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authorAlexei Starovoitov <ast@kernel.org>2023-04-03 21:50:25 -0700
committerAndrii Nakryiko <andrii@kernel.org>2023-04-04 16:57:16 -0700
commit91571a515d1bcdc280bb46423bb697ea7eb42ff3 (patch)
tree636320a1ffcdd78b5091e70cca1f5f1353472aef /net/core
parent63260df1396578226ac3134cf7f764690002e70e (diff)
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
Diffstat (limited to 'net/core')
-rw-r--r--net/core/bpf_sk_storage.c4
-rw-r--r--net/core/filter.c2
2 files changed, 3 insertions, 3 deletions
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index 085025c7130a..d4172534dfa8 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -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,
};
diff --git a/net/core/filter.c b/net/core/filter.c
index 1f2abf0f60e6..727c5269867d 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -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)