v4.19.13 snapshot.
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
new file mode 100644
index 0000000..e161f04
--- /dev/null
+++ b/lib/test_user_copy.c
@@ -0,0 +1,196 @@
+/*
+ * Kernel module for testing copy_to/from_user infrastructure.
+ *
+ * Copyright 2013 Google Inc. All Rights Reserved
+ *
+ * Authors:
+ * Kees Cook <keescook@chromium.org>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/mman.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+
+/*
+ * Several 32-bit architectures support 64-bit {get,put}_user() calls.
+ * As there doesn't appear to be anything that can safely determine
+ * their capability at compile-time, we just have to opt-out certain archs.
+ */
+#if BITS_PER_LONG == 64 || (!(defined(CONFIG_ARM) && !defined(MMU)) && \
+ !defined(CONFIG_M68K) && \
+ !defined(CONFIG_MICROBLAZE) && \
+ !defined(CONFIG_NIOS2) && \
+ !defined(CONFIG_PPC32) && \
+ !defined(CONFIG_SUPERH))
+# define TEST_U64
+#endif
+
+#define test(condition, msg) \
+({ \
+ int cond = (condition); \
+ if (cond) \
+ pr_warn("%s\n", msg); \
+ cond; \
+})
+
+static int __init test_user_copy_init(void)
+{
+ int ret = 0;
+ char *kmem;
+ char __user *usermem;
+ char *bad_usermem;
+ unsigned long user_addr;
+ u8 val_u8;
+ u16 val_u16;
+ u32 val_u32;
+#ifdef TEST_U64
+ u64 val_u64;
+#endif
+
+ kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
+ if (!kmem)
+ return -ENOMEM;
+
+ user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_ANONYMOUS | MAP_PRIVATE, 0);
+ if (user_addr >= (unsigned long)(TASK_SIZE)) {
+ pr_warn("Failed to allocate user memory\n");
+ kfree(kmem);
+ return -ENOMEM;
+ }
+
+ usermem = (char __user *)user_addr;
+ bad_usermem = (char *)user_addr;
+
+ /*
+ * Legitimate usage: none of these copies should fail.
+ */
+ memset(kmem, 0x3a, PAGE_SIZE * 2);
+ ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
+ "legitimate copy_to_user failed");
+ memset(kmem, 0x0, PAGE_SIZE);
+ ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
+ "legitimate copy_from_user failed");
+ ret |= test(memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE),
+ "legitimate usercopy failed to copy data");
+
+#define test_legit(size, check) \
+ do { \
+ val_##size = check; \
+ ret |= test(put_user(val_##size, (size __user *)usermem), \
+ "legitimate put_user (" #size ") failed"); \
+ val_##size = 0; \
+ ret |= test(get_user(val_##size, (size __user *)usermem), \
+ "legitimate get_user (" #size ") failed"); \
+ ret |= test(val_##size != check, \
+ "legitimate get_user (" #size ") failed to do copy"); \
+ if (val_##size != check) { \
+ pr_info("0x%llx != 0x%llx\n", \
+ (unsigned long long)val_##size, \
+ (unsigned long long)check); \
+ } \
+ } while (0)
+
+ test_legit(u8, 0x5a);
+ test_legit(u16, 0x5a5b);
+ test_legit(u32, 0x5a5b5c5d);
+#ifdef TEST_U64
+ test_legit(u64, 0x5a5b5c5d6a6b6c6d);
+#endif
+#undef test_legit
+
+ /*
+ * Invalid usage: none of these copies should succeed.
+ */
+
+ /* Prepare kernel memory with check values. */
+ memset(kmem, 0x5a, PAGE_SIZE);
+ memset(kmem + PAGE_SIZE, 0, PAGE_SIZE);
+
+ /* Reject kernel-to-kernel copies through copy_from_user(). */
+ ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
+ PAGE_SIZE),
+ "illegal all-kernel copy_from_user passed");
+
+ /* Destination half of buffer should have been zeroed. */
+ ret |= test(memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE),
+ "zeroing failure for illegal all-kernel copy_from_user");
+
+#if 0
+ /*
+ * When running with SMAP/PAN/etc, this will Oops the kernel
+ * due to the zeroing of userspace memory on failure. This needs
+ * to be tested in LKDTM instead, since this test module does not
+ * expect to explode.
+ */
+ ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
+ PAGE_SIZE),
+ "illegal reversed copy_from_user passed");
+#endif
+ ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
+ PAGE_SIZE),
+ "illegal all-kernel copy_to_user passed");
+ ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
+ PAGE_SIZE),
+ "illegal reversed copy_to_user passed");
+
+#define test_illegal(size, check) \
+ do { \
+ val_##size = (check); \
+ ret |= test(!get_user(val_##size, (size __user *)kmem), \
+ "illegal get_user (" #size ") passed"); \
+ ret |= test(val_##size != (size)0, \
+ "zeroing failure for illegal get_user (" #size ")"); \
+ if (val_##size != (size)0) { \
+ pr_info("0x%llx != 0\n", \
+ (unsigned long long)val_##size); \
+ } \
+ ret |= test(!put_user(val_##size, (size __user *)kmem), \
+ "illegal put_user (" #size ") passed"); \
+ } while (0)
+
+ test_illegal(u8, 0x5a);
+ test_illegal(u16, 0x5a5b);
+ test_illegal(u32, 0x5a5b5c5d);
+#ifdef TEST_U64
+ test_illegal(u64, 0x5a5b5c5d6a6b6c6d);
+#endif
+#undef test_illegal
+
+ vm_munmap(user_addr, PAGE_SIZE * 2);
+ kfree(kmem);
+
+ if (ret == 0) {
+ pr_info("tests passed.\n");
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+module_init(test_user_copy_init);
+
+static void __exit test_user_copy_exit(void)
+{
+ pr_info("unloaded.\n");
+}
+
+module_exit(test_user_copy_exit);
+
+MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
+MODULE_LICENSE("GPL");