
KAUTH_REQ_NETWORK_INTERFACE_BRIDGE_SETPRIV
Check if setting privileges parameters is allowed.
KAUTH_NETWORK_INTERFACE_PPP
Checks if operations performed on the ppp(4) network interface
are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_PPP_ADD
Checks if adding and enabling a ppp(4) interface to the
system is allowed.
KAUTH_NETWORK_INTERFACE_PVC
Check if operations performed on a PVC device (e.g. en(4)) are
allowed. req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_PVC_ADD
Check if adding a PVC device is allowed.
KAUTH_NETWORK_INTERFACE_SLIP
Checks if operations performed on the sl(4) network interface
are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_SLIP_ADD
Checks if adding and enabling a sl(4) interface to the
system is allowed.
KAUTH_NETWORK_INTERFACE_STRIP
Checks if operations performed on the strip(4) network interface
are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_STRIP_ADD
Check if adding and enabling a strip(4) interface to
the system is allowed.
KAUTH_NETWORK_INTERFACE_TUN
Checks if operations performed on the tun(4) network interface
are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_INTERFACE_TUN_ADD
Checks if adding and enabling a tun(4) interface to the
system is allowed.
KAUTH_NETWORK_IPSEC
Check if operations related to ipsec(4) connections are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_IPSEC_BYPASS
Check if bypassing ipsec(4) policy is allowed.
KAUTH_NETWORK_IPV6
Check if IPv6-specific operations are allowed. req can be one
of the following:
KAUTH_REQ_NETWORK_IPV6_HOPBYHOP
Check if setting hop-by-hop packet options is allowed.
KAUTH_REQ_NETWORK_IPV6_JOIN_MULTICAST
Check if joining a multicast network is allowed.
KAUTH_NETWORK_FORWSRCRT
Checks whether status of forwarding of source-routed packets can
be modified or not.
KAUTH_NETWORK_NFS
Check if an NFS related operation is allowed.
req can be any of the following:
KAUTH_REQ_NETWORK_NFS_EXPORT
Check if modifying the NFS export table is allowed.
KAUTH_REQ_NETWORK_NFS_SVC
Check if access to the NFS nfssvc(2) syscall is
allowed.
KAUTH_NETWORK_ROUTE
Checks if a routing-related request is allowed.
arg1 is the struct rt_msghdr * for the request.
KAUTH_NETWORK_SMB
Check if operations related to SMB are allowed.
req can be one of the following:
KAUTH_REQ_NETWORK_SMB_SHARE_ACCESS
Check if accessing an SMB share is allowed.
arg1 is a struct smb_share * describing the SMB share,
and arg2 is a mode_t with the desired access mode.
KAUTH_REQ_NETWORK_SMB_SHARE_CREATE
Check if creating an SMB share is allowed.
arg1 is a struct smb_sharespec * describing the share
to be created.
KAUTH_REQ_NETWORK_SMB_VC_ACCESS
Check if accessing an SMB VC is allowed.
arg1 is a struct smb_vc * describing the SMB VC, and
arg2 is a mode_t with the desired access mode.
KAUTH_REQ_NETWORK_SMB_VC_CREATE
Check if creating an SMB VC is allowed.
arg1 is a struct smb_vcspec * describing the VC to be
created.
KAUTH_NETWORK_SOCKET
Checks if a socket related operation is allowed.
req allows to indicate the type of the request to structure
listeners and callers easier. Supported request types:
KAUTH_REQ_NETWORK_SOCKET_RAWSOCK
Checks if opening a raw socket is allowed.
KAUTH_REQ_NETWORK_SOCKET_OPEN
Checks if opening a socket is allowed. arg1, arg2, and
arg3 are all int parameters describing the domain,
socket type, and protocol, respectively.
KAUTH_REQ_NETWORK_SOCKET_CANSEE
Checks if looking at the socket passed is allowed.
arg1 is a struct socket * describing the socket.
KAUTH_REQ_NETWORK_SOCKET_DROP
Checks if a connection can be dropped.
arg1 is a struct socket * describing the socket.
KAUTH_REQ_NETWORK_SOCKET_SETPRIV
Checks if setting privileged socket options is allowed.
arg1 is a struct socket * describing the socket, arg2
is a u_long describing the socket option.
Machine-dependent Scope
The machine-dependent (machdep) scope, "org.netbsd.kauth.machdep",
manages machine-dependent authorization requests in the kernel.
The authorization wrapper for this scope is declared as
int kauth_authorize_machdep(kauth_cred_t cred, kauth_action_t op, void
*arg0, void *arg1, void *arg2, void *arg3)
The actions on this scope provide a set that may or may not affect all
platforms. Below is a list of available actions, along with which
platforms are affected by each.
KAUTH_MACHDEP_CACHEFLUSH
Request to flush the whole CPU cache. Affects m68k Linux
emulation.
KAUTH_MACHDEP_CPU_UCODE_APPLY
Request to apply a CPU microcode to a CPU. This is related to
CPU_UCODE, see options(4). Affects i386 and xen.
KAUTH_MACHDEP_IOPERM_GET
Request to get the I/O permission level. Affects amd64, i386,
xen.
KAUTH_MACHDEP_IOPERM_SET
Request to set the I/O permission level. Affects amd64, i386,
xen.
KAUTH_MACHDEP_IOPL
Request to set the I/O privilege level. Affects amd64, i386,
xen.
KAUTH_MACHDEP_LDT_GET
Request to get the LDT (local descriptor table). Affects amd64,
i386, xen.
KAUTH_MACHDEP_LDT_SET
Request to set the LDT (local descriptor table). Affects amd64,
i386, xen.
KAUTH_MACHDEP_MTRR_GET
Request to get the MTRR (memory type range registers). Affects
amd64, i386, xen.
KAUTH_MACHDEP_MTRR_SET
Request to set the MTRR (memory type range registers). Affects
amd64, i386, xen.
KAUTH_MACHDEP_NVRAM
Request to access (read/write) the NVRAM. Affects i386.
KAUTH_MACHDEP_PXG
Request to start or stop the pxg(4) CPU. arg0 is true or false,
respectively. Affects pmax.
KAUTH_MACHDEP_UNMANAGEDMEM
Request to access unmanaged memory. Affects alpha, amd64, arm,
i386, powerpc, sh3, vax, x68k, xen.
Device Scope
The device scope, "org.netbsd.kauth.device", manages authorization
requests related to devices on the system. Devices can be, for example,
terminals, tape drives, Bluetooth accessories, and any other hardware.
Network devices specifically are handled by the network scope.
In addition to the standard authorization wrapper:
int kauth_authorize_device(kauth_cred_t cred, kauth_action_t op, void
*arg0, void *arg1, void *arg2, void *arg3)
this scope provides authorization wrappers for various device types.
int kauth_authorize_device_tty(kauth_cred_t cred, kauth_action_t op,
struct tty *tty)
Authorizes requests for terminal devices on the system. The third
argument, tty, is the terminal device in question. It is passed to the
listener as arg0. The second argument, op, is the action and can be one
of the following:
KAUTH_DEVICE_TTY_OPEN
Open the terminal device pointed to by tty.
KAUTH_DEVICE_TTY_PRIVSET
Set privileged settings on the terminal device pointed to by
tty.
KAUTH_DEVICE_TTY_STI
Use the "TIOCSTI" device ioctl(2), allowing to inject characters
into the terminal buffer, simulating terminal input.
KAUTH_DEVICE_TTY_VIRTUAL
Control the virtual console. tty is the current console tty(4).
int kauth_authorize_device_spec(kauth_cred_t cred, enum kauth_device_req
req, struct vnode *vp)
Authorizes requests for special files, usually disk devices, but also
direct memory access, on the system.
It passes KAUTH_DEVICE_RAWIO_SPEC as the action to the listener, and
accepts two arguments. req, passed to the listener as arg0, is access
requested, and can be one of KAUTH_REQ_DEVICE_RAWIO_SPEC_READ,
KAUTH_REQ_DEVICE_RAWIO_SPEC_WRITE, or KAUTH_REQ_DEVICE_RAWIO_SPEC_RW,
representing read, write, or both read/write access respectively. vp is
the vnode of the special file in question, and is passed to the listener
as arg1.
Keep in mind that it is the responsibility of the security model
developer to check whether the underlying device is a disk or the system
memory, using iskmemdev():
if ((vp->v_type == VCHR) &&
iskmemdev(vp->v_un.vu_specinfo->si_rdev))
/* system memory access */
int kauth_authorize_device_passthru(kauth_cred_t cred, dev_t dev, u_long
mode, void *data)
Authorizes hardware passthru requests, or user commands passed directly
to the hardware. These have the potential of resulting in direct disk
and/or memory access.
It passes KAUTH_DEVICE_RAWIO_PASSTHRU as the action to the listener, and
accepts three arguments. dev, passed as arg1 to the listener, is the
device for which the request is made. mode, passed as arg0 to the
listener, is a generic representation of the access mode requested. It
can be one or more (binary-OR'd) of the following:
KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_READ
KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_READCONF
KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_WRITE
KAUTH_REQ_DEVICE_RAWIO_PASSTHRU_WRITECONF
data, passed as arg2 to the listener, is device-specific data that may be
associated with the request.
Bluetooth Devices
Authorizing actions relevant to Bluetooth devices is done using the
standard authorization wrapper, with the following actions:
KAUTH_DEVICE_BLUETOOTH_BCSP
Check if operations on a bcsp(4) device are allowed.
arg0 is an enum kauth_device_req with one of the following
values:
KAUTH_REQ_DEVICE_BLUETOOTH_BCSP_ADD
Check if adding and enabling a bcsp(4) device is
allowed.
KAUTH_DEVICE_BLUETOOTH_BTUART
Check if operations on a btuart(4) device are allowed.
arg0 is an enum kauth_device_req with one of the following
values:
KAUTH_REQ_DEVICE_BLUETOOTH_BTUART_ADD
Check if adding and enabling a btuart(4) device is
allowed.
KAUTH_DEVICE_BLUETOOTH_RECV
Check if a packet can be received from the device.
arg0 is the packet type. For HCI_CMD_PKT packets, arg1 is the
opcode, for HCI_EVENT_PKT packets, arg1 is the event ID, and for
HCI_ACLDATA_PKT or HCI_SCODATA_PKT packets, arg1 is the
connection handle.
KAUTH_DEVICE_BLUETOOTH_SEND
Check if a packet can be sent to the device.
arg0 is a struct hci_unit * describing the HCI unit, arg1 is a
hci_cmd_hdr_t * describing the packet header.
KAUTH_DEVICE_BLUETOOTH_SETPRIV
Check if privileged settings can be changed.
arg0 is a struct hci_unit * describing the HCI unit, arg1 is a
struct btreq * describing the request, and arg2 is a u_long
describing the command.
Kernel random device
Authorization actions relevant to the kernel random device, rnd(4), is
done using the standard authorization wrapper, with the following
actions:
KAUTH_DEVICE_RND_ADDDATA
Check if adding data to the entropy pool is allowed.
KAUTH_DEVICE_RND_GETPRIV
Check if privileged settings and information can be retrieved.
KAUTH_DEVICE_RND_SETPRIV
Check if privileged settings can be changed.
Wscons devices
Authorization actions relevant to wscons(4) are done using the standard
authorization wrapper, with the following actions:
KAUTH_DEVICE_WSCONS_KEYBOARD_BELL
Check if setting the default bell is allowed.
KAUTH_DEVICE_WSCONS_KEYBOARD_KEYREPEAT
Check if setting the default key-repeat is allowed.
Vnode Scope
The vnode scope, "org.netbsd.kauth.vnode", authorizes operations made on
vnodes representing file system objects.
The authorization wrapper for this scope is declared as
int kauth_authorize_vnode(kauth_cred_t cred, kauth_action_t action,
vnode_t *vp, vnode_t *dvp, int fs_decision)
This scope is heavily used in file system code and can potentially affect
system-wide performance. Therefore, there are several things developers
should know when using it.
First, the action parameter is a bit-mask and multiple actions can be
binary-OR'd and authorized in a single call. Two helper functions help
generate the action value for a couple of common cases: translating file
system access to a kauth action and checking access to a vnode.
The first, kauth_mode_to_action(mode_t access_mode), and returns a
kauth_action_t representing the desired access modes. Another function,
kauth_access_action(mode_t access_mode, enum vtype v_type, mode_t
file_mode), returns a kauth_action_t suitable for use in many file system
access(2) implementations. It calls the aforementioned
kauth_mode_to_action(), but before returning also adds the
KAUTH_VNODE_IS_EXEC flag if needed. See below for the meaning of this
flag and how its necessity is determined.
Second, it is recommended to be very careful with adding listeners on
this scope. A special parameter, fs_decision, allows different file
systems to instrument different policies without adding their own
listener. This parameter is special because it also serves as a fall-
back decision when no secmodel(9) is present to prevent a fail-open
scenario. It can take either an errno(2) value or
"KAUTH_VNODE_REMOTEFS", indicating that the file system on which the
authorization is made is remote and cannot provide us with a fall-back
decision. In this case, kauth can only short-circuit the request but the
file system will have the last word if there is no definitive allow or
deny decision.
The value of fs_decision can be hard-coded or determined by calling an
internal function implementing a policy. For the latter case, genfs(9)
provides a set of helper functions that implement common policies that
file systems can use. The calling convention is as follows:
int error;
error = kauth_authorize_vnode(..., genfs_can_foo(...));
Actions on the vnode scope are of two types: operations and flags. An
operation is similar in concept to actions on other scopes in the sense
that it represents an operation desired by the caller. A flag is an
indicator of additional information about the vnode that a file system
can set in order to allow the listener to make a more informed decision.
Actions include the following:
KAUTH_VNODE_READ_DATA
Read file data.
KAUTH_VNODE_LIST_DIRECTORY
Read directory listing. Identical to the above.
KAUTH_VNODE_WRITE_DATA
Write file data.
KAUTH_VNODE_ADD_FILE
Add a file to a directory. Identical to the above.
KAUTH_VNODE_EXECUTE
Execute a file.
KAUTH_VNODE_SEARCH
Search (enter) a directory. Identical to the above.
KAUTH_VNODE_DELETE
Delete a file.
KAUTH_VNODE_APPEND_DATA
Append data to a file.
KAUTH_VNODE_ADD_SUBDIRECTORY
Add a subdirectory to a directory. Identical to the
above.
KAUTH_VNODE_READ_TIMES
Read the created, last accessed, and last modified times
of a file.
KAUTH_VNODE_WRITE_TIMES
Modify the created, last accessed, or last modified times
of a file.
KAUTH_VNODE_READ_FLAGS
Read file flags.
KAUTH_VNODE_WRITE_FLAGS
Modify file flags.
KAUTH_VNODE_READ_SYSFLAGS
Read file system flags.
KAUTH_VNODE_WRITE_SYSFLAGS
Modify file system flags.
KAUTH_VNODE_RENAME
Rename a file.
KAUTH_VNODE_CHANGE_OWNERSHIP
Change ownership of a file.
KAUTH_VNODE_READ_SECURITY
Read the permissions of a file.
KAUTH_VNODE_WRITE_SECURITY
Change the permissions of a file, for example by using
chmod(2).
KAUTH_VNODE_READ_ATTRIBUTES
Read attributes of a file.
KAUTH_VNODE_WRITE_ATTRIBUTES
Modify attributes of a file.
KAUTH_VNODE_READ_EXTATTRIBUTES
Read extended attributes of a file.
KAUTH_VNODE_WRITE_EXTATTRIBUTES
Modify extended attributes of a file.
KAUTH_VNODE_RETAIN_SUID
Check if retaining the set-user-id bit on files after
chown(2) is allowed.
KAUTH_VNODE_RETAIN_SGID
Check if retaining the set-group-id bit on files after
chown(2) is allowed.
KAUTH_VNODE_REVOKE
Revoke a file.
Flags include the following:
KAUTH_VNODE_IS_EXEC
The vnode is executable.
The macro FS_OBJECT_CAN_EXEC() can be used to help
determine if this flag should be set. This macro
determines a file system object to be executable if it is
a directory (in which case we say it is searchable) or if
it has at least one executable bit set in its mode.
Setting this flag helps a listener know that a vnode is
executable and is used in implementing privileged access
to files and directories while maintaining semantics that
prevent execution until a file is marked as an executable.
An example for using this in listener code is:
if (privileged) {
/* Always allow read/write; execute only if executable. */
if ((action & KAUTH_VNODE_EXECUTE) == 0 ||
(action & KAUTH_VNODE_IS_EXEC))
result = KAUTH_RESULT_ALLOW;
}
Finally, the vnode scope authorization wrapper returns
EACCES in case of an error, to maintain file system
semantics. File systems can override this value if
needed.
KAUTH_VNODE_HAS_SYSFLAGS
The file system object represented by the vnode has system
flags set.
KAUTH_VNODE_ACCESS
The authorization is advisory only and no actual operation
is to be performed. This is not implemented.
Credentials Scope
The credentials scope, "org.netbsd.kauth.cred", is a special scope used
internally by the kauth framework to provide hooking to credential-
related operations.
It is a "notify-only" scope, allowing hooking operations such as
initialization of new credentials, credential inheritance during a fork,
and copying and freeing of credentials. The main purpose for this scope
is to give a security model a way to control the aforementioned
operations, especially in cases where the credentials hold security
model-private data.
Notifications are made using the following function, which is internal to
kauth:
int kauth_cred_hook(kauth_cred_t cred, kauth_action_t action, void *arg0,
void *arg1)
With the following actions:
KAUTH_CRED_COPY
The credentials are being copied. cred are the credentials of
the lwp context doing the copy, and arg0 and arg1 are both
kauth_cred_t representing the "from" and "to" credentials,
respectively.
KAUTH_CRED_FORK
The credentials are being inherited from a parent to a child
process during a fork.
cred are the credentials of the lwp context doing the fork, and
arg0 and arg1 are both struct proc * of the parent and child
processes, respectively.
KAUTH_CRED_CHROOT
The credentials in cred belong to a process whose root directory
is changed through change_root() (see vfs(9) ).
Arg0 is the new struct cwdinfo * of the process.
KAUTH_CRED_FREE
The credentials in cred are being freed.
KAUTH_CRED_INIT
The credentials in cred are being initialized.
Since this is a notify-only scope, all listeners are required to return
KAUTH_RESULT_ALLOW.
Credentials Accessors and Mutators
kauth has a variety of accessor and mutator routines to handle
kauth_cred_t objects.
The following routines can be used to access and modify the user- and
group-ids in a kauth_cred_t:
uid_t kauth_cred_getuid(kauth_cred_t cred)
Returns the real user-id from cred.
uid_t kauth_cred_geteuid(kauth_cred_t cred)
Returns the effective user-id from cred.
uid_t kauth_cred_getsvuid(kauth_cred_t cred)
Returns the saved user-id from cred.
void kauth_cred_setuid(kauth_cred_t cred, uid_t uid)
Sets the real user-id in cred to uid.
void kauth_cred_seteuid(kauth_cred_t cred, uid_t uid)
Sets the effective user-id in cred to uid.
void kauth_cred_setsvuid(kauth_cred_t cred, uid_t uid)
Sets the saved user-id in cred to uid.
gid_t kauth_cred_getgid(kauth_cred_t cred)
Returns the real group-id from cred.
gid_t kauth_cred_getegid(kauth_cred_t cred)
Returns the effective group-id from cred.
gid_t kauth_cred_getsvgid(kauth_cred_t cred)
Returns the saved group-id from cred.
void kauth_cred_setgid(kauth_cred_t cred, gid_t gid)
Sets the real group-id in cred to gid.
void kauth_cred_setegid(kauth_cred_t cred, gid_t gid)
Sets the effective group-id in cred to gid.
void kauth_cred_setsvgid(kauth_cred_t cred, gid_t gid)
Sets the saved group-id in cred to gid.
u_int kauth_cred_getrefcnt(kauth_cred_t cred)
Return the reference count for cred.
The following routines can be used to access and modify the group list in
a kauth_cred_t:
int kauth_cred_ismember_gid(kauth_cred_t cred, gid_t gid, int *resultp)
Checks if the group-id gid is a member in the group list of
cred.
If it is, resultp will be set to one, otherwise, to zero.
The return value is an error code, or zero for success.
u_int kauth_cred_ngroups(kauth_cred_t cred)
Return the number of groups in the group list of cred.
gid_t kauth_cred_group(kauth_cred_t cred, u_int idx)
Return the group-id of the group at index idx in the group list
of cred.
int kauth_cred_setgroups(kauth_cred_t cred, const gid_t *groups, size_t
ngroups, uid_t gmuid, enum uio_seg seg)
Copy ngroups groups from array pointed to by groups to the group
list in cred, adjusting the number of groups in cred
appropriately. seg should be either UIO_USERSPACE or
UIO_SYSSPACE indicating whether groups is a user or kernel space
address.
Any groups remaining will be set to an invalid value.
gmuid is unused for now, and to maintain interface compatibility
with the Darwin KPI.
The return value is an error code, or zero for success.
int kauth_cred_getgroups(kauth_cred_t cred, gid_t *groups, size_t
ngroups, enum uio_seg seg)
Copy ngroups groups from the group list in cred to the buffer
pointed to by groups. seg should be either UIO_USERSPACE or
UIO_SYSSPACE indicating whether groups is a user or kernel space
address.
The return value is an error code, or zero for success.
Credential Private Data
kauth provides an interface to allow attaching security-model private
data to credentials.
The use of this interface has two parts that can be divided to direct and
indirect control of the private-data. Directly controlling the private
data is done by using the below routines, while the indirect control is
often dictated by events such as process fork, and is handled by
listening on the credentials scope (see above).
Attaching private data to credentials works by registering a key to serve
as a unique identifier, distinguishing various sets of private data that
may be associated with the credentials. Registering, and deregistering,
a key is done by using these routines:
int kauth_register_key(secmodel_t sm, kauth_key_t *keyp)
Register new key for private data for security model sm. keyp
will be used to return the key to be used in further calls.
The function returns 0 on success and an error code (see
errno(2)) on failure.
int kauth_deregister_key(kauth_key_t key)
Deregister private data key key.
Once registered, private data may be manipulated by the following
routines:
void kauth_cred_setdata(kauth_cred_t cred, kauth_key_t key, void *data)
Set private data for key in cred to be data.
void * kauth_cred_getdata(kauth_cred_t cred, kauth_key_t key)
Retrieve private data for key in cred.
Note that it is required to use the above routines every time the private
data is changed, i.e., using kauth_cred_getdata() and later modifying the
private data should be accompanied by a call to kauth_cred_setdata() with
the "new" private data.
Credential Inheritance and Reference Counting
kauth provides an interface for handling shared credentials.
When a kauth_cred_t is first allocated, its reference count is set to 1.
However, with time, its reference count can grow as more objects
(processes, LWPs, files, etc.) reference it.
The following routines are available for managing credentials reference
counting:
kauth_cred_t kauth_cred_hold(kauth_cred_t cred)
Increases reference count to cred by one and returns cred
verbatim.
void kauth_cred_free(kauth_cred_t cred)
Decreases the reference count to cred by one.
If the reference count dropped to zero, the memory used by cred
will be freed.
Credential inheritance happens during a fork(2), and is handled by the
following function:
void kauth_proc_fork(struct proc *parent, struct proc *child)
When called, it references the parent's credentials from the child, and
calls the credentials scope's hook with the KAUTH_CRED_FORK action to
allow security model-specific handling of the inheritance to take place.
Credentials Memory Management
Data-structures for credentials, listeners, and scopes are allocated from
memory pools managed by the pool(9) subsystem.
The kauth_cred_t objects have their own memory management routines:
kauth_cred_t kauth_cred_alloc(void)
Allocates a new kauth_cred_t, initializes its lock, and sets its
reference count to one.
Conversion Routines
Sometimes it might be necessary to convert a kauth_cred_t to userland's
view of credentials, a struct uucred, or vice versa.
The following routines are available for these cases:
void kauth_uucred_to_cred(kauth_cred_t cred, const struct uucred *uucred)
Convert userland's view of credentials to a kauth_cred_t.
This includes effective user- and group-ids, a number of groups,
and a group list. The reference count is set to one.
Note that kauth will try to copy as many groups as can be held
inside a kauth_cred_t.
void kauth_cred_to_uucred(struct uucred *uucred, const kauth_cred_t cred)
Convert kauth_cred_t to userland's view of credentials.
This includes effective user- and group-ids, a number of groups,
and a group list.
Note that kauth will try to copy as many groups as can be held
inside a struct uucred.
int kauth_cred_uucmp(kauth_cred_t cred, struct uucred *uucred)
Compares cred with the userland credentials in uucred.
Common values that will be compared are effective user- and
group-ids, and the group list.
Miscellaneous Routines
Other routines provided by kauth are:
void kauth_cred_clone(kauth_cred_t cred1, kauth_cred_t cred2)
Clone credentials from cred1 to cred2, except for the lock and
reference count.
kauth_cred_t kauth_cred_dup(kauth_cred_t cred)
Duplicate cred.
What this routine does is call kauth_cred_alloc() followed by a
call to kauth_cred_clone().
kauth_cred_t kauth_cred_copy(kauth_cred_t cred)
Works like kauth_cred_dup(), except for a few differences.
If cred already has a reference count of one, it will be
returned. Otherwise, a new kauth_cred_t will be allocated and
the credentials from cred will be cloned to it. Last, a call to
kauth_cred_free() for cred will be done.
kauth_cred_t kauth_cred_get(void)
Return the credentials associated with the current LWP. This
does not change the reference count of the resulting
kauth_cred_t object.
Scope Management
kauth provides routines to manage the creation and deletion of scopes on
the system.
Note that the built-in scopes, the "generic" scope and the "process"
scope, can't be deleted.
kauth_scope_t kauth_register_scope(const char *id, kauth_scope_callback_t
cb, void *cookie)
Register a new scope on the system. id is the name of the
scope, usually in reverse DNS-like notation. For example,
"org.netbsd.kauth.myscope". cb is the default listener, to
which authorization requests for this scope will be dispatched
to. cookie is optional user-data that will be passed to all
listeners during authorization on the scope.
void kauth_deregister_scope(kauth_scope_t scope)
Deregister scope from the scopes available on the system, and
free the kauth_scope_t object scope.
Listener Management
Listeners in kauth are authorization callbacks that are called during an
authorization request in the scope which they belong to.
When an authorization request is made, all listeners associated with a
scope are called to allow, deny, or defer the request.
It is enough for one listener to deny the request in order for the
request to be denied; but all listeners are called during an
authorization process none-the-less. All listeners are required to allow
the request for it to be granted, and in a case where all listeners defer
the request -- leaving the decision for other listeners -- the request is
denied.
The following KPI is provided for the management of listeners:
kauth_listener_t kauth_listen_scope(const char *id,
kauth_scope_callback_t cb, void *cookie)
Create a new listener on the scope with the id id, setting the
default listener to cb. cookie is optional user-data that will
be passed to the listener when called during an authorization
request.
void kauth_unlisten_scope(kauth_listener_t listener)
Removes listener from the scope which it belongs to, ensuring it
won't be called again, and frees the kauth_listener_t object
listener.
kauth provides no means for synchronization within listeners. It is the
programmer's responsibility to make sure data used by the listener is
properly locked during its use, as it can be accessed simultaneously from
the same listener called multiple times. It is also the programmer's
responsibility to do garbage collection after the listener, possibly
freeing any allocated data it used.
The common method to do the above is by having a reference count to each
listener. On entry to the listener, this reference count should be
raised; on exit, lowered.
During the removal of a listener, first kauth_scope_unlisten() should be
called to make sure the listener code will not be entered in the future.
Then, the code should wait (possibly sleeping) until the reference count
drops to zero. When that happens, it is safe to do the final cleanup.
Listeners might sleep, so no locks can be held when calling an
authorization wrapper.
EXAMPLES
Older code had no abstraction of the security model, so most privilege
checks looked like this:
if (suser(cred, &acflag) == 0)
/* allow privileged operation */
Using the new interface, you must ask for a specific privilege
explicitly. For example, checking whether it is possible to open a
socket would look something like this:
if (kauth_authorize_network(cred, KAUTH_NETWORK_SOCKET,
KAUTH_REQ_NETWORK_SOCKET_OPEN, PF_INET, SOCK_STREAM,
IPPROTO_TCP) == 0)
/* allow opening the socket */
Note that the securelevel implications were also integrated into the
kauth framework so you don't have to note anything special in the call to
the authorization wrapper, but rather just have to make sure the security
model handles the request as you expect it to.
To do that you can just grep(1) in the relevant security model directory
and have a look at the code.
EXTENDING KAUTH
Although kauth provides a large set of both detailed and more or less
generic requests, it might be needed eventually to introduce more scopes,
actions, or requests.
Adding a new scope should happen only when an entire subsystem is
introduced and it is assumed other parts of the kernel may want to
interfere with its inner-workings. When a subsystem that has the
potential of impacting the security of the system is introduced, existing
security modules must be updated to also handle actions on the newly
added scope.
New actions should be added when sets of operations not covered at all
belong in an already existing scope.
Requests (or sub-actions) can be added as subsets of existing actions
when an operation that belongs in an already covered area is introduced.
Note that all additions should include updates to this manual, the
security models shipped with NetBSD, and the example skeleton security
model.
SEE ALSO
secmodel(9)
HISTORY
The kernel authorization framework first appeared in Mac OS X 10.4.
The kernel authorization framework in NetBSD first appeared in
NetBSD 4.0, and is a clean-room implementation based on Apple TN2127,
available at http://developer.apple.com/technotes/tn2005/tn2127.html
NOTES
As kauth in NetBSD is still under active development, it is likely that
the ABI, and possibly the API, will differ between NetBSD versions.
Developers are to take notice of this fact in order to avoid building
code that expects one version of the ABI and running it in a system with
a different one.
AUTHORS
Elad Efrat <elad@NetBSD.org> implemented the kernel authorization
framework in NetBSD.
Jason R. Thorpe <thorpej@NetBSD.org> provided guidance and answered
questions about the Darwin implementation.
NetBSD 10.99 October 4, 2023 NetBSD 10.99