diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2023-01-09 18:47:59 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-01-20 14:26:18 +0000 |
| commit | 2198d07c509f1db4a1185d1f65aaada794c6ea59 (patch) | |
| tree | 959c8deb4f69da3440f51b57bd907b4af036f602 /arch/arm64/include/asm/scs.h | |
| parent | b7bfaa761d760e72a969d116517eaa12e404c262 (diff) | |
arm64: Always load shadow stack pointer directly from the task struct
All occurrences of the scs_load macro load the value of the shadow call
stack pointer from the task which is current at that point. So instead
of taking a task struct register argument in the scs_load macro to
specify the task struct to load from, let's always reference the current
task directly. This should make it much harder to exploit any
instruction sequences reloading the shadow call stack pointer register
from memory.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230109174800.3286265-2-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/scs.h')
| -rw-r--r-- | arch/arm64/include/asm/scs.h | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index ff7da1268a52..13df982a0808 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -10,15 +10,16 @@ #ifdef CONFIG_SHADOW_CALL_STACK scs_sp .req x18 - .macro scs_load tsk - ldr scs_sp, [\tsk, #TSK_TI_SCS_SP] + .macro scs_load_current + get_current_task scs_sp + ldr scs_sp, [scs_sp, #TSK_TI_SCS_SP] .endm .macro scs_save tsk str scs_sp, [\tsk, #TSK_TI_SCS_SP] .endm #else - .macro scs_load tsk + .macro scs_load_current .endm .macro scs_save tsk |