Commit e435b043 authored by Tengda Wu's avatar Tengda Wu Committed by Daniel Borkmann
Browse files

selftests/bpf: Test for null-pointer-deref bugfix in resolve_prog_type() 



This test verifies that resolve_prog_type() works as expected when
`attach_prog_fd` is not passed in.

`prog->aux->dst_prog` in resolve_prog_type() is assigned by
`attach_prog_fd`, and would be NULL if `attach_prog_fd` is not provided.

Loading EXT prog with bpf_dynptr_from_skb() kfunc call in this way will
lead to null-pointer-deref.

Verify that the null-pointer-deref bug in resolve_prog_type() is fixed.

Signed-off-by: default avatarTengda Wu <wutengda@huaweicloud.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240711145819.254178-3-wutengda@huaweicloud.com
parent f7866c35

tools/testing/selftests/bpf/verifier/calls.c

+13 −0
Original line number Diff line number Diff line
@@ -275,6 +275,19 @@ 
	.result_unpriv = REJECT,

	.result = ACCEPT,

},

{

	"calls: invalid kfunc call: must provide (attach_prog_fd, btf_id) pair when freplace",

	.insns = {

	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),

	BPF_EXIT_INSN(),

	},

	.prog_type = BPF_PROG_TYPE_EXT,

	.result = REJECT,

	.errstr = "Tracing programs must provide btf_id",

	.fixup_kfunc_btf_id = {

		{ "bpf_dynptr_from_skb", 0 },

	},

},

{

	"calls: basic sanity",

	.insns = {