... along with avc_has_perm_flags() itself, since now it's identical
to avc_has_perm() (as pointed out by Paul Moore)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
[PM: add "selinux:" prefix to subj and tweak for length]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

dump_common_audit_data() is safe to use under rcu_read_lock() now;
no need for AVC_NONBLOCKING and games around it
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

While trying to address a Coverity warning that the dev_name string
might end up unterminated when strcpy'ing it in
selinux_ib_endport_manage_subnet(), I realized that it is possible (and
simpler) to just pass the dev_name pointer directly, rather than copying
the string to a buffer.

The ibendport variable goes out of scope at the end of the function
anyway, so the lifetime of the dev_name pointer will never be shorter
than that of ibendport, thus we can safely just pass the dev_name
pointer and be done with it.
Signed-off-by: NOndrej Mosnacek <omosnace@redhat.com>
Acked-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Move management of the superblock->sb_security blob out of the
individual security modules and into the security infrastructure.
Instead of allocating the blobs from within the modules, the modules
tell the infrastructure how much space is required, and the space is
allocated there.

Cc: John Johansen <john.johansen@canonical.com>
Signed-off-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NMickaël Salaün <mic@linux.microsoft.com>
Reviewed-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210422154123.13086-6-mic@digikod.netSigned-off-by: NJames Morris <jamorris@linux.microsoft.com>

SELinux has a function, task_sid(), which returns the task's
objective credentials, but unfortunately is used in a few places
where the subjective task credentials should be used.  Most notably
in the new security_task_getsecid_subj() LSM hook.

This patch fixes this and attempts to make things more obvious by
introducing a new function, task_sid_subj(), and renaming the
existing task_sid() function to task_sid_obj().

This patch also adds an interesting function in task_sid_binder().
The task_sid_binder() function has a comment which hopefully
describes it's reason for being, but it basically boils down to the
simple fact that we can't safely access another task's subjective
credentials so in the case of binder we need to stick with the
objective credentials regardless.
Reviewed-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Of the three LSMs that implement the security_task_getsecid() LSM
hook, all three LSMs provide the task's objective security
credentials.  This turns out to be unfortunate as most of the hook's
callers seem to expect the task's subjective credentials, although
a small handful of callers do correctly expect the objective
credentials.

This patch is the first step towards fixing the problem: it splits
the existing security_task_getsecid() hook into two variants, one
for the subjective creds, one for the objective creds.

  void security_task_getsecid_subj(struct task_struct *p,
				   u32 *secid);
  void security_task_getsecid_obj(struct task_struct *p,
				  u32 *secid);

While this patch does fix all of the callers to use the correct
variant, in order to keep this patch focused on the callers and to
ease review, the LSMs continue to use the same implementation for
both hooks.  The net effect is that this patch should not change
the behavior of the kernel in any way, it will be up to the latter
LSM specific patches in this series to change the hook
implementations and return the correct credentials.

Acked-by: Mimi Zohar <zohar@linux.ibm.com> (IMA)
Acked-by: NCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Add a new hook that takes an existing super block and a new mount
with new options and determines if new options confict with an
existing mount or not.

A filesystem can use this new hook to determine if it can share
the an existing superblock with a new superblock for the new mount.
Signed-off-by: NOlga Kornievskaia <kolga@netapp.com>
Acked-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>
[PM: tweak the subject line, fix tab/space problems]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Now overlayfs allow unpriviliged mounts. That is root inside a non-init
user namespace can mount overlayfs. This is being added in 5.11 kernel.

Giuseppe tried to mount overlayfs with option "context" and it failed
with error -EACCESS.

$ su test
$ unshare -rm
$ mkdir -p lower upper work merged
$ mount -t overlay -o lowerdir=lower,workdir=work,upperdir=upper,userxattr,context='system_u:object_r:container_file_t:s0' none merged

This fails with -EACCESS. It works if option "-o context" is not specified.

Little debugging showed that selinux_set_mnt_opts() returns -EACCESS.

So this patch adds "overlay" to the list, where it is fine to specific
context from non init_user_ns.
Reported-by: NGiuseppe Scrivano <gscrivan@redhat.com>
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
[PM: trimmed the changelog from the description]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

When interacting with user namespace and non-user namespace aware
filesystem capabilities the vfs will perform various security checks to
determine whether or not the filesystem capabilities can be used by the
caller, whether they need to be removed and so on. The main
infrastructure for this resides in the capability codepaths but they are
called through the LSM security infrastructure even though they are not
technically an LSM or optional. This extends the existing security hooks
security_inode_removexattr(), security_inode_killpriv(),
security_inode_getsecurity() to pass down the mount's user namespace and
makes them aware of idmapped mounts.

In order to actually get filesystem capabilities from disk the
capability infrastructure exposes the get_vfs_caps_from_disk() helper.
For user namespace aware filesystem capabilities a root uid is stored
alongside the capabilities.

In order to determine whether the caller can make use of the filesystem
capability or whether it needs to be ignored it is translated according
to the superblock's user namespace. If it can be translated to uid 0
according to that id mapping the caller can use the filesystem
capabilities stored on disk. If we are accessing the inode that holds
the filesystem capabilities through an idmapped mount we map the root
uid according to the mount's user namespace. Afterwards the checks are
identical to non-idmapped mounts: reading filesystem caps from disk
enforces that the root uid associated with the filesystem capability
must have a mapping in the superblock's user namespace and that the
caller is either in the same user namespace or is a descendant of the
superblock's user namespace. For filesystems that are mountable inside
user namespace the caller can just mount the filesystem and won't
usually need to idmap it. If they do want to idmap it they can create an
idmapped mount and mark it with a user namespace they created and which
is thus a descendant of s_user_ns. For filesystems that are not
mountable inside user namespaces the descendant rule is trivially true
because the s_user_ns will be the initial user namespace.

If the initial user namespace is passed nothing changes so non-idmapped
mounts will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-11-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

When interacting with extended attributes the vfs verifies that the
caller is privileged over the inode with which the extended attribute is
associated. For posix access and posix default extended attributes a uid
or gid can be stored on-disk. Let the functions handle posix extended
attributes on idmapped mounts. If the inode is accessed through an
idmapped mount we need to map it according to the mount's user
namespace. Afterwards the checks are identical to non-idmapped mounts.
This has no effect for e.g. security xattrs since they don't store uids
or gids and don't perform permission checks on them like posix acls do.

Link: https://lore.kernel.org/r/20210121131959.646623-10-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NTycho Andersen <tycho@tycho.pizza>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

The inode_owner_or_capable() helper determines whether the caller is the
owner of the inode or is capable with respect to that inode. Allow it to
handle idmapped mounts. If the inode is accessed through an idmapped
mount it according to the mount's user namespace. Afterwards the checks
are identical to non-idmapped mounts. If the initial user namespace is
passed nothing changes so non-idmapped mounts will see identical
behavior as before.

Similarly, allow the inode_init_owner() helper to handle idmapped
mounts. It initializes a new inode on idmapped mounts by mapping the
fsuid and fsgid of the caller from the mount's user namespace. If the
initial user namespace is passed nothing changes so non-idmapped mounts
will see identical behavior as before.

Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NChristian Brauner <christian.brauner@ubuntu.com>

This change uses the anon_inodes and LSM infrastructure introduced in
the previous patches to give SELinux the ability to control
anonymous-inode files that are created using the new
anon_inode_getfd_secure() function.

A SELinux policy author detects and controls these anonymous inodes by
adding a name-based type_transition rule that assigns a new security
type to anonymous-inode files created in some domain. The name used
for the name-based transition is the name associated with the
anonymous inode for file listings --- e.g., "[userfaultfd]" or
"[perf_event]".

Example:

type uffd_t;
type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]";
allow sysadm_t uffd_t:anon_inode { create };

(The next patch in this series is necessary for making userfaultfd
support this new interface.  The example above is just
for exposition.)
Signed-off-by: NDaniel Colascione <dancol@google.com>
Signed-off-by: NLokesh Gidra <lokeshgidra@google.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

When a superblock is assigned the SECURITY_FS_USE_XATTR behavior by the
policy yet it lacks xattr support, try to fall back to genfs rather than
rejecting the mount. If a genfscon rule is found for the filesystem,
then change the behavior to SECURITY_FS_USE_GENFS, otherwise reject the
mount as before. A similar fallback is already done in security_fs_use()
if no behavior specification is found for the given filesystem.

This is needed e.g. for virtiofs, which may or may not support xattrs
depending on the backing host filesystem.

Example:
    # seinfo --genfs | grep ' ramfs'
       genfscon ramfs /  system_u:object_r:ramfs_t:s0
    # echo '(fsuse xattr ramfs (system_u object_r fs_t ((s0) (s0))))' >ramfs_xattr.cil
    # semodule -i ramfs_xattr.cil
    # mount -t ramfs none /mnt

Before:
    mount: /mnt: mount(2) system call failed: Operation not supported.

After:
    (mount succeeds)
    # ls -Zd /mnt
    system_u:object_r:ramfs_t:s0 /mnt

See also:
https://lore.kernel.org/selinux/20210105142148.GA3200@redhat.com/T/
https://github.com/fedora-selinux/selinux-policy/pull/478

Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

When inode has no listxattr op of its own (e.g. squashfs) vfs_listxattr
calls the LSM inode_listsecurity hooks to list the xattrs that LSMs will
intercept in inode_getxattr hooks.

When selinux LSM is installed but not initialized, it will list the
security.selinux xattr in inode_listsecurity, but will not intercept it
in inode_getxattr.  This results in -ENODATA for a getxattr call for an
xattr returned by listxattr.

This situation was manifested as overlayfs failure to copy up lower
files from squashfs when selinux is built-in but not initialized,
because ovl_copy_xattr() iterates the lower inode xattrs by
vfs_listxattr() and vfs_getxattr().

Match the logic of inode_listsecurity to that of inode_getxattr and
do not list the security.selinux xattr if selinux is not initialized.
Reported-by: NMichael Labriola <michael.d.labriola@gmail.com>
Tested-by: NMichael Labriola <michael.d.labriola@gmail.com>
Link: https://lore.kernel.org/linux-unionfs/2nv9d47zt7.fsf@aldarion.sourceruckus.org/
Fixes: c8e22261 ("selinux: allow reading labels before policy is loaded")
Cc: stable@vger.kernel.org#v5.9+
Signed-off-by: NAmir Goldstein <amir73il@gmail.com>
Reviewed-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

The MPTCP protocol uses a specific protocol value, even if
it's an extension to TCP. Additionally, MPTCP sockets
could 'fall-back' to TCP at run-time, depending on peer MPTCP
support and available resources.

As a consequence of the specific protocol number, selinux
applies the raw_socket class to MPTCP sockets.

Existing TCP application converted to MPTCP - or forced to
use MPTCP socket with user-space hacks - will need an
updated policy to run successfully.

This change lets selinux attach the TCP socket class to
MPTCP sockets, too, so that no policy changes are needed in
the above scenario.

Note that the MPTCP is setting, propagating and updating the
security context on all the subflows and related request
socket.

Link: https://lore.kernel.org/linux-security-module/CAHC9VhTaK3xx0hEGByD2zxfF7fadyPP1kb-WeWH_YCyq9X-sRg@mail.gmail.com/T/#tSigned-off-by: NPaolo Abeni <pabeni@redhat.com>
[PM: tweaked subject's prefix]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

A followup change to tcp_request_sock_op would have to drop the 'const'
qualifier from the 'route_req' function as the
'security_inet_conn_request' call is moved there - and that function
expects a 'struct sock *'.

However, it turns out its also possible to add a const qualifier to
security_inet_conn_request instead.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

As pointed out by Herbert in a recent related patch, the LSM hooks do
not have the necessary address family information to use the flowi
struct safely.  As none of the LSMs currently use any of the protocol
specific flowi information, replace the flowi pointers with pointers
to the address family independent flowi_common struct.
Reported-by: NHerbert Xu <herbert@gondor.apana.org.au>
Acked-by: NJames Morris <jamorris@linux.microsoft.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115Signed-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

It appears to have been needed for selinux_complete_init() in the past,
but today it's useless.
Signed-off-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

A previous fix, commit 83370b31 ("selinux: fix error initialization
in inode_doinit_with_dentry()"), changed how failures were handled
before a SELinux policy was loaded.  Unfortunately that patch was
potentially problematic for two reasons: it set the isec->initialized
state without holding a lock, and it didn't set the inode's SELinux
label to the "default" for the particular filesystem.  The later can
be a problem if/when a later attempt to revalidate the inode fails
and SELinux reverts to the existing inode label.

This patch should restore the default inode labeling that existed
before the original fix, without affecting the LABEL_INVALID marking
such that revalidation will still be attempted in the future.

Fixes: 83370b31 ("selinux: fix error initialization in inode_doinit_with_dentry()")
Reported-by: NSven Schnelle <svens@linux.ibm.com>
Tested-by: NSven Schnelle <svens@linux.ibm.com>
Reviewed-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Mark the inode security label as invalid if we cannot find
a dentry so that we will retry later rather than marking it
initialized with the unlabeled SID.

Fixes: 9287aed2 ("selinux: Convert isec->lock into a spinlock")
Signed-off-by: NTianyue Ren <rentianyue@kylinos.cn>
[PM: minor comment tweaks]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

As with the kernel_load_data LSM hook, add a "contents" flag to the
kernel_read_file LSM hook that indicates whether the LSM can expect
a matching call to the kernel_post_read_file LSM hook with the full
contents of the file. With the coming addition of partial file read
support for kernel_read_file*() API, the LSM will no longer be able
to always see the entire contents of a file during the read calls.

For cases where the LSM must read examine the complete file contents,
it will need to do so on its own every time the kernel_read_file
hook is called with contents=false (or reject such cases). Adjust all
existing LSMs to retain existing behavior.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are a few places in the kernel where LSMs would like to have
visibility into the contents of a kernel buffer that has been loaded or
read. While security_kernel_post_read_file() (which includes the
buffer) exists as a pairing for security_kernel_read_file(), no such
hook exists to pair with security_kernel_load_data().

Earlier proposals for just using security_kernel_post_read_file() with a
NULL file argument were rejected (i.e. "file" should always be valid for
the security_..._file hooks, but it appears at least one case was
left in the kernel during earlier refactoring. (This will be fixed in
a subsequent patch.)

Since not all cases of security_kernel_load_data() can have a single
contiguous buffer made available to the LSM hook (e.g. kexec image
segments are separately loaded), there needs to be a way for the LSM to
reason about its expectations of the hook coverage. In order to handle
this, add a "contents" argument to the "kernel_load_data" hook that
indicates if the newly added "kernel_post_load_data" hook will be called
with the full contents once loaded. That way, LSMs requiring full contents
can choose to unilaterally reject "kernel_load_data" with contents=false
(which is effectively the existing hook coverage), but when contents=true
they can allow it and later evaluate the "kernel_post_load_data" hook
once the buffer is loaded.

With this change, LSMs can gain coverage over non-file-backed data loads
(e.g. init_module(2) and firmware userspace helper), which will happen
in subsequent patches.

Additionally prepare IMA to start processing these cases.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NKP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-9-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move kernel_read_file* out of linux/fs.h to its own linux/kernel_read_file.h
include file. That header gets pulled in just about everywhere
and doesn't really need functions not related to the general fs interface.
Suggested-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NScott Branden <scott.branden@broadcom.com>
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Reviewed-by: NLuis Chamberlain <mcgrof@kernel.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NJames Morris <jamorris@linux.microsoft.com>
Link: https://lore.kernel.org/r/20200706232309.12010-2-scott.branden@broadcom.com
Link: https://lore.kernel.org/r/20201002173828.2099543-4-keescook@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

checkreqprot data member in selinux_state struct is accessed directly by
SELinux functions to get and set. This could cause unexpected read or
write access to this data member due to compiler optimizations and/or
compiler's reordering of access to this field.

Add helper functions to get and set checkreqprot data member in
selinux_state struct. These helper functions use READ_ONCE and
WRITE_ONCE macros to ensure atomic read or write of memory for
this data member.
Signed-off-by: NLakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Suggested-by: NPaul Moore <paul@paul-moore.com>
Acked-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Move the mutex used to synchronize policy changes (reloads and setting
of booleans) from selinux_fs_info to selinux_state and use it in
lockdep checks for rcu_dereference_protected() calls in the security
server functions.  This makes the dependency on the mutex explicit
in the code rather than relying on comments.
Signed-off-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Convert the policy read-write lock to RCU.  This is significantly
simplified by the earlier work to encapsulate the policy data
structures and refactor the policy load and boolean setting logic.
Move the latest_granting sequence number into the selinux_policy
structure so that it can be updated atomically with the policy.
Since removing the policy rwlock and moving latest_granting reduces
the selinux_ss structure to nothing more than a wrapper around the
selinux_policy pointer, get rid of the extra layer of indirection.

At present this change merely passes a hardcoded 1 to
rcu_dereference_check() in the cases where we know we do not need to
take rcu_read_lock(), with the preceding comment explaining why.
Alternatively we could pass fsi->mutex down from selinuxfs and
apply a lockdep check on it instead.

Based in part on earlier attempts to convert the policy rwlock
to RCU by Kaigai Kohei [1] and by Peter Enderborg [2].

[1] https://lore.kernel.org/selinux/6e2f9128-e191-ebb3-0e87-74bfccb0767f@tycho.nsa.gov/
[2] https://lore.kernel.org/selinux/20180530141104.28569-1-peter.enderborg@sony.com/Signed-off-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: NOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Drop a repeated word in comments.
{open, is, then}
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: selinux@vger.kernel.org
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org
[PM: fix subject line]
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

Currently SELinux denies attempts to remove the security.selinux xattr
always, even when permissive or no policy is loaded.  This was originally
motivated by the view that all files should be labeled, even if that label
is unlabeled_t, and we shouldn't permit files that were once labeled to
have their labels removed entirely.  This however prevents removing
SELinux xattrs in the case where one "disables" SELinux by not loading
a policy (e.g. a system where runtime disable is removed and selinux=0
was not specified).  Allow removing the xattr before SELinux is
initialized.  We could conceivably permit it even after initialization
if permissive, or introduce a separate permission check here.
Signed-off-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

This patch does for `getxattr` what commit 3e3e24b4 ("selinux: allow
labeling before policy is loaded") did for `setxattr`; it allows
querying the current SELinux label on disk before the policy is loaded.

One of the motivations described in that commit message also drives this
patch: for Fedora CoreOS (and eventually RHEL CoreOS), we want to be
able to move the root filesystem for example, from xfs to ext4 on RAID,
on first boot, at initrd time.[1]

Because such an operation works at the filesystem level, we need to be
able to read the SELinux labels first from the original root, and apply
them to the files of the new root. The previous commit enabled the
second part of this process; this commit enables the first part.

[1] https://github.com/coreos/fedora-coreos-tracker/issues/94Acked-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: NJonathan Lebon <jlebon@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Today security_bprm_set_creds has several implementations:
apparmor_bprm_set_creds, cap_bprm_set_creds, selinux_bprm_set_creds,
smack_bprm_set_creds, and tomoyo_bprm_set_creds.

Except for cap_bprm_set_creds they all test bprm->called_set_creds and
return immediately if it is true.  The function cap_bprm_set_creds
ignores bprm->calld_sed_creds entirely.

Create a new LSM hook security_bprm_creds_for_exec that is called just
before prepare_binprm in __do_execve_file, resulting in a LSM hook
that is called exactly once for the entire of exec.  Modify the bits
of security_bprm_set_creds that only want to be called once per exec
into security_bprm_creds_for_exec, leaving only cap_bprm_set_creds
behind.

Remove bprm->called_set_creds all of it's former users have been moved
to security_bprm_creds_for_exec.

Add or upate comments a appropriate to bring them up to date and
to reflect this change.

Link: https://lkml.kernel.org/r/87v9kszrzh.fsf_-_@x220.int.ebiederm.orgAcked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com> # For the LSM and Smack bits
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

Implement the watch_key security hook to make sure that a key grants the
caller View permission in order to set a watch on a key.

For the moment, the watch_devices security hook is left unimplemented as
it's not obvious what the object should be since the queue is global and
didn't previously exist.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Reviewed-by: NJames Morris <jamorris@linux.microsoft.com>

Since the meaning of combining the KEY_NEED_* constants is undefined, make
it so that you can't do that by turning them into an enum.

The enum is also given some extra values to represent special
circumstances, such as:

 (1) The '0' value is reserved and causes a warning to trap the parameter
     being unset.

 (2) The key is to be unlinked and we require no permissions on it, only
     the keyring, (this replaces the KEY_LOOKUP_FOR_UNLINK flag).

 (3) An override due to CAP_SYS_ADMIN.

 (4) An override due to an instantiation token being present.

 (5) The permissions check is being deferred to later key_permission()
     calls.

The extra values give the opportunity for LSMs to audit these situations.

[Note: This really needs overhauling so that lookup_user_key() tells
 key_task_permission() and the LSM what operation is being done and leaves
 it to those functions to decide how to map that onto the available
 permits.  However, I don't really want to make these change in the middle
 of the notifications patchset.]
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
cc: Paul Moore <paul@paul-moore.com>
cc: Stephen Smalley <stephen.smalley.work@gmail.com>
cc: Casey Schaufler <casey@schaufler-ca.com>
cc: keyrings@vger.kernel.org
cc: selinux@vger.kernel.org

Fix the SELinux netlink_send hook to properly handle multiple netlink
messages in a single sk_buff; each message is parsed and subject to
SELinux access control.  Prior to this patch, SELinux only inspected
the first message in the sk_buff.

Cc: stable@vger.kernel.org
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Reviewed-by: NStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Add Q_XQUOTAOFF, Q_XQUOTAON and Q_XSETQLIM to trigger filesystem quotamod
permission check.

Add Q_XGETQUOTA, Q_XGETQSTAT, Q_XGETQSTATV and Q_XGETNEXTQUOTA to trigger
filesystem quotaget permission check.
Signed-off-by: NRichard Haines <richard_c_haines@btinternet.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Add support for genfscon per-file labeling of bpffs files. This allows
for separate permissions for different pinned bpf objects, which may
be completely unrelated to each other.
Signed-off-by: NConnor O'Brien <connoro@google.com>
Signed-off-by: NSteven Moreland <smoreland@google.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Currently symlinks on kernel filesystems, like sysfs, are labeled on
creation with the parent filesystem root sid.

Allow symlinks to inherit the parent directory context, so fine-grained
kernfs labeling can be applied to symlinks too and checking contexts
doesn't complain about them.

For backward-compatibility this behavior is contained in a new policy
capability: genfs_seclabel_symlinks
Signed-off-by: NChristian Göttsche <cgzones@googlemail.com>
Acked-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

Deprecate setting the SELinux checkreqprot tunable to 1 via kernel
parameter or /sys/fs/selinux/checkreqprot.  Setting it to 0 is left
intact for compatibility since Android and some Linux distributions
do so for security and treat an inability to set it as a fatal error.
Eventually setting it to 0 will become a no-op and the kernel will
stop using checkreqprot's value internally altogether.

checkreqprot was originally introduced as a compatibility mechanism
for legacy userspace and the READ_IMPLIES_EXEC personality flag.
However, if set to 1, it weakens security by allowing mappings to be
made executable without authorization by policy.  The default value
for the SECURITY_SELINUX_CHECKREQPROT_VALUE config option was changed
from 1 to 0 in commit 2a35d196 ("selinux: change
CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE default") and both Android
and Linux distributions began explicitly setting
/sys/fs/selinux/checkreqprot to 0 some time ago.
Signed-off-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

It fits more naturally in selinux_state, since it reflects also global
state (the enforcing and policyload fields).
Signed-off-by: NOndrej Mosnacek <omosnace@redhat.com>
Reviewed-by: NStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NPaul Moore <paul@paul-moore.com>