Commit 762f8515 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

selftests/bpf: Add verifier test for d_path helper 



Adding verifier test for attaching tracing program and
calling d_path helper from within and testing that it's
allowed for dentry_open function and denied for 'd_path'
function with appropriate error.

Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/20200825192124.710397-13-jolsa@kernel.org
parent 68a26bc7

tools/testing/selftests/bpf/test_verifier.c

+18 −1
Original line number Diff line number Diff line
@@ -114,6 +114,7 @@ struct bpf_test { 
		bpf_testdata_struct_t retvals[MAX_TEST_RUNS];

	};

	enum bpf_attach_type expected_attach_type;

	const char *kfunc;

};



/* Note we want this to be 64 bit aligned so that the end of our array is
@@ -984,8 +985,24 @@ static void do_test_single(struct bpf_test *test, bool unpriv, 
		attr.log_level = 4;

	attr.prog_flags = pflags;



	if (prog_type == BPF_PROG_TYPE_TRACING && test->kfunc) {

		attr.attach_btf_id = libbpf_find_vmlinux_btf_id(test->kfunc,

						attr.expected_attach_type);

		if (attr.attach_btf_id < 0) {

			printf("FAIL\nFailed to find BTF ID for '%s'!\n",

				test->kfunc);

			(*errors)++;

			return;

		}

	}



	fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog));

	if (fd_prog < 0 && !bpf_probe_prog_type(prog_type, 0)) {



	/* BPF_PROG_TYPE_TRACING requires more setup and

	 * bpf_probe_prog_type won't give correct answer

	 */

	if (fd_prog < 0 && prog_type != BPF_PROG_TYPE_TRACING &&

	    !bpf_probe_prog_type(prog_type, 0)) {

		printf("SKIP (unsupported program type %d)\n", prog_type);

		skips++;

		goto close_fds;

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

0 → 100644
+37 −0
Original line number Diff line number Diff line 
{

	"d_path accept",

	.insns = {

	BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1, 0),

	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),

	BPF_MOV64_IMM(BPF_REG_6, 0),

	BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_6, 0),

	BPF_LD_IMM64(BPF_REG_3, 8),

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

	BPF_MOV64_IMM(BPF_REG_0, 0),

	BPF_EXIT_INSN(),

	},

	.result = ACCEPT,

	.prog_type = BPF_PROG_TYPE_TRACING,

	.expected_attach_type = BPF_TRACE_FENTRY,

	.kfunc = "dentry_open",

},

{

	"d_path reject",

	.insns = {

	BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_1, 0),

	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),

	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),

	BPF_MOV64_IMM(BPF_REG_6, 0),

	BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_6, 0),

	BPF_LD_IMM64(BPF_REG_3, 8),

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

	BPF_MOV64_IMM(BPF_REG_0, 0),

	BPF_EXIT_INSN(),

	},

	.errstr = "helper call is not allowed in probe",

	.result = REJECT,

	.prog_type = BPF_PROG_TYPE_TRACING,

	.expected_attach_type = BPF_TRACE_FENTRY,

	.kfunc = "d_path",

},

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