Re: [PATCH 2/2] kprobes: verify jprobe entry point

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

Namhyung Kim wrote:
> verify jprobe's entry point is a function entry point
> using kallsyms' offset value.
> 
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>

Looks good for me :) Thanks!

Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>


> ---
> 
> Here comes 3rd revision of the patch. Thanks to Masami Hiramatus for suggesting
> kallsyms_lookup_size_offset. :-)
> 
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 8f96701..1b0dbe0 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1339,14 +1339,18 @@ int __kprobes register_jprobes(struct jprobe **jps, int num)
>  	if (num <= 0)
>  		return -EINVAL;
>  	for (i = 0; i < num; i++) {
> -		unsigned long addr;
> +		unsigned long addr, offset;
>  		jp = jps[i];
>  		addr = arch_deref_entry_point(jp->entry);
> 
> -		/* Todo: Verify probepoint is a function entry point */
> -		jp->kp.pre_handler = setjmp_pre_handler;
> -		jp->kp.break_handler = longjmp_break_handler;
> -		ret = register_kprobe(&jp->kp);
> +		/* Verify probepoint is a function entry point */
> +		if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
> +		    offset = 0) {
> +			jp->kp.pre_handler = setjmp_pre_handler;
> +			jp->kp.break_handler = longjmp_break_handler;
> +			ret = register_kprobe(&jp->kp);
> +		} else
> +			ret = -EINVAL;
> 
>  		if (ret < 0) {
>  			if (i > 0)
> --
> 1.7.0.4
> 

-- 
Masami HIRAMATSU
2nd Research Dept.
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com