[PATCH v3 1/3] arm64: Change the on_*stack functions to take a size argument
Mark Rutland
mark.rutland at arm.com
Tue Dec 8 05:20:16 EST 2020
Hi Peter,
Thanks for bearing with all the review comments. The patches look good
to me now, and I've given this some light testing locally with a
tip-of-tree clang (testing KASAN with LKDTM, and a short soak under
Syzkaller with lots of debug enabled) and that hasn't highlighted any
problems.
So for the series:
Reviewed-by: Mark Rutland <mark.rutland at arm.com>
Tested-by: Mark Rutland <mark.rutland at arm.com>
Thanks,
Mark.
On Wed, Dec 02, 2020 at 09:12:22PM -0800, Peter Collingbourne wrote:
> unwind_frame() was previously implicitly checking that the frame
> record is in bounds of the stack by enforcing that FP is both aligned
> to 16 and in bounds of the stack. Once the FP alignment requirement
> is relaxed to 8 this will not be sufficient because it does not
> account for the case where FP points to 8 bytes before the end of the
> stack.
>
> Make the check explicit by changing the on_*stack functions to take a
> size argument and adjusting the callers to pass the appropriate sizes.
>
> Signed-off-by: Peter Collingbourne <pcc at google.com>
> Link: https://linux-review.googlesource.com/id/Ib7a3eb3eea41b0687ffaba045ceb2012d077d8b4
> ---
> arch/arm64/include/asm/processor.h | 12 +++++------
> arch/arm64/include/asm/sdei.h | 7 ++++---
> arch/arm64/include/asm/stacktrace.h | 32 ++++++++++++++---------------
> arch/arm64/kernel/ptrace.c | 2 +-
> arch/arm64/kernel/sdei.c | 16 ++++++++-------
> arch/arm64/kernel/stacktrace.c | 2 +-
> 6 files changed, 37 insertions(+), 34 deletions(-)
>
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index fce8cbecd6bc..bf3e07f67e79 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -318,13 +318,13 @@ long get_tagged_addr_ctrl(struct task_struct *task);
> * of header definitions for the use of task_stack_page.
> */
>
> -#define current_top_of_stack() \
> -({ \
> - struct stack_info _info; \
> - BUG_ON(!on_accessible_stack(current, current_stack_pointer, &_info)); \
> - _info.high; \
> +#define current_top_of_stack() \
> +({ \
> + struct stack_info _info; \
> + BUG_ON(!on_accessible_stack(current, current_stack_pointer, 1, &_info)); \
> + _info.high; \
> })
> -#define on_thread_stack() (on_task_stack(current, current_stack_pointer, NULL))
> +#define on_thread_stack() (on_task_stack(current, current_stack_pointer, 1, NULL))
>
> #endif /* __ASSEMBLY__ */
> #endif /* __ASM_PROCESSOR_H */
> diff --git a/arch/arm64/include/asm/sdei.h b/arch/arm64/include/asm/sdei.h
> index 63e0b92a5fbb..8bc30a5c4569 100644
> --- a/arch/arm64/include/asm/sdei.h
> +++ b/arch/arm64/include/asm/sdei.h
> @@ -42,8 +42,9 @@ unsigned long sdei_arch_get_entry_point(int conduit);
>
> struct stack_info;
>
> -bool _on_sdei_stack(unsigned long sp, struct stack_info *info);
> -static inline bool on_sdei_stack(unsigned long sp,
> +bool _on_sdei_stack(unsigned long sp, unsigned long size,
> + struct stack_info *info);
> +static inline bool on_sdei_stack(unsigned long sp, unsigned long size,
> struct stack_info *info)
> {
> if (!IS_ENABLED(CONFIG_VMAP_STACK))
> @@ -51,7 +52,7 @@ static inline bool on_sdei_stack(unsigned long sp,
> if (!IS_ENABLED(CONFIG_ARM_SDE_INTERFACE))
> return false;
> if (in_nmi())
> - return _on_sdei_stack(sp, info);
> + return _on_sdei_stack(sp, size, info);
>
> return false;
> }
> diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
> index eb29b1fe8255..77192df232bf 100644
> --- a/arch/arm64/include/asm/stacktrace.h
> +++ b/arch/arm64/include/asm/stacktrace.h
> @@ -69,14 +69,14 @@ extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
>
> DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
>
> -static inline bool on_stack(unsigned long sp, unsigned long low,
> - unsigned long high, enum stack_type type,
> - struct stack_info *info)
> +static inline bool on_stack(unsigned long sp, unsigned long size,
> + unsigned long low, unsigned long high,
> + enum stack_type type, struct stack_info *info)
> {
> if (!low)
> return false;
>
> - if (sp < low || sp >= high)
> + if (sp < low || sp + size < sp || sp + size > high)
> return false;
>
> if (info) {
> @@ -87,38 +87,38 @@ static inline bool on_stack(unsigned long sp, unsigned long low,
> return true;
> }
>
> -static inline bool on_irq_stack(unsigned long sp,
> +static inline bool on_irq_stack(unsigned long sp, unsigned long size,
> struct stack_info *info)
> {
> unsigned long low = (unsigned long)raw_cpu_read(irq_stack_ptr);
> unsigned long high = low + IRQ_STACK_SIZE;
>
> - return on_stack(sp, low, high, STACK_TYPE_IRQ, info);
> + return on_stack(sp, size, low, high, STACK_TYPE_IRQ, info);
> }
>
> static inline bool on_task_stack(const struct task_struct *tsk,
> - unsigned long sp,
> + unsigned long sp, unsigned long size,
> struct stack_info *info)
> {
> unsigned long low = (unsigned long)task_stack_page(tsk);
> unsigned long high = low + THREAD_SIZE;
>
> - return on_stack(sp, low, high, STACK_TYPE_TASK, info);
> + return on_stack(sp, size, low, high, STACK_TYPE_TASK, info);
> }
>
> #ifdef CONFIG_VMAP_STACK
> DECLARE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack);
>
> -static inline bool on_overflow_stack(unsigned long sp,
> +static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
> struct stack_info *info)
> {
> unsigned long low = (unsigned long)raw_cpu_ptr(overflow_stack);
> unsigned long high = low + OVERFLOW_STACK_SIZE;
>
> - return on_stack(sp, low, high, STACK_TYPE_OVERFLOW, info);
> + return on_stack(sp, size, low, high, STACK_TYPE_OVERFLOW, info);
> }
> #else
> -static inline bool on_overflow_stack(unsigned long sp,
> +static inline bool on_overflow_stack(unsigned long sp, unsigned long size,
> struct stack_info *info) { return false; }
> #endif
>
> @@ -128,21 +128,21 @@ static inline bool on_overflow_stack(unsigned long sp,
> * context.
> */
> static inline bool on_accessible_stack(const struct task_struct *tsk,
> - unsigned long sp,
> + unsigned long sp, unsigned long size,
> struct stack_info *info)
> {
> if (info)
> info->type = STACK_TYPE_UNKNOWN;
>
> - if (on_task_stack(tsk, sp, info))
> + if (on_task_stack(tsk, sp, size, info))
> return true;
> if (tsk != current || preemptible())
> return false;
> - if (on_irq_stack(sp, info))
> + if (on_irq_stack(sp, size, info))
> return true;
> - if (on_overflow_stack(sp, info))
> + if (on_overflow_stack(sp, size, info))
> return true;
> - if (on_sdei_stack(sp, info))
> + if (on_sdei_stack(sp, size, info))
> return true;
>
> return false;
> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
> index f49b349e16a3..b44d6981decb 100644
> --- a/arch/arm64/kernel/ptrace.c
> +++ b/arch/arm64/kernel/ptrace.c
> @@ -122,7 +122,7 @@ static bool regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
> {
> return ((addr & ~(THREAD_SIZE - 1)) ==
> (kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1))) ||
> - on_irq_stack(addr, NULL);
> + on_irq_stack(addr, sizeof(unsigned long), NULL);
> }
>
> /**
> diff --git a/arch/arm64/kernel/sdei.c b/arch/arm64/kernel/sdei.c
> index 793c46d6a447..ee8a13ce239b 100644
> --- a/arch/arm64/kernel/sdei.c
> +++ b/arch/arm64/kernel/sdei.c
> @@ -91,31 +91,33 @@ static int init_sdei_stacks(void)
> return err;
> }
>
> -static bool on_sdei_normal_stack(unsigned long sp, struct stack_info *info)
> +static bool on_sdei_normal_stack(unsigned long sp, unsigned long size,
> + struct stack_info *info)
> {
> unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_normal_ptr);
> unsigned long high = low + SDEI_STACK_SIZE;
>
> - return on_stack(sp, low, high, STACK_TYPE_SDEI_NORMAL, info);
> + return on_stack(sp, size, low, high, STACK_TYPE_SDEI_NORMAL, info);
> }
>
> -static bool on_sdei_critical_stack(unsigned long sp, struct stack_info *info)
> +static bool on_sdei_critical_stack(unsigned long sp, unsigned long size,
> + struct stack_info *info)
> {
> unsigned long low = (unsigned long)raw_cpu_read(sdei_stack_critical_ptr);
> unsigned long high = low + SDEI_STACK_SIZE;
>
> - return on_stack(sp, low, high, STACK_TYPE_SDEI_CRITICAL, info);
> + return on_stack(sp, size, low, high, STACK_TYPE_SDEI_CRITICAL, info);
> }
>
> -bool _on_sdei_stack(unsigned long sp, struct stack_info *info)
> +bool _on_sdei_stack(unsigned long sp, unsigned long size, struct stack_info *info)
> {
> if (!IS_ENABLED(CONFIG_VMAP_STACK))
> return false;
>
> - if (on_sdei_critical_stack(sp, info))
> + if (on_sdei_critical_stack(sp, size, info))
> return true;
>
> - if (on_sdei_normal_stack(sp, info))
> + if (on_sdei_normal_stack(sp, size, info))
> return true;
>
> return false;
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index fa56af1a59c3..ce613e22b58b 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -50,7 +50,7 @@ int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
> if (!tsk)
> tsk = current;
>
> - if (!on_accessible_stack(tsk, fp, &info))
> + if (!on_accessible_stack(tsk, fp, 16, &info))
> return -EINVAL;
>
> if (test_bit(info.type, frame->stacks_done))
> --
> 2.29.2.454.gaff20da3a2-goog
>
More information about the linux-arm-kernel
mailing list