Asking for a non-current task's stack can't be done without races
unless the task is frozen in kernel mode.  As far as I know,
vm_is_stack_for_task() never had a safe non-current use case.

The __unused annotation is because some KSTK_ESP implementations
ignore their parameter, which IMO is further justification for this
patch.
Signed-off-by: NAndy Lutomirski <luto@kernel.org>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/4c3f68f426e6c061ca98b4fc7ef85ffbb0a25b0c.1475257877.git.luto@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Right now, various places in the kernel check for the existence of
getxattr, setxattr, and removexattr inode operations and directly call
those operations.  Switch to helper functions and test for the IOP_XATTR
flag instead.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Right now LSM_AUDIT_DATA_PATH type contains "struct path" in union "u"
of common_audit_data. This information is used to print path of file
at the same time it is also used to get to dentry and inode. And this
inode information is used to get to superblock and device and print
device information.

This does not work well for layered filesystems like overlay where dentry
contained in path is overlay dentry and not the real dentry of underlying
file system. That means inode retrieved from dentry is also overlay
inode and not the real inode.

SELinux helpers like file_path_has_perm() are doing checks on inode
retrieved from file_inode(). This returns the real inode and not the
overlay inode. That means we are doing check on real inode but for audit
purposes we are printing details of overlay inode and that can be
confusing while debugging.

Hence, introduce a new type LSM_AUDIT_DATA_FILE which carries file
information and inode retrieved is real inode using file_inode(). That
way right avc denied information is given to user.

For example, following is one example avc before the patch.

  type=AVC msg=audit(1473360868.399:214): avc:  denied  { read open } for
    pid=1765 comm="cat"
    path="/root/.../overlay/container1/merged/readfile"
    dev="overlay" ino=21443
    scontext=unconfined_u:unconfined_r:test_overlay_client_t:s0:c10,c20
    tcontext=unconfined_u:object_r:test_overlay_files_ro_t:s0
    tclass=file permissive=0

It looks as follows after the patch.

  type=AVC msg=audit(1473360017.388:282): avc:  denied  { read open } for
    pid=2530 comm="cat"
    path="/root/.../overlay/container1/merged/readfile"
    dev="dm-0" ino=2377915
    scontext=unconfined_u:unconfined_r:test_overlay_client_t:s0:c10,c20
    tcontext=unconfined_u:object_r:test_overlay_files_ro_t:s0
    tclass=file permissive=0

Notice that now dev information points to "dm-0" device instead of
"overlay" device. This makes it clear that check failed on underlying
inode and not on the overlay inode.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
[PM: slight tweaks to the description to make checkpatch.pl happy]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Calculate what would be the label of newly created file and set that
secid in the passed creds.

Context of the task which is actually creating file is retrieved from
set of creds passed in. (old->security).
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Right now selinux_determine_inode_label() works on security pointer of
current task. Soon I need this to work on a security pointer retrieved
from a set of creds. So start passing in a pointer and caller can
decide where to fetch security pointer from.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

When a file is copied up in overlay, we have already created file on
upper/ with right label and there is no need to copy up selinux
label/xattr from lower file to upper file. In fact in case of context
mount, we don't want to copy up label as newly created file got its label
from context= option.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

A file is being copied up for overlay file system. Prepare a new set of
creds and set create_sid appropriately so that new file is created with
appropriate label.

Overlay inode has right label for both context and non-context mount
cases. In case of non-context mount, overlay inode will have the label
of lower file and in case of context mount, overlay inode will have
the label from context= mount option.
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

The IS_ENABLED() macro checks if a Kconfig symbol has been enabled
either built-in or as a module, use that macro instead of open coding
the same.
Signed-off-by: NJavier Martinez Canillas <javier@osg.samsung.com>
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This makes it possible to route the error to the appropriate
labelling engine.  CALIPSO is far less verbose than CIPSO
when encountering a bogus packet, so there is no need for a
CALIPSO error handler.
Signed-off-by: NHuw Davies <huw@codeweavers.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

In some cases, the lsm needs to add the label to the skbuff directly.
A NF_INET_LOCAL_OUT IPv6 hook is added to selinux to match the IPv4
behaviour.  This allows selinux to label the skbuffs that it requires.
Signed-off-by: NHuw Davies <huw@codeweavers.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Security labels from unprivileged mounts in user namespaces must
be ignored. Force superblocks from user namespaces whose labeling
behavior is to use xattrs to use mountpoint labeling instead.
For the mountpoint label, default to converting the current task
context into a form suitable for file objects, but also allow the
policy writer to specify a different label through policy
transition rules.

Pieced together from code snippets provided by Stephen Smalley.
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Acked-by: NJames Morris <james.l.morris@oracle.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

If a process gets access to a mount from a different user
namespace, that process should not be able to take advantage of
setuid files or selinux entrypoints from that filesystem.  Prevent
this by treating mounts from other mount namespaces and those not
owned by current_user_ns() or an ancestor as nosuid.

This will make it safer to allow more complex filesystems to be
mounted in non-root user namespaces.

This does not remove the need for MNT_LOCK_NOSUID.  The setuid,
setgid, and file capability bits can no longer be abused if code in
a user namespace were to clear nosuid on an untrusted filesystem,
but this patch, by itself, is insufficient to protect the system
from abuse of files that, when execed, would increase MAC privilege.

As a more concrete explanation, any task that can manipulate a
vfsmount associated with a given user namespace already has
capabilities in that namespace and all of its descendents.  If they
can cause a malicious setuid, setgid, or file-caps executable to
appear in that mount, then that executable will only allow them to
elevate privileges in exactly the set of namespaces in which they
are already privileges.

On the other hand, if they can cause a malicious executable to
appear with a dangerous MAC label, running it could change the
caller's security context in a way that should not have been
possible, even inside the namespace in which the task is confined.

As a hardening measure, this would have made CVE-2014-5207 much
more difficult to exploit.
Signed-off-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NSeth Forshee <seth.forshee@canonical.com>
Acked-by: NJames Morris <james.l.morris@oracle.com>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

The execstack check was only being applied on the main
process stack.  Thread stacks allocated via mmap were
only subject to the execmem permission check.  Augment
the check to apply to the current thread stack as well.
Note that this does NOT prevent making a different thread's
stack executable.
Suggested-by: NNick Kralevich <nnk@google.com>
Acked-by: NNick Kralevich <nnk@google.com>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Distinguish capability checks against a target associated
with the init user namespace versus capability checks against
a target associated with a non-init user namespace by defining
and using separate security classes for the latter.

This is needed to support e.g. Chrome usage of user namespaces
for the Chrome sandbox without needing to allow Chrome to also
exercise capabilities on targets in the init user namespace.
Suggested-by: NDan Walsh <dwalsh@redhat.com>
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

There is no point in trying to revalidate an inode's security label if
the security server is not yet initialized.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Since looking up an inode's label can result in revalidation, delay
the lookup as long as possible to limit the performance impact.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

There is no point in attempting to revalidate an inode's security
label when we are in the process of setting it.
Reported-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and neither can ever be NULL
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Utilize existing kernel_read_file hook on kernel module load.
Add module_load permission to the system class.

Enforces restrictions on kernel module origin when calling the
finit_module syscall. The hook checks that source type has
permission module_load for the target type.
Example for finit_module:

allow foo bar_file:system module_load;

Similarly restrictions are enforced on kernel module loading when
calling the init_module syscall. The hook checks that source
type has permission module_load with itself as the target object
because the kernel module is sourced from the calling process.
Example for init_module:

allow foo foo:system module_load;
Signed-off-by: NJeff Vander Stoep <jeffv@google.com>
[PM: fixed return value of selinux_kernel_read_file()]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

We lookup the tracing parent in two places, using effectively the
same code, let's consolidate it.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

There really is no need for LABEL_MISSING as we really only care if
the inode's label is INVALID or INITIALIZED.  Also adjust the
revalidate code to reload the label whenever the label is not
INITIALIZED so we are less sensitive to label state in the future.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

We don't have to worry about socket inodes being invalidated so
use inode_security_novalidate() to fetch the inode's security blob.
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The inode_getsecid hook is called from contexts in which sleeping is not
allowed, so we cannot revalidate inode security labels from there. Use
the non-validating version of inode_security() instead.
Reported-by: NBenjamin Coddington <bcodding@redhat.com>
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Access to tty->tty_files list is always per-tty, never for all ttys
simultaneously. Replace global tty_files_lock spinlock with per-tty
->files_lock. Initialize when the ->tty_files list is inited, in
alloc_tty_struct().
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 5d226df4 has introduced a performance regression of about
10% in the UnixBench pipe benchmark.  It turns out that the call
to inode_security in selinux_file_permission can be moved below
the zero-mask test and that inode_security_revalidate can be
removed entirely, which brings us back to roughly the original
performance.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Any process is able to send netlink messages with invalid types.
Make the warning rate-limited to prevent too much log spam.

The warning is supposed to help to find misbehaving programs, so
print the triggering command name and pid.
Reported-by: NFlorian Weimer <fweimer@redhat.com>
Signed-off-by: NVladis Dronov <vdronov@redhat.com>
[PM: subject line tweak to make checkpatch.pl happy]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

When fetching an inode's security label, check if it is still valid, and
try reloading it if it is not. Reloading will fail when we are in RCU
context which doesn't allow sleeping, or when we can't find a dentry for
the inode.  (Reloading happens via iop->getxattr which takes a dentry
parameter.)  When reloading fails, continue using the old, invalid
label.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Add a hook to invalidate an inode's security label when the cached
information becomes invalid.

Add the new hook in selinux: set a flag when a security label becomes
invalid.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: NJames Morris <james.l.morris@oracle.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Add functions dentry_security and inode_security for accessing
inode->i_security.  These functions initially don't do much, but they
will later be used to revalidate the security labels when necessary.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Make the inode argument of the inode_getsecid hook non-const so that we
can use it to revalidate invalid security labels.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Make the inode argument of the inode_getsecurity hook non-const so that
we can use it to revalidate invalid security labels.
Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Generalize selinux_skb_sk() added in commit 212cd089
("selinux: fix random read in selinux_ip_postroute_compat()")
so that we can use it other contexts.

Use it right away in selinux_netlbl_skbuff_setsid()

Fixes: ca6fb065 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In commit e446f9df ("net: synack packets can be attached to request
sockets"), I missed one remaining case of invalid skb->sk->sk_security
access.

Dmitry Vyukov got a KASan report pointing to it.

Add selinux_skb_sk() helper that is responsible to get back to the
listener if skb is attached to a request socket, instead of
duplicating the logic.

Fixes: ca6fb065 ("tcp: attach SYNACK messages to request sockets instead of listener")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The size of struct file_security_struct is 16byte at my setup.
But, the real allocation size for per each file_security_struct
is 64bytes in my setup that kmalloc min size is 64bytes
because ARCH_DMA_MINALIGN is 64.

This allocation is called every times at file allocation(alloc_file()).
So, the total slack memory size(allocated size - request size)
is increased exponentially.

E.g) Min Kmalloc Size : 64bytes, Unit : bytes
      Allocated Size | Request Size | Slack Size | Allocation Count
    ---------------------------------------------------------------
         770048      |    192512    |   577536   |      12032

At the result, this change reduce memory usage 42bytes per each
file_security_struct
Signed-off-by: NSangwoo <sangwoo2.park@lge.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
[PM: removed extra subject prefix]
Signed-off-by: NPaul Moore <pmoore@redhat.com>

Fixes the following sparse warning:

 security/selinux/hooks.c:3242:5: warning: symbol 'ioctl_has_perm' was
 not declared. Should it be static?
Signed-off-by: NGeliang Tang <geliangtang@163.com>
Acked-by: NJeff Vander Stoep <jeffv@google.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>

security_context_to_sid() expects a const char* argument, so there's
no point in casting away the const qualifier of value.
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <pmoore@redhat.com>