PMC/SYSV/...).
No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.
Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: arch@ (parts by rwatson, trasz, jhb)
X-MFC after: to be determined in last commit with code from this project
of allocating what ever the user asks for up to "ngroups_max + 1". On
systems with large values of kern.ngroups this will be more efficient.
The now redundant check that the array is large enough in
kern_getgroups() is deliberate to allow this change to be merged to
stable/8 without breaking potential third party consumers of the API.
Reported by: bde
MFC after: 28 days
kern.ngroups+1. kern.ngroups can range from NGROUPS_MAX=1023 to
INT_MAX-1. Given that the Windows group limit is 1024, this range
should be sufficient for most applications.
MFC after: 1 month
specific macros for each audit argument type. This makes it easier to
follow call-graphs, especially for automated analysis tools (such as
fxr).
In MFC, we should leave the existing AUDIT_ARG() macros as they may be
used by third-party kernel modules.
Suggested by: brooks
Approved by: re (kib)
Obtained from: TrustedBSD Project
MFC after: 1 week
NGROUPS_MAX, eliminate ABI dependencies on them, and raise the to 1024
and 1023 respectively. (Previously they were equal, but under a close
reading of POSIX, NGROUPS_MAX was defined to be too large by 1 since it
is the number of supplemental groups, not total number of groups.)
The bulk of the change consists of converting the struct ucred member
cr_groups from a static array to a pointer. Do the equivalent in
kinfo_proc.
Introduce new interfaces crcopysafe() and crsetgroups() for duplicating
a process credential before modifying it and for setting group lists
respectively. Both interfaces take care for the details of allocating
groups array. crsetgroups() takes care of truncating the group list
to the current maximum (NGROUPS) if necessary. In the future,
crsetgroups() may be responsible for insuring invariants such as sorting
the supplemental groups to allow groupmember() to be implemented as a
binary search.
Because we can not change struct xucred without breaking application
ABIs, we leave it alone and introduce a new XU_NGROUPS value which is
always 16 and is to be used or NGRPS as appropriate for things such as
NFS which need to use no more than 16 groups. When feasible, truncate
the group list rather than generating an error.
Minor changes:
- Reduce the number of hand rolled versions of groupmember().
- Do not assign to both cr_gid and cr_groups[0].
- Modify ipfw to cache ucreds instead of part of their contents since
they are immutable once referenced by more than one entity.
Submitted by: Isilon Systems (initial implementation)
X-MFC after: never
PR: bin/113398 kern/133867
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.
Discussed with: pjd
count of the number of registered policies.
Rather than unconditionally locking sockets before passing them into MAC,
lock them in the MAC entry points only if mac_policy_count is non-zero.
This avoids locking overhead for a number of socket system calls when no
policies are registered, eliminating measurable overhead for the MAC
Framework for the socket subsystem when there are no active policies.
Possibly socket locks should be acquired by policies if they are required
for socket labels, which would further avoid locking overhead when there
are policies but they don't require labeling of sockets, or possibly
don't even implement socket controls.
Obtained from: TrustedBSD Project
assigning ifnets from one vnet to another. Deletion of vnets is not
yet supported.
The interface is implemented as an ioctl extension so that no syscalls
had to be introduced. This should be acceptable given that the new
interface will be used for a short / interim period only, until the
new jail management framwork gains the capability of managing vnets.
This method for managing vimages / vnets has been in use for the past
7 years without any observable issues.
The userland tool to be used in conjunction with the interim API can be
found in p4: //depot/projects/vimage-commit2/src/usr.sbin/vimage/... and
will most probably never get commited to svn.
While here, bump copyright notices in kern_vimage.c and vimage.h to
cover work done in year 2009.
Approved by: julian (mentor)
Discussed with: bz, rwatson
by creating a child jail, which is visible to that jail and to any
parent jails. Child jails may be restricted more than their parents,
but never less. Jail names reflect this hierarchy, being MIB-style
dot-separated strings.
Every thread now points to a jail, the default being prison0, which
contains information about the physical system. Prison0's root
directory is the same as rootvnode; its hostname is the same as the
global hostname, and its securelevel replaces the global securelevel.
Note that the variable "securelevel" has actually gone away, which
should not cause any problems for code that properly uses
securelevel_gt() and securelevel_ge().
Some jail-related permissions that were kept in global variables and
set via sysctls are now per-jail settings. The sysctls still exist for
backward compatibility, used only by the now-deprecated jail(2) system
call.
Approved by: bz (mentor)
virtualized instances of hostname and domainname, as well as a new top-level
virtualization struct vimage, which holds pointers to struct vnet and struct
vprocg. Struct vprocg is likely to become replaced in the near future with
a new jail management API import.
As a consequence of this change, change struct ucred to point to a struct
vimage, instead of directly pointing to a vnet.
Merge vnet / vimage / ucred refcounting infrastructure from p4 / vimage
branch.
Permit kldload / kldunload operations to be executed only from the default
vimage context.
This change should have no functional impact on nooptions VIMAGE kernel
builds.
Reviewed by: bz
Approved by: julian (mentor)
naming by renaming certain "proc" entry points to "cred" entry points,
reflecting their manipulation of credentials. For some entry points,
the process was passed into the framework but not into policies; in
these cases, stop passing in the process since we don't need it.
mac_proc_check_setaudit -> mac_cred_check_setaudit
mac_proc_check_setaudit_addr -> mac_cred_check_setaudit_addr
mac_proc_check_setauid -> mac_cred_check_setauid
mac_proc_check_setegid -> mac_cred_check_setegid
mac_proc_check_seteuid -> mac_cred_check_seteuid
mac_proc_check_setgid -> mac_cred_check_setgid
mac_proc_check_setgroups -> mac_cred_ceck_setgroups
mac_proc_check_setregid -> mac_cred_check_setregid
mac_proc_check_setresgid -> mac_cred_check_setresgid
mac_proc_check_setresuid -> mac_cred_check_setresuid
mac_proc_check_setreuid -> mac_cred_check_setreuid
mac_proc_check_setuid -> mac_cred_check_setuid
Obtained from: TrustedBSD Project
Sponsored by: Google, Inc.
error is not EAGAIN. Several sysctls that inspect another process use
p_candebug() for checking access right for the curproc. p_candebug()
returns EAGAIN for some reasons, in particular, for the process doing
exec() now. If execing process tries to lock Giant, we get a livelock,
because sysctl handlers are covered by Giant, and often do not sleep.
Break the livelock by dropping Giant and allowing other threads to
execute in the EAGAIN loop.
Also, do not return EAGAIN from p_candebug() when process is executing,
use more appropriate EBUSY error [1].
Reported and tested by: pho
Suggested by: rwatson [1]
Reviewed by: rwatson, des
MFC after: 1 week
credentials from inp_cred which is also available after the
socket is gone.
Switch cr_canseesocket consumers to cr_canseeinpcb.
This removes an extra acquisition of the socket lock.
Reviewed by: rwatson
MFC after: 3 months (set timer; decide then)
from Mac OS X Leopard--rationalize naming for entry points to
the following general forms:
mac_<object>_<method/action>
mac_<object>_check_<method/action>
The previous naming scheme was inconsistent and mostly
reversed from the new scheme. Also, make object types more
consistent and remove spaces from object types that contain
multiple parts ("posix_sem" -> "posixsem") to make mechanical
parsing easier. Introduce a new "netinet" object type for
certain IPv4/IPv6-related methods. Also simplify, slightly,
some entry point names.
All MAC policy modules will need to be recompiled, and modules
not updates as part of this commit will need to be modified to
conform to the new KPI.
Sponsored by: SPARTA (original patches against Mac OS X)
Obtained from: TrustedBSD Project, Apple Computer
some cases, move to priv_check() if it was an operation on a thread and
no other flags were present.
Eliminate caller-side jail exception checking (also now-unused); jail
privilege exception code now goes solely in kern_jail.c.
We can't yet eliminate suser() due to some cases in the KAME code where
a privilege check is performed and then used in many different deferred
paths. Do, however, move those prototypes to priv.h.
Reviewed by: csjp
Obtained from: TrustedBSD Project
embedded storage in struct ucred. This allows audit state to be cached
with the thread, avoiding locking operations with each system call, and
makes it available in asynchronous execution contexts, such as deep in
the network stack or VFS.
Reviewed by: csjp
Approved by: re (kensmith)
Obtained from: TrustedBSD Project
- Remove also "MP SAFE" after prior "MPSAFE" pass. (suggested by bde)
- Remove extra blank lines in some cases.
- Add extra blank lines in some cases.
- Remove no-op comments consisting solely of the function name, the word
"syscall", or the system call name.
- Add punctuation.
- Re-wrap some comments.
system calls now enter without Giant held, and then in some cases, acquire
Giant explicitly.
Remove a number of other MPSAFE annotations in the credential code and
tweak one or two other adjacent comments.
privilege for threads and credentials. Unlike the existing suser(9)
interface, priv(9) exposes a named privilege identifier to the privilege
checking code, allowing more complex policies regarding the granting of
privilege to be expressed. Two interfaces are provided, replacing the
existing suser(9) interface:
suser(td) -> priv_check(td, priv)
suser_cred(cred, flags) -> priv_check_cred(cred, priv, flags)
A comprehensive list of currently available kernel privileges may be
found in priv.h. New privileges are easily added as required, but the
comments on adding privileges found in priv.h and priv(9) should be read
before doing so.
The new privilege interface exposed sufficient information to the
privilege checking routine that it will now be possible for jail to
determine whether a particular privilege is granted in the check routine,
rather than relying on hints from the calling context via the
SUSER_ALLOWJAIL flag. For now, the flag is maintained, but a new jail
check function, prison_priv_check(), is exposed from kern_jail.c and used
by the privilege check routine to determine if the privilege is permitted
in jail. As a result, a centralized list of privileges permitted in jail
is now present in kern_jail.c.
The MAC Framework is now also able to instrument privilege checks, both
to deny privileges otherwise granted (mac_priv_check()), and to grant
privileges otherwise denied (mac_priv_grant()), permitting MAC Policy
modules to implement privilege models, as well as control a much broader
range of system behavior in order to constrain processes running with
root privilege.
The suser() and suser_cred() functions remain implemented, now in terms
of priv_check() and the PRIV_ROOT privilege, for use during the transition
and possibly continuing use by third party kernel modules that have not
been updated. The PRIV_DRIVER privilege exists to allow device drivers to
check privilege without adopting a more specific privilege identifier.
This change does not modify the actual security policy, rather, it
modifies the interface for privilege checks so changes to the security
policy become more feasible.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
begun with a repo-copy of mac.h to mac_framework.h. sys/mac.h now
contains the userspace and user<->kernel API and definitions, with all
in-kernel interfaces moved to mac_framework.h, which is now included
across most of the kernel instead.
This change is the first step in a larger cleanup and sweep of MAC
Framework interfaces in the kernel, and will not be MFC'd.
Obtained from: TrustedBSD Project
Sponsored by: SPARTA
with other commonly used sysctl name spaces, rather than declaring them
all over the place.
MFC after: 1 month
Sponsored by: nCircle Network Security, Inc.
ibcs2_[gs]etgroups() rather than using the stackgap. This also makes
ibcs2_[gs]etgroups() MPSAFE. Also, it cleans up one bit of weirdness in
the old setgroups() where it allocated an entire credential just so it had
a place to copy the group list into. Now setgroups just allocates a
NGROUPS_MAX array on the stack that it copies into and then passes to
kern_setgroups().
mac_check_proc_wait(), which control the ability to wait4() specific
processes. This permits MAC policies to limit information flow from
children that have changed label, although has to be handled carefully
due to common programming expectations regarding the behavior of
wait4(). The cr_seeotheruids() check in p_canwait() is #if 0'd for
this reason.
The mac_stub and mac_test policies are updated to reflect these new
entry points.
Sponsored by: SPAWAR, SPARTA
Obtained from: TrustedBSD Project
of system calls to manipulate elements of the process credential,
including:
setuid() mac_check_proc_setuid()
seteuid() mac_check_proc_seteuid()
setgid() mac_check_proc_setgid()
setegid() mac_check_proc_setegid()
setgroups() mac_check_proc_setgroups()
setreuid() mac_check_proc_setreuid()
setregid() mac_check_proc_setregid()
setresuid() mac_check_proc_setresuid()
setresgid() mac_check_rpoc_setresgid()
MAC checks are performed before other existing security checks; both
current credential and intended modifications are passed as arguments
to the entry points. The mac_test and mac_stub policies are updated.
Submitted by: Samy Al Bahra <samy@kerneled.org>
Obtained from: TrustedBSD Project
create kernel threads and call rfork(2) with RFTHREAD flag set in this case,
which puts parent and child into the same threading group. As a result
all threads that belong to the same program end up in the same threading
group.
This is similar to what linuxthreads port does, though in this case we don't
have a luxury of having access to the source code and there is no definite
way to differentiate linux_clone() called for threading purposes from other
uses, so that we have to resort to heuristics.
Allow SIGTHR to be delivered between all processes in the same threading
group previously it has been blocked for s[ug]id processes.
This also should improve locking of the same file descriptor from different
threads in programs running under linux compat layer.
PR: kern/72922
Reported by: Andriy Gapon <avg@icyb.net.ua>
Idea suggested by: rwatson
former is callable from user space and the latter from the kernel one. Make
kernel version take additional argument which tells if the respective call
should check for additional restrictions for sending signals to suid/sugid
applications or not.
Make all emulation layers using non-checked version, since signal numbers in
emulation layers can have different meaning that in native mode and such
protection can cause misbehaviour.
As a result remove LIBTHR from the signals allowed to be delivered to a
suid/sugid application.
Requested (sorta) by: rwatson
MFC after: 2 weeks
suid application. The problem is that Linux applications using old Linux
threads (pre-NPTL) use signal 32 (linux SIGRTMIN) for communication between
thread-processes. If such an linux application is installed suid or sgid
and security.bsd.conservative_signals=1 (default), then permission will be
denied to send such a signal and the application will freeze.
I believe the same will be true for native applications that use libthr,
since libthr uses SIGTHR for implementing conditional variables.
PR: 72922
Submitted by: Andriy Gapon <avg@icyb.net.ua>
MFC after: 2 weeks
in diagnostics. It has outlived its usefulness and has started
causing panics for people who turn on DIAGNOSTIC, in what is otherwise
good code.
MFC after: 2 days
somewhat clearer, but more importantly allows for a consistent naming
scheme for suser_cred flags.
The old name is still defined, but will be removed in a few days (unless I
hear any complaints...)
Discussed with: rwatson, scottl
Requested by: jhb
thread-local pointer, in practice that thread needs to be curthread. If
we're running with INVARIANTS, generate a warning if not. If we have
KDB compiled in, generate a stack trace. This doesn't fire at all in my
local test environment, but could be irritating if it fires frequently
for someone, so there will be motivation to fix things quickly when it
does.
SOCK_LOCK(so):
- Hold socket lock over calls to MAC entry points reading or
manipulating socket labels.
- Assert socket lock in MAC entry point implementations.
- When externalizing the socket label, first make a thread-local
copy while holding the socket lock, then release the socket lock
to externalize to userspace.
The uidinfo code appears to be MPSAFE, and is referenced without Giant
elsewhere. While this grab of Giant was only made in fairly rare
circumstances (actually GC'ing on refcount==0), grabbing Giant here
potentially introduces lock order issues with any locks held by the
caller. So this probably won't help performance much unless you change
credentials a lot in an application, and leave a lot of file descriptors
and cached credentials around. However, it simplifies locking down
consumers of the credential interfaces.
Bumped into by: sam
Appeased: tjr
and the mpo_create_cred() MAC policy entry point to
mpo_copy_cred_label(). This is more consistent with similar entry
points for creation and label copying, as mac_create_cred() was
called from crdup() as opposed to during process creation. For
a number of policies, this removes the requirement for special
handling when copying credential labels, and improves consistency.
Approved by: re (scottl)
Obtained from: TrustedBSD Project
Sponsored by: DARPA, Network Associates Laboratories
to see_other_uids but with the logical conversion. This is based
on (but not identical to) the patch submitted by Samy Al Bahra.
Submitted by: Samy Al Bahra <samy@kerneled.com>
special signal-delivery protections for setugid processes. In the
event that a system is relying on "unusual" signal delivery to
processes that change their credentials, this can be used to work
around application problems.
Also, add SIGALRM to the set of signals permitted to be delivered to
setugid processes by unprivileged subjects.
Reported by: Joe Greco <jgreco@ns.sol.net>
multiple mutex pools with different options and sizes. Mutex pools can
be created with either the default sleep mutexes or with spin mutexes.
A dynamically created mutex pool can now be destroyed if it is no longer
needed.
Create two pools by default, one that matches the existing pool that
uses the MTX_NOWITNESS option that should be used for building higher
level locks, and a new pool with witness checking enabled.
Modify the users of the existing mutex pool to use the appropriate pool
in the new implementation.
Reviewed by: jhb
as the target process' pid, it may exist if the process forked before leaving
the pgrp.
Thix fixes a panic that happens when calling setpgid to make a process
re-enter the pgrp with the same pgid as its pid if the pgrp still exists.
kernel access control.
Implement inter-process access control entry points for the MAC
framework. This permits policy modules to augment the decision
making process for process and socket visibility, process debugging,
re-scheduling, and signaling.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
kernel access control.
Invoke the necessary MAC entry points to maintain labels on
process credentials. In particular, invoke entry points for
the initialization and destruction of struct ucred, the copying
of struct ucred, and permit the initial labels to be set for
both process 0 (parent of all kernel processes) and process 1
(parent of all user processes).
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
uifind() with a proc lock held.
change_ruid() and change_euid() have been modified to take a uidinfo
structure which will be pre-allocated by callers, they will then
call uihold() on the uidinfo structure so that the caller's logic
is simplified.
This allows one to call uifind() before locking the proc struct and
thereby avoid a potential blocking allocation with the proc lock
held.
This may need revisiting, perhaps keeping a spare uidinfo allocated
per process to handle this situation or re-examining if the proc
lock needs to be held over the entire operation of changing real
or effective user id.
Submitted by: Don Lewis <dl-freebsd@catspoiler.org>
pointer instead of a proc pointer and require the process pointed to
by the second argument to be locked. We now use the thread ucred reference
for the credential checks in p_can*() as a result. p_canfoo() should now
no longer need Giant.
allocate a blank cred first, lock the process, perform checks on the
old process credential, copy the old process credential into the new
blank credential, modify the new credential, update the process
credential pointer, unlock the process, and cleanup rather than trying
to allocate a new credential after performing the checks on the old
credential.
- Cleanup _setugid() a little bit.
- setlogin() doesn't need Giant thanks to pgrp/session locking and
td_ucred.
securelevel_*() to be NULL for a while now.
- Use KASSERT() instead of if (foo) panic(); to optimize the
!INVARIANTS case.
Submitted by: Martin Faxer <gmh003532@brfmasthugget.se>
general cleanup of the API. The entire API now consists of two functions
similar to the pre-KSE API. The suser() function takes a thread pointer
as its only argument. The td_ucred member of this thread must be valid
so the only valid thread pointers are curthread and a few kernel threads
such as thread0. The suser_cred() function takes a pointer to a struct
ucred as its first argument and an integer flag as its second argument.
The flag is currently only used for the PRISON_ROOT flag.
Discussed on: smp@
disablement assumptions in kern_fork.c by adding another API call,
cpu_critical_fork_exit(). Cleanup the td_savecrit field by moving it
from MI to MD. Temporarily move cpu_critical*() from <arch>/include/cpufunc.h
to <arch>/<arch>/critical.c (stage-2 will clean this up).
Implement interrupt deferral for i386 that allows interrupts to remain
enabled inside critical sections. This also fixes an IPI interlock bug,
and requires uses of icu_lock to be enclosed in a true interrupt disablement.
This is the stage-1 commit. Stage-2 will occur after stage-1 has stabilized,
and will move cpu_critical*() into its own header file(s) + other things.
This commit may break non-i386 architectures in trivial ways. This should
be temporary.
Reviewed by: core
Approved by: core
code that is still not safe. suser() reads p_ucred so it still needs
Giant for the time being. This should allow kern.giant.proc to be set
to 0 for the time being.
Move the network code from using cr_cansee() to check whether a
socket is visible to a requesting credential to using a new
function, cr_canseesocket(), which accepts a subject credential
and object socket. Implement cr_canseesocket() so that it does a
prison check, a uid check, and add a comment where shortly a MAC
hook will go. This will allow MAC policies to seperately
instrument the visibility of sockets from the visibility of
processes.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
NULL, turn warning printf's into panic's, since this call has been
restructured such that a NULL cred would result in a page fault anyway.
There appears to be one case where NULL is explicitly passed in in the
sysctl code, and this is believed to be in error, so will be modified.
Securelevels now always require a credential context so that per-jail
securelevels are properly implemented.
Obtained from: TrustedBSD Project
Sponsored by: NAI Labs
Discussed with: bde
method-based inter-process security checks. To do this, introduce
a new cr_seeotheruids(u1, u2) function, which encapsulates the
"see_other_uids" logic. Call out to this policy following the
jail security check for all of {debug,sched,see,signal} inter-process
checks. This more consistently enforces the check, and makes the
check easy to modify. Eventually, it may be that this check should
become a MAC policy, loaded via a module.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
- Add a cred_free_thread() function (conditional on DIAGNOSTICS) that drops
a per-thread ucred reference to be used in debugging code when leaving
the kernel.
fully protect p_ucred yet so Giant is needed until all the p_ucred
locking is done. This is the original reason td_ucred was not used
immediately after its addition. Unfortunately, not using td_ucred is
not enough to avoid problems. Since p_ucred could be stale, we could
actually be dereferencing a stale pointer to dink with the refcount, so
we really need Giant to avoid foot-shooting. This allows td_ucred to
be safely used as well.
spares (the size of the field was changed from u_short to u_int to
reflect what it really ends up being). Accordingly, change users of
xucred to set and check this field as appropriate. In the kernel,
this is being done inside the new cru2x() routine which takes a
`struct ucred' and fills out a `struct xucred' according to the
former. This also has the pleasant sideaffect of removing some
duplicate code.
Reviewed by: rwatson
New locks are:
- pgrpsess_lock which locks the whole pgrps and sessions,
- pg_mtx which protects the pgrp members, and
- s_mtx which protects the session members.
Please refer to sys/proc.h for the coverage of these locks.
Changes on the pgrp/session interface:
- pgfind() needs the pgrpsess_lock held.
- The caller of enterpgrp() is responsible to allocate a new pgrp and
session.
- Call enterthispgrp() in order to enter an existing pgrp.
- pgsignal() requires a pgrp lock held.
Reviewed by: jhb, alfred
Tested on: cvsup.jp.FreeBSD.org
(which is a quad-CPU machine running -current)
reaquiring it. In the same vein, don't bother dropping the thread cred
when goinf ot userland. We are guaranteed to nned it when we come back,
(which we are guaranteed to do).
Reviewed by: jhb@freebsd.org, bde@freebsd.org (slightly different version)
authorized based on a subject credential rather than a subject process.
This will permit the same logic to be reused in situations where only
the credential generating the signal is available, such as in the
delivery of SIGIO.
- Because of two clauses, the automatic success against curproc,
and the session semantics for SIGCONT, not all logic can be pushed
into cr_cansignal(), but those cases should not apply for most other
consumers of cr_cansignal().
- This brings the base system inter-process authorization code more
into line with the MAC implementation.
Obtained from: TrustedBSD Project
Sponsored by: DARPA, NAI Labs
