Stacked filesystems such as overlayfs do not currently provide the
necessary mechanisms for LSMs to properly enforce access controls on the
mmap() and mprotect() operations. In order to resolve this gap, a LSM
security blob is being added to the backing_file struct and the following
new LSM hooks are being created:
security_backing_file_alloc()
security_backing_file_free()
security_mmap_backing_file()
The first two hooks are to manage the lifecycle of the LSM security blob
in the backing_file struct, while the third provides a new mmap() access
control point for the underlying backing file. It is also expected that
LSMs will likely want to update their security_file_mprotect() callback
to address issues with their mprotect() controls, but that does not
require a change to the security_file_mprotect() LSM hook.
There are a three other small changes to support these new LSM hooks:
* Pass the user file associated with a backing file down to
alloc_empty_backing_file() so it can be included in the
security_backing_file_alloc() hook.
* Add getter and setter functions for the backing_file struct LSM blob
as the backing_file struct remains private to fs/file_table.c.
* Constify the file struct field in the LSM common_audit_data struct to
better support LSMs that need to pass a const file struct pointer into
the common LSM audit code.
Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL()
and supplying a fixup.
Cc: stable@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-unionfs@vger.kernel.org
Cc: linux-erofs@lists.ozlabs.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
While reworking the LSM initialization code the
/proc/sys/vm/mmap_min_addr handler was inadvertently caught up in the
change and the procfs entry wasn't setup when CONFIG_SECURITY was not
selected at kernel build time. This patch restores the previous behavior
and ensures that the procfs entry is setup regardless of the
CONFIG_SECURITY state.
Future work will improve upon this, likely by moving the procfs handler
into the mm subsystem, but this patch should resolve the immediate
regression.
Fixes: 4ab5efcc28 ("lsm: consolidate all of the LSM framework initcalls")
Reported-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Tested-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
We need to directly allocate the cred's LSM state for the initial task
when we initialize the LSM framework. Unfortunately, this results in a
RCU related type mismatch, use the unrcu_pointer() macro to handle this
a bit more elegantly.
The explicit type casting still remains as we need to work around the
constification of current->cred in this particular case.
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The LSM framework itself registers a small number of initcalls, this
patch converts these initcalls into the new initcall mechanism.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Currently the individual LSMs register their own initcalls, and while
this should be harmless, it can be wasteful in the case where a LSM
is disabled at boot as the initcall will still be executed. This
patch introduces support for managing the initcalls in the LSM
framework, and future patches will convert the existing LSMs over to
this new mechanism.
Only initcall types which are used by the current in-tree LSMs are
supported, additional initcall types can easily be added in the future
if needed.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move away from an init specific init_debug() macro to a more general
lsm_pr()/lsm_pr_cont()/lsm_pr_dbg() set of macros that are available
both before and after init. In the process we do a number of minor
changes to improve the LSM initialization output and cleanup the code
somewhat.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Add function header comments for lsm_static_call_init() and
early_security_init(), tweak the existing comment block for
security_add_hooks().
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
With only security_init() calling lsm_init_ordered, it makes little
sense to keep lsm_init_ordered() as a standalone function. Fold
lsm_init_ordered() into security_init().
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Rename initialize_lsm() to be more consistent with the rest of the LSM
initialization changes and rework the function itself to better fit
with the "exit on fail" coding pattern.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Convert the lsm_blob_size fields to unsigned integers as there is no
current need for them to be negative, change "lsm_set_blob_size()" to
"lsm_blob_size_update()" to better reflect reality, and perform some
other minor cleanups to the associated code.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Rename ordered_lsm_parse() to lsm_order_parse() for the sake of
consistency with the other LSM initialization routines, and also
do some minor rework of the function. Aside from some minor style
decisions, the majority of the rework involved shuffling the order
of the LSM_FLAG_LEGACY and LSM_ORDER_FIRST code so that the
LSM_FLAG_LEGACY checks are handled first; it is important to note
that this doesn't affect the order in which the LSMs are registered.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Rename append_ordered_lsm() to lsm_order_append() to better match
convention and do some rework. The rework includes moving the
LSM_FLAG_EXCLUSIVE logic from lsm_prepare() to lsm_order_append()
in order to consolidate the individual LSM append/activation code,
and adding logic to skip appending explicitly disabled LSMs to the
active LSM list.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
In addition to style changes, rename set_enabled() to lsm_enabled_set()
and is_enabled() to lsm_is_enabled() to better fit within the LSM
initialization code.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The LSM currently has a lot of code to maintain a list of the currently
active LSMs in a human readable string, with the only user being the
"/sys/kernel/security/lsm" code. Let's drop all of that code and
generate the string on first use and then cache it for subsequent use.
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move the LSM active count and lsm_id list declarations out of a header
that is visible across the kernel and into a header that is limited to
the LSM framework. This not only helps keep the include/linux headers
smaller and cleaner, it helps prevent misuse of these variables.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Rename the builtin_lsm_order variable to lsm_order_builtin,
chosen_lsm_order to lsm_order_cmdline, chosen_major_lsm to
lsm_order_legacy, ordered_lsms[] to lsm_order[], and exclusive
to lsm_exclusive.
This patch also renames the associated kernel command line parsing
functions and adds some basic function comment blocks. The parsing
function choose_major_lsm() was renamed to lsm_choose_security(),
choose_lsm_order() to lsm_choose_lsm(), and enable_debug() to
lsm_debug_enable().
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Reduce the duplication between the lsm_id struct and the DEFINE_LSM()
definition by linking the lsm_id struct directly into the individual
LSM's DEFINE_LSM() instance.
Linking the lsm_id into the LSM definition also allows us to simplify
the security_add_hooks() function by removing the code which populates
the lsm_idlist[] array and moving it into the normal LSM startup code
where the LSM list is parsed and the individual LSMs are enabled,
making for a cleaner implementation with less overhead at boot.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The new name more closely fits the rest of the naming scheme in
security/lsm_init.c. This patch also adds a trivial comment block to
the top of the function.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
With only one caller of lsm_early_cred() and lsm_early_task(), insert
the functions' code directly into the caller and ger rid of the two
functions.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
There are three common for loop patterns in the LSM initialization code
to loop through the ordered LSM list and the registered "early" LSMs.
This patch implements these loop patterns as macros to help simplify the
code and reduce the chance for errors.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Continue to pull code out of security/security.c to help improve
readability by pulling all of the LSM framework initialization
code out into a new file.
No code changes.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
