On Fri, Dec 01, 2023 at 03:36:26PM +0100, Ilya Leoshkevich wrote:
> On Tue, 2023-11-28 at 10:28 +0100, Jiri Olsa wrote:
> > We need to be able to skip ip address check for caller in following
> > changes. Adding checkip argument to allow that.
> >
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > arch/arm64/net/bpf_jit_comp.c | 3 ++-
> > arch/riscv/net/bpf_jit_comp64.c | 5 +++--
> > arch/s390/net/bpf_jit_comp.c | 3 ++-
> > arch/x86/net/bpf_jit_comp.c | 24 +++++++++++++-----------
> > include/linux/bpf.h | 2 +-
> > kernel/bpf/arraymap.c | 8 ++++----
> > kernel/bpf/core.c | 2 +-
> > kernel/bpf/trampoline.c | 12 ++++++------
> > 8 files changed, 32 insertions(+), 27 deletions(-)
>
> [...]
>
> > --- a/arch/x86/net/bpf_jit_comp.c
> > +++ b/arch/x86/net/bpf_jit_comp.c
> > @@ -435,19 +435,21 @@ static int __bpf_arch_text_poke(void *ip, enum
> > bpf_text_poke_type t,
> > }
> >
> > int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
> > - void *old_addr, void *new_addr)
> > + void *old_addr, void *new_addr, bool checkip)
> > {
> > - if (!is_kernel_text((long)ip) &&
> > - !is_bpf_text_address((long)ip))
> > - /* BPF poking in modules is not supported */
> > - return -EINVAL;
> > + if (checkip) {
> > + if (!is_kernel_text((long)ip) &&
> > + !is_bpf_text_address((long)ip))
> > + /* BPF poking in modules is not supported */
> > + return -EINVAL;
> >
> > - /*
> > - * See emit_prologue(), for IBT builds the trampoline hook is
> > preceded
> > - * with an ENDBR instruction.
> > - */
> > - if (is_endbr(*(u32 *)ip))
> > - ip += ENDBR_INSN_SIZE;
> > + /*
> > + * See emit_prologue(), for IBT builds the trampoline
> > hook is preceded
> > + * with an ENDBR instruction.
> > + */
> > + if (is_endbr(*(u32 *)ip))
> > + ip += ENDBR_INSN_SIZE;
>
> Do we really want to skip the IP adjustment too?
the idea was that with __bpf_arch_text_poke you are aware of what you
are updating, so there's no need for extra checking
anyway this version got deprecated and I just sent v3 which is bit
different without this change
thanks,
jirka
>
> > + }
> >
> > return __bpf_arch_text_poke(ip, t, old_addr, new_addr);
> > }
>
> [...]
