York Jasper Niebuhr ba42b524a0 mm: init_mlocked_on_free_v3 ... Implements the "init_mlocked_on_free" boot option. When this boot option is enabled, any mlock'ed pages are zeroed on free. If the pages are munlock'ed beforehand, no initialization takes place. This boot option is meant to combat the performance hit of "init_on_free" as reported in commit 6471384af2 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options"). With "init_mlocked_on_free=1" only relevant data is freed while everything else is left untouched by the kernel. Correspondingly, this patch introduces no performance hit for unmapping non-mlock'ed memory. The unmapping overhead for purely mlocked memory was measured to be approximately 13%. Realistically, most systems mlock only a fraction of the total memory so the real-world system overhead should be close to zero. Optimally, userspace programs clear any key material or other confidential memory before exit and munlock the according memory regions. If a program crashes, userspace key managers fail to do this job. Accordingly, no munlock operations are performed so the data is caught and zeroed by the kernel. Should the program not crash, all memory will ideally be munlocked so no overhead is caused. CONFIG_INIT_MLOCKED_ON_FREE_DEFAULT_ON can be set to enable "init_mlocked_on_free" by default. Link: https://lkml.kernel.org/r/20240329145605.149917-1-yjnworkstation@gmail.com Signed-off-by: York Jasper Niebuhr <yjnworkstation@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: York Jasper Niebuhr <yjnworkstation@gmail.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2024-04-25 20:56:29 -07:00
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apparmor	lsm: use 32-bit compatible data types in LSM syscalls	2024-03-14 11:31:26 -04:00
bpf	…
integrity	lsm/stable-6.9 PR 20240312	2024-03-12 20:03:34 -07:00
keys	…
landlock	landlock: Use f_cred in security_file_open() hook	2024-03-08 18:22:16 +01:00
loadpin	…
lockdown	…
safesetid	…
selinux	selinux: avoid dereference of garbage after mount failure	2024-04-01 23:32:35 -04:00
smack	lsm: use 32-bit compatible data types in LSM syscalls	2024-03-14 11:31:26 -04:00
tomoyo	…
yama	…
Kconfig	…
Kconfig.hardening	mm: init_mlocked_on_free_v3	2024-04-25 20:56:29 -07:00
Makefile	…
commoncap.c	…
device_cgroup.c	…
inode.c	…
lsm_audit.c	…
lsm_syscalls.c	lsm: use 32-bit compatible data types in LSM syscalls	2024-03-14 11:31:26 -04:00
min_addr.c	…
security.c	security: Place security_path_post_mknod() where the original IMA call was	2024-04-03 10:21:32 -07:00