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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
Christian Brauner 72b3897e78
security: add get, remove and set acl hook
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

So far posix acls were passed as a void blob to the security and
integrity modules. Some of them like evm then proceed to interpret the
void pointer and convert it into the kernel internal struct posix acl
representation to perform their integrity checking magic. This is
obviously pretty problematic as that requires knowledge that only the
vfs is guaranteed to have and has lead to various bugs. Add a proper
security hook for setting posix acls and pass down the posix acls in
their appropriate vfs format instead of hacking it through a void
pointer stored in the uapi format.

In the next patches we implement the hooks for the few security modules
that do actually have restrictions on posix acls.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:28 +02:00
Günther Noack 3350607dc5
security: Create file_truncate hook from path_truncate hook
Like path_truncate, the file_truncate hook also restricts file
truncation, but is called in the cases where truncation is attempted
on an already-opened file.

This is required in a subsequent commit to handle ftruncate()
operations differently to truncate() operations.

Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20221018182216.301684-2-gnoack3000@gmail.com
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-10-19 09:01:40 +02:00
Linus Torvalds 26b84401da lsm/stable-6.1 PR 20221003
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Merge tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull LSM updates from Paul Moore:
 "Seven patches for the LSM layer and we've got a mix of trivial and
  significant patches. Highlights below, starting with the smaller bits
  first so they don't get lost in the discussion of the larger items:

   - Remove some redundant NULL pointer checks in the common LSM audit
     code.

   - Ratelimit the lockdown LSM's access denial messages.

     With this change there is a chance that the last visible lockdown
     message on the console is outdated/old, but it does help preserve
     the initial series of lockdown denials that started the denial
     message flood and my gut feeling is that these might be the more
     valuable messages.

   - Open userfaultfds as readonly instead of read/write.

     While this code obviously lives outside the LSM, it does have a
     noticeable impact on the LSMs with Ondrej explaining the situation
     in the commit description. It is worth noting that this patch
     languished on the VFS list for over a year without any comments
     (objections or otherwise) so I took the liberty of pulling it into
     the LSM tree after giving fair notice. It has been in linux-next
     since the end of August without any noticeable problems.

   - Add a LSM hook for user namespace creation, with implementations
     for both the BPF LSM and SELinux.

     Even though the changes are fairly small, this is the bulk of the
     diffstat as we are also including BPF LSM selftests for the new
     hook.

     It's also the most contentious of the changes in this pull request
     with Eric Biederman NACK'ing the LSM hook multiple times during its
     development and discussion upstream. While I've never taken NACK's
     lightly, I'm sending these patches to you because it is my belief
     that they are of good quality, satisfy a long-standing need of
     users and distros, and are in keeping with the existing nature of
     the LSM layer and the Linux Kernel as a whole.

     The patches in implement a LSM hook for user namespace creation
     that allows for a granular approach, configurable at runtime, which
     enables both monitoring and control of user namespaces. The general
     consensus has been that this is far preferable to the other
     solutions that have been adopted downstream including outright
     removal from the kernel, disabling via system wide sysctls, or
     various other out-of-tree mechanisms that users have been forced to
     adopt since we haven't been able to provide them an upstream
     solution for their requests. Eric has been steadfast in his
     objections to this LSM hook, explaining that any restrictions on
     the user namespace could have significant impact on userspace.
     While there is the possibility of impacting userspace, it is
     important to note that this solution only impacts userspace when it
     is requested based on the runtime configuration supplied by the
     distro/admin/user. Frederick (the pathset author), the LSM/security
     community, and myself have tried to work with Eric during
     development of this patchset to find a mutually acceptable
     solution, but Eric's approach and unwillingness to engage in a
     meaningful way have made this impossible. I have CC'd Eric directly
     on this pull request so he has a chance to provide his side of the
     story; there have been no objections outside of Eric's"

* tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lockdown: ratelimit denial messages
  userfaultfd: open userfaultfds with O_RDONLY
  selinux: Implement userns_create hook
  selftests/bpf: Add tests verifying bpf lsm userns_create hook
  bpf-lsm: Make bpf_lsm_userns_create() sleepable
  security, lsm: Introduce security_create_user_ns()
  lsm: clean up redundant NULL pointer check
2022-10-03 17:51:52 -07:00
Luis Chamberlain 2a58401240 lsm,io_uring: add LSM hooks for the new uring_cmd file op
io-uring cmd support was added through ee692a21e9 ("fs,io_uring:
add infrastructure for uring-cmd"), this extended the struct
file_operations to allow a new command which each subsystem can use
to enable command passthrough. Add an LSM specific for the command
passthrough which enables LSMs to inspect the command details.

This was discussed long ago without no clear pointer for something
conclusive, so this enables LSMs to at least reject this new file
operation.

[0] https://lkml.kernel.org/r/8adf55db-7bab-f59d-d612-ed906b948d19@schaufler-ca.com

Cc: stable@vger.kernel.org
Fixes: ee692a21e9 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-26 11:19:43 -04:00
Frederick Lawler 7cd4c5c210 security, lsm: Introduce security_create_user_ns()
User namespaces are an effective tool to allow programs to run with
permission without requiring the need for a program to run as root. User
namespaces may also be used as a sandboxing technique. However, attackers
sometimes leverage user namespaces as an initial attack vector to perform
some exploit. [1,2,3]

While it is not the unprivileged user namespace functionality, which
causes the kernel to be exploitable, users/administrators might want to
more granularly limit or at least monitor how various processes use this
functionality, while vulnerable kernel subsystems are being patched.

Preventing user namespace already creation comes in a few of forms in
order of granularity:

        1. /proc/sys/user/max_user_namespaces sysctl
        2. Distro specific patch(es)
        3. CONFIG_USER_NS

To block a task based on its attributes, the LSM hook cred_prepare is a
decent candidate for use because it provides more granular control, and
it is called before create_user_ns():

        cred = prepare_creds()
                security_prepare_creds()
                        call_int_hook(cred_prepare, ...
        if (cred)
                create_user_ns(cred)

Since security_prepare_creds() is meant for LSMs to copy and prepare
credentials, access control is an unintended use of the hook. [4]
Further, security_prepare_creds() will always return a ENOMEM if the
hook returns any non-zero error code.

This hook also does not handle the clone3 case which requires us to
access a user space pointer to know if we're in the CLONE_NEW_USER
call path which may be subject to a TOCTTOU attack.

Lastly, cred_prepare is called in many call paths, and a targeted hook
further limits the frequency of calls which is a beneficial outcome.
Therefore introduce a new function security_create_user_ns() with an
accompanying userns_create LSM hook.

With the new userns_create hook, users will have more control over the
observability and access control over user namespace creation. Users
should expect that normal operation of user namespaces will behave as
usual, and only be impacted when controls are implemented by users or
administrators.

This hook takes the prepared creds for LSM authors to write policy
against. On success, the new namespace is applied to credentials,
otherwise an error is returned.

Links:
1. https://nvd.nist.gov/vuln/detail/CVE-2022-0492
2. https://nvd.nist.gov/vuln/detail/CVE-2022-25636
3. https://nvd.nist.gov/vuln/detail/CVE-2022-34918
4. https://lore.kernel.org/all/1c4b1c0d-12f6-6e9e-a6a3-cdce7418110c@schaufler-ca.com/

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Frederick Lawler <fred@cloudflare.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-16 17:32:46 -04:00
Micah Morton fcfe0ac2fc security: Add LSM hook to setgroups() syscall
Give the LSM framework the ability to filter setgroups() syscalls. There
are already analagous hooks for the set*uid() and set*gid() syscalls.
The SafeSetID LSM will use this new hook to ensure setgroups() calls are
allowed by the installed security policy. Tested by putting print
statement in security_task_fix_setgroups() hook and confirming that it
gets hit when userspace does a setgroups() syscall.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
2022-07-15 18:21:49 +00:00
Linus Torvalds cb44e4f061 Landlock updates for v5.19-rc1
Important changes:
 * improve the path_rename LSM hook implementations for RENAME_EXCHANGE;
 * fix a too-restrictive filesystem control for a rare corner case;
 * set the nested sandbox limitation to 16 layers;
 * add a new LANDLOCK_ACCESS_FS_REFER access right to properly handle
   file reparenting (i.e. full rename and link support);
 * add new tests and documentation;
 * format code with clang-format to make it easier to maintain and
   contribute.
 
 Related patch series:
 * [PATCH v1 0/7] Landlock: Clean up coding style with clang-format
   https://lore.kernel.org/r/20220506160513.523257-1-mic@digikod.net
 * [PATCH v2 00/10] Minor Landlock fixes and new tests
   https://lore.kernel.org/r/20220506160820.524344-1-mic@digikod.net
 * [PATCH v3 00/12] Landlock: file linking and renaming support
   https://lore.kernel.org/r/20220506161102.525323-1-mic@digikod.net
 * [PATCH v2] landlock: Explain how to support Landlock
   https://lore.kernel.org/r/20220513112743.156414-1-mic@digikod.net
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Merge tag 'landlock-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux

Pull Landlock updates from Mickaël Salaün:

 - improve the path_rename LSM hook implementations for RENAME_EXCHANGE;

 - fix a too-restrictive filesystem control for a rare corner case;

 - set the nested sandbox limitation to 16 layers;

 - add a new LANDLOCK_ACCESS_FS_REFER access right to properly handle
   file reparenting (i.e. full rename and link support);

 - add new tests and documentation;

 - format code with clang-format to make it easier to maintain and
   contribute.

* tag 'landlock-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux: (30 commits)
  landlock: Explain how to support Landlock
  landlock: Add design choices documentation for filesystem access rights
  landlock: Document good practices about filesystem policies
  landlock: Document LANDLOCK_ACCESS_FS_REFER and ABI versioning
  samples/landlock: Add support for file reparenting
  selftests/landlock: Add 11 new test suites dedicated to file reparenting
  landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER
  LSM: Remove double path_rename hook calls for RENAME_EXCHANGE
  landlock: Move filesystem helpers and add a new one
  landlock: Fix same-layer rule unions
  landlock: Create find_rule() from unmask_layers()
  landlock: Reduce the maximum number of layers to 16
  landlock: Define access_mask_t to enforce a consistent access mask size
  selftests/landlock: Test landlock_create_ruleset(2) argument check ordering
  landlock: Change landlock_restrict_self(2) check ordering
  landlock: Change landlock_add_rule(2) argument check ordering
  selftests/landlock: Add tests for O_PATH
  selftests/landlock: Fully test file rename with "remove" access
  selftests/landlock: Extend access right tests to directories
  selftests/landlock: Add tests for unknown access rights
  ...
2022-05-24 13:09:13 -07:00
Mickaël Salaün 100f59d964
LSM: Remove double path_rename hook calls for RENAME_EXCHANGE
In order to be able to identify a file exchange with renameat2(2) and
RENAME_EXCHANGE, which will be useful for Landlock [1], propagate the
rename flags to LSMs.  This may also improve performance because of the
switch from two set of LSM hook calls to only one, and because LSMs
using this hook may optimize the double check (e.g. only one lock,
reduce the number of path walks).

AppArmor, Landlock and Tomoyo are updated to leverage this change.  This
should not change the current behavior (same check order), except
(different level of) speed boosts.

[1] https://lore.kernel.org/r/20220221212522.320243-1-mic@digikod.net

Cc: James Morris <jmorris@namei.org>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Serge E. Hallyn <serge@hallyn.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-7-mic@digikod.net
2022-05-23 13:27:58 +02:00
Christian Göttsche 1af0e4a023 security: declare member holding string literal const
The struct security_hook_list member lsm is assigned in
security_add_hooks() with string literals passed from the individual
security modules.  Declare the function parameter and the struct member
const to signal their immutability.

Reported by Clang [-Wwrite-strings]:

    security/selinux/hooks.c:7388:63: error: passing 'const char [8]'
      to parameter of type 'char *' discards qualifiers
      [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
            security_add_hooks(selinux_hooks,
                               ARRAY_SIZE(selinux_hooks), selinux);
                                                          ^~~~~~~~~
    ./include/linux/lsm_hooks.h:1629:11: note: passing argument to
      parameter 'lsm' here
                                    char *lsm);
                                          ^

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-13 14:51:06 -04:00
Ondrej Mosnacek 5e50f5d4ff security: add sctp_assoc_established hook
security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.

Fixes: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Based-on-patch-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-02-15 15:03:38 -05:00
Ondrej Mosnacek 52f982f00b security,selinux: remove security_add_mnt_opt()
Its last user has been removed in commit f2aedb713c ("NFS: Add
fs_context support.").

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-12-06 13:46:24 -05:00
Paul Moore 6326948f94 lsm: security_task_getsecid_subj() -> security_current_getsecid_subj()
The security_task_getsecid_subj() LSM hook invites misuse by allowing
callers to specify a task even though the hook is only safe when the
current task is referenced.  Fix this by removing the task_struct
argument to the hook, requiring LSM implementations to use the
current task.  While we are changing the hook declaration we also
rename the function to security_current_getsecid_subj() in an effort
to reinforce that the hook captures the subjective credentials of the
current task and not an arbitrary task on the system.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-11-22 17:52:47 -05:00
Paul Moore 32a370abf1 net,lsm,selinux: revert the security_sctp_assoc_established() hook
This patch reverts two prior patches, e7310c9402
("security: implement sctp_assoc_established hook in selinux") and
7c2ef0240e ("security: add sctp_assoc_established hook"), which
create the security_sctp_assoc_established() LSM hook and provide a
SELinux implementation.  Unfortunately these two patches were merged
without proper review (the Reviewed-by and Tested-by tags from
Richard Haines were for previous revisions of these patches that
were significantly different) and there are outstanding objections
from the SELinux maintainers regarding these patches.

Work is currently ongoing to correct the problems identified in the
reverted patches, as well as others that have come up during review,
but it is unclear at this point in time when that work will be ready
for inclusion in the mainline kernel.  In the interest of not keeping
objectionable code in the kernel for multiple weeks, and potentially
a kernel release, we are reverting the two problematic patches.

Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-11-12 12:07:02 -05:00
Xin Long 7c2ef0240e security: add sctp_assoc_established hook
security_sctp_assoc_established() is added to replace
security_inet_conn_established() called in
sctp_sf_do_5_1E_ca(), so that asoc can be accessed in security
subsystem and save the peer secid to asoc->peer_secid.

v1->v2:
  - fix the return value of security_sctp_assoc_established() in
    security.h, found by kernel test robot and Ondrej.

Fixes: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: Richard Haines <richard_c_haines@btinternet.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-03 11:09:20 +00:00
Xin Long c081d53f97 security: pass asoc to sctp_assoc_request and sctp_sk_clone
This patch is to move secid and peer_secid from endpoint to association,
and pass asoc to sctp_assoc_request and sctp_sk_clone instead of ep. As
ep is the local endpoint and asoc represents a connection, and in SCTP
one sk/ep could have multiple asoc/connection, saving secid/peer_secid
for new asoc will overwrite the old asoc's.

Note that since asoc can be passed as NULL, security_sctp_assoc_request()
is moved to the place right after the new_asoc is created in
sctp_sf_do_5_1B_init() and sctp_sf_do_unexpected_init().

v1->v2:
  - fix the description of selinux_netlbl_skbuff_setsid(), as Jakub noticed.
  - fix the annotation in selinux_sctp_assoc_request(), as Richard Noticed.

Fixes: 72e89f5008 ("security: Add support for SCTP security hooks")
Reported-by: Prashanth Prahlad <pprahlad@redhat.com>
Reviewed-by: Richard Haines <richard_c_haines@btinternet.com>
Tested-by: Richard Haines <richard_c_haines@btinternet.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-11-03 11:09:20 +00:00
Vivek Goyal 15bf32398a security: Return xattr name from security_dentry_init_security()
Right now security_dentry_init_security() only supports single security
label and is used by SELinux only. There are two users of this hook,
namely ceph and nfs.

NFS does not care about xattr name. Ceph hardcodes the xattr name to
security.selinux (XATTR_NAME_SELINUX).

I am making changes to fuse/virtiofs to send security label to virtiofsd
and I need to send xattr name as well. I also hardcoded the name of
xattr to security.selinux.

Stephen Smalley suggested that it probably is a good idea to modify
security_dentry_init_security() to also return name of xattr so that
we can avoid this hardcoding in the callers.

This patch adds a new parameter "const char **xattr_name" to
security_dentry_init_security() and LSM puts the name of xattr
too if caller asked for it (xattr_name != NULL).

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: James Morris <jamorris@linux.microsoft.com>
[PM: fixed typos in the commit description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-20 08:17:08 -04:00
Todd Kjos 52f8869337 binder: use cred instead of task for selinux checks
Since binder was integrated with selinux, it has passed
'struct task_struct' associated with the binder_proc
to represent the source and target of transactions.
The conversion of task to SID was then done in the hook
implementations. It turns out that there are race conditions
which can result in an incorrect security context being used.

Fix by using the 'struct cred' saved during binder_open and pass
it to the selinux subsystem.

Cc: stable@vger.kernel.org # 5.14 (need backport for earlier stables)
Fixes: 79af73079d ("Add security hooks to binder and implement the hooks for SELinux.")
Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2021-10-14 20:48:04 -04:00