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Message-ID: <20170214204039.GA125586@beast>
Date: Tue, 14 Feb 2017 12:40:39 -0800
From: Kees Cook <keescook@...omium.org>
To: linux-kernel@...r.kernel.org
Cc: Hoeun Ryu <hoeun.ryu@...il.com>, kernel-hardening@...ts.openwall.com
Subject: [PATCH] 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.
Signed-off-by: Kees Cook <keescook@...omium.org>
---
lib/test_user_copy.c | 45 ++++++++++++++++++++++++++++++++++-----------
1 file changed, 34 insertions(+), 11 deletions(-)
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index ac3a60ba9331..49569125b7c5 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -40,8 +40,11 @@ static int __init test_user_copy_init(void)
char __user *usermem;
char *bad_usermem;
unsigned long user_addr;
- unsigned long value = 0x5A;
char *zerokmem;
+ u8 val_u8;
+ u16 val_u16;
+ u32 val_u32;
+ u64 val_u64;
kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
if (!kmem)
@@ -72,10 +75,20 @@ static int __init test_user_copy_init(void)
"legitimate copy_from_user failed");
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");
+
+#define test_legit(size) \
+ do { \
+ ret |= test(get_user(val_##size, (size __user *)usermem), \
+ "legitimate get_user (" #size ") failed"); \
+ ret |= test(put_user(val_##size, (size __user *)usermem), \
+ "legitimate put_user (" #size ") failed"); \
+ } while (0)
+
+ test_legit(u8);
+ test_legit(u16);
+ test_legit(u32);
+ test_legit(u64);
+#undef test_legit
/*
* Invalid usage: none of these copies should succeed.
@@ -112,12 +125,22 @@ 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 ")"); \
+ 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);
+ test_illegal(u64, 0x5a5b5c5d6a6b6c6d);
+#undef test_illegal
vm_munmap(user_addr, PAGE_SIZE * 2);
out_zerokmem:
--
2.7.4
--
Kees Cook
Pixel Security
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