On Thu, 29 Feb 2024 22:58:54 +0100
Jiri Olsa <olsaj...@gmail.com> wrote:
> 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 for testing!
Let me pick this to probe/fixes.
Thank you,
>
> 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);
> >
> >
--
Masami Hiramatsu (Google) <mhira...@kernel.org>
