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Pull security subsystem updates from James Morris:
"In this patchset, we finally get an SELinux update, with Paul Moore
taking over as maintainer of that code.
Also a significant update for the Keys subsystem, as well as
maintenance updates to Smack, IMA, TPM, and Apparmor"
and since I wanted to know more about the updates to key handling,
here's the explanation from David Howells on that:
"Okay. There are a number of separate bits. I'll go over the big bits
and the odd important other bit, most of the smaller bits are just
fixes and cleanups. If you want the small bits accounting for, I can
do that too.
(1) Keyring capacity expansion.
KEYS: Consolidate the concept of an 'index key' for key access
KEYS: Introduce a search context structure
KEYS: Search for auth-key by name rather than target key ID
Add a generic associative array implementation.
KEYS: Expand the capacity of a keyring
Several of the patches are providing an expansion of the capacity of a
keyring. Currently, the maximum size of a keyring payload is one page.
Subtract a small header and then divide up into pointers, that only gives
you ~500 pointers on an x86_64 box. However, since the NFS idmapper uses
a keyring to store ID mapping data, that has proven to be insufficient to
the cause.
Whatever data structure I use to handle the keyring payload, it can only
store pointers to keys, not the keys themselves because several keyrings
may point to a single key. This precludes inserting, say, and rb_node
struct into the key struct for this purpose.
I could make an rbtree of records such that each record has an rb_node
and a key pointer, but that would use four words of space per key stored
in the keyring. It would, however, be able to use much existing code.
I selected instead a non-rebalancing radix-tree type approach as that
could have a better space-used/key-pointer ratio. I could have used the
radix tree implementation that we already have and insert keys into it by
their serial numbers, but that means any sort of search must iterate over
the whole radix tree. Further, its nodes are a bit on the capacious side
for what I want - especially given that key serial numbers are randomly
allocated, thus leaving a lot of empty space in the tree.
So what I have is an associative array that internally is a radix-tree
with 16 pointers per node where the index key is constructed from the key
type pointer and the key description. This means that an exact lookup by
type+description is very fast as this tells us how to navigate directly to
the target key.
I made the data structure general in lib/assoc_array.c as far as it is
concerned, its index key is just a sequence of bits that leads to a
pointer. It's possible that someone else will be able to make use of it
also. FS-Cache might, for example.
(2) Mark keys as 'trusted' and keyrings as 'trusted only'.
KEYS: verify a certificate is signed by a 'trusted' key
KEYS: Make the system 'trusted' keyring viewable by userspace
KEYS: Add a 'trusted' flag and a 'trusted only' flag
KEYS: Separate the kernel signature checking keyring from module signing
These patches allow keys carrying asymmetric public keys to be marked as
being 'trusted' and allow keyrings to be marked as only permitting the
addition or linkage of trusted keys.
Keys loaded from hardware during kernel boot or compiled into the kernel
during build are marked as being trusted automatically. New keys can be
loaded at runtime with add_key(). They are checked against the system
keyring contents and if their signatures can be validated with keys that
are already marked trusted, then they are marked trusted also and can
thus be added into the master keyring.
Patches from Mimi Zohar make this usable with the IMA keyrings also.
(3) Remove the date checks on the key used to validate a module signature.
X.509: Remove certificate date checks
It's not reasonable to reject a signature just because the key that it was
generated with is no longer valid datewise - especially if the kernel
hasn't yet managed to set the system clock when the first module is
loaded - so just remove those checks.
(4) Make it simpler to deal with additional X.509 being loaded into the kernel.
KEYS: Load *.x509 files into kernel keyring
KEYS: Have make canonicalise the paths of the X.509 certs better to deduplicate
The builder of the kernel now just places files with the extension ".x509"
into the kernel source or build trees and they're concatenated by the
kernel build and stuffed into the appropriate section.
(5) Add support for userspace kerberos to use keyrings.
KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches
KEYS: Implement a big key type that can save to tmpfs
Fedora went to, by default, storing kerberos tickets and tokens in tmpfs.
We looked at storing it in keyrings instead as that confers certain
advantages such as tickets being automatically deleted after a certain
amount of time and the ability for the kernel to get at these tokens more
easily.
To make this work, two things were needed:
(a) A way for the tickets to persist beyond the lifetime of all a user's
sessions so that cron-driven processes can still use them.
The problem is that a user's session keyrings are deleted when the
session that spawned them logs out and the user's user keyring is
deleted when the UID is deleted (typically when the last log out
happens), so neither of these places is suitable.
I've added a system keyring into which a 'persistent' keyring is
created for each UID on request. Each time a user requests their
persistent keyring, the expiry time on it is set anew. If the user
doesn't ask for it for, say, three days, the keyring is automatically
expired and garbage collected using the existing gc. All the kerberos
tokens it held are then also gc'd.
(b) A key type that can hold really big tickets (up to 1MB in size).
The problem is that Active Directory can return huge tickets with lots
of auxiliary data attached. We don't, however, want to eat up huge
tracts of unswappable kernel space for this, so if the ticket is
greater than a certain size, we create a swappable shmem file and dump
the contents in there and just live with the fact we then have an
inode and a dentry overhead. If the ticket is smaller than that, we
slap it in a kmalloc()'d buffer"
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (121 commits)
KEYS: Fix keyring content gc scanner
KEYS: Fix error handling in big_key instantiation
KEYS: Fix UID check in keyctl_get_persistent()
KEYS: The RSA public key algorithm needs to select MPILIB
ima: define '_ima' as a builtin 'trusted' keyring
ima: extend the measurement list to include the file signature
kernel/system_certificate.S: use real contents instead of macro GLOBAL()
KEYS: fix error return code in big_key_instantiate()
KEYS: Fix keyring quota misaccounting on key replacement and unlink
KEYS: Fix a race between negating a key and reading the error set
KEYS: Make BIG_KEYS boolean
apparmor: remove the "task" arg from may_change_ptraced_domain()
apparmor: remove parent task info from audit logging
apparmor: remove tsk field from the apparmor_audit_struct
apparmor: fix capability to not use the current task, during reporting
Smack: Ptrace access check mode
ima: provide hash algo info in the xattr
ima: enable support for larger default filedata hash algorithms
ima: define kernel parameter 'ima_template=' to change configured default
ima: add Kconfig default measurement list template
...
The reporting of the parent task info is a vestage from old versions of
apparmor. The need for this information was removed by unique null-
profiles before apparmor was upstreamed so remove this info from logging.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Mediation is based off of the cred but auditing includes the current
task which may not be related to the actual request.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Provide userspace the ability to introspect a sha1 hash value for each
profile currently loaded.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Add the ability to take in and report a human readable profile attachment
string for profiles so that attachment specifications can be easily
inspected.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Add basic interface files to access namespace and profile information.
The interface files are created when a profile is loaded and removed
when the profile or namespace is removed.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Allow emulating the default profile behavior from boot, by allowing
loading of a profile in the unconfined state into a new NS.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
namespaces now completely use the unconfined profile to track the
refcount and rcu freeing cycle. So rework the code to simplify (track
everything through the profile path right up to the end), and move the
rcu_head from policy base to profile as the namespace no longer needs
it.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
ns->unconfined is being used read side without locking, nor rcu but is
being updated when a namespace is removed. This works for the root ns
which is never removed but has a race window and can cause failures when
children namespaces are removed.
Also ns and ns->unconfined have a circular refcounting dependency that
is problematic and must be broken. Currently this is done incorrectly
when the namespace is destroyed.
Fix this by forward referencing unconfined via the replacedby infrastructure
instead of directly updating the ns->unconfined pointer.
Remove the circular refcount dependency by making the ns and its unconfined
profile share the same refcount.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
remove the use of replaced by chaining and move to profile invalidation
and lookup to handle task replacement.
Replacement chaining can result in large chains of profiles being pinned
in memory when one profile in the chain is use. With implicit labeling
this will be even more of a problem, so move to a direct lookup method.
Signed-off-by: John Johansen <john.johansen@canonical.com>
previously profiles had to be loaded one at a time, which could result
in cases where a replacement of a set would partially succeed, and then fail
resulting in inconsistent policy.
Allow multiple profiles to replaced "atomically" so that the replacement
either succeeds or fails for the entire set of profiles.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The sid is not going to be a direct property of a profile anymore, instead
it will be directly related to the label, and the profile will pickup
a label back reference.
For null-profiles replace the use of sid with a per namespace unique
id.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
The "permipc" command is unused and unfinished, remove it.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Cc: John Johansen <john.johansen@canonical.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
apparmor is the only LSM that uses the common_audit_data tsk field.
Instead of making all LSMs pay for the stack space move the aa usage into
the apparmor_audit_data.
Signed-off-by: Eric Paris <eparis@redhat.com>
Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop. This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union. Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the base support for the new policy extensions. This does not bring
any additional functionality, or change current semantics.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Move the path name lookup failure messages into the main path name lookup
routine, as the information is useful in more than just aa_path_perm.
Also rename aa_get_name to aa_path_name as it is not getting a reference
counted object with a corresponding put fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Update aa_dfa_match so that it doesn't result in an input string being
walked twice (once to get its length and another time to match)
Add a single step functions
aa_dfa_next
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
If the xindex value stored in the accept tables is 0, the extraction of
that value will result in an underflow (0 - 4).
In properly compiled policy this should not happen for file rules but
it may be possible for other rule types in the future.
To exploit this underflow a user would have to be able to load a corrupt
policy, which requires CAP_MAC_ADMIN, overwrite system policy in kernel
memory or know of a compiler error resulting in the flaw being present
for loaded policy (no such flaw is known at this time).
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
The audit permission flag, that specifies an audit message should be
provided when an operation is allowed, was being ignored in some cases.
This is because the auto audit mode (which determines the audit mode from
system flags) was incorrectly assigned the same value as audit mode. The
shared value would result in messages that should be audited going through
a second evaluation as to whether they should be audited based on the
auto audit, resulting in some messages being dropped.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Since the parser needs to know which rlimits are known to the kernel,
export the list via a mask file in the "rlimit" subdirectory in the
securityfs "features" directory.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Create the "file" directory in the securityfs for tracking features
related to files.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
This adds the "features" subdirectory to the AppArmor securityfs
to display boolean features flags and the known capability mask.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Use a file tree structure to represent the AppArmor securityfs.
Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
module_param(bool) used to counter-intuitively take an int. In
fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy
trick.
It's time to remove the int/unsigned int option. For this version
it'll simply give a warning, but it'll break next kernel version.
Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Remove kobject.h from files which don't need it, notably,
sched.h and fs.h.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove path.h from sched.h and other files.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2.6.36 introduced the abilitiy to specify the task that is having its
rlimits set. Update mediation to ensure that confined tasks can only
set their own group_leader as expected by current policy.
Add TODO note about extending policy to support setting other tasks
rlimits.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
The basic routines and defines for AppArmor policy. AppArmor policy
is defined by a few basic components.
profiles - the basic unit of confinement contain all the information
to enforce policy on a task
Profiles tend to be named after an executable that they
will attach to but this is not required.
namespaces - a container for a set of profiles that will be used
during attachment and transitions between profiles.
sids - which provide a unique id for each profile
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
AppArmor policy is loaded in a platform independent flattened binary
stream. Verify and unpack the data converting it to the internal
format needed for enforcement.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
ipc:
AppArmor ipc is currently limited to mediation done by file mediation
and basic ptrace tests. Improved mediation is a wip.
rlimits:
AppArmor provides basic abilities to set and control rlimits at
a per profile level. Only resources specified in a profile are controled
or set. AppArmor rules set the hard limit to a value <= to the current
hard limit (ie. they can not currently raise hard limits), and if
necessary will lower the soft limit to the new hard limit value.
AppArmor does not track resource limits to reset them when a profile
is left so that children processes inherit the limits set by the
parent even if they are not confined by the same profile.
Capabilities: AppArmor provides a per profile mask of capabilities,
that will further restrict.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
AppArmor routines for controling domain transitions, which can occur at
exec or through self directed change_profile/change_hat calls.
Unconfined tasks are checked at exec against the profiles in the confining
profile namespace to determine if a profile should be attached to the task.
Confined tasks execs are controlled by the profile which provides rules
determining which execs are allowed and if so which profiles should be
transitioned to.
Self directed domain transitions allow a task to request transition
to a given profile. If the transition is allowed then the profile will
be applied, either immeditately or at exec time depending on the request.
Immeditate self directed transitions have several security limitations
but have uses in setting up stub transition profiles and other limited
cases.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
AppArmor does files enforcement via pathname matching. Matching is done
at file open using a dfa match engine. Permission is against the final
file object not parent directories, ie. the traversal of directories
as part of the file match is implicitly allowed. In the case of nonexistant
files (creation) permissions are checked against the target file not the
directory. eg. In case of creating the file /dir/new, permissions are
checked against the match /dir/new not against /dir/.
The permissions for matches are currently stored in the dfa accept table,
but this will change to allow for dfa reuse and also to allow for sharing
of wider accept states.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
