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| author | Ard Biesheuvel <ardb@kernel.org> | 2023-01-09 18:47:59 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-11 23:02:59 +0900 |
| commit | 2dd0f8994da14bd59c2f5d2b56849308caed193c (patch) | |
| tree | 8d07605ef32b461f20e0a8403d38f7af13904486 | |
| parent | 06003e3975238a91999914b20bb96d9b84603f6e (diff) | |
| download | linux-stable-2dd0f8994da14bd59c2f5d2b56849308caed193c.tar.gz linux-stable-2dd0f8994da14bd59c2f5d2b56849308caed193c.tar.bz2 linux-stable-2dd0f8994da14bd59c2f5d2b56849308caed193c.zip | |
arm64: Always load shadow stack pointer directly from the task struct
commit 2198d07c509f1db4a1185d1f65aaada794c6ea59 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/scs.h | 7 | ||||
| -rw-r--r-- | arch/arm64/kernel/entry.S | 4 | ||||
| -rw-r--r-- | arch/arm64/kernel/head.S | 2 |
3 files changed, 7 insertions, 6 deletions
diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index 8297bccf0784..5cd4d09bc69d 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -9,15 +9,16 @@ #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 diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index e28137d64b76..20e25083eced 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -272,7 +272,7 @@ alternative_if ARM64_HAS_ADDRESS_AUTH alternative_else_nop_endif 1: - scs_load tsk + scs_load_current .else add x21, sp, #PT_REGS_SIZE get_current_task tsk @@ -845,7 +845,7 @@ SYM_FUNC_START(cpu_switch_to) msr sp_el0, x1 ptrauth_keys_install_kernel x1, x8, x9, x10 scs_save x0 - scs_load x1 + scs_load_current ret SYM_FUNC_END(cpu_switch_to) NOKPROBE(cpu_switch_to) diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 2196aad7b55b..cdbbc95eb49d 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -404,7 +404,7 @@ SYM_FUNC_END(create_kernel_mapping) stp xzr, xzr, [sp, #S_STACKFRAME] add x29, sp, #S_STACKFRAME - scs_load \tsk + scs_load_current adr_l \tmp1, __per_cpu_offset ldr w\tmp2, [\tsk, #TSK_TI_CPU] |