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authorNadav Amit <namit@vmware.com>2019-04-26 16:22:46 -0700
committerIngo Molnar <mingo@kernel.org>2019-04-30 12:37:52 +0200
commit4fc19708b165c1c152fa1f12f6600e66184b7786 (patch)
treedecf3f3cd8a8ab9d636cec86360843039c0eff3e /init
parent13585fa0668c724efab9635aaeef6ec390217415 (diff)
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x86/alternatives: Initialize temporary mm for patching
To prevent improper use of the PTEs that are used for text patching, the next patches will use a temporary mm struct. Initailize it by copying the init mm. The address that will be used for patching is taken from the lower area that is usually used for the task memory. Doing so prevents the need to frequently synchronize the temporary-mm (e.g., when BPF programs are installed), since different PGDs are used for the task memory. Finally, randomize the address of the PTEs to harden against exploits that use these PTEs. Suggested-by: Andy Lutomirski <luto@kernel.org> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Nadav Amit <namit@vmware.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: ard.biesheuvel@linaro.org Cc: deneen.t.dock@intel.com Cc: kernel-hardening@lists.openwall.com Cc: kristen@linux.intel.com Cc: linux_dti@icloud.com Cc: will.deacon@arm.com Link: https://lkml.kernel.org/r/20190426232303.28381-8-nadav.amit@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'init')
-rw-r--r--init/main.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/init/main.c b/init/main.c
index 7d4025d665eb..95dd9406ee31 100644
--- a/init/main.c
+++ b/init/main.c
@@ -504,6 +504,8 @@ void __init __weak thread_stack_cache_init(void)
void __init __weak mem_encrypt_init(void) { }
+void __init __weak poking_init(void) { }
+
bool initcall_debug;
core_param(initcall_debug, initcall_debug, bool, 0644);
@@ -737,6 +739,7 @@ asmlinkage __visible void __init start_kernel(void)
taskstats_init_early();
delayacct_init();
+ poking_init();
check_bugs();
acpi_subsystem_init();