diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b55842033073..dda3b94d9661 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -229,8 +229,7 @@ struct bpf_call_arg_meta { bool pkt_access; int regno; int access_size; - s64 msize_smax_value; - u64 msize_umax_value; + u64 msize_max_value; int ref_obj_id; int func_id; u32 btf_id; @@ -3571,11 +3570,15 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, } else if (arg_type_is_mem_size(arg_type)) { bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); - /* remember the mem_size which may be used later - * to refine return values. + /* This is used to refine r0 return value bounds for helpers + * that enforce this value as an upper bound on return values. + * See do_refine_retval_range() for helpers that can refine + * the return value. C type of helper is u32 so we pull register + * bound from umax_value however, if negative verifier errors + * out. Only upper bounds can be learned because retval is an + * int type and negative retvals are allowed. */ - meta->msize_smax_value = reg->smax_value; - meta->msize_umax_value = reg->umax_value; + meta->msize_max_value = reg->umax_value; /* The register is SCALAR_VALUE; the access check * happens using its boundaries. @@ -4118,10 +4121,10 @@ static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type, func_id != BPF_FUNC_probe_read_str)) return; - ret_reg->smax_value = meta->msize_smax_value; - ret_reg->umax_value = meta->msize_umax_value; + ret_reg->smax_value = meta->msize_max_value; __reg_deduce_bounds(ret_reg); __reg_bound_offset(ret_reg); + __update_reg_bounds(ret_reg); } static int |