const qualify the struct ctl_table argument in the proc_handler function
signatures. This is a prerequisite to moving the static ctl_table
structs into .rodata data which will ensure that proc_handler function
pointers cannot be modified.
This patch has been generated by the following coccinelle script:
```
virtual patch
@r1@
identifier ctl, write, buffer, lenp, ppos;
identifier func !~ "appldata_(timer|interval)_handler|sched_(rt|rr)_handler|rds_tcp_skbuf_handler|proc_sctp_do_(hmac_alg|rto_min|rto_max|udp_port|alpha_beta|auth|probe_interval)";
@@
int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos);
@r2@
identifier func, ctl, write, buffer, lenp, ppos;
@@
int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int write, void *buffer, size_t *lenp, loff_t *ppos)
{ ... }
@r3@
identifier func;
@@
int func(
- struct ctl_table *
+ const struct ctl_table *
,int , void *, size_t *, loff_t *);
@r4@
identifier func, ctl;
@@
int func(
- struct ctl_table *ctl
+ const struct ctl_table *ctl
,int , void *, size_t *, loff_t *);
@r5@
identifier func, write, buffer, lenp, ppos;
@@
int func(
- struct ctl_table *
+ const struct ctl_table *
,int write, void *buffer, size_t *lenp, loff_t *ppos);
```
* Code formatting was adjusted in xfs_sysctl.c to comply with code
conventions. The xfs_stats_clear_proc_handler,
xfs_panic_mask_proc_handler and xfs_deprecated_dointvec_minmax where
adjusted.
* The ctl_table argument in proc_watchdog_common was const qualified.
This is called from a proc_handler itself and is calling back into
another proc_handler, making it necessary to change it as part of the
proc_handler migration.
Co-developed-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Co-developed-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Joel Granados <j.granados@samsung.com>
Document the unused function parameter of yama_relation_cleanup() to please kernel doc warnings. Signed-off-by: Christian Göttsche <cgzones@googlemail.com> Reviewed-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20240315125418.273104-2-cgzones@googlemail.com Signed-off-by: Kees Cook <kees@kernel.org>
This commit comes at the tail end of a greater effort to remove the empty elements at the end of the ctl_table arrays (sentinels) which will reduce the overall build time size of the kernel and run time memory bloat by ~64 bytes per sentinel (further information Link : https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/) Remove the sentinel from all files under security/ that register a sysctl table. Signed-off-by: Joel Granados <j.granados@samsung.com> Acked-by: Kees Cook <keescook@chromium.org> # loadpin & yama Tested-by: Valentin Schneider <vschneid@redhat.com> Reviewed-by: Valentin Schneider <vschneid@redhat.com> [PM: subject line tweaks] Signed-off-by: Paul Moore <paul@paul-moore.com>
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>
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>
Pull sysctl updates from Luis Chamberlain: "This only does a few sysctl moves from the kernel/sysctl.c file, the rest of the work has been put towards deprecating two API calls which incur recursion and prevent us from simplifying the registration process / saving memory per move. Most of the changes have been soaking on linux-next since v6.3-rc3. I've slowed down the kernel/sysctl.c moves due to Matthew Wilcox's feedback that we should see if we could *save* memory with these moves instead of incurring more memory. We currently incur more memory since when we move a syctl from kernel/sysclt.c out to its own file we end up having to add a new empty sysctl used to register it. To achieve saving memory we want to allow syctls to be passed without requiring the end element being empty, and just have our registration process rely on ARRAY_SIZE(). Without this, supporting both styles of sysctls would make the sysctl registration pretty brittle, hard to read and maintain as can be seen from Meng Tang's efforts to do just this [0]. Fortunately, in order to use ARRAY_SIZE() for all sysctl registrations also implies doing the work to deprecate two API calls which use recursion in order to support sysctl declarations with subdirectories. And so during this development cycle quite a bit of effort went into this deprecation effort. I've annotated the following two APIs are deprecated and in few kernel releases we should be good to remove them: - register_sysctl_table() - register_sysctl_paths() During this merge window we should be able to deprecate and unexport register_sysctl_paths(), we can probably do that towards the end of this merge window. Deprecating register_sysctl_table() will take a bit more time but this pull request goes with a few example of how to do this. As it turns out each of the conversions to move away from either of these two API calls *also* saves memory. And so long term, all these changes *will* prove to have saved a bit of memory on boot. The way I see it then is if remove a user of one deprecated call, it gives us enough savings to move one kernel/sysctl.c out from the generic arrays as we end up with about the same amount of bytes. Since deprecating register_sysctl_table() and register_sysctl_paths() does not require maintainer coordination except the final unexport you'll see quite a bit of these changes from other pull requests, I've just kept the stragglers after rc3" Link: https://lkml.kernel.org/r/ZAD+cpbrqlc5vmry@bombadil.infradead.org [0] * tag 'sysctl-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (29 commits) fs: fix sysctls.c built mm: compaction: remove incorrect #ifdef checks mm: compaction: move compaction sysctl to its own file mm: memory-failure: Move memory failure sysctls to its own file arm: simplify two-level sysctl registration for ctl_isa_vars ia64: simplify one-level sysctl registration for kdump_ctl_table utsname: simplify one-level sysctl registration for uts_kern_table ntfs: simplfy one-level sysctl registration for ntfs_sysctls coda: simplify one-level sysctl registration for coda_table fs/cachefiles: simplify one-level sysctl registration for cachefiles_sysctls xfs: simplify two-level sysctl registration for xfs_table nfs: simplify two-level sysctl registration for nfs_cb_sysctls nfs: simplify two-level sysctl registration for nfs4_cb_sysctls lockd: simplify two-level sysctl registration for nlm_sysctls proc_sysctl: enhance documentation xen: simplify sysctl registration for balloon md: simplify sysctl registration hv: simplify sysctl registration scsi: simplify sysctl registration with register_sysctl() csky: simplify alignment sysctl registration ...
register_sysctl_paths() is only need if you have directories with entries, simplify this by using register_sysctl(). Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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>
A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.
Clean this up properly, and define a proper enum for the notification
mode. Now we have:
- TWA_NONE. This is 0, same as before the original change, meaning no
notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
notification.
Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.
Fixes: e91b48162332 ("task_work: teach task_work_add() to do signal_wake_up()")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>