privileges(5) Standards, Environments, and Macros privileges(5)NAMEprivileges - process privilege model
DESCRIPTION
Solaris software implements a set of privileges that provide fine-
grained control over the actions of processes. The possession of a cer‐
tain privilege allows a process to perform a specific set of restricted
operations.
The change to a primarily privilege-based security model in the Solaris
operating system gives developers an opportunity to restrict processes
to those privileged operations actually needed instead of all (super-
user) or no privileges (non-zero UIDs). Additionally, a set of previ‐
ously unrestricted operations now requires a privilege; these privi‐
leges are dubbed the "basic" privileges and are by default given to all
processes.
Taken together, all defined privileges with the exception of the
"basic" privileges compose the set of privileges that are traditionally
associated with the root user. The "basic" privileges are "privileges"
unprivileged processes were accustomed to having.
The defined privileges are:
PRIV_CONTRACT_EVENT
Allow a process to request reliable delivery of events to an event
endpoint.
Allow a process to include events in the critical event set term of
a template which could be generated in volume by the user.
PRIV_CONTRACT_OBSERVER
Allow a process to observe contract events generated by contracts
created and owned by users other than the process's effective user
ID.
Allow a process to open contract event endpoints belonging to con‐
tracts created and owned by users other than the process's effec‐
tive user ID.
PRIV_CPC_CPU
Allow a process to access per-CPU hardware performance counters.
PRIV_DTRACE_KERNEL
Allow DTrace kernel-level tracing.
PRIV_DTRACE_PROC
Allow DTrace process-level tracing. Allow process-level tracing
probes to be placed and enabled in processes to which the user has
permissions.
PRIV_DTRACE_USER
Allow DTrace user-level tracing. Allow use of the syscall and pro‐
file DTrace providers to examine processes to which the user has
permissions.
PRIV_FILE_CHOWN
Allow a process to change a file's owner user ID. Allow a process
to change a file's group ID to one other than the process's effec‐
tive group ID or one of the process's supplemental group IDs.
PRIV_FILE_CHOWN_SELF
Allow a process to give away its files. A process with this privi‐
lege will run as if {_POSIX_CHOWN_RESTRICTED} is not in effect.
PRIV_FILE_DAC_EXECUTE
Allow a process to execute an executable file whose permission bits
or ACL would otherwise disallow the process execute permission.
PRIV_FILE_DAC_READ
Allow a process to read a file or directory whose permission bits
or ACL would otherwise disallow the process read permission.
PRIV_FILE_DAC_SEARCH
Allow a process to search a directory whose permission bits or ACL
would not otherwise allow the process search permission.
PRIV_FILE_DAC_WRITE
Allow a process to write a file or directory whose permission bits
or ACL do not allow the process write permission. All privileges
are required to write files owned by UID 0 in the absence of an
effective UID of 0.
PRIV_FILE_DOWNGRADE_SL
Allow a process to set the sensitivity label of a file or directory
to a sensitivity label that does not dominate the existing sensi‐
tivity label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_FILE_LINK_ANY
Allow a process to create hardlinks to files owned by a UID differ‐
ent from the process's effective UID.
PRIV_FILE_OWNER
Allow a process that is not the owner of a file to modify that
file's access and modification times. Allow a process that is not
the owner of a directory to modify that directory's access and mod‐
ification times. Allow a process that is not the owner of a file or
directory to remove or rename a file or directory whose parent
directory has the "save text image after execution" (sticky) bit
set. Allow a process that is not the owner of a file to mount a
namefs upon that file. Allow a process that is not the owner of a
file or directory to modify that file's or directory's permission
bits or ACL.
PRIV_FILE_SETID
Allow a process to change the ownership of a file or write to a
file without the set-user-ID and set-group-ID bits being cleared.
Allow a process to set the set-group-ID bit on a file or directory
whose group is not the process's effective group or one of the
process's supplemental groups. Allow a process to set the set-user-
ID bit on a file with different ownership in the presence of
PRIV_FILE_OWNER. Additional restrictions apply when creating or
modifying a setuid 0 file.
PRIV_FILE_UPGRADE_SL
Allow a process to set the sensitivity label of a file or directory
to a sensitivity label that dominates the existing sensitivity
label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_GRAPHICS_ACCESS
Allow a process to make privileged ioctls to graphics devices. Typ‐
ically only an xserver process needs to have this privilege. A
process with this privilege is also allowed to perform privileged
graphics device mappings.
PRIV_GRAPHICS_MAP
Allow a process to perform privileged mappings through a graphics
device.
PRIV_IPC_DAC_READ
Allow a process to read a System V IPC Message Queue, Semaphore
Set, or Shared Memory Segment whose permission bits would not oth‐
erwise allow the process read permission.
PRIV_IPC_DAC_WRITE
Allow a process to write a System V IPC Message Queue, Semaphore
Set, or Shared Memory Segment whose permission bits would not oth‐
erwise allow the process write permission.
PRIV_IPC_OWNER
Allow a process that is not the owner of a System V IPC Message
Queue, Semaphore Set, or Shared Memory Segment to remove, change
ownership of, or change permission bits of the Message Queue, Sema‐
phore Set, or Shared Memory Segment.
PRIV_NET_ACCESS
Allow a process to open a TCP, UDP, SDP or SCTP network endpoint.
PRIV_NET_BINDMLP
Allow a process to bind to a port that is configured as a multi-
level port (MLP) for the process's zone. This privilege applies to
both shared address and zone-specific address MLPs. See
tnzonecfg(4) from the Trusted Extensions manual pages for informa‐
tion on configuring MLP ports.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_NET_ICMPACCESS
Allow a process to send and receive ICMP packets.
PRIV_NET_MAC_AWARE
Allow a process to set the NET_MAC_AWARE process flag by using
setpflags(2). This privilege also allows a process to set the
SO_MAC_EXEMPT socket option by using setsockopt(3SOCKET). The
NET_MAC_AWARE process flag and the SO_MAC_EXEMPT socket option both
allow a local process to communicate with an unlabeled peer if the
local process's label dominates the peer's default label, or if the
local process runs in the global zone.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_NET_PRIVADDR
Allow a process to bind to a privileged port number. The privilege
port numbers are 1-1023 (the traditional UNIX privileged ports) as
well as those ports marked as "udp/tcp_extra_priv_ports" with the
exception of the ports reserved for use by NFS.
PRIV_NET_RAWACCESS
Allow a process to have direct access to the network layer.
PRIV_PROC_AUDIT
Allow a process to generate audit records. Allow a process to get
its own audit pre-selection information.
PRIV_PROC_CHROOT
Allow a process to change its root directory.
PRIV_PROC_CLOCK_HIGHRES
Allow a process to use high resolution timers.
PRIV_PROC_EXEC
Allow a process to call execve(2).
PRIV_PROC_FORK
Allow a process to call fork(2), fork1(2), or vfork(2).
PRIV_PROC_INFO
Allow a process to examine the status of processes other than those
to which it can send signals. Processes that cannot be examined
cannot be seen in /proc and appear not to exist.
PRIV_PROC_LOCK_MEMORY
Allow a process to lock pages in physical memory.
PRIV_PROC_OWNER
Allow a process to send signals to other processes and inspect and
modify the process state in other processes, regardless of owner‐
ship. When modifying another process, additional restrictions
apply: the effective privilege set of the attaching process must be
a superset of the target process's effective, permitted, and inher‐
itable sets; the limit set must be a superset of the target's limit
set; if the target process has any UID set to 0 all privilege must
be asserted unless the effective UID is 0. Allow a process to bind
arbitrary processes to CPUs.
PRIV_PROC_PRIOCNTL
Allow a process to elevate its priority above its current level.
Allow a process to change its scheduling class to any scheduling
class, including the RT class.
PRIV_PROC_SESSION
Allow a process to send signals or trace processes outside its ses‐
sion.
PRIV_PROC_SETID
Allow a process to set its UIDs at will, assuming UID 0 requires
all privileges to be asserted.
PRIV_PROC_TASKID
Allow a process to assign a new task ID to the calling process.
PRIV_PROC_ZONE
Allow a process to trace or send signals to processes in other
zones. See zones(5).
PRIV_SYS_ACCT
Allow a process to enable and disable and manage accounting through
acct(2).
PRIV_SYS_ADMIN
Allow a process to perform system administration tasks such as set‐
ting node and domain name and specifying coreadm(1M) and nscd(1M)
settings
PRIV_SYS_AUDIT
Allow a process to start the (kernel) audit daemon. Allow a process
to view and set audit state (audit user ID, audit terminal ID,
audit sessions ID, audit pre-selection mask). Allow a process to
turn off and on auditing. Allow a process to configure the audit
parameters (cache and queue sizes, event to class mappings, and
policy options).
PRIV_SYS_CONFIG
Allow a process to perform various system configuration tasks.
Allow filesystem-specific administrative procedures, such as
filesystem configuration ioctls, quota calls, creation and deletion
of snapshots, and manipulating the PCFS bootsector.
PRIV_SYS_DEVICES
Allow a process to create device special files. Allow a process to
successfully call a kernel module that calls the kernel
drv_priv(9F) function to check for allowed access. Allow a process
to open the real console device directly. Allow a process to open
devices that have been exclusively opened.
PRIV_SYS_IPC_CONFIG
Allow a process to increase the size of a System V IPC Message
Queue buffer.
PRIV_SYS_LINKDIR
Allow a process to unlink and link directories.
PRIV_SYS_MOUNT
Allow a process to mount and unmount filesystems that would other‐
wise be restricted (that is, most filesystems except namefs). Allow
a process to add and remove swap devices.
PRIV_SYS_IP_CONFIG
Allow a process to configure a system's network interfaces and
routes. Allow a process to configure network parameters for TCP/IP
using ndd. Allow a process access to otherwise restricted TCP/IP
information using ndd. Allow a process to configure IPsec. Allows a
process to pop anchored STREAMs modules with matching zoneid.
PRIV_SYS_NET_CONFIG
Allow a process to do all that PRIV_SYS_IP_CONFIG allows, plus the
following: push the rpcmod STREAMS module, INSERT/REMOVE STREAMS
modules on locations other than the top of the module stack, and
configure data-links (NICs).
PRIV_SYS_NFS
Allow a process to provide NFS service: start NFS kernel threads,
perform NFS locking operations, bind to NFS reserved ports: ports
2049 (nfs) and port 4045 (lockd).
PRIV_SYS_RES_CONFIG
Allow a process to create and delete processor sets, assign CPUs to
processor sets and override the PSET_NOESCAPE property. Allow a
process to change the operational status of CPUs in the system
using p_online(2). Allow a process to configure filesystem quotas.
Allow a process to configure resource pools and bind processes to
pools.
PRIV_SYS_RESOURCE
Allow a process to exceed the resource limits imposed on it by
setrlimit(2) and setrctl(2).
PRIV_SYS_SUSER_COMPAT
Allow a process to successfully call a third party loadable module
that calls the kernel suser() function to check for allowed access.
This privilege exists only for third party loadable module compati‐
bility and is not used by Solaris proper.
PRIV_SYS_TIME
Allow a process to manipulate system time using any of the appro‐
priate system calls: stime(2), adjtime(2), and ntp_adjtime(2).
PRIV_SYS_TRANS_LABEL
Allow a process to translate labels that are not dominated by the
process's sensitivity label to and from an external string form.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_COLORMAP
Allow a process to override colormap restrictions.
Allow a process to install or remove colormaps.
Allow a process to retrieve colormap cell entries allocated by
other processes.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_CONFIG
Allow a process to configure or destroy resources that are perma‐
nently retained by the X server.
Allow a process to use SetScreenSaver to set the screen saver time‐
out value
Allow a process to use ChangeHosts to modify the display access
control list.
Allow a process to use GrabServer.
Allow a process to use the SetCloseDownMode request that can retain
window, pixmap, colormap, property, cursor, font, or graphic con‐
text resources.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_DAC_READ
Allow a process to read from a window resource that it does not own
(has a different user ID).
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_DAC_WRITE
Allow a process to write to or create a window resource that it
does not own (has a different user ID). A newly created window
property is created with the window's user ID.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_DEVICES
Allow a process to perform operations on window input devices.
Allow a process to get and set keyboard and pointer controls.
Allow a process to modify pointer button and key mappings.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_DGA
Allow a process to use the direct graphics access (DGA) X protocol
extensions. Direct process access to the frame buffer is still
required. Thus the process must have MAC and DAC privileges that
allow access to the frame buffer, or the frame buffer must be allo‐
cated to the process.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_DOWNGRADE_SL
Allow a process to set the sensitivity label of a window resource
to a sensitivity label that does not dominate the existing sensi‐
tivity label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_FONTPATH
Allow a process to set a font path.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_MAC_READ
Allow a process to read from a window resource whose sensitivity
label is not equal to the process sensitivity label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_MAC_WRITE
Allow a process to create a window resource whose sensitivity label
is not equal to the process sensitivity label. A newly created win‐
dow property is created with the window's sensitivity label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_SELECTION
Allow a process to request inter-window data moves without the
intervention of the selection confirmer.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
PRIV_WIN_UPGRADE_SL
Allow a process to set the sensitivity label of a window resource
to a sensitivity label that dominates the existing sensitivity
label.
This privilege is interpreted only if the system is configured with
Trusted Extensions.
Of the privileges listed above, the privileges PRIV_FILE_LINK_ANY,
PRIV_PROC_INFO, PRIV_PROC_SESSION, PRIV_NET_ACCESS, PRIV_PROC_FORK and
PRIV_PROC_EXEC are considered "basic" privileges. These are privileges
that used to be always available to unprivileged processes. By default,
processes still have the basic privileges.
The privileges PRIV_PROC_SETID and PRIV_PROC_AUDIT must be present in
the Limit set (see below) of a process in order for set-uid root execs
to be successful, that is, get an effective UID of 0 and additional
privileges.
The privilege implementation in Solaris extends the process credential
with four privilege sets:
I, the inheritable set The privileges inherited on exec.
P, the permitted set The maximum set of privileges for the
process.
E, the effective set The privileges currently in effect.
L, the limit set The upper bound of the privileges a process
and its offspring can obtain. Changes to L
take effect on the next exec.
The sets I, P and E are typically identical to the basic set of privi‐
leges for unprivileged processes. The limit set is typically the full
set of privileges.
Each process has a Privilege Awareness State (PAS) that can take the
value PA (privilege-aware) and NPA (not-PA). PAS is a transitional
mechanism that allows a choice between full compatibility with the old
superuser model and completely ignoring the effective UID.
To facilitate the discussion, we introduce the notion of "observed
effective set" (oE) and "observed permitted set" (oP) and the implemen‐
tation sets iE and iP.
A process becomes privilege-aware either by manipulating the effective,
permitted, or limit privilege sets through setppriv(2) or by using
setpflags(2). In all cases, oE and oP are invariant in the process of
becoming privilege-aware. In the process of becoming privilege-aware,
the following assignments take place:
iE = oE
iP = oP
When a process is privilege-aware, oE and oP are invariant under UID
changes. When a process is not privilege-aware, oE and oP are observed
as follows:
oE = euid == 0 ? L : iE
oP = (euid == 0 || ruid == 0 || suid == 0) ? L : iP
When a non-privilege-aware process has an effective UID of 0, it can
exercise the privileges contained in its limit set, the upper bound of
its privileges. If a non-privilege-aware process has any of the UIDs 0,
it will appear to be capable of potentially exercising all privileges
in L.
It is possible for a process to return to the non-privilege aware state
using setpflags(). The kernel will always attempt this on exec(2). This
operation is permitted only if the following conditions are met:
o If any of the UIDs is equal to 0, P must be equal to L.
o If the effective UID is equal to 0, E must be equal to L.
When a process gives up privilege awareness, the following assignments
take place:
if (euid == 0) iE = L & I
if (any uid == 0) iP = L & I
The privileges obtained when not having a UID of 0 are the inheritable
set of the process restricted by the limit set.
Only privileges in the process's (observed) effective privilege set
allow the process to perform restricted operations. A process can use
any of the privilege manipulation functions to add or remove privileges
from the privilege sets. Privileges can be removed always. Only privi‐
leges found in the permitted set can be added to the effective and
inheritable set. The limit set cannot grow. The inheritable set can be
larger than the permitted set.
When a process performs an exec(2), the kernel will first try to relin‐
quish privilege awareness before making the following privilege set
modifications:
E' = P' = I' = L & I
L is unchanged
If a process has not manipulated its privileges, the privilege sets
effectively remain the same, as E, P and I are already identical.
The limit set is enforced at exec time.
To run a non-privilege-aware application in a backward-compatible man‐
ner, a privilege-aware application should start the non-privilege-aware
application with I=basic.
For most privileges, absence of the privilege simply results in a fail‐
ure. In some instances, the absense of a privilege can cause system
calls to behave differently. In other instances, the removal of a priv‐
ilege can force a set-uid application to seriously malfunction. Privi‐
leges of this type are considered "unsafe". When a process is lacking
any of the unsafe privileges from its limit set, the system will not
honor the set-uid bit of set-uid root applications. The following
unsafe privileges have been identified: proc_setid, sys_resource and
proc_audit.
Privilege Escalation
In certain circumstances, a single privilege could lead to a process
gaining one or more additional privileges that were not explicitly
granted to that process. To prevent such an escalation of privileges,
the security policy will require explicit permission for those addi‐
tional privileges.
Common examples of escalation are those mechanisms that allow modifica‐
tion of system resources through "raw'' interfaces; for example, chang‐
ing kernel data structures through /dev/kmem or changing files through
/dev/dsk/*. Escalation also occurs when a process controls processes
with more privileges than the controlling process. A special case of
this is manipulating or creating objects owned by UID 0 or trying to
obtain UID 0 using setuid(2). The special treatment of UID 0 is needed
because the UID 0 owns all system configuration files and ordinary file
protection mechanisms allow processes with UID 0 to modify the system
configuration. With appropriate file modifications, a given process
running with an effective UID of 0 can gain all privileges.
In situations where a process might obtain UID 0, the security policy
requires additional privileges, up to the full set of privileges. Such
restrictions could be relaxed or removed at such time as additional
mechanisms for protection of system files became available. There are
no such mechanisms in the current Solaris release.
The use of UID 0 processes should be limited as much as possible. They
should be replaced with programs running under a different UID but with
exactly the privileges they need.
Daemons that never need to exec subprocesses should remove the
PRIV_PROC_EXEC privilege from their permitted and limit sets.
Assigned Privileges and Safeguards
When privileges are assigned to a user, the system administrator could
give that user more powers than intended. The administrator should con‐
sider whether safeguards are needed. For example, if the
PRIV_PROC_LOCK_MEMORY privilege is given to a user, the administrator
should consider setting the project.max-locked-memory resource control
as well, to prevent that user from locking all memory.
Privilege Debugging
When a system call fails with a permission error, it is not always
immediately obvious what caused the problem. To debug such a problem,
you can use a tool called privilege debugging. When privilege debugging
is enabled for a process, the kernel reports missing privileges on the
controlling terminal of the process. (Enable debugging for a process
with the -D option of ppriv(1).) Additionally, the administrator can
enable system-wide privilege debugging by setting the system(4) vari‐
able priv_debug using:
set priv_debug = 1
On a running system, you can use mdb(1) to change this variable.
Privilege Administration
The Solaris Management Console (see smc(1M)) is the preferred method of
modifying privileges for a command. Use usermod(1M) or smrole(1M) to
assign privileges to or modify privileges for, respectively, a user or
a role. Use ppriv(1) to enumerate the privileges supported on a system
and truss(1) to determine which privileges a program requires.
SEE ALSOmdb(1), ppriv(1), add_drv(1M), ifconfig(1M), lockd(1M), nfsd(1M),
rem_drv(1M), update_drv(1M), Intro(2), access(2), acct(2), acl(2), adj‐
time(2), audit(2), auditon(2), auditsvc(2), chmod(2), chown(2),
chroot(2), creat(2), exec(2), fcntl(2), fork(2), fpathconf(2),
getacct(2), getpflags(2), getppriv(2), getsid(2), kill(2), link(2),
memcntl(2), mknod(2), mount(2), msgctl(2), nice(2), ntp_adjtime(2),
open(2), p_online(2), priocntl(2), priocntlset(2), processor_bind(2),
pset_bind(2), pset_create(2), readlink(2), resolvepath(2), rmdir(2),
semctl(2), setauid(2), setegid(2), seteuid(2), setgid(2), setgroups(2),
setpflags(2), setppriv(2), setrctl(2), setregid(2), setreuid(2), setr‐
limit(2), settaskid(2), setuid(2), shmctl(2), shmget(2), shmop(2),
sigsend(2), stat(2), statvfs(2), stime(2), swapctl(2), sysinfo(2), uad‐
min(2), ulimit(2), umount(2), unlink(2), utime(2), utimes(2),
bind(3SOCKET), door_ucred(3DOOR), priv_addset(3C), priv_set(3C),
priv_getbyname(3C), priv_getbynum(3C), priv_set_to_str(3C),
priv_str_to_set(3C), socket(3SOCKET), t_bind(3NSL), timer_create(3RT),
ucred_get(3C), exec_attr(4), proc(4), system(4), user_attr(4),
ddi_cred(9F), drv_priv(9F), priv_getbyname(9F), priv_policy(9F),
priv_policy_choice(9F), priv_policy_only(9F)NOTES
Removal of any of the basic privileges from a process leaves it in a
non-standards compliant state, may cause unexpected application fail‐
ures, and should only be performed with full knowledge of the potential
side effects.
SunOS 5.10 19 Apr 2010 privileges(5)
