[PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.

From: thinker.li@gmail.com
To: bpf@vger.kernel.org, ast@kernel.org, martin.lau@linux.dev,
	song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Cc: sinquersw@gmail.com, kuifeng@meta.com,
	Kui-Feng Lee <thinker.li@gmail.com>
Subject: [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.
Date: Wed, 14 Feb 2024 18:24:01 -0800	[thread overview]
Message-ID: <20240215022401.1882010-1-thinker.li@gmail.com> (raw)

From: Kui-Feng Lee <thinker.li@gmail.com>

Recently, cfi_stubs were introduced. However, existing struct_ops types
that are not in the upstream may not be aware of this, resulting in kernel
crashes. By rejecting struct_ops types that do not provide cfi_stubs during
registration, these crashes can be avoided.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 kernel/bpf/bpf_struct_ops.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 0d7be97a2411..e35958142dce 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
 	}
 	sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
 
+	if (!st_ops->cfi_stubs) {
+		pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
+		return -EINVAL;
+	}
+
 	type_id = btf_find_by_name_kind(btf, st_ops->name,
 					BTF_KIND_STRUCT);
 	if (type_id < 0) {
-- 
2.34.1

