From 4c5d7bc63775b40631b75f6c59a3a3005455262d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 14 Feb 2017 12:38:07 -0800 Subject: usercopy: Add tests for all get_user() sizes The existing test was only exercising native unsigned long size get_user(). For completeness, we should check all sizes. But we must skip some 32-bit architectures that don't implement a 64-bit get_user(). These new tests actually uncovered a bug in ARM's 64-bit get_user() zeroing. Signed-off-by: Kees Cook --- lib/test_user_copy.c | 89 ++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 76 insertions(+), 13 deletions(-) (limited to 'lib') diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c index 73ff7a628e3a..6f335a3d4ae2 100644 --- a/lib/test_user_copy.c +++ b/lib/test_user_copy.c @@ -25,6 +25,23 @@ #include #include +/* + * 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) @@ -61,14 +83,39 @@ static int __init test_user_copy_init(void) /* * Legitimate usage: none of these copies should fail. */ - ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE), - "legitimate copy_from_user failed"); + 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"); + 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. @@ -105,12 +152,28 @@ static int __init test_user_copy_init(void) PAGE_SIZE), "illegal reversed copy_to_user passed"); - value = 0x5a; - ret |= test(!get_user(value, (unsigned long __user *)kmem), - "illegal get_user passed"); - ret |= test(value != 0, "zeroing failure for illegal get_user"); - 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); -- cgit v1.2.3