[LTP] [PATCH v3 2/2] Add mseal01 test

Andrea Cervesato
2024-08-01T12:44:26Z

From: Andrea Cervesato <andrea.cervesato@suse.com>

This is a smoke test that verifies if mseal() protects specific VMA
portions of a process. According to documentation, the syscall should
protect memory from the following actions:

- unmapping, moving to another location, and shrinking the size, via
munmap() and mremap()
- moving or expanding a different VMA into the current location, via
mremap()
- modifying a VMA via mmap(MAP_FIXED)
- mprotect() and pkey_mprotect()
- destructive madvice() behaviors (e.g. MADV_DONTNEED) for anonymous
memory, when users don’t have write permission to the memory

Any of the described actions is recognized via EPERM errno.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
testcases/kernel/syscalls/mseal/.gitignore | 1 +
testcases/kernel/syscalls/mseal/Makefile | 7 ++
testcases/kernel/syscalls/mseal/mseal01.c | 156 +++++++++++++++++++++++++++++
3 files changed, 164 insertions(+)

diff --git a/testcases/kernel/syscalls/mseal/.gitignore b/testcases/kernel/syscalls/mseal/.gitignore
new file mode 100644
index 000000000..e13090994
--- /dev/null
+++ b/testcases/kernel/syscalls/mseal/.gitignore
@@ -0,0 +1 @@
+mseal01
diff --git a/testcases/kernel/syscalls/mseal/Makefile b/testcases/kernel/syscalls/mseal/Makefile
new file mode 100644
index 000000000..35317f446
--- /dev/null
+++ b/testcases/kernel/syscalls/mseal/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2023 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+
+top_srcdir ?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/mseal/mseal01.c b/testcases/kernel/syscalls/mseal/mseal01.c
new file mode 100644
index 000000000..eb2f4d588
--- /dev/null
+++ b/testcases/kernel/syscalls/mseal/mseal01.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * This is a smoke test that verifies if mseal() protects specific VMA portions
+ * of a process. According to documentation, the syscall should protect memory
+ * from the following actions:
+ *
+ * - unmapping, moving to another location, and shrinking the size, via munmap()
+ * and mremap()
+ * - moving or expanding a different VMA into the current location, via mremap()
+ * - modifying a VMA via mmap(MAP_FIXED)
+ * - mprotect() and pkey_mprotect()
+ * - destructive madvice() behaviors (e.g. MADV_DONTNEED) for anonymous memory,
+ * when users don’t have write permission to the memory
+ *
+ * Any of the described actions is recognized via EPERM errno.
+ */
+
+#define _GNU_SOURCE
+
+#include "tst_test.h"
+#include "lapi/syscalls.h"
+
+#define MEMPAGES 8
+#define MEMSEAL 2
+
+static void *mem_addr;
+static int mem_size;
+static int mem_offset;
+static int mem_alignment;
+
+static inline int sys_mseal(void *start, size_t len)
+{
+ return tst_syscall(__NR_mseal, start, len, 0);
+}
+
+static void test_mprotect(void)
+{
+ TST_EXP_FAIL(mprotect(mem_addr, mem_size, PROT_NONE), EPERM);
+}
+
+static void test_pkey_mprotect(void)
+{
+ int ret;
+ int pkey;
+
+ pkey = tst_syscall(__NR_pkey_alloc, 0, 0);
+ if (pkey == -1) {
+ if (errno == EINVAL)
+ tst_brk(TCONF, "pku is not supported on this CPU");
+
+ tst_brk(TBROK | TERRNO, "pkey_alloc() error");
+ }
+
+ TST_EXP_FAIL(tst_syscall(__NR_pkey_mprotect,
+ mem_addr, mem_size,
+ PROT_NONE,
+ pkey),
+ EPERM);
+
+ ret = tst_syscall(__NR_pkey_free, pkey);
+ if (ret == -1)
+ tst_brk(TBROK | TERRNO, "pkey_free() error");
+}
+
+static void test_madvise(void)
+{
+ TST_EXP_FAIL(madvise(mem_addr, mem_size, MADV_DONTNEED), EPERM);
+}
+
+static void test_munmap(void)
+{
+ TST_EXP_FAIL(munmap(mem_addr, mem_size), EPERM);
+}
+
+static void test_mremap_resize(void)
+{
+ void *new_addr;
+ size_t new_size = 2 * mem_alignment;
+
+ new_addr = SAFE_MMAP(NULL, mem_size,
+ PROT_READ,
+ MAP_ANONYMOUS | MAP_PRIVATE,
+ -1, 0);
+
+ TST_EXP_FAIL_PTR_VOID(mremap(mem_addr, mem_size, new_size,
+ MREMAP_MAYMOVE | MREMAP_FIXED,
+ new_addr),
+ EPERM);
+
+ SAFE_MUNMAP(new_addr, new_size);
+}
+
+static void test_mmap_change_prot(void)
+{
+ TST_EXP_FAIL_PTR_VOID(mmap(mem_addr, mem_size,
+ PROT_READ,
+ MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED,
+ -1, 0), EPERM);
+}
+
+static struct tcase {
+ void (*func_test)(void);
+ int prot;
+ char *message;
+} tcases[] = {
+ {test_mprotect, PROT_READ | PROT_WRITE, "mprotect() availability"},
+ {test_pkey_mprotect, PROT_READ | PROT_WRITE, "pkey_mprotect() availability"},
+ {test_madvise, PROT_READ, "madvise() availability"},
+ {test_munmap, PROT_READ | PROT_WRITE, "munmap() availability from child"},
+ {test_mremap_resize, PROT_READ | PROT_WRITE, "mremap() address move/resize"},
+ {test_mmap_change_prot, PROT_READ | PROT_WRITE, "mmap() protection change"},
+};
+
+static void run(unsigned int n)
+{
+ /* the reason why we spawn a child is that mseal() will
+ * protect VMA until process will call _exit()
+ */
+ if (!SAFE_FORK()) {
+ struct tcase *tc = &tcases[n];
+
+ mem_addr = SAFE_MMAP(NULL, mem_size,
+ tc->prot,
+ MAP_ANONYMOUS | MAP_PRIVATE,
+ -1, 0);
+
+ tst_res(TINFO, "Testing %s", tc->message);
+
+ TST_EXP_PASS(sys_mseal(mem_addr + mem_offset, mem_alignment));
+
+ tc->func_test();
+ _exit(0);
+ }
+}
+
+static void setup(void)
+{
+ mem_alignment = getpagesize();
+ mem_size = mem_alignment * MEMPAGES;
+ mem_offset = mem_alignment * MEMSEAL;
+}
+
+static struct tst_test test = {
+ .test = run,
+ .tcnt = ARRAY_SIZE(tcases),
+ .setup = setup,
+ .min_kver = "6.10",
+ .forks_child = 1,
+};
+

--
2.43.0