diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-02-02 17:31:40 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-16 20:06:41 +0100 |
| commit | 40ad0b937384e4b1c48539557443f4a8f1bc0848 (patch) | |
| tree | 65e7cedfa00b365f8848b33b2132e845474adb84 /arch | |
| parent | 9444427e9f43132642120fb9104b911cda5c5d8b (diff) | |
arm64: entry: Apply BP hardening for suspicious interrupts from EL0
Commit 30d88c0e3ace upstream.
It is possible to take an IRQ from EL0 following a branch to a kernel
address in such a way that the IRQ is prioritised over the instruction
abort. Whilst an attacker would need to get the stars to align here,
it might be sufficient with enough calibration so perform BP hardening
in the rare case that we see a kernel address in the ELR when handling
an IRQ from EL0.
Reported-by: Dan Hettena <dhettena@nvidia.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/entry.S | 5 | ||||
| -rw-r--r-- | arch/arm64/mm/fault.c | 6 |
2 files changed, 11 insertions, 0 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 425fb034f705..78647eda6d0d 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -828,6 +828,11 @@ el0_irq_naked: #endif ct_user_exit +#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR + tbz x22, #55, 1f + bl do_el0_irq_bp_hardening +1: +#endif irq_handler #ifdef CONFIG_TRACE_IRQFLAGS diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index c402d74e33c4..dd8f5197b549 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -707,6 +707,12 @@ asmlinkage void __exception do_mem_abort(unsigned long addr, unsigned int esr, arm64_notify_die("", regs, &info, esr); } +asmlinkage void __exception do_el0_irq_bp_hardening(void) +{ + /* PC has already been checked in entry.S */ + arm64_apply_bp_hardening(); +} + asmlinkage void __exception do_el0_ia_bp_hardening(unsigned long addr, unsigned int esr, struct pt_regs *regs) |