Commit c25b2ae1 authored by Hao Luo's avatar Hao Luo Committed by Alexei Starovoitov

bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL

We have introduced a new type to make bpf_reg composable, by
allocating bits in the type to represent flags.

One of the flags is PTR_MAYBE_NULL which indicates a pointer
may be NULL. This patch switches the qualified reg_types to
use this flag. The reg_types changed in this patch include:

1. PTR_TO_MAP_VALUE_OR_NULL
2. PTR_TO_SOCKET_OR_NULL
3. PTR_TO_SOCK_COMMON_OR_NULL
4. PTR_TO_TCP_SOCK_OR_NULL
5. PTR_TO_BTF_ID_OR_NULL
6. PTR_TO_MEM_OR_NULL
7. PTR_TO_RDONLY_BUF_OR_NULL
8. PTR_TO_RDWR_BUF_OR_NULL
Signed-off-by: default avatarHao Luo <haoluo@google.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20211217003152.48334-5-haoluo@google.com
parent 3c480732
......@@ -465,18 +465,15 @@ enum bpf_reg_type {
PTR_TO_CTX, /* reg points to bpf_context */
CONST_PTR_TO_MAP, /* reg points to struct bpf_map */
PTR_TO_MAP_VALUE, /* reg points to map element value */
PTR_TO_MAP_VALUE_OR_NULL,/* points to map elem value or NULL */
PTR_TO_MAP_KEY, /* reg points to a map element key */
PTR_TO_STACK, /* reg == frame_pointer + offset */
PTR_TO_PACKET_META, /* skb->data - meta_len */
PTR_TO_PACKET, /* reg points to skb->data */
PTR_TO_PACKET_END, /* skb->data + headlen */
PTR_TO_FLOW_KEYS, /* reg points to bpf_flow_keys */
PTR_TO_SOCKET, /* reg points to struct bpf_sock */
PTR_TO_SOCKET_OR_NULL, /* reg points to struct bpf_sock or NULL */
PTR_TO_SOCK_COMMON, /* reg points to sock_common */
PTR_TO_SOCK_COMMON_OR_NULL, /* reg points to sock_common or NULL */
PTR_TO_TCP_SOCK, /* reg points to struct tcp_sock */
PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
PTR_TO_TP_BUFFER, /* reg points to a writable raw tp's buffer */
PTR_TO_XDP_SOCK, /* reg points to struct xdp_sock */
/* PTR_TO_BTF_ID points to a kernel struct that does not need
......@@ -494,18 +491,21 @@ enum bpf_reg_type {
* been checked for null. Used primarily to inform the verifier
* an explicit null check is required for this struct.
*/
PTR_TO_BTF_ID_OR_NULL,
PTR_TO_MEM, /* reg points to valid memory region */
PTR_TO_MEM_OR_NULL, /* reg points to valid memory region or NULL */
PTR_TO_RDONLY_BUF, /* reg points to a readonly buffer */
PTR_TO_RDONLY_BUF_OR_NULL, /* reg points to a readonly buffer or NULL */
PTR_TO_RDWR_BUF, /* reg points to a read/write buffer */
PTR_TO_RDWR_BUF_OR_NULL, /* reg points to a read/write buffer or NULL */
PTR_TO_PERCPU_BTF_ID, /* reg points to a percpu kernel variable */
PTR_TO_FUNC, /* reg points to a bpf program function */
PTR_TO_MAP_KEY, /* reg points to a map element key */
__BPF_REG_TYPE_MAX,
/* Extended reg_types. */
PTR_TO_MAP_VALUE_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MAP_VALUE,
PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCKET,
PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | PTR_TO_SOCK_COMMON,
PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | PTR_TO_TCP_SOCK,
PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | PTR_TO_BTF_ID,
PTR_TO_MEM_OR_NULL = PTR_MAYBE_NULL | PTR_TO_MEM,
/* This must be the last entry. Its purpose is to ensure the enum is
* wide enough to hold the higher bits reserved for bpf_type_flag.
*/
......
......@@ -18,6 +18,8 @@
* that converting umax_value to int cannot overflow.
*/
#define BPF_MAX_VAR_SIZ (1 << 29)
/* size of type_str_buf in bpf_verifier. */
#define TYPE_STR_BUF_LEN 64
/* Liveness marks, used for registers and spilled-regs (in stack slots).
* Read marks propagate upwards until they find a write mark; they record that
......@@ -484,6 +486,8 @@ struct bpf_verifier_env {
/* Same as scratched_regs but for stack slots */
u64 scratched_stack_slots;
u32 prev_log_len, prev_insn_print_len;
/* buffer used in reg_type_str() to generate reg_type string */
char type_str_buf[TYPE_STR_BUF_LEN];
};
__printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,
......
......@@ -4940,10 +4940,13 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
/* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
u32 type, flag;
type = base_type(ctx_arg_info->reg_type);
flag = type_flag(ctx_arg_info->reg_type);
if (ctx_arg_info->offset == off &&
(ctx_arg_info->reg_type == PTR_TO_RDONLY_BUF_OR_NULL ||
ctx_arg_info->reg_type == PTR_TO_RDWR_BUF_OR_NULL)) {
(type == PTR_TO_RDWR_BUF || type == PTR_TO_RDONLY_BUF) &&
(flag & PTR_MAYBE_NULL)) {
info->reg_type = ctx_arg_info->reg_type;
return true;
}
......
......@@ -174,9 +174,9 @@ static const struct bpf_iter_reg bpf_map_elem_reg_info = {
.ctx_arg_info_size = 2,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__bpf_map_elem, key),
PTR_TO_RDONLY_BUF_OR_NULL },
PTR_TO_RDONLY_BUF | PTR_MAYBE_NULL },
{ offsetof(struct bpf_iter__bpf_map_elem, value),
PTR_TO_RDWR_BUF_OR_NULL },
PTR_TO_RDWR_BUF | PTR_MAYBE_NULL },
},
};
......
This diff is collapsed.
......@@ -929,7 +929,7 @@ static struct bpf_iter_reg bpf_sk_storage_map_reg_info = {
{ offsetof(struct bpf_iter__bpf_sk_storage_map, sk),
PTR_TO_BTF_ID_OR_NULL },
{ offsetof(struct bpf_iter__bpf_sk_storage_map, value),
PTR_TO_RDWR_BUF_OR_NULL },
PTR_TO_RDWR_BUF | PTR_MAYBE_NULL },
},
.seq_info = &iter_seq_info,
};
......
......@@ -1564,7 +1564,7 @@ static struct bpf_iter_reg sock_map_iter_reg = {
.ctx_arg_info_size = 2,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__sockmap, key),
PTR_TO_RDONLY_BUF_OR_NULL },
PTR_TO_RDONLY_BUF | PTR_MAYBE_NULL },
{ offsetof(struct bpf_iter__sockmap, sk),
PTR_TO_BTF_ID_OR_NULL },
},
......
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