Namhyung Kim schrieb:
> verify jprobe's entry point is a function entry point
> using kallsyms' offset value.
>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxx>
>
> ---
>
> 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)
I am a bit converned about this code here:
if (kallsyms_lookup_size_offset(addr, NULL, &offset) && offset == 0)
offset is set inside kallsyms_lookup_size_offset(), right ?
but can you guarantee that the calling sequence is the same on all processors ?
(it is not in case of functions).
perhaps it is more secure (and readable) to do:
ret=kallsyms_lookup_size_offset(addr, NULL, &offset);
if ( ret && offset == 0 )
just my 2 cents,
re,
wh
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