From 617fde87812e2335a88ab10606772a0485e5481f Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 2 Feb 2018 17:31:39 +0000 Subject: [PATCH] arm64: entry: Apply BP hardening for high-priority synchronous exceptions commit 5dfc6ed27710 upstream. Software-step and PC alignment fault exceptions have higher priority than instruction abort exceptions, so apply the BP hardening hooks there too if the user PC appears to reside in kernel space. Reported-by: Dan Hettena Reviewed-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Alex Shi Conflicts: expand enable_da_f to 'msr daifclr, #(8 | 4 | 1)' in arch/arm64/kernel/entry.S --- arch/arm64/kernel/entry.S | 6 ++++-- arch/arm64/mm/fault.c | 9 +++++++++ 2 files changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 20a978bce628..f8768ab38cfb 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -626,8 +626,10 @@ el0_sp_pc: * Stack or PC alignment exception handling */ mrs x26, far_el1 - // enable interrupts before calling the main handler - enable_dbg_and_irq + msr daifclr, #(8 | 4 | 1) +#ifdef CONFIG_TRACE_IRQFLAGS + bl trace_hardirqs_off +#endif ct_user_exit mov x0, x26 mov x1, x25 diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c95b194d1c6e..6120a1486054 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -617,6 +617,12 @@ asmlinkage void __exception do_sp_pc_abort(unsigned long addr, struct siginfo info; struct task_struct *tsk = current; + if (user_mode(regs)) { + if (instruction_pointer(regs) > TASK_SIZE) + arm64_apply_bp_hardening(); + local_irq_enable(); + } + if (show_unhandled_signals && unhandled_signal(tsk, SIGBUS)) pr_info_ratelimited("%s[%d]: %s exception: pc=%p sp=%p\n", tsk->comm, task_pid_nr(tsk), @@ -676,6 +682,9 @@ asmlinkage int __exception do_debug_exception(unsigned long addr, if (interrupts_enabled(regs)) trace_hardirqs_off(); + if (user_mode(regs) && instruction_pointer(regs) > TASK_SIZE) + arm64_apply_bp_hardening(); + if (!inf->fn(addr, esr, regs)) { rv = 1; } else { -- 2.17.1