Commit Graph

220 Commits (master)

Author SHA1 Message Date
Paul Moore cdc028812f lsm: introduce an initcall mechanism into the LSM framework
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>
2025-10-22 19:24:24 -04:00
Paul Moore 291271e691 lsm: cleanup the LSM blob size code
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>
2025-10-22 19:24:21 -04:00
Paul Moore 935d508d4d lsm: get rid of the lsm_names list and do some cleanup
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>
2025-10-22 19:24:19 -04:00
Paul Moore 9f9dc69e06 lsm: replace the name field with a pointer to the lsm_id struct
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>
2025-10-22 19:24:18 -04:00
Paul Moore 67a4b6a89b lsm: split the init code out into lsm_init.c
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>
2025-10-22 19:24:16 -04:00
Blaise Boscaccy 5816bf4273 lsm,selinux: Add LSM blob support for BPF objects
This patch introduces LSM blob support for BPF maps, programs, and
tokens to enable LSM stacking and multiplexing of LSM modules that
govern BPF objects. Additionally, the existing BPF hooks used by
SELinux have been updated to utilize the new blob infrastructure,
removing the assumption of exclusive ownership of the security
pointer.

Signed-off-by: Blaise Boscaccy <bboscaccy@linux.microsoft.com>
[PM: dropped local variable init, style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-08-11 17:56:09 -04:00
KP Singh 417c5643cd lsm: replace indirect LSM hook calls with static calls
LSM hooks are currently invoked from a linked list as indirect calls
which are invoked using retpolines as a mitigation for speculative
attacks (Branch History / Target injection) and add extra overhead which
is especially bad in kernel hot paths:

security_file_ioctl:
   0xff...0320 <+0>:	endbr64
   0xff...0324 <+4>:	push   %rbp
   0xff...0325 <+5>:	push   %r15
   0xff...0327 <+7>:	push   %r14
   0xff...0329 <+9>:	push   %rbx
   0xff...032a <+10>:	mov    %rdx,%rbx
   0xff...032d <+13>:	mov    %esi,%ebp
   0xff...032f <+15>:	mov    %rdi,%r14
   0xff...0332 <+18>:	mov    $0xff...7030,%r15
   0xff...0339 <+25>:	mov    (%r15),%r15
   0xff...033c <+28>:	test   %r15,%r15
   0xff...033f <+31>:	je     0xff...0358 <security_file_ioctl+56>
   0xff...0341 <+33>:	mov    0x18(%r15),%r11
   0xff...0345 <+37>:	mov    %r14,%rdi
   0xff...0348 <+40>:	mov    %ebp,%esi
   0xff...034a <+42>:	mov    %rbx,%rdx

   0xff...034d <+45>:	call   0xff...2e0 <__x86_indirect_thunk_array+352>
   			       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    Indirect calls that use retpolines leading to overhead, not just due
    to extra instruction but also branch misses.

   0xff...0352 <+50>:	test   %eax,%eax
   0xff...0354 <+52>:	je     0xff...0339 <security_file_ioctl+25>
   0xff...0356 <+54>:	jmp    0xff...035a <security_file_ioctl+58>
   0xff...0358 <+56>:	xor    %eax,%eax
   0xff...035a <+58>:	pop    %rbx
   0xff...035b <+59>:	pop    %r14
   0xff...035d <+61>:	pop    %r15
   0xff...035f <+63>:	pop    %rbp
   0xff...0360 <+64>:	jmp    0xff...47c4 <__x86_return_thunk>

The indirect calls are not really needed as one knows the addresses of
enabled LSM callbacks at boot time and only the order can possibly
change at boot time with the lsm= kernel command line parameter.

An array of static calls is defined per LSM hook and the static calls
are updated at boot time once the order has been determined.

With the hook now exposed as a static call, one can see that the
retpolines are no longer there and the LSM callbacks are invoked
directly:

security_file_ioctl:
   0xff...0ca0 <+0>:	endbr64
   0xff...0ca4 <+4>:	nopl   0x0(%rax,%rax,1)
   0xff...0ca9 <+9>:	push   %rbp
   0xff...0caa <+10>:	push   %r14
   0xff...0cac <+12>:	push   %rbx
   0xff...0cad <+13>:	mov    %rdx,%rbx
   0xff...0cb0 <+16>:	mov    %esi,%ebp
   0xff...0cb2 <+18>:	mov    %rdi,%r14
   0xff...0cb5 <+21>:	jmp    0xff...0cc7 <security_file_ioctl+39>
  			       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   Static key enabled for SELinux

   0xffffffff818f0cb7 <+23>:	jmp    0xff...0cde <security_file_ioctl+62>
   				^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

   Static key enabled for BPF LSM. This is something that is changed to
   default to false to avoid the existing side effect issues of BPF LSM
   [1] in a subsequent patch.

   0xff...0cb9 <+25>:	xor    %eax,%eax
   0xff...0cbb <+27>:	xchg   %ax,%ax
   0xff...0cbd <+29>:	pop    %rbx
   0xff...0cbe <+30>:	pop    %r14
   0xff...0cc0 <+32>:	pop    %rbp
   0xff...0cc1 <+33>:	cs jmp 0xff...0000 <__x86_return_thunk>
   0xff...0cc7 <+39>:	endbr64
   0xff...0ccb <+43>:	mov    %r14,%rdi
   0xff...0cce <+46>:	mov    %ebp,%esi
   0xff...0cd0 <+48>:	mov    %rbx,%rdx
   0xff...0cd3 <+51>:	call   0xff...3230 <selinux_file_ioctl>
   			       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   Direct call to SELinux.

   0xff...0cd8 <+56>:	test   %eax,%eax
   0xff...0cda <+58>:	jne    0xff...0cbd <security_file_ioctl+29>
   0xff...0cdc <+60>:	jmp    0xff...0cb7 <security_file_ioctl+23>
   0xff...0cde <+62>:	endbr64
   0xff...0ce2 <+66>:	mov    %r14,%rdi
   0xff...0ce5 <+69>:	mov    %ebp,%esi
   0xff...0ce7 <+71>:	mov    %rbx,%rdx
   0xff...0cea <+74>:	call   0xff...e220 <bpf_lsm_file_ioctl>
   			       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   Direct call to BPF LSM.

   0xff...0cef <+79>:	test   %eax,%eax
   0xff...0cf1 <+81>:	jne    0xff...0cbd <security_file_ioctl+29>
   0xff...0cf3 <+83>:	jmp    0xff...0cb9 <security_file_ioctl+25>
   0xff...0cf5 <+85>:	endbr64
   0xff...0cf9 <+89>:	mov    %r14,%rdi
   0xff...0cfc <+92>:	mov    %ebp,%esi
   0xff...0cfe <+94>:	mov    %rbx,%rdx
   0xff...0d01 <+97>:	pop    %rbx
   0xff...0d02 <+98>:	pop    %r14
   0xff...0d04 <+100>:	pop    %rbp
   0xff...0d05 <+101>:	ret
   0xff...0d06 <+102>:	int3
   0xff...0d07 <+103>:	int3
   0xff...0d08 <+104>:	int3
   0xff...0d09 <+105>:	int3

While this patch uses static_branch_unlikely indicating that an LSM hook
is likely to be not present. In most cases this is still a better choice
as even when an LSM with one hook is added, empty slots are created for
all LSM hooks (especially when many LSMs that do not initialize most
hooks are present on the system).

There are some hooks that don't use the call_int_hook or
call_void_hook. These hooks are updated to use a new macro called
lsm_for_each_hook where the lsm_callback is directly invoked as an
indirect call.

Below are results of the relevant Unixbench system benchmarks with BPF LSM
and SELinux enabled with default policies enabled with and without these
patches.

Benchmark                                          Delta(%): (+ is better)
==========================================================================
Execl Throughput                                             +1.9356
File Write 1024 bufsize 2000 maxblocks                       +6.5953
Pipe Throughput                                              +9.5499
Pipe-based Context Switching                                 +3.0209
Process Creation                                             +2.3246
Shell Scripts (1 concurrent)                                 +1.4975
System Call Overhead                                         +2.7815
System Benchmarks Index Score (Partial Only):                +3.4859

In the best case, some syscalls like eventfd_create benefitted to about
~10%.

Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-22 12:24:10 -04:00
Deven Bowers b55d26bd18 block,lsm: add LSM blob and new LSM hooks for block devices
This patch introduces a new LSM blob to the block_device structure,
enabling the security subsystem to store security-sensitive data related
to block devices. Currently, for a device mapper's mapped device containing
a dm-verity target, critical security information such as the roothash and
its signing state are not readily accessible. Specifically, while the
dm-verity volume creation process passes the dm-verity roothash and its
signature from userspace to the kernel, the roothash is stored privately
within the dm-verity target, and its signature is discarded
post-verification. This makes it extremely hard for the security subsystem
to utilize these data.

With the addition of the LSM blob to the block_device structure, the
security subsystem can now retain and manage important security metadata
such as the roothash and the signing state of a dm-verity by storing them
inside the blob. Access decisions can then be based on these stored data.

The implementation follows the same approach used for security blobs in
other structures like struct file, struct inode, and struct superblock.
The initialization of the security blob occurs after the creation of the
struct block_device, performed by the security subsystem. Similarly, the
security blob is freed by the security subsystem before the struct
block_device is deallocated or freed.

This patch also introduces a new hook security_bdev_setintegrity() to save
block device's integrity data to the new LSM blob. For example, for
dm-verity, it can use this hook to expose its roothash and signing state
to LSMs, then LSMs can save these data into the LSM blob.

Please note that the new hook should be invoked every time the security
information is updated to keep these data current. For example, in
dm-verity, if the mapping table is reloaded and configured to use a
different dm-verity target with a new roothash and signing information,
the previously stored data in the LSM blob will become obsolete. It is
crucial to re-invoke the hook to refresh these data and ensure they are up
to date. This necessity arises from the design of device-mapper, where a
device-mapper device is first created, and then targets are subsequently
loaded into it. These targets can be modified multiple times during the
device's lifetime. Therefore, while the LSM blob is allocated during the
creation of the block device, its actual contents are not initialized at
this stage and can change substantially over time. This includes
alterations from data that the LSM 'trusts' to those it does not, making
it essential to handle these changes correctly. Failure to address this
dynamic aspect could potentially allow for bypassing LSM checks.

Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: merge fuzz, subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-20 14:02:33 -04:00
Paul Moore 711f5c5ce6 lsm: cleanup lsm_hooks.h
Some cleanup and style corrections for lsm_hooks.h.

 * Drop the lsm_inode_alloc() extern declaration, it is not needed.
 * Relocate lsm_get_xattr_slot() and extern variables in the file to
   improve grouping of related objects.
 * Don't use tabs to needlessly align structure fields.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-08-12 14:49:37 -04:00
Casey Schaufler 61a1dcdceb lsm: infrastructure management of the perf_event security blob
Move management of the perf_event->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.  There are no longer any modules that require the perf_event_free()
hook.  The hook definition has been removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:52 -04:00
Casey Schaufler 66de33a0bb lsm: infrastructure management of the infiniband blob
Move management of the infiniband security blob out of the individual
security modules and into the LSM infrastructure.  The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the ib_free() hook.
The hook definition has been removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:52 -04:00
Casey Schaufler a39c0f77db lsm: infrastructure management of the dev_tun blob
Move management of the dev_tun security blob out of the individual
security modules and into the LSM infrastructure.  The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the dev_tun_free hook.
The hook definition has been removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:51 -04:00
Casey Schaufler 5f8d28f6d7 lsm: infrastructure management of the key security blob
Move management of the key->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.  There are
no existing modules that require a key_free hook, so the call to it and
the definition for it have been removed.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:51 -04:00
Casey Schaufler 2aff9d20d5 lsm: infrastructure management of the sock security
Move management of the sock->sk_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.

Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-29 16:54:50 -04:00
Casey Schaufler a04a119808 LSM: syscalls for current process attributes
Create a system call lsm_get_self_attr() to provide the security
module maintained attributes of the current process.
Create a system call lsm_set_self_attr() to set a security
module maintained attribute of the current process.
Historically these attributes have been exposed to user space via
entries in procfs under /proc/self/attr.

The attribute value is provided in a lsm_ctx structure. The structure
identifies the size of the attribute, and the attribute value. The format
of the attribute value is defined by the security module. A flags field
is included for LSM specific information. It is currently unused and must
be 0. The total size of the data, including the lsm_ctx structure and any
padding, is maintained as well.

struct lsm_ctx {
        __u64 id;
        __u64 flags;
        __u64 len;
        __u64 ctx_len;
        __u8 ctx[];
};

Two new LSM hooks are used to interface with the LSMs.
security_getselfattr() collects the lsm_ctx values from the
LSMs that support the hook, accounting for space requirements.
security_setselfattr() identifies which LSM the attribute is
intended for and passes it along.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
Casey Schaufler f3b8788cde LSM: Identify modules by more than name
Create a struct lsm_id to contain identifying information about Linux
Security Modules (LSMs). At inception this contains the name of the
module and an identifier associated with the security module.  Change
the security_add_hooks() interface to use this structure.  Change the
individual modules to maintain their own struct lsm_id and pass it to
security_add_hooks().

The values are for LSM identifiers are defined in a new UAPI
header file linux/lsm.h. Each existing LSM has been updated to
include it's LSMID in the lsm_id.

The LSM ID values are sequential, with the oldest module
LSM_ID_CAPABILITY being the lowest value and the existing modules
numbered in the order they were included in the main line kernel.
This is an arbitrary convention for assigning the values, but
none better presents itself. The value 0 is defined as being invalid.
The values 1-99 are reserved for any special case uses which may
arise in the future. This may include attributes of the LSM
infrastructure itself, possibly related to namespacing or network
attribute management. A special range is identified for such attributes
to help reduce confusion for developers unfamiliar with LSMs.

LSM attribute values are defined for the attributes presented by
modules that are available today. As with the LSM IDs, The value 0
is defined as being invalid. The values 1-99 are reserved for any
special case uses which may arise in the future.

Cc: linux-security-module <linux-security-module@vger.kernel.org>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Mickael Salaun <mic@digikod.net>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Nacked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[PM: forward ported beyond v6.6 due merge window changes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
Roberto Sassu 6bcdfd2cac security: Allow all LSMs to provide xattrs for inode_init_security hook
Currently, the LSM infrastructure supports only one LSM providing an xattr
and EVM calculating the HMAC on that xattr, plus other inode metadata.

Allow all LSMs to provide one or multiple xattrs, by extending the security
blob reservation mechanism. Introduce the new lbs_xattr_count field of the
lsm_blob_sizes structure, so that each LSM can specify how many xattrs it
needs, and the LSM infrastructure knows how many xattr slots it should
allocate.

Modify the inode_init_security hook definition, by passing the full
xattr array allocated in security_inode_init_security(), and the current
number of xattr slots in that array filled by LSMs. The first parameter
would allow EVM to access and calculate the HMAC on xattrs supplied by
other LSMs, the second to not leave gaps in the xattr array, when an LSM
requested but did not provide xattrs (e.g. if it is not initialized).

Introduce lsm_get_xattr_slot(), which LSMs can call as many times as the
number specified in the lbs_xattr_count field of the lsm_blob_sizes
structure. During each call, lsm_get_xattr_slot() increments the number of
filled xattrs, so that at the next invocation it returns the next xattr
slot to fill.

Cleanup security_inode_init_security(). Unify the !initxattrs and
initxattrs case by simply not allocating the new_xattrs array in the
former. Update the documentation to reflect the changes, and fix the
description of the xattr name, as it is not allocated anymore.

Adapt both SELinux and Smack to use the new definition of the
inode_init_security hook, and to call lsm_get_xattr_slot() to obtain and
fill the reserved slots in the xattr array.

Move the xattr->name assignment after the xattr->value one, so that it is
done only in case of successful memory allocation.

Finally, change the default return value of the inode_init_security hook
from zero to -EOPNOTSUPP, so that BPF LSM correctly follows the hook
conventions.

Reported-by: Nicolas Bouchinet <nicolas.bouchinet@clip-os.org>
Link: https://lore.kernel.org/linux-integrity/Y1FTSIo+1x+4X0LS@archlinux/
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: minor comment and variable tweaks, approved by RS]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-07-10 13:59:37 -04:00
Linus Torvalds 08e30833f8 lsm/stable-6.4 PR 20230420
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Merge tag 'lsm-pr-20230420' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Move the LSM hook comment blocks into security/security.c

   For many years the LSM hook comment blocks were located in a very odd
   place, include/linux/lsm_hooks.h, where they lived on their own,
   disconnected from both the function prototypes and definitions.

   In keeping with current kernel conventions, this moves all of these
   comment blocks to the top of the function definitions, transforming
   them into the kdoc format in the process. This should make it much
   easier to maintain these comments, which are the main source of LSM
   hook documentation.

   For the most part the comment contents were left as-is, although some
   glaring errors were corrected. Expect additional edits in the future
   as we slowly update and correct the comment blocks.

   This is the bulk of the diffstat.

 - Introduce LSM_ORDER_LAST

   Similar to how LSM_ORDER_FIRST is used to specify LSMs which should
   be ordered before "normal" LSMs, the LSM_ORDER_LAST is used to
   specify LSMs which should be ordered after "normal" LSMs.

   This is one of the prerequisites for transitioning IMA/EVM to a
   proper LSM.

 - Remove the security_old_inode_init_security() hook

   The security_old_inode_init_security() LSM hook only allows for a
   single xattr which is problematic both for LSM stacking and the
   IMA/EVM-as-a-LSM effort. This finishes the conversion over to the
   security_inode_init_security() hook and removes the single-xattr LSM
   hook.

 - Fix a reiserfs problem with security xattrs

   During the security_old_inode_init_security() removal work it became
   clear that reiserfs wasn't handling security xattrs properly so we
   fixed it.

* tag 'lsm-pr-20230420' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (32 commits)
  reiserfs: Add security prefix to xattr name in reiserfs_security_write()
  security: Remove security_old_inode_init_security()
  ocfs2: Switch to security_inode_init_security()
  reiserfs: Switch to security_inode_init_security()
  security: Remove integrity from the LSM list in Kconfig
  Revert "integrity: double check iint_cache was initialized"
  security: Introduce LSM_ORDER_LAST and set it for the integrity LSM
  device_cgroup: Fix typo in devcgroup_css_alloc description
  lsm: fix a badly named parameter in security_get_getsecurity()
  lsm: fix doc warnings in the LSM hook comments
  lsm: styling fixes to security/security.c
  lsm: move the remaining LSM hook comments to security/security.c
  lsm: move the io_uring hook comments to security/security.c
  lsm: move the perf hook comments to security/security.c
  lsm: move the bpf hook comments to security/security.c
  lsm: move the audit hook comments to security/security.c
  lsm: move the binder hook comments to security/security.c
  lsm: move the sysv hook comments to security/security.c
  lsm: move the key hook comments to security/security.c
  lsm: move the xfrm hook comments to security/security.c
  ...
2023-04-24 11:21:50 -07:00
Lukas Bulwahn 3401333188 selinux: clean up dead code after removing runtime disable
Commit f22f9aaf6c ("selinux: remove the runtime disable functionality")
removes the config SECURITY_SELINUX_DISABLE. This results in some dead code
in lsm_hooks.h.

Remove this dead code.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-24 16:15:42 -04:00
Paul Moore f22f9aaf6c selinux: remove the runtime disable functionality
After working with the larger SELinux-based distros for several
years, we're finally at a place where we can disable the SELinux
runtime disable functionality.  The existing kernel deprecation
notice explains the functionality and why we want to remove it:

  The selinuxfs "disable" node allows SELinux to be disabled at
  runtime prior to a policy being loaded into the kernel.  If
  disabled via this mechanism, SELinux will remain disabled until
  the system is rebooted.

  The preferred method of disabling SELinux is via the "selinux=0"
  boot parameter, but the selinuxfs "disable" node was created to
  make it easier for systems with primitive bootloaders that did not
  allow for easy modification of the kernel command line.
  Unfortunately, allowing for SELinux to be disabled at runtime makes
  it difficult to secure the kernel's LSM hooks using the
  "__ro_after_init" feature.

It is that last sentence, mentioning the '__ro_after_init' hardening,
which is the real motivation for this change, and if you look at the
diffstat you'll see that the impact of this patch reaches across all
the different LSMs, helping prevent tampering at the LSM hook level.

From a SELinux perspective, it is important to note that if you
continue to disable SELinux via "/etc/selinux/config" it may appear
that SELinux is disabled, but it is simply in an uninitialized state.
If you load a policy with `load_policy -i`, you will see SELinux
come alive just as if you had loaded the policy during early-boot.

It is also worth noting that the "/sys/fs/selinux/disable" file is
always writable now, regardless of the Kconfig settings, but writing
to the file has no effect on the system, other than to display an
error on the console if a non-zero/true value is written.

Finally, in the several years where we have been working on
deprecating this functionality, there has only been one instance of
someone mentioning any user visible breakage.  In this particular
case it was an individual's kernel test system, and the workaround
documented in the deprecation notice ("selinux=0" on the kernel
command line) resolved the issue without problem.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-20 12:34:23 -04:00
Roberto Sassu 42994ee3cd security: Introduce LSM_ORDER_LAST and set it for the integrity LSM
Introduce LSM_ORDER_LAST, to satisfy the requirement of LSMs needing to be
last, e.g. the 'integrity' LSM, without changing the kernel command line or
configuration.

Also, set this order for the 'integrity' LSM. While not enforced, this is
the only LSM expected to use it.

Similarly to LSM_ORDER_FIRST, LSMs with LSM_ORDER_LAST are always enabled
and put at the end of the LSM list, if selected in the kernel
configuration. Setting one of these orders alone, does not cause the LSMs
to be selected and compiled built-in in the kernel.

Finally, for LSM_ORDER_MUTABLE LSMs, set the found variable to true if an
LSM is found, regardless of its order. In this way, the kernel would not
wrongly report that the LSM is not built-in in the kernel if its order is
LSM_ORDER_LAST.

Fixes: 79f7865d84 ("LSM: Introduce "lsm=" for boottime LSM selection")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-10 18:31:35 -05:00
Paul Moore e261301c85 lsm: move the remaining LSM hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 1cd2aca64a lsm: move the io_uring hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 452b670c72 lsm: move the perf hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 55e853201a lsm: move the bpf hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore b14faf9c94 lsm: move the audit hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 1427ddbe5c lsm: move the binder hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 43fad28218 lsm: move the sysv hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore ecc419a445 lsm: move the key hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 742b99456e lsm: move the xfrm hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore ac318aed54 lsm: move the Infiniband hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 4a49f592e9 lsm: move the SCTP hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 6b6bbe8c02 lsm: move the socket hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 2c2442fd46 lsm: move the AF_UNIX hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 2bcf51bf2f lsm: move the netlink hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 130c53bfee lsm: move the task hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore a0fd6480de lsm: move the file hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 9348944b77 lsm: move the kernfs hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 916e32584d lsm: move the inode hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 08526a902c lsm: move the filesystem hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 36819f1855 lsm: move the fs_context hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Paul Moore 1661372c91 lsm: move the program execution hook comments to security/security.c
This patch relocates the LSM hook function comments to the function
definitions, in keeping with the current kernel conventions.  This
should make the hook descriptions more easily discoverable and easier
to maintain.

While formatting changes have been done to better fit the kernel-doc
style, content changes have been kept to a minimum and limited to
text which was obviously incorrect and/or outdated.  It is expected
the future patches will improve the quality of the function header
comments.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-06 13:41:07 -05:00
Christian Brauner 39f60c1cce
fs: port xattr to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00
Linus Torvalds c76ff350bd lsm/stable-6.2 PR 20221212
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Merge tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improve the error handling in the device cgroup such that memory
   allocation failures when updating the access policy do not
   potentially alter the policy.

 - Some minor fixes to reiserfs to ensure that it properly releases
   LSM-related xattr values.

 - Update the security_socket_getpeersec_stream() LSM hook to take
   sockptr_t values.

   Previously the net/BPF folks updated the getsockopt code in the
   network stack to leverage the sockptr_t type to make it easier to
   pass both kernel and __user pointers, but unfortunately when they did
   so they didn't convert the LSM hook.

   While there was/is no immediate risk by not converting the LSM hook,
   it seems like this is a mistake waiting to happen so this patch
   proactively does the LSM hook conversion.

 - Convert vfs_getxattr_alloc() to return an int instead of a ssize_t
   and cleanup the callers. Internally the function was never going to
   return anything larger than an int and the callers were doing some
   very odd things casting the return value; this patch fixes all that
   and helps bring a bit of sanity to vfs_getxattr_alloc() and its
   callers.

 - More verbose, and helpful, LSM debug output when the system is booted
   with "lsm.debug" on the command line. There are examples in the
   commit description, but the quick summary is that this patch provides
   better information about which LSMs are enabled and the ordering in
   which they are processed.

 - General comment and kernel-doc fixes and cleanups.

* tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: Fix description of fs_context_parse_param
  lsm: Add/fix return values in lsm_hooks.h and fix formatting
  lsm: Clarify documentation of vm_enough_memory hook
  reiserfs: Add missing calls to reiserfs_security_free()
  lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths
  device_cgroup: Roll back to original exceptions after copy failure
  LSM: Better reporting of actual LSMs at boot
  lsm: make security_socket_getpeersec_stream() sockptr_t safe
  audit: Fix some kernel-doc warnings
  lsm: remove obsoleted comments for security hooks
  fs: edit a comment made in bad taste
2022-12-13 09:47:48 -08:00
Linus Torvalds 299e2b1967 Landlock updates for v6.2-rc1
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Merge tag 'landlock-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux

Pull landlock updates from Mickaël Salaün:
 "This adds file truncation support to Landlock, contributed by Günther
  Noack. As described by Günther [1], the goal of these patches is to
  work towards a more complete coverage of file system operations that
  are restrictable with Landlock.

  The known set of currently unsupported file system operations in
  Landlock is described at [2]. Out of the operations listed there,
  truncate is the only one that modifies file contents, so these patches
  should make it possible to prevent the direct modification of file
  contents with Landlock.

  The new LANDLOCK_ACCESS_FS_TRUNCATE access right covers both the
  truncate(2) and ftruncate(2) families of syscalls, as well as open(2)
  with the O_TRUNC flag. This includes usages of creat() in the case
  where existing regular files are overwritten.

  Additionally, this introduces a new Landlock security blob associated
  with opened files, to track the available Landlock access rights at
  the time of opening the file. This is in line with Unix's general
  approach of checking the read and write permissions during open(), and
  associating this previously checked authorization with the opened
  file. An ongoing patch documents this use case [3].

  In order to treat truncate(2) and ftruncate(2) calls differently in an
  LSM hook, we split apart the existing security_path_truncate hook into
  security_path_truncate (for truncation by path) and
  security_file_truncate (for truncation of previously opened files)"

Link: https://lore.kernel.org/r/20221018182216.301684-1-gnoack3000@gmail.com [1]
Link: https://www.kernel.org/doc/html/v6.1/userspace-api/landlock.html#filesystem-flags [2]
Link: https://lore.kernel.org/r/20221209193813.972012-1-mic@digikod.net [3]

* tag 'landlock-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux:
  samples/landlock: Document best-effort approach for LANDLOCK_ACCESS_FS_REFER
  landlock: Document Landlock's file truncation support
  samples/landlock: Extend sample tool to support LANDLOCK_ACCESS_FS_TRUNCATE
  selftests/landlock: Test ftruncate on FDs created by memfd_create(2)
  selftests/landlock: Test FD passing from restricted to unrestricted processes
  selftests/landlock: Locally define __maybe_unused
  selftests/landlock: Test open() and ftruncate() in multiple scenarios
  selftests/landlock: Test file truncation support
  landlock: Support file truncation
  landlock: Document init_layer_masks() helper
  landlock: Refactor check_access_path_dual() into is_access_to_paths_allowed()
  security: Create file_truncate hook from path_truncate hook
2022-12-13 09:14:50 -08:00
Roberto Sassu 577cc1434e lsm: Fix description of fs_context_parse_param
The fs_context_parse_param hook already has a description, which seems the
right one according to the code.

Fixes: 8eb687bc80 ("lsm: Add/fix return values in lsm_hooks.h and fix formatting")
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-12-09 12:22:56 -05:00
Roberto Sassu 8eb687bc80 lsm: Add/fix return values in lsm_hooks.h and fix formatting
Ensure that for non-void LSM hooks there is a description of the return
values.

Also, replace spaces with tab for indentation, remove empty lines between
the hook description and the list of parameters, adjust semicolons and add
the period at the end of the parameter description.

Finally, move the description of gfp parameter of the
xfrm_policy_alloc_security hook together with the others.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
[PM: /replaces./replaced./]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-12-06 19:16:58 -05:00
Roberto Sassu 361dd63ed5 lsm: Clarify documentation of vm_enough_memory hook
include/linux/lsm_hooks.h reports the result of the LSM infrastructure to
the callers, not what LSMs should return to the LSM infrastructure.

Clarify that and add that if all LSMs return a positive value
__vm_enough_memory() will be called with cap_sys_admin set. If at least one
LSM returns 0 or negative, it will be called with cap_sys_admin cleared.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-12-06 17:11:37 -05:00
Paul Moore b10b9c342f lsm: make security_socket_getpeersec_stream() sockptr_t safe
Commit 4ff09db1b7 ("bpf: net: Change sk_getsockopt() to take the
sockptr_t argument") made it possible to call sk_getsockopt()
with both user and kernel address space buffers through the use of
the sockptr_t type.  Unfortunately at the time of conversion the
security_socket_getpeersec_stream() LSM hook was written to only
accept userspace buffers, and in a desire to avoid having to change
the LSM hook the commit author simply passed the sockptr_t's
userspace buffer pointer.  Since the only sk_getsockopt() callers
at the time of conversion which used kernel sockptr_t buffers did
not allow SO_PEERSEC, and hence the
security_socket_getpeersec_stream() hook, this was acceptable but
also very fragile as future changes presented the possibility of
silently passing kernel space pointers to the LSM hook.

There are several ways to protect against this, including careful
code review of future commits, but since relying on code review to
catch bugs is a recipe for disaster and the upstream eBPF maintainer
is "strongly against defensive programming", this patch updates the
LSM hook, and all of the implementations to support sockptr_t and
safely handle both user and kernel space buffers.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-11-04 23:25:30 -04:00
Gaosheng Cui 3437d67a8d lsm: remove obsoleted comments for security hooks
Remove the following obsoleted comments for security hooks:

1. sb_copy_data, the hook function has been removed since
commit 5b40023911 ("LSM: turn sb_eat_lsm_opts() into a method").

2. sb_parse_opts_str, the hook function has been removed since
commit 757cbe597f ("LSM: new method: ->sb_add_mnt_opt()").

They are obsoleted comments, so remove them.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subj line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-10-25 19:57:47 -04:00