selftests/bpf: Add verifier tests for bpf arg ARG_CONST_MAP_PTR_OR_NULL

Use helper bpf_redirect_map() and bpf_redirect_map_multi() to test bpf
arg ARG_CONST_MAP_PTR and ARG_CONST_MAP_PTR_OR_NULL. Make sure the
map arg could be verified correctly when it is NULL or valid map
pointer.

Add devmap and devmap_hash in struct bpf_test due to bpf_redirect_{map,
map_multi} limit.

Test result:
 ]# ./test_verifier 702 705
 torvalds#702/p ARG_CONST_MAP_PTR: null pointer OK
 torvalds#703/p ARG_CONST_MAP_PTR: valid map pointer OK
 torvalds#704/p ARG_CONST_MAP_PTR_OR_NULL: null pointer for ex_map OK
 torvalds#705/p ARG_CONST_MAP_PTR_OR_NULL: valid map pointer for ex_map OK
 Summary: 4 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

tools/testing/selftests/bpf/test_verifier.c

@@ -50,7 +50,7 @@
 #define MAX_INSNS	BPF_MAXINSNS
 #define MAX_TEST_INSNS	1000000
 #define MAX_FIXUPS	8
-#define MAX_NR_MAPS	20
+#define MAX_NR_MAPS	22
 #define MAX_TEST_RUNS	8
 #define POINTER_VALUE	0xcafe4all
 #define TEST_DATA_LEN	64
@@ -87,6 +87,8 @@ struct bpf_test {
 	int fixup_sk_storage_map[MAX_FIXUPS];
 	int fixup_map_event_output[MAX_FIXUPS];
 	int fixup_map_reuseport_array[MAX_FIXUPS];
+	int fixup_map_devmap[MAX_FIXUPS];
+	int fixup_map_devmap_hash[MAX_FIXUPS];
 	const char *errstr;
 	const char *errstr_unpriv;
 	uint32_t insn_processed;
@@ -640,6 +642,8 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
 	int *fixup_sk_storage_map = test->fixup_sk_storage_map;
 	int *fixup_map_event_output = test->fixup_map_event_output;
 	int *fixup_map_reuseport_array = test->fixup_map_reuseport_array;
+	int *fixup_map_devmap = test->fixup_map_devmap;
+	int *fixup_map_devmap_hash = test->fixup_map_devmap_hash;
 
 	if (test->fill_helper) {
 		test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn));
@@ -817,6 +821,22 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
 			fixup_map_reuseport_array++;
 		} while (*fixup_map_reuseport_array);
 	}
+	if (*fixup_map_devmap) {
+		map_fds[20] = __create_map(BPF_MAP_TYPE_DEVMAP,
+					   sizeof(u32), sizeof(u32), 1, 0);
+		do {
+			prog[*fixup_map_devmap].imm = map_fds[20];
+			fixup_map_devmap++;
+		} while (*fixup_map_devmap);
+	}
+	if (*fixup_map_devmap_hash) {
+		map_fds[21] = __create_map(BPF_MAP_TYPE_DEVMAP_HASH,
+					   sizeof(u32), sizeof(u32), 1, 0);
+		do {
+			prog[*fixup_map_devmap_hash].imm = map_fds[21];
+			fixup_map_devmap_hash++;
+		} while (*fixup_map_devmap_hash);
+	}
 }
 
 struct libcap {

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

@@ -60,3 +60,73 @@
 	.result = ACCEPT,
 	.retval = 1,
 },
+{
+	"ARG_CONST_MAP_PTR: null pointer",
+	.insns = {
+		/* bpf_redirect_map arg1 (map) */
+		BPF_MOV64_IMM(BPF_REG_1, 0),
+		/* bpf_redirect_map arg2 (ifindex) */
+		BPF_MOV64_IMM(BPF_REG_2, 0),
+		/* bpf_redirect_map arg3 (flags) */
+		BPF_MOV64_IMM(BPF_REG_3, 0),
+		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
+		BPF_EXIT_INSN(),
+	},
+	.result = REJECT,
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.errstr = "R1 type=inv expected=map_ptr",
+},
+{
+	"ARG_CONST_MAP_PTR: valid map pointer",
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_1, 0),
+		/* bpf_redirect_map arg1 (map) */
+		BPF_LD_MAP_FD(BPF_REG_1, 0),
+		/* bpf_redirect_map arg2 (ifindex) */
+		BPF_MOV64_IMM(BPF_REG_2, 0),
+		/* bpf_redirect_map arg3 (flags) */
+		BPF_MOV64_IMM(BPF_REG_3, 0),
+		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
+		BPF_EXIT_INSN(),
+	},
+	.fixup_map_devmap = { 1 },
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_XDP,
+},
+{
+	"ARG_CONST_MAP_PTR_OR_NULL: null pointer for ex_map",
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_1, 0),
+		/* bpf_redirect_map_multi arg1 (in_map) */
+		BPF_LD_MAP_FD(BPF_REG_1, 0),
+		/* bpf_redirect_map_multi arg2 (ex_map) */
+		BPF_MOV64_IMM(BPF_REG_2, 0),
+		/* bpf_redirect_map_multi arg3 (flags) */
+		BPF_MOV64_IMM(BPF_REG_3, 0),
+		BPF_EMIT_CALL(BPF_FUNC_redirect_map_multi),
+		BPF_EXIT_INSN(),
+	},
+	.fixup_map_devmap = { 1 },
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.retval = 4,
+},
+{
+	"ARG_CONST_MAP_PTR_OR_NULL: valid map pointer for ex_map",
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_1, 0),
+		/* bpf_redirect_map_multi arg1 (in_map) */
+		BPF_LD_MAP_FD(BPF_REG_1, 0),
+		/* bpf_redirect_map_multi arg2 (ex_map) */
+		BPF_LD_MAP_FD(BPF_REG_2, 1),
+		/* bpf_redirect_map_multi arg3 (flags) */
+		BPF_MOV64_IMM(BPF_REG_3, 0),
+		BPF_EMIT_CALL(BPF_FUNC_redirect_map_multi),
+		BPF_EXIT_INSN(),
+	},
+	.fixup_map_devmap = { 1 },
+	.fixup_map_devmap_hash = { 3 },
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.retval = 4,
+},