Re: [PATCH] riscv: fix out of bounds in walk_stackframe

[Greg KH]

On Fri, Sep 29, 2023 at 07:12:40AM +0800, Edward AD wrote:
> Add vmalloc and kernel addresses check to prevent invalid access.
> 
> Closes: https://lore.kernel.org/all/20230926105949.1025995-2-twuufnxlz@xxxxxxxxx/
> Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly")
> Reported-and-test-by: syzbot+8d2757d62d403b2d9275@xxxxxxxxxxxxxxxxxxxxxxxxx
> Link: https://lore.kernel.org/all/0000000000000170df0605ccf91a@xxxxxxxxxx/T/
> Signed-off-by: Edward AD <twuufnxlz@xxxxxxxxx>
> ---
>  arch/riscv/kernel/stacktrace.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index 64a9c093aef9..031a4a35c1d0 100644
> --- a/arch/riscv/kernel/stacktrace.c
> +++ b/arch/riscv/kernel/stacktrace.c
> @@ -54,6 +54,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
>  			break;
>  		/* Unwind stack frame */
>  		frame = (struct stackframe *)fp - 1;
> +		if ((is_vmalloc_addr(frame) && !pfn_valid(page_to_pfn(vmalloc_to_page(frame)))) || 
> +		     !virt_addr_valid(frame))
> +			break;
>  		sp = fp;
>  		if (regs && (regs->epc == pc) && (frame->fp & 0x7)) {
>  			fp = frame->ra;
> -- 
> 2.25.1
> 

Hi,

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