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authorLinus Torvalds <torvalds@linux-foundation.org>2017-02-21 17:53:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-21 17:53:23 -0800
commit4a0853bf88c8f56e1c01eda02e6625aed09d55d9 (patch)
tree767b2d9cd3da81e2c21adcc63ce9fadec7008bf3
parent6d1dd93ea0d0f0fb61b5450a2668896028ce3f75 (diff)
parent4c5d7bc63775b40631b75f6c59a3a3005455262d (diff)
Merge tag 'usercopy-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull usercopy test updates from Kees Cook: "This improves the usercopy tests: - check zeroing on failed copy_from_user()/get_user() (caught bug on ARM) - adjust tests for SMAP/PAN (can't zero userspace memory on failure)" * tag 'usercopy-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: usercopy: Add tests for all get_user() sizes usercopy: Adjust tests to deal with SMAP/PAN usercopy: add testcases to check zeroing on failure
-rw-r--r--lib/test_user_copy.c117
1 files changed, 103 insertions, 14 deletions
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index 0ecef3e4690e..6f335a3d4ae2 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -25,6 +25,23 @@
#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_AVR32) && \
+ !defined(CONFIG_BLACKFIN) && \
+ !defined(CONFIG_M32R) && \
+ !defined(CONFIG_M68K) && \
+ !defined(CONFIG_MICROBLAZE) && \
+ !defined(CONFIG_MN10300) && \
+ !defined(CONFIG_NIOS2) && \
+ !defined(CONFIG_PPC32) && \
+ !defined(CONFIG_SUPERH))
+# define TEST_U64
+#endif
+
#define test(condition, msg) \
({ \
int cond = (condition); \
@@ -40,7 +57,12 @@ static int __init test_user_copy_init(void)
char __user *usermem;
char *bad_usermem;
unsigned long user_addr;
- unsigned long value = 0x5A;
+ 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)
@@ -58,33 +80,100 @@ static int __init test_user_copy_init(void)
usermem = (char __user *)user_addr;
bad_usermem = (char *)user_addr;
- /* Legitimate usage: none of these should fail. */
- ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
- "legitimate copy_from_user failed");
+ /*
+ * 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");
- ret |= test(get_user(value, (unsigned long __user *)usermem),
- "legitimate get_user failed");
- ret |= test(put_user(value, (unsigned long __user *)usermem),
- "legitimate put_user failed");
-
- /* Invalid usage: none of these should succeed. */
+ 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");
- ret |= test(!get_user(value, (unsigned long __user *)kmem),
- "illegal get_user passed");
- ret |= test(!put_user(value, (unsigned long __user *)kmem),
- "illegal put_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);