freebsd-dev/sys/security/mac/mac_process.c

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/*-
* Copyright (c) 1999, 2000, 2001, 2002 Robert N. M. Watson
* Copyright (c) 2001 Ilmar S. Habibulin
* Copyright (c) 2001, 2002, 2003 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed by Robert Watson and Ilmar Habibulin for the
* TrustedBSD Project.
*
* This software was developed for the FreeBSD Project in part by Network
* Associates Laboratories, the Security Research Division of Network
* Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
* as part of the DARPA CHATS research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
2003-06-11 00:56:59 +00:00
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_mac.h"
#include <sys/param.h>
#include <sys/condvar.h>
#include <sys/imgact.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/mac.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/file.h>
#include <sys/namei.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <sys/mac_policy.h>
#include <security/mac/mac_internal.h>
int mac_enforce_process = 1;
SYSCTL_INT(_security_mac, OID_AUTO, enforce_process, CTLFLAG_RW,
&mac_enforce_process, 0, "Enforce MAC policy on inter-process operations");
TUNABLE_INT("security.mac.enforce_process", &mac_enforce_process);
int mac_enforce_vm = 1;
SYSCTL_INT(_security_mac, OID_AUTO, enforce_vm, CTLFLAG_RW,
&mac_enforce_vm, 0, "Enforce MAC policy on vm operations");
TUNABLE_INT("security.mac.enforce_vm", &mac_enforce_vm);
static int mac_mmap_revocation = 1;
SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation, CTLFLAG_RW,
&mac_mmap_revocation, 0, "Revoke mmap access to files on subject "
"relabel");
static int mac_mmap_revocation_via_cow = 0;
SYSCTL_INT(_security_mac, OID_AUTO, mmap_revocation_via_cow, CTLFLAG_RW,
&mac_mmap_revocation_via_cow, 0, "Revoke mmap access to files via "
"copy-on-write semantics, or by removing all write access");
#ifdef MAC_DEBUG
static unsigned int nmaccreds, nmacprocs;
SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, creds, CTLFLAG_RD,
&nmaccreds, 0, "number of ucreds in use");
SYSCTL_UINT(_security_mac_debug_counters, OID_AUTO, procs, CTLFLAG_RD,
&nmacprocs, 0, "number of procs in use");
#endif
static void mac_cred_mmapped_drop_perms_recurse(struct thread *td,
struct ucred *cred, struct vm_map *map);
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
struct label *
mac_cred_label_alloc(void)
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
struct label *label;
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
label = mac_labelzone_alloc(M_WAITOK);
MAC_PERFORM(init_cred_label, label);
MAC_DEBUG_COUNTER_INC(&nmaccreds);
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
return (label);
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
}
Move MAC label storage for mbufs into m_tags from the m_pkthdr structure, returning some additional room in the first mbuf in a chain, and avoiding feature-specific contents in the mbuf header. To do this: - Modify mbuf_to_label() to extract the tag, returning NULL if not found. - Introduce mac_init_mbuf_tag() which does most of the work mac_init_mbuf() used to do, except on an m_tag rather than an mbuf. - Scale back mac_init_mbuf() to perform m_tag allocation and invoke mac_init_mbuf_tag(). - Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since m_tag's are now GC'd deep in the m_tag/mbuf code rather than at a higher level when mbufs are directly free()'d. - Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related notions. - Generally change all references to mbuf labels so that they use mbuf_to_label() rather than &mbuf->m_pkthdr.label. This required no changes in the MAC policies (yay!). - Tweak mbuf release routines to not call mac_destroy_mbuf(), tag destruction takes care of it for us now. - Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() -- the existing m_tag support does all this for us. Note that we can no longer just zero the m_tag list on the target mbuf, rather, we have to delete the chain because m_tag's will already be hung off freshly allocated mbuf's. - Tweak m_tag copying routines so that if we're copying a MAC m_tag, we don't do a binary copy, rather, we initialize the new storage and do a deep copy of the label. - Remove use of MAC_FLAG_INITIALIZED in a few bizarre places having to do with mbuf header copies previously. - When an mbuf is copied in ip_input(), we no longer need to explicitly copy the label because it will get handled by the m_tag code now. - No longer any weird handling of MAC labels in if_loop.c during header copies. - Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test. In mac_test, handle the label==NULL case, since it can be dynamically loaded. In order to improve performance with this change, introduce the notion of "lazy MAC label allocation" -- only allocate m_tag storage for MAC labels if we're running with a policy that uses MAC labels on mbufs. Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS flag in their load-time flags field during declaration. Note: this opens up the possibility of post-boot policy modules getting back NULL slot entries even though they have policy invariants of non-NULL slot entries, as the policy might have been loaded after the mbuf was allocated, leaving the mbuf without label storage. Policies that cannot handle this case must be declared as NOTLATE, or must be modified. - mac_labelmbufs holds the current cumulative status as to whether any policies require mbuf labeling or not. This is updated whenever the active policy set changes by the function mac_policy_updateflags(). The function iterates the list and checks whether any have the flag set. Write access to this variable is protected by the policy list; read access is currently not protected for performance reasons. This might change if it causes problems. - Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update function to assert appropriate locks. - This makes allocation in mac_init_mbuf() conditional on the flag. Reviewed by: sam Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-04-14 20:39:06 +00:00
void
mac_init_cred(struct ucred *cred)
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
cred->cr_label = mac_cred_label_alloc();
}
static struct label *
mac_proc_label_alloc(void)
{
struct label *label;
label = mac_labelzone_alloc(M_WAITOK);
MAC_PERFORM(init_proc_label, label);
MAC_DEBUG_COUNTER_INC(&nmacprocs);
return (label);
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
}
void
mac_init_proc(struct proc *p)
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
p->p_label = mac_proc_label_alloc();
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
}
void
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_cred_label_free(struct label *label)
{
MAC_PERFORM(destroy_cred_label, label);
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_labelzone_free(label);
MAC_DEBUG_COUNTER_DEC(&nmaccreds);
}
void
mac_destroy_cred(struct ucred *cred)
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_cred_label_free(cred->cr_label);
cred->cr_label = NULL;
}
static void
mac_proc_label_free(struct label *label)
{
MAC_PERFORM(destroy_proc_label, label);
mac_labelzone_free(label);
MAC_DEBUG_COUNTER_DEC(&nmacprocs);
}
void
mac_destroy_proc(struct proc *p)
Move MAC label storage for mbufs into m_tags from the m_pkthdr structure, returning some additional room in the first mbuf in a chain, and avoiding feature-specific contents in the mbuf header. To do this: - Modify mbuf_to_label() to extract the tag, returning NULL if not found. - Introduce mac_init_mbuf_tag() which does most of the work mac_init_mbuf() used to do, except on an m_tag rather than an mbuf. - Scale back mac_init_mbuf() to perform m_tag allocation and invoke mac_init_mbuf_tag(). - Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since m_tag's are now GC'd deep in the m_tag/mbuf code rather than at a higher level when mbufs are directly free()'d. - Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related notions. - Generally change all references to mbuf labels so that they use mbuf_to_label() rather than &mbuf->m_pkthdr.label. This required no changes in the MAC policies (yay!). - Tweak mbuf release routines to not call mac_destroy_mbuf(), tag destruction takes care of it for us now. - Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() -- the existing m_tag support does all this for us. Note that we can no longer just zero the m_tag list on the target mbuf, rather, we have to delete the chain because m_tag's will already be hung off freshly allocated mbuf's. - Tweak m_tag copying routines so that if we're copying a MAC m_tag, we don't do a binary copy, rather, we initialize the new storage and do a deep copy of the label. - Remove use of MAC_FLAG_INITIALIZED in a few bizarre places having to do with mbuf header copies previously. - When an mbuf is copied in ip_input(), we no longer need to explicitly copy the label because it will get handled by the m_tag code now. - No longer any weird handling of MAC labels in if_loop.c during header copies. - Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test. In mac_test, handle the label==NULL case, since it can be dynamically loaded. In order to improve performance with this change, introduce the notion of "lazy MAC label allocation" -- only allocate m_tag storage for MAC labels if we're running with a policy that uses MAC labels on mbufs. Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS flag in their load-time flags field during declaration. Note: this opens up the possibility of post-boot policy modules getting back NULL slot entries even though they have policy invariants of non-NULL slot entries, as the policy might have been loaded after the mbuf was allocated, leaving the mbuf without label storage. Policies that cannot handle this case must be declared as NOTLATE, or must be modified. - mac_labelmbufs holds the current cumulative status as to whether any policies require mbuf labeling or not. This is updated whenever the active policy set changes by the function mac_policy_updateflags(). The function iterates the list and checks whether any have the flag set. Write access to this variable is protected by the policy list; read access is currently not protected for performance reasons. This might change if it causes problems. - Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update function to assert appropriate locks. - This makes allocation in mac_init_mbuf() conditional on the flag. Reviewed by: sam Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-04-14 20:39:06 +00:00
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_proc_label_free(p->p_label);
p->p_label = NULL;
Move MAC label storage for mbufs into m_tags from the m_pkthdr structure, returning some additional room in the first mbuf in a chain, and avoiding feature-specific contents in the mbuf header. To do this: - Modify mbuf_to_label() to extract the tag, returning NULL if not found. - Introduce mac_init_mbuf_tag() which does most of the work mac_init_mbuf() used to do, except on an m_tag rather than an mbuf. - Scale back mac_init_mbuf() to perform m_tag allocation and invoke mac_init_mbuf_tag(). - Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since m_tag's are now GC'd deep in the m_tag/mbuf code rather than at a higher level when mbufs are directly free()'d. - Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related notions. - Generally change all references to mbuf labels so that they use mbuf_to_label() rather than &mbuf->m_pkthdr.label. This required no changes in the MAC policies (yay!). - Tweak mbuf release routines to not call mac_destroy_mbuf(), tag destruction takes care of it for us now. - Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() -- the existing m_tag support does all this for us. Note that we can no longer just zero the m_tag list on the target mbuf, rather, we have to delete the chain because m_tag's will already be hung off freshly allocated mbuf's. - Tweak m_tag copying routines so that if we're copying a MAC m_tag, we don't do a binary copy, rather, we initialize the new storage and do a deep copy of the label. - Remove use of MAC_FLAG_INITIALIZED in a few bizarre places having to do with mbuf header copies previously. - When an mbuf is copied in ip_input(), we no longer need to explicitly copy the label because it will get handled by the m_tag code now. - No longer any weird handling of MAC labels in if_loop.c during header copies. - Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test. In mac_test, handle the label==NULL case, since it can be dynamically loaded. In order to improve performance with this change, introduce the notion of "lazy MAC label allocation" -- only allocate m_tag storage for MAC labels if we're running with a policy that uses MAC labels on mbufs. Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS flag in their load-time flags field during declaration. Note: this opens up the possibility of post-boot policy modules getting back NULL slot entries even though they have policy invariants of non-NULL slot entries, as the policy might have been loaded after the mbuf was allocated, leaving the mbuf without label storage. Policies that cannot handle this case must be declared as NOTLATE, or must be modified. - mac_labelmbufs holds the current cumulative status as to whether any policies require mbuf labeling or not. This is updated whenever the active policy set changes by the function mac_policy_updateflags(). The function iterates the list and checks whether any have the flag set. Write access to this variable is protected by the policy list; read access is currently not protected for performance reasons. This might change if it causes problems. - Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update function to assert appropriate locks. - This makes allocation in mac_init_mbuf() conditional on the flag. Reviewed by: sam Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-04-14 20:39:06 +00:00
}
int
mac_externalize_cred_label(struct label *label, char *elements,
char *outbuf, size_t outbuflen)
{
int error;
MAC_EXTERNALIZE(cred, label, elements, outbuf, outbuflen);
Clean up locking for the MAC Framework: (1) Accept that we're now going to use mutexes, so don't attempt to avoid treating them as mutexes. This cleans up locking accessor function names some. (2) Rename variables to _mtx, _cv, _count, simplifying the naming. (3) Add a new form of the _busy() primitive that conditionally makes the list busy: if there are entries on the list, bump the busy count. If there are no entries, don't bump the busy count. Return a boolean indicating whether or not the busy count was bumped. (4) Break mac_policy_list into two lists: one with the same name holding dynamic policies, and a new list, mac_static_policy_list, which holds policies loaded before mac_late and without the unload flag set. The static list may be accessed without holding the busy count, since it can't change at run-time. (5) In general, prefer making the list busy conditionally, meaning we pay only one mutex lock per entry point if all modules are on the static list, rather than two (since we don't have to lower the busy count when we're done with the framework). For systems running just Biba or MLS, this will halve the mutex accesses in the network stack, and may offer a substantial performance benefits. (6) Lay the groundwork for a dynamic-free kernel option which eliminates all locking associated with dynamically loaded or unloaded policies, for pre-configured systems requiring maximum performance but less run-time flexibility. These changes have been running for a few weeks on MAC development branch systems. Approved by: re (jhb) Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-05-07 17:49:24 +00:00
return (error);
}
int
mac_internalize_cred_label(struct label *label, char *string)
{
int error;
MAC_INTERNALIZE(cred, label, string);
return (error);
}
/*
* Initialize MAC label for the first kernel process, from which other
* kernel processes and threads are spawned.
*/
void
mac_create_proc0(struct ucred *cred)
{
MAC_PERFORM(create_proc0, cred);
}
/*
* Initialize MAC label for the first userland process, from which other
* userland processes and threads are spawned.
*/
void
mac_create_proc1(struct ucred *cred)
{
MAC_PERFORM(create_proc1, cred);
}
void
mac_thread_userret(struct thread *td)
{
MAC_PERFORM(thread_userret, td);
}
/*
* When a new process is created, its label must be initialized. Generally,
* this involves inheritence from the parent process, modulo possible
* deltas. This function allows that processing to take place.
*/
void
mac_copy_cred(struct ucred *src, struct ucred *dest)
{
MAC_PERFORM(copy_cred_label, src->cr_label, dest->cr_label);
}
int
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_execve_enter(struct image_params *imgp, struct mac *mac_p)
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
struct label *label;
struct mac mac;
char *buffer;
int error;
if (mac_p == NULL)
return (0);
error = copyin(mac_p, &mac, sizeof(mac));
if (error)
return (error);
error = mac_check_structmac_consistent(&mac);
if (error)
return (error);
buffer = malloc(mac.m_buflen, M_MACTEMP, M_WAITOK);
error = copyinstr(mac.m_string, buffer, mac.m_buflen, NULL);
if (error) {
free(buffer, M_MACTEMP);
return (error);
}
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
label = mac_cred_label_alloc();
error = mac_internalize_cred_label(label, buffer);
free(buffer, M_MACTEMP);
if (error) {
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
mac_cred_label_free(label);
return (error);
Move MAC label storage for mbufs into m_tags from the m_pkthdr structure, returning some additional room in the first mbuf in a chain, and avoiding feature-specific contents in the mbuf header. To do this: - Modify mbuf_to_label() to extract the tag, returning NULL if not found. - Introduce mac_init_mbuf_tag() which does most of the work mac_init_mbuf() used to do, except on an m_tag rather than an mbuf. - Scale back mac_init_mbuf() to perform m_tag allocation and invoke mac_init_mbuf_tag(). - Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since m_tag's are now GC'd deep in the m_tag/mbuf code rather than at a higher level when mbufs are directly free()'d. - Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related notions. - Generally change all references to mbuf labels so that they use mbuf_to_label() rather than &mbuf->m_pkthdr.label. This required no changes in the MAC policies (yay!). - Tweak mbuf release routines to not call mac_destroy_mbuf(), tag destruction takes care of it for us now. - Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() -- the existing m_tag support does all this for us. Note that we can no longer just zero the m_tag list on the target mbuf, rather, we have to delete the chain because m_tag's will already be hung off freshly allocated mbuf's. - Tweak m_tag copying routines so that if we're copying a MAC m_tag, we don't do a binary copy, rather, we initialize the new storage and do a deep copy of the label. - Remove use of MAC_FLAG_INITIALIZED in a few bizarre places having to do with mbuf header copies previously. - When an mbuf is copied in ip_input(), we no longer need to explicitly copy the label because it will get handled by the m_tag code now. - No longer any weird handling of MAC labels in if_loop.c during header copies. - Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test. In mac_test, handle the label==NULL case, since it can be dynamically loaded. In order to improve performance with this change, introduce the notion of "lazy MAC label allocation" -- only allocate m_tag storage for MAC labels if we're running with a policy that uses MAC labels on mbufs. Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS flag in their load-time flags field during declaration. Note: this opens up the possibility of post-boot policy modules getting back NULL slot entries even though they have policy invariants of non-NULL slot entries, as the policy might have been loaded after the mbuf was allocated, leaving the mbuf without label storage. Policies that cannot handle this case must be declared as NOTLATE, or must be modified. - mac_labelmbufs holds the current cumulative status as to whether any policies require mbuf labeling or not. This is updated whenever the active policy set changes by the function mac_policy_updateflags(). The function iterates the list and checks whether any have the flag set. Write access to this variable is protected by the policy list; read access is currently not protected for performance reasons. This might change if it causes problems. - Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update function to assert appropriate locks. - This makes allocation in mac_init_mbuf() conditional on the flag. Reviewed by: sam Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-04-14 20:39:06 +00:00
}
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
imgp->execlabel = label;
Move MAC label storage for mbufs into m_tags from the m_pkthdr structure, returning some additional room in the first mbuf in a chain, and avoiding feature-specific contents in the mbuf header. To do this: - Modify mbuf_to_label() to extract the tag, returning NULL if not found. - Introduce mac_init_mbuf_tag() which does most of the work mac_init_mbuf() used to do, except on an m_tag rather than an mbuf. - Scale back mac_init_mbuf() to perform m_tag allocation and invoke mac_init_mbuf_tag(). - Replace mac_destroy_mbuf() with mac_destroy_mbuf_tag(), since m_tag's are now GC'd deep in the m_tag/mbuf code rather than at a higher level when mbufs are directly free()'d. - Add mac_copy_mbuf_tag() to support m_copy_pkthdr() and related notions. - Generally change all references to mbuf labels so that they use mbuf_to_label() rather than &mbuf->m_pkthdr.label. This required no changes in the MAC policies (yay!). - Tweak mbuf release routines to not call mac_destroy_mbuf(), tag destruction takes care of it for us now. - Remove MAC magic from m_copy_pkthdr() and m_move_pkthdr() -- the existing m_tag support does all this for us. Note that we can no longer just zero the m_tag list on the target mbuf, rather, we have to delete the chain because m_tag's will already be hung off freshly allocated mbuf's. - Tweak m_tag copying routines so that if we're copying a MAC m_tag, we don't do a binary copy, rather, we initialize the new storage and do a deep copy of the label. - Remove use of MAC_FLAG_INITIALIZED in a few bizarre places having to do with mbuf header copies previously. - When an mbuf is copied in ip_input(), we no longer need to explicitly copy the label because it will get handled by the m_tag code now. - No longer any weird handling of MAC labels in if_loop.c during header copies. - Add MPC_LOADTIME_FLAG_LABELMBUFS flag to Biba, MLS, mac_test. In mac_test, handle the label==NULL case, since it can be dynamically loaded. In order to improve performance with this change, introduce the notion of "lazy MAC label allocation" -- only allocate m_tag storage for MAC labels if we're running with a policy that uses MAC labels on mbufs. Policies declare this intent by setting the MPC_LOADTIME_FLAG_LABELMBUFS flag in their load-time flags field during declaration. Note: this opens up the possibility of post-boot policy modules getting back NULL slot entries even though they have policy invariants of non-NULL slot entries, as the policy might have been loaded after the mbuf was allocated, leaving the mbuf without label storage. Policies that cannot handle this case must be declared as NOTLATE, or must be modified. - mac_labelmbufs holds the current cumulative status as to whether any policies require mbuf labeling or not. This is updated whenever the active policy set changes by the function mac_policy_updateflags(). The function iterates the list and checks whether any have the flag set. Write access to this variable is protected by the policy list; read access is currently not protected for performance reasons. This might change if it causes problems. - Add MAC_POLICY_LIST_ASSERT_EXCLUSIVE() to permit the flags update function to assert appropriate locks. - This makes allocation in mac_init_mbuf() conditional on the flag. Reviewed by: sam Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-04-14 20:39:06 +00:00
return (0);
}
void
mac_execve_exit(struct image_params *imgp)
{
Modify the MAC Framework so that instead of embedding a (struct label) in various kernel objects to represent security data, we embed a (struct label *) pointer, which now references labels allocated using a UMA zone (mac_label.c). This allows the size and shape of struct label to be varied without changing the size and shape of these kernel objects, which become part of the frozen ABI with 5-STABLE. This opens the door for boot-time selection of the number of label slots, and hence changes to the bound on the number of simultaneous labeled policies at boot-time instead of compile-time. This also makes it easier to embed label references in new objects as required for locking/caching with fine-grained network stack locking, such as inpcb structures. This change also moves us further in the direction of hiding the structure of kernel objects from MAC policy modules, not to mention dramatically reducing the number of '&' symbols appearing in both the MAC Framework and MAC policy modules, and improving readability. While this results in minimal performance change with MAC enabled, it will observably shrink the size of a number of critical kernel data structures for the !MAC case, and should have a small (but measurable) performance benefit (i.e., struct vnode, struct socket) do to memory conservation and reduced cost of zeroing memory. NOTE: Users of MAC must recompile their kernel and all MAC modules as a result of this change. Because this is an API change, third party MAC modules will also need to be updated to make less use of the '&' symbol. Suggestions from: bmilekic Obtained from: TrustedBSD Project Sponsored by: DARPA, Network Associates Laboratories
2003-11-12 03:14:31 +00:00
if (imgp->execlabel != NULL) {
mac_cred_label_free(imgp->execlabel);
imgp->execlabel = NULL;
}
}
/*
* When relabeling a process, call out to the policies for the maximum
* permission allowed for each object type we know about in its
* memory space, and revoke access (in the least surprising ways we
* know) when necessary. The process lock is not held here.
*/
void
mac_cred_mmapped_drop_perms(struct thread *td, struct ucred *cred)
{
/* XXX freeze all other threads */
mac_cred_mmapped_drop_perms_recurse(td, cred,
&td->td_proc->p_vmspace->vm_map);
/* XXX allow other threads to continue */
}
static __inline const char *
prot2str(vm_prot_t prot)
{
switch (prot & VM_PROT_ALL) {
case VM_PROT_READ:
return ("r--");
case VM_PROT_READ | VM_PROT_WRITE:
return ("rw-");
case VM_PROT_READ | VM_PROT_EXECUTE:
return ("r-x");
case VM_PROT_READ | VM_PROT_WRITE | VM_PROT_EXECUTE:
return ("rwx");
case VM_PROT_WRITE:
return ("-w-");
case VM_PROT_EXECUTE:
return ("--x");
case VM_PROT_WRITE | VM_PROT_EXECUTE:
return ("-wx");
default:
return ("---");
}
}
static void
mac_cred_mmapped_drop_perms_recurse(struct thread *td, struct ucred *cred,
struct vm_map *map)
{
struct vm_map_entry *vme;
int result;
vm_prot_t revokeperms;
vm_object_t object;
vm_ooffset_t offset;
struct vnode *vp;
if (!mac_mmap_revocation)
return;
vm_map_lock_read(map);
for (vme = map->header.next; vme != &map->header; vme = vme->next) {
if (vme->eflags & MAP_ENTRY_IS_SUB_MAP) {
mac_cred_mmapped_drop_perms_recurse(td, cred,
vme->object.sub_map);
continue;
}
/*
* Skip over entries that obviously are not shared.
*/
if (vme->eflags & (MAP_ENTRY_COW | MAP_ENTRY_NOSYNC) ||
!vme->max_protection)
continue;
/*
* Drill down to the deepest backing object.
*/
offset = vme->offset;
object = vme->object.vm_object;
if (object == NULL)
continue;
while (object->backing_object != NULL) {
object = object->backing_object;
offset += object->backing_object_offset;
}
/*
* At the moment, vm_maps and objects aren't considered
* by the MAC system, so only things with backing by a
* normal object (read: vnodes) are checked.
*/
if (object->type != OBJT_VNODE)
continue;
vp = (struct vnode *)object->handle;
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
result = vme->max_protection;
mac_check_vnode_mmap_downgrade(cred, vp, &result);
VOP_UNLOCK(vp, 0, td);
/*
* Find out what maximum protection we may be allowing
* now but a policy needs to get removed.
*/
revokeperms = vme->max_protection & ~result;
if (!revokeperms)
continue;
printf("pid %ld: revoking %s perms from %#lx:%ld "
"(max %s/cur %s)\n", (long)td->td_proc->p_pid,
prot2str(revokeperms), (u_long)vme->start,
(long)(vme->end - vme->start),
prot2str(vme->max_protection), prot2str(vme->protection));
vm_map_lock_upgrade(map);
/*
* This is the really simple case: if a map has more
* max_protection than is allowed, but it's not being
* actually used (that is, the current protection is
* still allowed), we can just wipe it out and do
* nothing more.
*/
if ((vme->protection & revokeperms) == 0) {
vme->max_protection -= revokeperms;
} else {
if (revokeperms & VM_PROT_WRITE) {
/*
* In the more complicated case, flush out all
* pending changes to the object then turn it
* copy-on-write.
*/
vm_object_reference(object);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
VM_OBJECT_LOCK(object);
vm_object_page_clean(object,
OFF_TO_IDX(offset),
OFF_TO_IDX(offset + vme->end - vme->start +
PAGE_MASK),
OBJPC_SYNC);
VM_OBJECT_UNLOCK(object);
VOP_UNLOCK(vp, 0, td);
vm_object_deallocate(object);
/*
* Why bother if there's no read permissions
* anymore? For the rest, we need to leave
* the write permissions on for COW, or
* remove them entirely if configured to.
*/
if (!mac_mmap_revocation_via_cow) {
vme->max_protection &= ~VM_PROT_WRITE;
vme->protection &= ~VM_PROT_WRITE;
} if ((revokeperms & VM_PROT_READ) == 0)
vme->eflags |= MAP_ENTRY_COW |
MAP_ENTRY_NEEDS_COPY;
}
if (revokeperms & VM_PROT_EXECUTE) {
vme->max_protection &= ~VM_PROT_EXECUTE;
vme->protection &= ~VM_PROT_EXECUTE;
}
if (revokeperms & VM_PROT_READ) {
vme->max_protection = 0;
vme->protection = 0;
}
pmap_protect(map->pmap, vme->start, vme->end,
vme->protection & ~revokeperms);
vm_map_simplify_entry(map, vme);
}
vm_map_lock_downgrade(map);
}
vm_map_unlock_read(map);
}
/*
* When the subject's label changes, it may require revocation of privilege
* to mapped objects. This can't be done on-the-fly later with a unified
* buffer cache.
*/
void
mac_relabel_cred(struct ucred *cred, struct label *newlabel)
{
MAC_PERFORM(relabel_cred, cred, newlabel);
}
int
mac_check_cred_relabel(struct ucred *cred, struct label *newlabel)
{
int error;
MAC_CHECK(check_cred_relabel, cred, newlabel);
return (error);
}
int
mac_check_cred_visible(struct ucred *u1, struct ucred *u2)
{
int error;
if (!mac_enforce_process)
return (0);
MAC_CHECK(check_cred_visible, u1, u2);
return (error);
}
int
mac_check_proc_debug(struct ucred *cred, struct proc *proc)
{
int error;
PROC_LOCK_ASSERT(proc, MA_OWNED);
if (!mac_enforce_process)
return (0);
MAC_CHECK(check_proc_debug, cred, proc);
return (error);
}
int
mac_check_proc_sched(struct ucred *cred, struct proc *proc)
{
int error;
PROC_LOCK_ASSERT(proc, MA_OWNED);
if (!mac_enforce_process)
return (0);
MAC_CHECK(check_proc_sched, cred, proc);
return (error);
}
int
mac_check_proc_signal(struct ucred *cred, struct proc *proc, int signum)
{
int error;
PROC_LOCK_ASSERT(proc, MA_OWNED);
if (!mac_enforce_process)
return (0);
MAC_CHECK(check_proc_signal, cred, proc, signum);
return (error);
}