Commit Graph

250 Commits

Author SHA1 Message Date
Gleb Smirnoff
c8358c6e0d Call crextend() before copying old credentials to the new credentials
and replace crcopysafe by crcopy as crcopysafe is is not intended to be
safe in a threaded environment, it drops PROC_LOCK() in while() that
can lead to unexpected results, such as overwrite kernel memory.

In my POV crcopysafe() needs special attention. For now I do not see
any problems with this function, but who knows.

Submitted by:	dchagin
Found by:	trinity
Security:	SA-16:04.linux
2016-01-14 10:16:25 +00:00
Mateusz Guzik
cd672ca60f Get rid of lim_update_thread and cred_update_thread.
Their primary use was in thread_cow_update to free up old resources.
Freeing had to be done with proc lock held and _cow_ funcs already knew
how to free old structs.
2015-07-16 14:30:11 +00:00
Mateusz Guzik
4ea6a9a28f Generalised support for copy-on-write structures shared by threads.
Thread credentials are maintained as follows: each thread has a pointer to
creds and a reference on them. The pointer is compared with proc's creds on
userspace<->kernel boundary and updated if needed.

This patch introduces a counter which can be compared instead, so that more
structures can use this scheme without adding more comparisons on the boundary.
2015-06-10 10:43:59 +00:00
Mateusz Guzik
ffb34484ee cred: add proc_set_cred_init helper
proc_set_cred_init can be used to set first credentials of a new
process.

Update proc_set_cred assertions so that it only expects already used
processes.

This fixes panics where p_ucred of a new process happens to be non-NULL.

Reviewed by:	kib
2015-03-21 20:24:54 +00:00
Mateusz Guzik
daf63fd2f9 cred: add proc_set_cred helper
The goal here is to provide one place altering process credentials.

This eases debugging and opens up posibilities to do additional work when such
an action is performed.
2015-03-16 00:10:03 +00:00
Konstantin Belousov
677258f7e7 Add procctl(2) PROC_TRACE_CTL command to enable or disable debugger
attachment to the process.  Note that the command is not intended to
be a security measure, rather it is an obfuscation feature,
implemented for parity with other operating systems.

Discussed with:	jilles, rwatson
Man page fixes by:	rwatson
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-01-18 15:13:11 +00:00
Mateusz Guzik
a99500a912 Extend struct ucred with group table.
This saves one malloc + free with typical cases and better utilizes
memory.

Submitted by:	Tiwei Bie <btw mail.ustc.edu.cn> (slightly modified)
X-Additional:	JuniorJobs project
2014-11-05 02:08:37 +00:00
Dag-Erling Smørgrav
bccb6d5aa1 [SA-14:25] Fix kernel stack disclosure in setlogin(2) / getlogin(2).
[SA-14:26] Fix remote command execution in ftp(1).

Approved by:	so (des)
2014-11-04 23:29:29 +00:00
Mateusz Guzik
b90638866e Fix up an assertion in kern_setgroups, it should compare with ngroups_max + 1
Bug introdued in r273685.

Noted by: Tiwei Bie <btw mail.ustc.edu.cn>
2014-10-26 14:25:42 +00:00
Mateusz Guzik
7e9a456a53 Tidy up sys_setgroups and kern_setgroups.
- 'groups' initialization to NULL is always ovewrwriten before use, so plug it
- get rid of 'goto out'
- kern_setgroups's callers already validate ngrp, so only assert the condition
- ngrp  is an u_int, so 'ngrp < 1' is more readable as 'ngrp == 0'

No functional changes.
2014-10-26 06:04:09 +00:00
Mateusz Guzik
92b064f43d Use a temporary buffer in sys_setgroups for requests with <= XU_NGROUPS groups.
Submitted by:	Tiwei Bie <btw mail.ustc.edu.cn>
X-Additional: JuniorJobs project
MFC after:	2 weeks
2014-10-26 05:39:42 +00:00
Mateusz Guzik
07b384cbe2 Eliminate unnecessary memory allocation in sys_getgroups and its ibcs2 counterpart. 2014-10-21 23:08:46 +00:00
Mateusz Guzik
25108069ec Get rid of crshared. 2014-10-05 02:16:53 +00:00
Mateusz Guzik
abd386bafe Fix getppid for traced processes.
Traced processes always have the tracer set as the parent.
Utilize proc_realparent to obtain the right process when needed.

Reviewed by:	kib
MFC after:	1 week
2014-08-24 09:04:09 +00:00
Baptiste Daroussin
6f0a5dea71 Style fix
MFC after:	1 day
2012-11-14 10:33:12 +00:00
Baptiste Daroussin
6f68699fbd return ERANGE if the buffer is too small to contain the login as documented in
the manpage

Reviewed by:	cognet, kib
MFC after:	1 month
2012-11-14 10:32:12 +00:00
Hiroki Sato
ca54e1aee3 Fix a typo. (s/nessesary/necessary/) 2012-01-08 18:48:36 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Edward Tomasz Napierala
e4dcb7046a Notify racct when process credentials change.
Sponsored by:	The FreeBSD Foundation
Reviewed by:	kib (earlier version)
2011-03-31 18:12:04 +00:00
Edward Tomasz Napierala
2bfc50bc4f Add two new system calls, setloginclass(2) and getloginclass(2). This makes
it possible for the kernel to track login class the process is assigned to,
which is required for RCTL.  This change also make setusercontext(3) call
setloginclass(2) and makes it possible to retrieve current login class using
id(1).

Reviewed by:	kib (as part of a larger patch)
2011-03-05 12:40:35 +00:00
Alexander Leidinger
de5b19526b Add some FEATURE macros for various features (AUDIT/CAM/IPC/KTR/MAC/NFS/NTP/
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
2011-02-25 10:11:01 +00:00
Edward Tomasz Napierala
1a996ed1d8 Revert r210225 - turns out I was wrong; the "/*-" is not license-only
thing; it's also used to indicate that the comment should not be automatically
rewrapped.

Explained by:	cperciva@
2010-07-18 20:57:53 +00:00
Edward Tomasz Napierala
805cc58ac0 The "/*-" comment marker is supposed to denote copyrights. Remove non-copyright
occurences from sys/sys/ and sys/kern/.
2010-07-18 20:23:10 +00:00
Brooks Davis
9126964cdb Only allocate the space we need before calling kern_getgroups instead
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
2010-01-15 07:18:46 +00:00
Brooks Davis
412f9500e2 Replace the static NGROUPS=NGROUPS_MAX+1=1024 with a dynamic
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
2010-01-12 07:49:34 +00:00
Jamie Gritton
7afcbc18b3 Remove the interim vimage containers, struct vimage and struct procg,
and the ioctl-based interface that supported them.

Approved by:	re (kib), bz (mentor)
2009-07-17 14:48:21 +00:00
Jamie Gritton
9dce97d788 Remove crcopy call from seteuid now that it calls crcopysafe.
Reviewed by:	brooks
Approved by:	re (kib), bz (mentor)
2009-07-08 21:45:48 +00:00
Robert Watson
14961ba789 Replace AUDIT_ARG() with variable argument macros with a set more more
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
2009-06-27 13:58:44 +00:00
Brooks Davis
7f92e57820 Change crsetgroups_locked() (called by crsetgroups()) to sort the
supplemental groups using insertion sort.  Use this property in
groupmember() to let us use a binary search instead of the previous
linear search.
2009-06-20 20:29:21 +00:00
Brooks Davis
838d985825 Rework the credential code to support larger values of NGROUPS and
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
2009-06-19 17:10:35 +00:00
Robert Watson
bcf11e8d00 Move "options MAC" from opt_mac.h to opt_global.h, as it's now in GENERIC
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
2009-06-05 14:55:22 +00:00
Robert Watson
f93bfb23dc Add internal 'mac_policy_count' counter to the MAC Framework, which is a
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
2009-06-02 18:26:17 +00:00
Marko Zec
feb08d06b9 Introduce an interm userland-kernel API for creating vnets and
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
2009-05-31 12:10:04 +00:00
Jamie Gritton
0304c73163 Add hierarchical jails. A jail may further virtualize its environment
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)
2009-05-27 14:11:23 +00:00
Marko Zec
29b02909eb Introduce a new virtualization container, provisionally named vprocg, to hold
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)
2009-05-08 14:11:06 +00:00
Robert Watson
6f6174a762 Improve the consistency of MAC Framework and MAC policy entry point
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.
2009-03-08 10:58:37 +00:00
Konstantin Belousov
af80b2c901 The userland_sysctl() function retries sysctl_root() until returned
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
2008-12-12 12:06:28 +00:00
Dag-Erling Smørgrav
1ede983cc9 Retire the MALLOC and FREE macros. They are an abomination unto style(9).
MFC after:	3 months
2008-10-23 15:53:51 +00:00
Bjoern A. Zeeb
f08ef6c595 Add cr_canseeinpcb() doing checks using the cached socket
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)
2008-10-17 16:26:16 +00:00
Robert Watson
30d239bc4c Merge first in a series of TrustedBSD MAC Framework KPI changes
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
2007-10-24 19:04:04 +00:00
Robert Watson
32f9753cfb Eliminate now-unused SUSER_ALLOWJAIL arguments to priv_check_cred(); in
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
2007-06-12 00:12:01 +00:00
Robert Watson
faef53711b Move per-process audit state from a pointer in the proc structure to
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
2007-06-07 22:27:15 +00:00
Robert Watson
873fbcd776 Further system call comment cleanup:
- 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.
2007-03-05 13:10:58 +00:00
Robert Watson
0c14ff0eb5 Remove 'MPSAFE' annotations from the comments above most system calls: all
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.
2007-03-04 22:36:48 +00:00
Robert Watson
ef08c42034 Sort copyrights together.
MFC after:	3 days
2007-01-08 20:37:02 +00:00
Robert Watson
800c940832 Add a new priv(9) kernel interface for checking the availability of
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>
2006-11-06 13:37:19 +00:00
Robert Watson
aed5570872 Complete break-out of sys/sys/mac.h into sys/security/mac/mac_framework.h
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
2006-10-22 11:52:19 +00:00
Robert Watson
5702e0965e Declare security and security.bsd sysctl hierarchies in sysctl.h along
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.
2006-09-17 20:00:36 +00:00
John Baldwin
3cb83e714d Add kern_setgroups() and kern_getgroups() and use them to implement
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().
2006-07-06 21:32:20 +00:00
Wayne Salamon
2f8a46d5ff Audit the arguments (user/group IDs) for the system calls that set these IDs.
Obtained from: TrustedBSD Project
Approved by: rwatson (mentor)
2006-02-06 00:32:33 +00:00