Commit 3e000833 authored by Kui-Feng Lee's avatar Kui-Feng Lee Committed by Martin KaFai Lau
Browse files

bpf: Check cfi_stubs before registering a struct_ops type. 



Recently, st_ops->cfi_stubs was introduced. However, the upcoming new
struct_ops support (e.g. sched_ext) is not aware of this and does not
provide its own cfi_stubs. The kernel ends up NULL dereferencing the
st_ops->cfi_stubs.

Considering struct_ops supports kernel module now, this NULL check
is necessary. This patch is to reject struct_ops registration
that does not provide a cfi_stubs.

Signed-off-by: default avatarKui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240222021105.1180475-2-thinker.li@gmail.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent 58fd62e0

kernel/bpf/bpf_struct_ops.c

+5 −0
Original line number Diff line number Diff line
@@ -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("struct_ops for %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) {