[PATCH bpf-next 2/2] selftests/bpf: add new negative tests for xattr related BPF kfuncs

[Matt Bobrowski <mattbobrowski@google.com>]

Add a set of negative tests to verify the newly enforced constraints
applied to xattr related BPF kfuncs.

Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
---
 .../selftests/bpf/prog_tests/fs_kfuncs.c      | 13 ++++++++++++
 .../bpf/progs/test_set_remove_xattr.c         | 21 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c b/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c
index 43a26ec69a8e..168ffcdccc4a 100644
--- a/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c
+++ b/tools/testing/selftests/bpf/prog_tests/fs_kfuncs.c
@@ -128,6 +128,11 @@ static void test_set_remove_xattr(void)
 	if (!ASSERT_OK_PTR(skel, "test_set_remove_xattr__open_and_load"))
 		return;
 
+	/* Prepare the long name for negative test */
+	memset(skel->bss->long_name, 'a', 256);
+	memcpy(skel->bss->long_name, "security.bpf.", 13);
+	skel->bss->long_name[256] = '\0';
+
 	/* Set security.bpf.foo to "hello" */
 	err = setxattr(testfile, skel->rodata->xattr_foo, value_foo, strlen(value_foo) + 1, 0);
 	if (err && errno == EOPNOTSUPP) {
@@ -188,6 +193,14 @@ static void test_set_remove_xattr(void)
 	ASSERT_TRUE(skel->bss->locked_remove_security_selinux_fail,
 		    "locked_remove_security_selinux_fail");
 
+	ASSERT_EQ(skel->bss->ret_name_empty, -ERANGE, "ret_code_name_empty");
+	ASSERT_EQ(skel->bss->ret_name_too_long, -ERANGE,
+		  "ret_code_name_too_long");
+	ASSERT_EQ(skel->bss->ret_value_too_large, -E2BIG,
+		  "ret_code_value_too_large");
+	ASSERT_EQ(skel->bss->ret_invalid_flags, -EINVAL,
+		  "ret_code_invalid_flags");
+
 out:
 	close(fd);
 	test_set_remove_xattr__destroy(skel);
diff --git a/tools/testing/selftests/bpf/progs/test_set_remove_xattr.c b/tools/testing/selftests/bpf/progs/test_set_remove_xattr.c
index 6a612cf168d3..7c857d665eae 100644
--- a/tools/testing/selftests/bpf/progs/test_set_remove_xattr.c
+++ b/tools/testing/selftests/bpf/progs/test_set_remove_xattr.c
@@ -17,6 +17,14 @@ static const char xattr_selinux[] = "security.selinux";
 char value_bar[] = "world";
 char read_value[32];
 
+const char xattr_negative[] = "security.bpf.negative";
+int ret_code_name_empty;
+int ret_code_name_too_long;
+int ret_code_value_too_large;
+int ret_code_invalid_flags;
+char long_name[257];
+char large_value[65537];
+
 bool set_security_bpf_bar_success;
 bool remove_security_bpf_bar_success;
 bool set_security_selinux_fail;
@@ -73,6 +81,19 @@ int BPF_PROG(test_inode_getxattr, struct dentry *dentry, char *name)
 			remove_security_selinux_fail = true;
 	}
 
+	bpf_dynptr_from_mem(read_value, sizeof(read_value), 0, &value_ptr);
+	ret_code_name_empty = bpf_get_dentry_xattr(dentry, "", &value_ptr);
+	ret_code_name_too_long =
+		bpf_get_dentry_xattr(dentry, long_name, &value_ptr);
+
+	bpf_dynptr_from_mem(large_value, sizeof(large_value), 0, &value_ptr);
+	ret_code_value_too_large =
+		bpf_set_dentry_xattr(dentry, xattr_negative, &value_ptr, 0);
+
+	bpf_dynptr_from_mem(value_bar, sizeof(value_bar), 0, &value_ptr);
+	ret_code_invalid_flags = bpf_set_dentry_xattr(dentry, xattr_negative,
+						      &value_ptr, 0xFFFF);
+
 	return 0;
 }
 
-- 
2.54.0.545.g6539524ca2-goog