On Wed, Sep 09, 2020 at 06:11:55PM +0100, Lorenz Bauer wrote:
> The mapping between bpf_arg_type and bpf_reg_type is encoded in a big
> hairy if statement that is hard to follow. The debug output also leaves
> to be desired: if a reg_type doesn't match we only print one of the
> options, instead printing all the valid ones.
>
> Convert the if statement into a table which is then used to drive type
> checking. If none of the reg_types match we print all options, e.g.:
>
> R2 type=rdonly_buf expected=fp, pkt, pkt_meta, map_value
>
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> ---
> include/linux/bpf.h | 1 +
> kernel/bpf/verifier.c | 189 +++++++++++++++++++++++++-----------------
> 2 files changed, 116 insertions(+), 74 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index aabbc8bb52bd..7cf7e90f55bb 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -292,6 +292,7 @@ enum bpf_arg_type {
> ARG_PTR_TO_ALLOC_MEM, /* pointer to dynamically allocated memory */
> ARG_PTR_TO_ALLOC_MEM_OR_NULL, /* pointer to dynamically allocated memory or NULL */
> ARG_CONST_ALLOC_SIZE_OR_ZERO, /* number of allocated bytes requested */
> + __BPF_ARG_TYPE_MAX,
> };
>
> /* type of values returned from helper functions */
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index ebf900fceaf0..9c9728c81d4c 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -3856,12 +3856,6 @@ static bool arg_type_is_mem_size(enum bpf_arg_type type)
> type == ARG_CONST_SIZE_OR_ZERO;
> }
>
> -static bool arg_type_is_alloc_mem_ptr(enum bpf_arg_type type)
> -{
> - return type == ARG_PTR_TO_ALLOC_MEM ||
> - type == ARG_PTR_TO_ALLOC_MEM_OR_NULL;
> -}
> -
> static bool arg_type_is_alloc_size(enum bpf_arg_type type)
> {
> return type == ARG_CONST_ALLOC_SIZE_OR_ZERO;
> @@ -3910,14 +3904,121 @@ static int resolve_map_arg_type(struct bpf_verifier_env *env,
> return 0;
> }
>
> +struct bpf_reg_types {
> + const enum bpf_reg_type types[10];
> +};
> +
> +static const struct bpf_reg_types map_key_value_types = {
> + .types = {
> + PTR_TO_STACK,
> + PTR_TO_PACKET,
> + PTR_TO_PACKET_META,
> + PTR_TO_MAP_VALUE,
> + },
> +};
> +
> +static const struct bpf_reg_types sock_types = {
> + .types = {
> + PTR_TO_SOCK_COMMON,
> + PTR_TO_SOCKET,
> + PTR_TO_TCP_SOCK,
> + PTR_TO_XDP_SOCK,
> + },
> +};
> +
> +static const struct bpf_reg_types mem_types = {
> + .types = {
> + PTR_TO_STACK,
> + PTR_TO_PACKET,
> + PTR_TO_PACKET_META,
> + PTR_TO_MAP_VALUE,
> + PTR_TO_MEM,
> + PTR_TO_RDONLY_BUF,
> + PTR_TO_RDWR_BUF,
> + },
> +};
> +
> +static const struct bpf_reg_types int_ptr_types = {
> + .types = {
> + PTR_TO_STACK,
> + PTR_TO_PACKET,
> + PTR_TO_PACKET_META,
> + PTR_TO_MAP_VALUE,
> + },
> +};
> +
> +static const struct bpf_reg_types fullsock_types = {
> + .types = {
> + PTR_TO_SOCKET,
> + PTR_TO_BTF_ID,
PTR_TO_BTF_ID should be added at the sockmap-iter-update patch instead.
Others lgtm.
