Currently variable size is a unsigned size_t, hence comparisons to
see if it is less than zero (for error checking) will always be
false. Fix this by making size a ssize_t
Detected by CoverityScan, CID#1466080 ("Unsigned compared against 0")
Fixes: 8e51f9087f ("apparmor: Add support for attaching profiles via xattr, presence and value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Overlapping domain attachments using the current longest left exact
match fail in some simple cases, and with the fix to ensure consistent
behavior by failing unresolvable attachments it becomes important to
do a better job.
eg. under the current match the following are unresolvable where
the alternation is clearly a better match under the most specific
left match rule.
/**
/{bin/,}usr/
Use a counting match that detects when a loop in the state machine is
enter, and return the match count to provide a better specific left
match resolution.
Signed-off-by: John Johansen <john.johansen@canonical.com>
This converts profile attachment based on xattrs to a fixed extended
conditional using dfa matching.
This has a couple of advantages
- pattern matching can be used for the xattr match
- xattrs can be optional for an attachment or marked as required
- the xattr attachment conditional will be able to be combined with
other extended conditionals when the flexible extended conditional
work lands.
The xattr fixed extended conditional is appended to the xmatch
conditional. If an xattr attachment is specified the profile xmatch
will be generated regardless of whether there is a pattern match on
the executable name.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Make it possible to tie Apparmor profiles to the presence of one or more
extended attributes, and optionally their values. An example usecase for
this is to automatically transition to a more privileged Apparmor profile
if an executable has a valid IMA signature, which can then be appraised
by the IMA subsystem.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Domain transition so far have been largely blocked by no new privs,
unless the transition has been provably a subset of the previous
confinement. There was a couple problems with the previous
implementations,
- transitions that weren't explicitly a stack but resulted in a subset
of confinement were disallowed
- confinement subsets were only calculated from the previous
confinement instead of the confinement being enforced at the time of
no new privs, so transitions would have to get progressively
tighter.
Fix this by detecting and storing a reference to the task's
confinement at the "time" no new privs is set. This reference is then
used to determine whether a transition is a subsystem of the
confinement at the time no new privs was set.
Unfortunately the implementation is less than ideal in that we have to
detect no new privs after the fact when a task attempts a domain
transition. This is adequate for the currently but will not work in a
stacking situation where no new privs could be conceivably be set in
both the "host" and in the container.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Now that file contexts have been moved into file, and task context
fns() and data have been split from the context, only the cred context
remains in context.h so rename to cred.h to better reflect what it
deals with.
Signed-off-by: John Johansen <john.johansen@canonical.com>
now that cred_ctx has been removed we can rename task_ctxs from tctx
without causing confusion.
Signed-off-by: John Johansen <john.johansen@canonical.com>
With the task domain change information now stored in the task->security
context, the cred->security context only stores the label. We can get
rid of the cred_ctx and directly reference the label, removing a layer
of indirection, and unneeded extra allocations.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The task domain change info is task specific and its and abuse of
the cred to store the information in there. Now that a task->security
field exists store it in the proper place.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The intended behaviour in apparmor profile matching is to flag a
conflict if two profiles match equally well. However, right now a
conflict is generated if another profile has the same match length even
if that profile doesn't actually match. Fix the logic so we only
generate a conflict if the profiles match.
Fixes: 844b8292b6 ("apparmor: ensure that undecidable profile attachments fail")
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
It used to be that unconfined would never attach. However that is not
the case anymore as some special profiles can be marked as unconfined,
that are not the namespaces unconfined profile, and may have an
attachment.
Fixes: f1bd904175 ("apparmor: add the base fns() for domain labels")
Signed-off-by: John Johansen <john.johansen@canonical.com>
Profiles that have an undecidable overlap in their attachments are
being incorrectly handled. Instead of failing to attach the first one
encountered is being used.
eg.
profile A /** { .. }
profile B /*foo { .. }
have an unresolvable longest left attachment, they both have an exact
match on / and then have an overlapping expression that has no clear
winner.
Currently the winner will be the profile that is loaded first which
can result in non-deterministic behavior. Instead in this situation
the exec should fail.
Fixes: 898127c34e ("AppArmor: functions for domain transitions")
Signed-off-by: John Johansen <john.johansen@canonical.com>
- in preparation for secid mapping add support for absolute root view
based labels
- add base infastructure for socket mediation
- add mount mediation
- add signal mediation
+ minor cleanups and changes
- be defensive, ensure unconfined profiles have dfas initialized
- add more debug asserts to apparmorfs
- enable policy unpacking to audit different reasons for failure
- cleanup conditional check for label in label_print
- Redundant condition: prev_ns. in [label.c:1498]
+ Bug Fixes
- fix regression in apparmorfs DAC access permissions
- fix build failure on sparc caused by undeclared signals
- fix sparse report of incorrect type assignment when freeing label proxies
- fix race condition in null profile creation
- Fix an error code in aafs_create()
- Fix logical error in verify_header()
- Fix shadowed local variable in unpack_trans_table()
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Merge tag 'apparmor-pr-2017-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor
Pull apparmor updates from John Johansen:
"This is the apparmor pull request, similar to SELinux and seccomp.
It's the same series that I was sent to James' security tree + one
regression fix that was found after the series was sent to James and
would have been sent for v4.14-rc2.
Features:
- in preparation for secid mapping add support for absolute root view
based labels
- add base infastructure for socket mediation
- add mount mediation
- add signal mediation
minor cleanups and changes:
- be defensive, ensure unconfined profiles have dfas initialized
- add more debug asserts to apparmorfs
- enable policy unpacking to audit different reasons for failure
- cleanup conditional check for label in label_print
- Redundant condition: prev_ns. in [label.c:1498]
Bug Fixes:
- fix regression in apparmorfs DAC access permissions
- fix build failure on sparc caused by undeclared signals
- fix sparse report of incorrect type assignment when freeing label proxies
- fix race condition in null profile creation
- Fix an error code in aafs_create()
- Fix logical error in verify_header()
- Fix shadowed local variable in unpack_trans_table()"
* tag 'apparmor-pr-2017-09-22' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
apparmor: fix apparmorfs DAC access permissions
apparmor: fix build failure on sparc caused by undeclared signals
apparmor: fix incorrect type assignment when freeing proxies
apparmor: ensure unconfined profiles have dfas initialized
apparmor: fix race condition in null profile creation
apparmor: move new_null_profile to after profile lookup fns()
apparmor: add base infastructure for socket mediation
apparmor: add more debug asserts to apparmorfs
apparmor: make policy_unpack able to audit different info messages
apparmor: add support for absolute root view based labels
apparmor: cleanup conditional check for label in label_print
apparmor: add mount mediation
apparmor: add the ability to mediate signals
apparmor: Redundant condition: prev_ns. in [label.c:1498]
apparmor: Fix an error code in aafs_create()
apparmor: Fix logical error in verify_header()
apparmor: Fix shadowed local variable in unpack_trans_table()
The AppArmor bprm_secureexec hook can be merged with the bprm_set_creds
hook since it's dealing with the same information, and all of the details
are finalized during the first call to the bprm_set_creds hook via
prepare_binprm() (subsequent calls due to binfmt_script, etc, are ignored
via bprm->called_set_creds).
Here, all the comments describe how secureexec is actually calculated
during bprm_set_creds, so this actually does it, drops the bprm flag that
was being used internally by AppArmor, and drops the bprm_secureexec hook.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
The cred_prepared bprm flag has a misleading name. It has nothing to do
with the bprm_prepare_cred hook, and actually tracks if bprm_set_creds has
been called. Rename this flag and improve its comment.
Cc: David Howells <dhowells@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Begin the actual switch to using domain labels by storing them on
the context and converting the label to a singular profile where
possible.
Signed-off-by: John Johansen <john.johansen@canonical.com>
There are still a few places where profile replacement fails to update
and a stale profile is used for mediation. Fix this by moving to
accessing the current label through a critical section that will
always ensure mediation is using the current label regardless of
whether the tasks cred has been updated or not.
Signed-off-by: John Johansen <john.johansen@canonical.com>
There is no reason to have the small stubs that don't use domain
private functions in domain.c, instead move them to lsm.c and make
them static.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Dynamically allocating buffers is problematic and is an extra layer
that is a potntial point of failure and can slow down mediation.
Change path lookup to use the preallocated per cpu buffers.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Pull namespace updates from Eric Biederman:
"There is a lot here. A lot of these changes result in subtle user
visible differences in kernel behavior. I don't expect anything will
care but I will revert/fix things immediately if any regressions show
up.
From Seth Forshee there is a continuation of the work to make the vfs
ready for unpriviled mounts. We had thought the previous changes
prevented the creation of files outside of s_user_ns of a filesystem,
but it turns we missed the O_CREAT path. Ooops.
Pavel Tikhomirov and Oleg Nesterov worked together to fix a long
standing bug in the implemenation of PR_SET_CHILD_SUBREAPER where only
children that are forked after the prctl are considered and not
children forked before the prctl. The only known user of this prctl
systemd forks all children after the prctl. So no userspace
regressions will occur. Holding earlier forked children to the same
rules as later forked children creates a semantic that is sane enough
to allow checkpoing of processes that use this feature.
There is a long delayed change by Nikolay Borisov to limit inotify
instances inside a user namespace.
Michael Kerrisk extends the API for files used to maniuplate
namespaces with two new trivial ioctls to allow discovery of the
hierachy and properties of namespaces.
Konstantin Khlebnikov with the help of Al Viro adds code that when a
network namespace exits purges it's sysctl entries from the dcache. As
in some circumstances this could use a lot of memory.
Vivek Goyal fixed a bug with stacked filesystems where the permissions
on the wrong inode were being checked.
I continue previous work on ptracing across exec. Allowing a file to
be setuid across exec while being ptraced if the tracer has enough
credentials in the user namespace, and if the process has CAP_SETUID
in it's own namespace. Proc files for setuid or otherwise undumpable
executables are now owned by the root in the user namespace of their
mm. Allowing debugging of setuid applications in containers to work
better.
A bug I introduced with permission checking and automount is now
fixed. The big change is to mark the mounts that the kernel initiates
as a result of an automount. This allows the permission checks in sget
to be safely suppressed for this kind of mount. As the permission
check happened when the original filesystem was mounted.
Finally a special case in the mount namespace is removed preventing
unbounded chains in the mount hash table, and making the semantics
simpler which benefits CRIU.
The vfs fix along with related work in ima and evm I believe makes us
ready to finish developing and merge fully unprivileged mounts of the
fuse filesystem. The cleanups of the mount namespace makes discussing
how to fix the worst case complexity of umount. The stacked filesystem
fixes pave the way for adding multiple mappings for the filesystem
uids so that efficient and safer containers can be implemented"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc/sysctl: Don't grab i_lock under sysctl_lock.
vfs: Use upper filesystem inode in bprm_fill_uid()
proc/sysctl: prune stale dentries during unregistering
mnt: Tuck mounts under others instead of creating shadow/side mounts.
prctl: propagate has_child_subreaper flag to every descendant
introduce the walk_process_tree() helper
nsfs: Add an ioctl() to return owner UID of a userns
fs: Better permission checking for submounts
exit: fix the setns() && PR_SET_CHILD_SUBREAPER interaction
vfs: open() with O_CREAT should not create inodes with unknown ids
nsfs: Add an ioctl() to return the namespace type
proc: Better ownership of files for non-dumpable tasks in user namespaces
exec: Remove LSM_UNSAFE_PTRACE_CAP
exec: Test the ptracer's saved cred to see if the tracee can gain caps
exec: Don't reset euid and egid when the tracee has CAP_SETUID
inotify: Convert to using per-namespace limits
With previous changes every location that tests for
LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the
LSM_UNSAFE_PTRACE_CAP redundant, so remove it.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Moving the use of fqname to later allows learning profiles to be based
on the fqname request instead of just the hname. It also allows cleaning
up some of the name parsing and lookup by allowing the use of
the fqlookupn_profile() lib fn.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The aad macro can replace aad strings when it is not intended to. Switch
to a fn macro so it is only applied when intended.
Also at the same time cleanup audit_data initialization by putting
common boiler plate behind a macro, and dropping the gfp_t parameter
which will become useless.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Having ops be an integer that is an index into an op name table is
awkward and brittle. Every op change requires an edit for both the
op constant and a string in the table. Instead switch to using const
strings directly, eliminating the need for the table that needs to
be kept in sync.
Signed-off-by: John Johansen <john.johansen@canonical.com>
When possible its better to name a learning profile after the missing
profile in question. This allows for both more informative names and
for profile reuse.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Policy namespaces will be diverging from profile management and
expanding so put it in its own file.
Signed-off-by: John Johansen <john.johansen@canonical.com>
After a policy replacement, the task cred may be out of date and need
to be updated. However change_hat is using the stale profiles from
the out of date cred resulting in either: a stale profile being applied
or, incorrect failure when searching for a hat profile as it has been
migrated to the new parent profile.
Fixes: 01e2b670aa (failure to find hat)
Fixes: 898127c34e (stale policy being applied)
Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1000287
Cc: stable@vger.kernel.org
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
The target profile name was not being correctly audited in a few
cases because the target variable was not being set and gotos
passed the code to set it at apply:
Since it is always based on new_profile just drop the target var
and conditionally report based on new_profile.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
The current behavior is confusing as it causes exec failures to report
the executable is missing instead of identifying that apparmor
caused the failure.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
Instead of using a vector of security operations
with explicit, special case stacking of the capability
and yama hooks use lists of hooks with capability and
yama hooks included as appropriate.
The security_operations structure is no longer required.
Instead, there is a union of the function pointers that
allows all the hooks lists to use a common mechanism for
list management while retaining typing. Each module
supplies an array describing the hooks it provides instead
of a sparsely populated security_operations structure.
The description includes the element that gets put on
the hook list, avoiding the issues surrounding individual
element allocation.
The method for registering security modules is changed to
reflect the information available. The method for removing
a module, currently only used by SELinux, has also changed.
It should be generic now, however if there are potential
race conditions based on ordering of hook removal that needs
to be addressed by the calling module.
The security hooks are called from the lists and the first
failure is returned.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <james.l.morris@oracle.com>
Since seccomp transitions between threads requires updates to the
no_new_privs flag to be atomic, the flag must be part of an atomic flag
set. This moves the nnp flag into a separate task field, and introduces
accessors.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Unless task == current ptrace_parent(task) is not safe even under
rcu_read_lock() and most of the current users are not right.
So may_change_ptraced_domain(task) looks wrong as well. However it
is always called with task == current so the code is actually fine.
Remove this argument to make this fact clear.
Note: perhaps we should simply kill ptrace_parent(), it buys almost
nothing. And it is obviously racy, perhaps this should be fixed.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
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>
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>
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>
Colin Ian King