bpf: Teach verifier that certain helpers accept NULL pointer.

bpf_[sk|inode|task|cgrp]_storage_[get|delete]() and bpf_get_socket_cookie() helpers
perform run-time check that sk|inode|task|cgrp pointer != NULL.
Teach verifier about this fact and allow bpf programs to pass
PTR_TO_BTF_ID | PTR_MAYBE_NULL into such helpers.
It will be used in the subsequent patch that will do
bpf_sk_storage_get(.., skb->sk, ...);
Even when 'skb' pointer is trusted the 'sk' pointer may be NULL.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/bpf/20230404045029.82870-5-alexei.starovoitov@gmail.com
This commit is contained in:
Alexei Starovoitov 2023-04-03 21:50:25 -07:00 committed by Andrii Nakryiko
parent 63260df139
commit 91571a515d
5 changed files with 11 additions and 11 deletions

View File

@ -224,7 +224,7 @@ const struct bpf_func_proto bpf_cgrp_storage_get_proto = {
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &bpf_cgroup_btf_id[0],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
@ -235,6 +235,6 @@ const struct bpf_func_proto bpf_cgrp_storage_delete_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &bpf_cgroup_btf_id[0],
};

View File

@ -229,7 +229,7 @@ const struct bpf_func_proto bpf_inode_storage_get_proto = {
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &bpf_inode_storage_btf_ids[0],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
@ -240,6 +240,6 @@ const struct bpf_func_proto bpf_inode_storage_delete_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &bpf_inode_storage_btf_ids[0],
};

View File

@ -338,7 +338,7 @@ const struct bpf_func_proto bpf_task_storage_get_recur_proto = {
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
@ -349,7 +349,7 @@ const struct bpf_func_proto bpf_task_storage_get_proto = {
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
@ -360,7 +360,7 @@ const struct bpf_func_proto bpf_task_storage_delete_recur_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
};
@ -369,6 +369,6 @@ const struct bpf_func_proto bpf_task_storage_delete_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],
};

View File

@ -412,7 +412,7 @@ const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = {
.gpl_only = false,
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,
.arg4_type = ARG_ANYTHING,
@ -424,7 +424,7 @@ const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = {
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_CONST_MAP_PTR,
.arg2_type = ARG_PTR_TO_BTF_ID,
.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,
.arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
.allowed = bpf_sk_storage_tracing_allowed,
};

View File

@ -4998,7 +4998,7 @@ const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto = {
.func = bpf_get_socket_ptr_cookie,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
.arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON | PTR_MAYBE_NULL,
};
BPF_CALL_1(bpf_get_socket_cookie_sock_ops, struct bpf_sock_ops_kern *, ctx)