From: Alexei Starovoitov <[email protected]>
Date: Wed, 6 Apr 2016 19:39:21 -0700
> verifier is using the following structure to track the state of registers:
> struct reg_state {
> enum bpf_reg_type type;
> union {
> int imm;
> struct bpf_map *map_ptr;
> };
> };
> and later on in states_equal() does memcmp(&old->regs[i], &cur->regs[i],..)
> to find equivalent states.
> Throughout the code of verifier there are assignements to 'imm' and 'map_ptr'
> fields and it's not obvious that most of the assignments into 'imm' don't
> need to clear extra 4 bytes (like mark_reg_unknown_value() does) to make sure
> that memcmp doesn't go over junk left from 'map_ptr' assignment.
>
> Simplify the code by converting 'int' into 'long'
>
> Suggested-by: Daniel Borkmann <[email protected]>
> Signed-off-by: Alexei Starovoitov <[email protected]>
Applied, thanks Daniel.
