allows registration of callbacks that can be used later for
cross-secmodel "safe" communication.
When a secmodel wishes to know a property maintained by another
secmodel, it has to submit a request to it so the other secmodel can
proceed to evaluating the request. This is done through the
secmodel_eval(9) call; example:
bool isroot;
error = secmodel_eval("org.netbsd.secmodel.suser", "is-root",
cred, &isroot);
if (error == 0 && !isroot)
result = KAUTH_RESULT_DENY;
This one asks the suser module if the credentials are assumed to be root
when evaluated by suser module. If the module is present, it will
respond. If absent, the call will return an error.
Args and command are arbitrarily defined; it's up to the secmodel(9) to
document what it expects.
Typical example is securelevel testing: when someone wants to know
whether securelevel is raised above a certain level or not, the caller
has to request this property to the secmodel_securelevel(9) module.
Given that securelevel module may be absent from system's context (thus
making access to the global "securelevel" variable impossible or
unsafe), this API can cope with this absence and return an error.
We are using secmodel_eval(9) to implement a secmodel_extensions(9)
module, which plugs with the bsd44, suser and securelevel secmodels
to provide the logic behind curtain, usermount and user_set_cpu_affinity
modes, without adding hooks to traditional secmodels. This solves a
real issue with the current secmodel(9) code, as usermount or
user_set_cpu_affinity are not really tied to secmodel_suser(9).
The secmodel_eval(9) is also used to restrict security.models settings
when securelevel is above 0, through the "is-securelevel-above"
evaluation:
- curtain can be enabled any time, but cannot be disabled if
securelevel is above 0.
- usermount/user_set_cpu_affinity can be disabled any time, but cannot
be enabled if securelevel is above 0.
Regarding sysctl(7) entries:
curtain and usermount are now found under security.models.extensions
tree. The security.curtain and vfs.generic.usermount are still
accessible for backwards compat.
Documentation is incoming, I am proof-reading my writings.
Written by elad@, reviewed and tested (anita test + interact for rights
tests) by me. ok elad@.
See also
http://mail-index.netbsd.org/tech-security/2011/11/29/msg000422.html
XXX might consider va0 mapping too.
XXX Having a secmodel(9) specific printf (like aprint_*) for reporting
secmodel(9) errors might be a good idea, but I am not sure on how
to design such a function right now.
secmodel module(7), so there is no point in calling suser/securelevel
routines from bsd44. This leads to unwanted cross-secmodel dependencies.
Do not call secmodel_bsd44_init() from secmodel_overlay_init(). Doing so
resets all curtain/securelevel values, which is not really needed when
loading an overlay filter.
Remove the secmodel_register/deregister comments, they will be
implemented differently in an upcoming patch.
ok elad@ (via private mail).
- Separate the suser part of the bsd44 secmodel into its own secmodel
and directory, pending even more cleanups. For revision history
purposes, the original location of the files was
src/sys/secmodel/bsd44/secmodel_bsd44_suser.c
src/sys/secmodel/bsd44/suser.h
- Add a man-page for secmodel_suser(9) and update the one for
secmodel_bsd44(9).
- Add a "secmodel" module class and use it. Userland program and
documentation updated.
- Manage secmodel count (nsecmodels) through the module framework.
This eliminates the need for secmodel_{,de}register() calls in
secmodel code.
- Prepare for secmodel modularization by adding relevant module bits.
The secmodels don't allow auto unload. The bsd44 secmodel depends
on the suser and securelevel secmodels. The overlay secmodel depends
on the bsd44 secmodel. As the module class is only cosmetic, and to
prevent ambiguity, the bsd44 and overlay secmodels are prefixed with
"secmodel_".
- Adapt the overlay secmodel to recent changes (mainly vnode scope).
- Stop using link-sets for the sysctl node(s) creation.
- Keep sysctl variables under nodes of their relevant secmodels. In
other words, don't create duplicates for the suser/securelevel
secmodels under the bsd44 secmodel, as the latter is merely used
for "grouping".
- For the suser and securelevel secmodels, "advertise presence" in
relevant sysctl nodes (sysctl.security.models.{suser,securelevel}).
- Get rid of the LKM preprocessor stuff.
- As secmodels are now modules, there's no need for an explicit call
to secmodel_start(); it's handled by the module framework. That
said, the module framework was adjusted to properly load secmodels
early during system startup.
- Adapt rump to changes: Instead of using empty stubs for securelevel,
simply use the suser secmodel. Also replace secmodel_start() with a
call to secmodel_suser_start().
- 5.99.20.
Testing was done on i386 ("release" build). Spearated module_init()
changes were tested on sparc and sparc64 as well by martin@ (thanks!).
Mailing list reference:
http://mail-index.netbsd.org/tech-kern/2009/09/25/msg006135.html
some requests to the device scope:
KAUTH_DEVICE_BLUETOOTH_SEND_COMMAND
KAUTH_DEVICE_BLUETOOTH_RECV_COMMAND
KAUTH_DEVICE_BLUETOOTH_RECV_EVENT
KAUTH_DEVICE_BLUETOOTH_RECV_DATA
and a listener tied to the HCI protocol that will approve the basic
minimum to be sent and received.
handle the requests in the bsd44_suser listener by approving all
when the credential is root.
operations, specifically quota and block allocation from reserved space.
Modify ufs_quotactl() to accomodate passing "mp" earlier by vfs_busy()ing
it a little bit higher.
Mailing list reference:
http://mail-index.netbsd.org/tech-kern/2009/04/26/msg004936.html
Note that the umapfs request mentioned in this thread was NOT added as
there is still on-going discussion regarding the proper implementation.
Make the FreeBSD and Linux compat code convert the parameters to their
native representation and call the native routines.
Remove KAUTH_PROCESS_SCHEDULER_GET/SET.
Update documentation and examples.
XXX: For now, only the Linux compat code does the priority conversion
XXX: right.
Linux priority conversion code from yamt@, thanks!
Okay yamt@.
words, don't pass an action and a request, and just use a single action to
indicate what is the operation in question.
This is the first step in fixing PR/37986, which calls for policy/priority
checking in the secmodel code. Right now we're lacking room for another
parameter required to make a decision, and this change makes room for such.
- Add a KAUTH_PROCESS_SCHEDULER action, to handle scheduler related
requests, and add specific requests for set/get scheduler policy and
set/get scheduler parameters.
- Add a KAUTH_PROCESS_KEVENT_FILTER action, to handle kevent(2) related
requests.
- Add a KAUTH_DEVICE_TTY_STI action to handle requests to TIOCSTI.
- Add requests for the KAUTH_PROCESS_CANSEE action, indicating what
process information is being looked at (entry itself, args, env,
open files).
- Add requests for the KAUTH_PROCESS_RLIMIT action indicating set/get.
- Add requests for the KAUTH_PROCESS_CORENAME action indicating set/get.
- Make bsd44 secmodel code handle the newly added rqeuests appropriately.
All of the above make it possible to issue finer-grained kauth(9) calls in
many places, removing some KAUTH_GENERIC_ISSUSER requests.
- Remove the "CAN" from KAUTH_PROCESS_CAN{KTRACE,PROCFS,PTRACE,SIGNAL}.
Discussed with christos@ and yamt@.
Been running in my tree for over a month at least.
Reviewed and okay yamt@, and special thanks to him as well as rittera@
for making this possible through fixing NDIS to not call fork1() with
l1 != curlwp.
allow certain operations.
The suser module of the bsd44 secmodel code was made aware of the missing
operations that were explicitly allowed in the securelevel module, and
the logic in the latter was modified to a default defer, deny where not
allowed.
This concept, which is the correct way to write secmodel code, was first
brought up by pavel@ a long time ago.
okay christos@.
While it's true that it's part of the traditional 4.4BSD security model,
there may come a time where a different "primary" security model used for
fine-grained privileges (ie., splitting root's responsibilities to various
privileges that can be assigned) may want to still have a securelevel
setting.
Idea from Daniel Carosone:
http://mail-index.netbsd.org/tech-security/2006/08/25/0001.html
The location of the removed files, for reference, was:
src/secmodel/bsd44/secmodel_bsd44_securelevel.c
src/secmodel/bsd44/securelevel.h
P_*/L_* naming convention, and rename the in-kernel flags to avoid
conflict. (P_ -> PK_, L_ -> LW_ ). Add back the (now unused) LSDEAD
constant.
Restores source compatibility with pre-newlock2 tools like ps or top.
Reviewed by Andrew Doran.
jym