selftests/bpf: set BPF_F_TEST_SANITY_SCRIPT by default

Make sure to set BPF_F_TEST_SANITY_STRICT program flag by default across
most verifier tests (and a bunch of others that set custom prog flags).

There are currently two tests that do fail validation, if enforced
strictly: verifier_bounds/crossing_64_bit_signed_boundary_2 and
verifier_bounds/crossing_32_bit_signed_boundary_2. To accommodate them,
we teach test_loader a flag negation:

__flag(!<flagname>) will *clear* specified flag, allowing easy opt-out.

We apply __flag(!BPF_F_TEST_SANITY_STRICT) to these to tests.

Also sprinkle BPF_F_TEST_SANITY_STRICT everywhere where we already set
test-only BPF_F_TEST_RND_HI32 flag, for completeness.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231112010609.848406-12-andrii@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/bpf_verif_scale.c

@@ -35,7 +35,7 @@ static int check_load(const char *file, enum bpf_prog_type type)
 	}
 
 	bpf_program__set_type(prog, type);
-	bpf_program__set_flags(prog, BPF_F_TEST_RND_HI32);
+	bpf_program__set_flags(prog, BPF_F_TEST_RND_HI32 | BPF_F_TEST_SANITY_STRICT);
 	bpf_program__set_log_level(prog, 4 | extra_prog_load_log_flags);
 
 	err = bpf_object__load(obj);

tools/testing/selftests/bpf/progs/verifier_bounds.c

@@ -965,6 +965,7 @@ l0_%=:	r0 = 0;						\
 SEC("xdp")
 __description("bound check with JMP_JSLT for crossing 64-bit signed boundary")
 __success __retval(0)
+__flag(!BPF_F_TEST_SANITY_STRICT) /* known sanity violation */
 __naked void crossing_64_bit_signed_boundary_2(void)
 {
 	asm volatile ("					\
@@ -1046,6 +1047,7 @@ l0_%=:	r0 = 0;						\
 SEC("xdp")
 __description("bound check with JMP32_JSLT for crossing 32-bit signed boundary")
 __success __retval(0)
+__flag(!BPF_F_TEST_SANITY_STRICT) /* known sanity violation */
 __naked void crossing_32_bit_signed_boundary_2(void)
 {
 	asm volatile ("					\

tools/testing/selftests/bpf/test_loader.c

@@ -153,6 +153,14 @@ static int parse_retval(const char *str, int *val, const char *name)
 	return parse_int(str, val, name);
 }
 
+static void update_flags(int *flags, int flag, bool clear)
+{
+	if (clear)
+		*flags &= ~flag;
+	else
+		*flags |= flag;
+}
+
 /* Uses btf_decl_tag attributes to describe the expected test
  * behavior, see bpf_misc.h for detailed description of each attribute
  * and attribute combinations.
@@ -171,6 +179,7 @@ static int parse_test_spec(struct test_loader *tester,
 	memset(spec, 0, sizeof(*spec));
 
 	spec->prog_name = bpf_program__name(prog);
+	spec->prog_flags = BPF_F_TEST_SANITY_STRICT; /* by default be strict */
 
 	btf = bpf_object__btf(obj);
 	if (!btf) {
@@ -187,7 +196,8 @@ static int parse_test_spec(struct test_loader *tester,
 	for (i = 1; i < btf__type_cnt(btf); i++) {
 		const char *s, *val, *msg;
 		const struct btf_type *t;
-		int tmp;
+		bool clear;
+		int flags;
 
 		t = btf__type_by_id(btf, i);
 		if (!btf_is_decl_tag(t))
@@ -253,23 +263,30 @@ static int parse_test_spec(struct test_loader *tester,
 				goto cleanup;
 		} else if (str_has_pfx(s, TEST_TAG_PROG_FLAGS_PFX)) {
 			val = s + sizeof(TEST_TAG_PROG_FLAGS_PFX) - 1;
+
+			clear = val[0] == '!';
+			if (clear)
+				val++;
+
 			if (strcmp(val, "BPF_F_STRICT_ALIGNMENT") == 0) {
-				spec->prog_flags |= BPF_F_STRICT_ALIGNMENT;
+				update_flags(&spec->prog_flags, BPF_F_STRICT_ALIGNMENT, clear);
 			} else if (strcmp(val, "BPF_F_ANY_ALIGNMENT") == 0) {
-				spec->prog_flags |= BPF_F_ANY_ALIGNMENT;
+				update_flags(&spec->prog_flags, BPF_F_ANY_ALIGNMENT, clear);
 			} else if (strcmp(val, "BPF_F_TEST_RND_HI32") == 0) {
-				spec->prog_flags |= BPF_F_TEST_RND_HI32;
+				update_flags(&spec->prog_flags, BPF_F_TEST_RND_HI32, clear);
 			} else if (strcmp(val, "BPF_F_TEST_STATE_FREQ") == 0) {
-				spec->prog_flags |= BPF_F_TEST_STATE_FREQ;
+				update_flags(&spec->prog_flags, BPF_F_TEST_STATE_FREQ, clear);
 			} else if (strcmp(val, "BPF_F_SLEEPABLE") == 0) {
-				spec->prog_flags |= BPF_F_SLEEPABLE;
+				update_flags(&spec->prog_flags, BPF_F_SLEEPABLE, clear);
 			} else if (strcmp(val, "BPF_F_XDP_HAS_FRAGS") == 0) {
-				spec->prog_flags |= BPF_F_XDP_HAS_FRAGS;
+				update_flags(&spec->prog_flags, BPF_F_XDP_HAS_FRAGS, clear);
+			} else if (strcmp(val, "BPF_F_TEST_SANITY_STRICT") == 0) {
+				update_flags(&spec->prog_flags, BPF_F_TEST_SANITY_STRICT, clear);
 			} else /* assume numeric value */ {
-				err = parse_int(val, &tmp, "test prog flags");
+				err = parse_int(val, &flags, "test prog flags");
 				if (err)
 					goto cleanup;
-				spec->prog_flags |= tmp;
+				update_flags(&spec->prog_flags, flags, clear);
 			}
 		}
 	}

tools/testing/selftests/bpf/test_sock_addr.c

@@ -680,6 +680,7 @@ static int load_path(const struct sock_addr_test *test, const char *path)
 	bpf_program__set_type(prog, BPF_PROG_TYPE_CGROUP_SOCK_ADDR);
 	bpf_program__set_expected_attach_type(prog, test->expected_attach_type);
 	bpf_program__set_flags(prog, BPF_F_TEST_RND_HI32);
+	bpf_program__set_flags(prog, BPF_F_TEST_SANITY_STRICT);
 
 	err = bpf_object__load(obj);
 	if (err) {

tools/testing/selftests/bpf/test_verifier.c

@@ -1588,7 +1588,7 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 	if (fixup_skips != skips)
 		return;
 
-	pflags = BPF_F_TEST_RND_HI32;
+	pflags = BPF_F_TEST_RND_HI32 | BPF_F_TEST_SANITY_STRICT;
 	if (test->flags & F_LOAD_WITH_STRICT_ALIGNMENT)
 		pflags |= BPF_F_STRICT_ALIGNMENT;
 	if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)

tools/testing/selftests/bpf/testing_helpers.c

@@ -276,7 +276,7 @@ int bpf_prog_test_load(const char *file, enum bpf_prog_type type,
 	if (type != BPF_PROG_TYPE_UNSPEC && bpf_program__type(prog) != type)
 		bpf_program__set_type(prog, type);
 
-	flags = bpf_program__flags(prog) | BPF_F_TEST_RND_HI32;
+	flags = bpf_program__flags(prog) | BPF_F_TEST_RND_HI32 | BPF_F_TEST_SANITY_STRICT;
 	bpf_program__set_flags(prog, flags);
 
 	err = bpf_object__load(obj);
@@ -299,7 +299,7 @@ int bpf_test_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
 {
 	LIBBPF_OPTS(bpf_prog_load_opts, opts,
 		.kern_version = kern_version,
-		.prog_flags = BPF_F_TEST_RND_HI32,
+		.prog_flags = BPF_F_TEST_RND_HI32 | BPF_F_TEST_SANITY_STRICT,
 		.log_level = extra_prog_load_log_flags,
 		.log_buf = log_buf,
 		.log_size = log_buf_sz,