201 Commits
Author SHA1 Message Date
Ryan FosterandSerge Hallyn 24e9b431b5 security: Add KUnit tests for kuid_root_in_ns and vfsuid_root_in_currentns
Add comprehensive KUnit tests for the namespace-related capability
functions that Serge Hallyn refactored in commit 9891d2f79a
("Clarify the rootid_owns_currentns").

The tests verify:
- Basic functionality: UID 0 in init namespace, invalid vfsuid,
  non-zero UIDs
- Actual namespace traversal: Creating user namespaces with different
  UID mappings where uid 0 maps to different kuids (e.g., 1000, 2000,
  3000)
- Hierarchy traversal: Testing multiple nested namespaces to verify
  correct namespace hierarchy traversal

This addresses the feedback to "test the actual functionality" by
creating real user namespaces with different values for the
namespace's uid 0, rather than just basic input validation.

The test file is included at the end of commoncap.c when
CONFIG_SECURITY_COMMONCAP_KUNIT_TEST is enabled, following the
standard kernel pattern (e.g., scsi_lib.c, ext4/mballoc.c). This
allows tests to access static functions in the same compilation unit
without modifying production code based on test configuration.

The tests require CONFIG_USER_NS to be enabled since they rely on user
namespace mapping functionality. The Kconfig dependency ensures the
tests only build when this requirement is met.

All 7 tests pass:
- test_vfsuid_root_in_currentns_init_ns
- test_vfsuid_root_in_currentns_invalid
- test_vfsuid_root_in_currentns_nonzero
- test_kuid_root_in_ns_init_ns_uid0
- test_kuid_root_in_ns_init_ns_nonzero
- test_kuid_root_in_ns_with_mapping
- test_kuid_root_in_ns_with_different_mappings

Updated MAINTAINER capabilities to include commoncap test

Signed-off-by: Ryan Foster <foster.ryan.r@gmail.com>
Signed-off-by: Serge Hallyn <sergeh@kernel.org>
2026-01-09 11:28:28 -06:00
Linus Torvalds 2061f18ad7 Merge tag 'caps-pr-20251204' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux
Pull capabilities update from Serge Hallyn:
 "Ryan Foster had sent a patch to add testing of the
  rootid_owns_currentns() function. That patch pointed out
  that this function was not as clear as it should be. Fix it:

   - Clarify the intent of the function in the name

   - Split the function so that the base functionality is easier to test
     from a kunit test"

* tag 'caps-pr-20251204' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux:
  Clarify the rootid_owns_currentns
2025-12-04 20:10:28 -08:00
Serge HallynandSerge Hallyn 9891d2f79a Clarify the rootid_owns_currentns
Split most of the rootid_owns_currentns() functionality
into a more generic rootid_owns_ns() function which
will be easier to write tests for.

Rename the functions and variables to make clear that
the ids being tested could be any uid.

Signed-off-by: Serge Hallyn <serge@hallyn.com>
CC: Ryan Foster <foster.ryan.r@gmail.com>
CC: Christian Brauner <brauner@kernel.org>

---
v2: change the function parameter documentation to mollify the bot.
2025-11-18 18:00:19 -06:00
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
Eric W. BiedermanandSerge Hallyn 337490f000 exec: Correct the permission check for unsafe exec
Max Kellerman recently experienced a problem[1] when calling exec with
differing uid and euid's and he triggered the logic that is supposed
to only handle setuid executables.

When exec isn't changing anything in struct cred it doesn't make sense
to go into the code that is there to handle the case when the
credentials change.

When looking into the history of the code I discovered that this issue
was not present in Linux-2.4.0-test12 and was introduced in
Linux-2.4.0-prerelease when the logic for handling this case was moved
from prepare_binprm to compute_creds in fs/exec.c.

The bug introdused was to comparing euid in the new credentials with
uid instead of euid in the old credentials, when testing if setuid
had changed the euid.

Since triggering the keep ptrace limping along case for setuid
executables makes no sense when it was not a setuid exec revert back
to the logic present in Linux-2.4.0-test12.

This removes the confusingly named and subtlety incorrect helpers
is_setuid and is_setgid, that helped this bug to persist.

The varaiable is_setid is renamed to id_changed (it's Linux-2.4.0-test12)
as the old name describes what matters rather than it's cause.

The code removed in Linux-2.4.0-prerelease was:
-       /* Set-uid? */
-       if (mode & S_ISUID) {
-               bprm->e_uid = inode->i_uid;
-               if (bprm->e_uid != current->euid)
-                       id_change = 1;
-       }
-
-       /* Set-gid? */
-       /*
-        * If setgid is set but no group execute bit then this
-        * is a candidate for mandatory locking, not a setgid
-        * executable.
-        */
-       if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
-               bprm->e_gid = inode->i_gid;
-               if (!in_group_p(bprm->e_gid))
-                       id_change = 1;

Linux-2.4.0-prerelease added the current logic as:
+       if (bprm->e_uid != current->uid || bprm->e_gid != current->gid ||
+           !cap_issubset(new_permitted, current->cap_permitted)) {
+                current->dumpable = 0;
+
+               lock_kernel();
+               if (must_not_trace_exec(current)
+                   || atomic_read(&current->fs->count) > 1
+                   || atomic_read(&current->files->count) > 1
+                   || atomic_read(&current->sig->count) > 1) {
+                       if(!capable(CAP_SETUID)) {
+                               bprm->e_uid = current->uid;
+                               bprm->e_gid = current->gid;
+                       }
+                       if(!capable(CAP_SETPCAP)) {
+                               new_permitted = cap_intersect(new_permitted,
+                                                       current->cap_permitted);
+                       }
+               }
+               do_unlock = 1;
+       }

I have condenced the logic from Linux-2.4.0-test12 to just:
	id_changed = !uid_eq(new->euid, old->euid) || !in_group_p(new->egid);

This change is userspace visible, but I don't expect anyone to care.

For the bug that is being fixed to trigger bprm->unsafe has to be set.
The variable bprm->unsafe is set when ptracing an executable, when
sharing a working directory, or when no_new_privs is set.  Properly
testing for cases that are safe even in those conditions and doing
nothing special should not affect anyone.  Especially if they were
previously ok with their credentials getting munged

To minimize behavioural changes the code continues to set secureexec
when euid != uid or when egid != gid.

[1] https://lkml.kernel.org/r/20250306082615.174777-1-max.kellermann@ionos.com

Reported-by: Max Kellermann <max.kellermann@ionos.com>
Fixes: 64444d3d0d7f ("Linux version 2.4.0-prerelease")
v1: https://lkml.kernel.org/r/878qmxsuy8.fsf@email.froward.int.ebiederm.org
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Reviewed-by: Jann Horn <jannh@google.com>
Acked-by: Kees Cook <kees@kernel.org>
2025-06-23 10:38:39 -05:00
Dr. David Alan GilbertandSerge Hallyn 4ae89b1fe7 capability: Remove unused has_capability
The vanilla has_capability() function has been unused since 2018's
commit dcb569cf6a ("Smack: ptrace capability use fixes")

Remove it.

Fixup a comment in security/commoncap.c that referenced it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Serge Hallyn <sergeh@kernel.org>
2025-03-07 22:03:09 -06:00
Linus Torvalds 754916d4a2 Merge tag 'caps-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux
Pull capabilities updates from Serge Hallyn:

 - remove the cap_mmap_file() hook, as it simply returned the default
   return value and so doesn't need to exist (Paul Moore)

 - add a trace event for cap_capable() (Jordan Rome)

* tag 'caps-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/sergeh/linux:
  security: add trace event for cap_capable
  capabilities: remove cap_mmap_file()
2025-01-23 08:00:16 -08:00
Mickaël SalaünandKees Cook a0623b2a1d security: Add EXEC_RESTRICT_FILE and EXEC_DENY_INTERACTIVE securebits
The new SECBIT_EXEC_RESTRICT_FILE, SECBIT_EXEC_DENY_INTERACTIVE, and
their *_LOCKED counterparts are designed to be set by processes setting
up an execution environment, such as a user session, a container, or a
security sandbox.  Unlike other securebits, these ones can be set by
unprivileged processes.  Like seccomp filters or Landlock domains, the
securebits are inherited across processes.

When SECBIT_EXEC_RESTRICT_FILE is set, programs interpreting code should
control executable resources according to execveat(2) + AT_EXECVE_CHECK
(see previous commit).

When SECBIT_EXEC_DENY_INTERACTIVE is set, a process should deny
execution of user interactive commands (which excludes executable
regular files).

Being able to configure each of these securebits enables system
administrators or owner of image containers to gradually validate the
related changes and to identify potential issues (e.g. with interpreter
or audit logs).

It should be noted that unlike other security bits, the
SECBIT_EXEC_RESTRICT_FILE and SECBIT_EXEC_DENY_INTERACTIVE bits are
dedicated to user space willing to restrict itself.  Because of that,
they only make sense in the context of a trusted environment (e.g.
sandbox, container, user session, full system) where the process
changing its behavior (according to these bits) and all its parent
processes are trusted.  Otherwise, any parent process could just execute
its own malicious code (interpreting a script or not), or even enforce a
seccomp filter to mask these bits.

Such a secure environment can be achieved with an appropriate access
control (e.g. mount's noexec option, file access rights, LSM policy) and
an enlighten ld.so checking that libraries are allowed for execution
e.g., to protect against illegitimate use of LD_PRELOAD.

Ptrace restrictions according to these securebits would not make sense
because of the processes' trust assumption.

Scripts may need some changes to deal with untrusted data (e.g. stdin,
environment variables), but that is outside the scope of the kernel.

See chromeOS's documentation about script execution control and the
related threat model:
https://www.chromium.org/chromium-os/developer-library/guides/security/noexec-shell-scripts/

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Paul Moore <paul@paul-moore.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Jeff Xu <jeffxu@chromium.org>
Tested-by: Jeff Xu <jeffxu@chromium.org>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20241212174223.389435-3-mic@digikod.net
Signed-off-by: Kees Cook <kees@kernel.org>
2024-12-18 17:00:29 -08:00
Jordan RomeandSerge Hallyn d48da4d5ed security: add trace event for cap_capable
In cases where we want a stable way to observe/trace
cap_capable (e.g. protection from inlining and API updates)
add a tracepoint that passes:
- The credentials used
- The user namespace of the resource being accessed
- The user namespace in which the credential provides the
capability to access the targeted resource
- The capability to check for
- The return value of the check

Signed-off-by: Jordan Rome <linux@jordanrome.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Link: https://lore.kernel.org/r/20241204155911.1817092-1-linux@jordanrome.com
Signed-off-by: Serge Hallyn <sergeh@kernel.org>
2024-12-04 20:59:21 -06:00
Paul MooreandSerge Hallyn 3f4f1f8a1a capabilities: remove cap_mmap_file()
The cap_mmap_file() LSM callback returns the default value for the
security_mmap_file() LSM hook and can be safely removed.

Signed-off-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Serge Hallyn <sergeh@kernel.org>
2024-12-04 20:56:28 -06:00
Xu KuohaiandPaul Moore be72a57527 lsm: Refactor return value of LSM hook vm_enough_memory
To be consistent with most LSM hooks, convert the return value of
hook vm_enough_memory to 0 or a negative error code.

Before:
- Hook vm_enough_memory returns 1 if permission is granted, 0 if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 1.

After:
- Hook vm_enough_memory reutrns 0 if permission is granted, negative
  error code if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 0.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-07-31 14:46:51 -04:00
Paul Moore b1a867eeb8 lsm: mark the lsm_id variables are marked as static
As the kernel test robot helpfully reminded us, all of the lsm_id
instances defined inside the various LSMs should be marked as static.
The one exception is Landlock which uses its lsm_id variable across
multiple source files with an extern declaration in a header file.

Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-11-12 22:54:42 -05:00
Casey SchauflerandPaul Moore 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
Khadija KamranandPaul Moore 4a00c67306 lsm: constify 'file' parameter in security_bprm_creds_from_file()
The 'bprm_creds_from_file' hook has implementation registered in
commoncap. Looking at the function implementation we observe that the
'file' parameter is not changing.

Mark the 'file' parameter of LSM hook security_bprm_creds_from_file() as
'const' since it will not be changing in the LSM hook.

Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-09-13 18:09:35 -04:00
Khadija KamranandPaul Moore 6672efbb68 lsm: constify the 'target' parameter in security_capget()
Three LSMs register the implementations for the "capget" hook: AppArmor,
SELinux, and the normal capability code. Looking at the function
implementations we may observe that the first parameter "target" is not
changing.

Mark the first argument "target" of LSM hook security_capget() as
"const" since it will not be changing in the LSM hook.

cap_capget() LSM hook declaration exceeds the 80 characters per line
limit. Split the function declaration to multiple lines to decrease the
line length.

Signed-off-by: Khadija Kamran <kamrankhadijadj@gmail.com>
Acked-by: John Johansen <john.johansen@canonical.com>
[PM: align the cap_capget() declaration, spelling fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-08-08 16:48:47 -04:00
Paul Moore 4432b50744 lsm: fix a number of misspellings
A random collection of spelling fixes for source files in the LSM
layer.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-05-25 17:52:15 -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
Linus Torvalds f122a08b19 capability: just use a 'u64' instead of a 'u32[2]' array
Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words.  It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.

That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more.  And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation.  It's a lose-lose
situation.

So just change the 'u32[2]' into a 'u64' and be done with it.

We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).

So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.

This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently.  By just using a saner data structure, it went from

	unsigned __capi;
	CAP_FOR_EACH_U32(__capi) {
		if (a.cap[__capi] != b.cap[__capi])
			return false;
	}
	return true;

to just being

	return a.val == b.val;

instead.  Which is rather more obvious both to humans and to compilers.

Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-03-01 10:01:22 -08:00
Christian Brauner 4d7ca40901 fs: port vfs{g,u}id helpers 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 09:24:30 +01:00
Christian Brauner 9452e93e6d fs: port privilege checking helpers 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 09:24:29 +01:00
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
Christian Brauner 4609e1f18e fs: port ->permission() to pass 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 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 e1212e9b6f Merge tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping
Pull vfsuid updates from Christian Brauner:
 "Last cycle we introduced the vfs{g,u}id_t types and associated helpers
  to gain type safety when dealing with idmapped mounts. That initial
  work already converted a lot of places over but there were still some
  left,

  This converts all remaining places that still make use of non-type
  safe idmapping helpers to rely on the new type safe vfs{g,u}id based
  helpers.

  Afterwards it removes all the old non-type safe helpers"

* tag 'fs.vfsuid.conversion.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
  fs: remove unused idmapping helpers
  ovl: port to vfs{g,u}id_t and associated helpers
  fuse: port to vfs{g,u}id_t and associated helpers
  ima: use type safe idmapping helpers
  apparmor: use type safe idmapping helpers
  caps: use type safe idmapping helpers
  fs: use type safe idmapping helpers
  mnt_idmapping: add missing helpers
2022-12-12 19:20:05 -08:00
Paul Moore f6fbd8cbf3 lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths
The vfs_getxattr_alloc() function currently returns a ssize_t value
despite the fact that it only uses int values internally for return
values.  Fix this by converting vfs_getxattr_alloc() to return an
int type and adjust the callers as necessary.  As part of these
caller modifications, some of the callers are fixed to properly free
the xattr value buffer on both success and failure to ensure that
memory is not leaked in the failure case.

Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-11-18 17:07:03 -05:00