From c9a1ff316bc9b1d1806a4366d0aef6e18833ba52 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Wed, 17 Jun 2020 18:56:24 -0400 Subject: x86/stackprotector: Pre-initialize canary for secondary CPUs The idle tasks created for each secondary CPU already have a random stack canary generated by fork(). Copy the canary to the percpu variable before starting the secondary CPU which removes the need to call boot_init_stack_canary(). Signed-off-by: Brian Gerst Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20200617225624.799335-1-brgerst@gmail.com --- arch/x86/include/asm/stackprotector.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'arch/x86/include/asm/stackprotector.h') diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index 9804a7957f4e..7fb482f0f25b 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -90,6 +90,15 @@ static __always_inline void boot_init_stack_canary(void) #endif } +static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle) +{ +#ifdef CONFIG_X86_64 + per_cpu(fixed_percpu_data.stack_canary, cpu) = idle->stack_canary; +#else + per_cpu(stack_canary.canary, cpu) = idle->stack_canary; +#endif +} + static inline void setup_stack_canary_segment(int cpu) { #ifdef CONFIG_X86_32 @@ -119,6 +128,9 @@ static inline void load_stack_canary_segment(void) static inline void setup_stack_canary_segment(int cpu) { } +static inline void cpu_init_stack_canary(int cpu, struct task_struct *idle) +{ } + static inline void load_stack_canary_segment(void) { #ifdef CONFIG_X86_32 -- cgit v1.2.3