kernel/linux.git/security/yama, branch v6.6.131

Merge tag 'sysctl-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux

2023-04-27T23:52:33+00:00

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 ...

yama: simplfy sysctls with register_sysctl()

2023-04-13T18:49:20+00:00

register_sysctl_paths() is only need if you have directories with entries, simplify this by using register_sysctl(). Acked-by: Kees Cook Signed-off-by: Luis Chamberlain

selinux: remove the runtime disable functionality

2023-03-20T16:34:23+00:00

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 Signed-off-by: Paul Moore

task_work: cleanup notification modes

2020-10-17T21:05:30+00:00

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 Signed-off-by: Jens Axboe

sysctl: pass kernel pointers to ->proc_handler

2020-04-27T06:07:40+00:00

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 Acked-by: Andrey Ignatov Signed-off-by: Al Viro

proc/sysctl: add shared variables for range check

2019-07-19T00:08:07+00:00

In the sysctl code the proc_dointvec_minmax() function is often used to validate the user supplied value between an allowed range. This function uses the extra1 and extra2 members from struct ctl_table as minimum and maximum allowed value. On sysctl handler declaration, in every source file there are some readonly variables containing just an integer which address is assigned to the extra1 and extra2 members, so the sysctl range is enforced. The special values 0, 1 and INT_MAX are very often used as range boundary, leading duplication of variables like zero=0, one=1, int_max=INT_MAX in different source files: $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l 248 Add a const int array containing the most commonly used values, some macros to refer more easily to the correct array member, and use them instead of creating a local one for every object file. This is the bloat-o-meter output comparing the old and new binary compiled with the default Fedora config: # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164) Data old new delta sysctl_vals - 12 +12 __kstrtab_sysctl_vals - 12 +12 max 14 10 -4 int_max 16 - -16 one 68 - -68 zero 128 28 -100 Total: Before=20583249, After=20583085, chg -0.00% [mcroce@redhat.com: tipc: remove two unused variables] Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com [akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c] [arnd@arndb.de: proc/sysctl: make firmware loader table conditional] Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de [akpm@linux-foundation.org: fix fs/eventpoll.c] Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com Signed-off-by: Matteo Croce Signed-off-by: Arnd Bergmann Acked-by: Kees Cook Reviewed-by: Aaron Tomlin Cc: Matthew Wilcox Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier - Makefile/Kconfig

2019-05-21T08:50:46+00:00

Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

Yama: mark local symbols as static

2019-03-28T17:02:29+00:00

sparse complains that Yama defines functions and a variable as non-static even though they don't exist in any header. Fix it by making them static. Co-developed-by: Mukesh Ojha Signed-off-by: Mukesh Ojha Signed-off-by: Jann Horn [kees: merged similar static-ness fixes into a single patch] Link: https://lkml.kernel.org/r/20190326230841.87834-1-jannh@google.com Link: https://lkml.kernel.org/r/1553673018-19234-1-git-send-email-mojha@codeaurora.org Signed-off-by: Kees Cook Signed-off-by: James Morris

Merge tag 'v5.0-rc3' into next-general

2019-01-22T22:33:10+00:00

Sync to Linux 5.0-rc3 to pull in the VFS changes which impacted a lot of the LSM code.