[PATCH v8 mm-new 11/12] selftests/bpf: add test cases for invalid thp_adjust usage

[Yafang Shao <laoar.shao@gmail.com>]

1. The trusted vma->vm_mm pointer can be null and must be checked before
   dereferencing.
2. The trusted mm->owner pointer can be null and must be checked before
   dereferencing.
3. Sleepable programs are prohibited because the call site operates under
   RCU protection.

Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
 .../selftests/bpf/prog_tests/thp_adjust.c     |  7 +++++
 .../bpf/progs/test_thp_adjust_sleepable.c     | 22 ++++++++++++++
 .../bpf/progs/test_thp_adjust_trusted_owner.c | 30 +++++++++++++++++++
 .../bpf/progs/test_thp_adjust_trusted_vma.c   | 27 +++++++++++++++++
 4 files changed, 86 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/test_thp_adjust_sleepable.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_owner.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_vma.c

diff --git a/tools/testing/selftests/bpf/prog_tests/thp_adjust.c b/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
index 72b2ec31025a..2e9864732c11 100644
--- a/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
+++ b/tools/testing/selftests/bpf/prog_tests/thp_adjust.c
@@ -4,6 +4,9 @@
 #include <sys/mman.h>
 #include <test_progs.h>
 #include "test_thp_adjust.skel.h"
+#include "test_thp_adjust_sleepable.skel.h"
+#include "test_thp_adjust_trusted_vma.skel.h"
+#include "test_thp_adjust_trusted_owner.skel.h"
 
 #define LEN (16 * 1024 * 1024) /* 16MB */
 #define THP_ENABLED_FILE "/sys/kernel/mm/transparent_hugepage/enabled"
@@ -278,4 +281,8 @@ void test_thp_adjust(void)
 		subtest_thp_policy_update();
 
 	thp_adjust_destroy();
+
+	RUN_TESTS(test_thp_adjust_trusted_vma);
+	RUN_TESTS(test_thp_adjust_trusted_owner);
+	RUN_TESTS(test_thp_adjust_sleepable);
 }
diff --git a/tools/testing/selftests/bpf/progs/test_thp_adjust_sleepable.c b/tools/testing/selftests/bpf/progs/test_thp_adjust_sleepable.c
new file mode 100644
index 000000000000..4db78f2f0b2d
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_thp_adjust_sleepable.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops.s/thp_get_order")
+__failure __msg("attach to unsupported member thp_get_order of struct bpf_thp_ops")
+int BPF_PROG(thp_sleepable, struct vm_area_struct *vma, enum tva_type tva_type,
+	     unsigned long orders)
+{
+	return -1;
+}
+
+SEC(".struct_ops.link")
+struct bpf_thp_ops vma_ops = {
+	.thp_get_order = (void *)thp_sleepable,
+};
diff --git a/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_owner.c b/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_owner.c
new file mode 100644
index 000000000000..88bb09cb7cc2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_owner.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops/thp_get_order")
+__failure __msg("R3 pointer arithmetic on rcu_ptr_or_null_ prohibited, null-check it first")
+int BPF_PROG(thp_trusted_owner, struct vm_area_struct *vma, enum tva_type tva_type,
+	     unsigned long orders)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	struct task_struct *p;
+
+	if (!mm)
+		return 0;
+
+	p = mm->owner;
+	bpf_printk("The task name is %s\n", p->comm);
+	return -1;
+}
+
+SEC(".struct_ops.link")
+struct bpf_thp_ops vma_ops = {
+	.thp_get_order = (void *)thp_trusted_owner,
+};
diff --git a/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_vma.c b/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_vma.c
new file mode 100644
index 000000000000..df7b0c160153
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_thp_adjust_trusted_vma.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops/thp_get_order")
+__failure __msg("R1 invalid mem access 'trusted_ptr_or_null_'")
+int BPF_PROG(thp_trusted_vma, struct vm_area_struct *vma, enum tva_type tva_type,
+	     unsigned long orders)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	struct task_struct *p = mm->owner;
+
+	if (!p)
+		return 0;
+	return -1;
+}
+
+SEC(".struct_ops.link")
+struct bpf_thp_ops vma_ops = {
+	.thp_get_order = (void *)thp_trusted_vma,
+};
-- 
2.47.3