On Thu, Feb 29, 2024 at 08:22:47PM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhira...@kernel.org>
>
> Fix to allocate fprobe::entry_data_size buffer with rethook instances.
> If fprobe doesn't allocate entry_data_size buffer for each rethook instance,
> fprobe entry handler can cause a buffer overrun when storing entry data in
> entry handler.
>
> Reported-by: Jiri Olsa <olsaj...@gmail.com>
Tested-by: Jiri Olsa <olsaj...@gmail.com>
thanks,
jirka
> Fixes: 4bbd93455659 ("kprobes: kretprobe scalability improvement")
> Cc: sta...@vger.kernel.org
> Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
> ---
> kernel/trace/fprobe.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
> index 6cd2a4e3afb8..9ff018245840 100644
> --- a/kernel/trace/fprobe.c
> +++ b/kernel/trace/fprobe.c
> @@ -189,9 +189,6 @@ static int fprobe_init_rethook(struct fprobe *fp, int num)
> {
> int size;
>
> - if (num <= 0)
> - return -EINVAL;
> -
> if (!fp->exit_handler) {
> fp->rethook = NULL;
> return 0;
> @@ -199,15 +196,16 @@ static int fprobe_init_rethook(struct fprobe *fp, int
> num)
>
> /* Initialize rethook if needed */
> if (fp->nr_maxactive)
> - size = fp->nr_maxactive;
> + num = fp->nr_maxactive;
> else
> - size = num * num_possible_cpus() * 2;
> - if (size <= 0)
> + num *= num_possible_cpus() * 2;
> + if (num <= 0)
> return -EINVAL;
>
> + size = sizeof(struct fprobe_rethook_node) + fp->entry_data_size;
> +
> /* Initialize rethook */
> - fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler,
> - sizeof(struct fprobe_rethook_node), size);
> + fp->rethook = rethook_alloc((void *)fp, fprobe_exit_handler, size, num);
> if (IS_ERR(fp->rethook))
> return PTR_ERR(fp->rethook);
>
>
