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
