Add basic success/failure checking of the user string functions which
copy or find the length of userland strings.
The following cases are checked:
- strncpy_from_user() with legitimate user to kernel addresses, illegal
all-kernel and reversed addresses, and legitimate all-kernel
addresses.
- strnlen_user() with a legitimate user address, an illegal kernel
address, and a legitimate kernel address.
New tests:
- legitimate strncpy_from_user
- legitimate strnlen_user
- illegal all-kernel strncpy_from_user
- illegal reversed strncpy_from_user
- illegal strnlen_user
- legitimate all-kernel strncpy_from_user
- legitimate kernel strnlen_user
Signed-off-by: James Hogan <james.ho...@imgtec.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Andrew Morton <a...@linux-foundation.org>
---
Changes in v2:
- Drop strlen_user test. Microblaze doesn't define it, and nothing
actually uses it. IMO it should be removed, and there's no point
testing it in the mean time.
---
lib/test_user_copy.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index 450b4c379c61..56af2439d2be 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -70,6 +70,10 @@ static int __init test_user_copy_init(void)
"legitimate put_user failed");
ret |= test(clear_user(usermem, PAGE_SIZE) != 0,
"legitimate clear_user passed");
+ ret |= test(strncpy_from_user(kmem, usermem, PAGE_SIZE) < 0,
+ "legitimate strncpy_from_user failed");
+ ret |= test(strnlen_user(usermem, PAGE_SIZE) == 0,
+ "legitimate strnlen_user failed");
ret |= test(!access_ok(VERIFY_READ, usermem, PAGE_SIZE * 2),
"legitimate access_ok VERIFY_READ failed");
@@ -109,6 +113,14 @@ static int __init test_user_copy_init(void)
"illegal put_user passed");
ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != PAGE_SIZE,
"illegal kernel clear_user passed");
+ ret |= test(strncpy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
+ PAGE_SIZE) >= 0,
+ "illegal all-kernel strncpy_from_user passed");
+ ret |= test(strncpy_from_user(bad_usermem, (char __user *)kmem,
+ PAGE_SIZE) >= 0,
+ "illegal reversed strncpy_from_user passed");
+ ret |= test(strnlen_user((char __user *)kmem, PAGE_SIZE) != 0,
+ "illegal strnlen_user passed");
/*
* If unchecked user accesses (__*) on this architecture cannot access
@@ -175,6 +187,11 @@ static int __init test_user_copy_init(void)
"legitimate kernel put_user failed");
ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != 0,
"legitimate kernel clear_user failed");
+ ret |= test(strncpy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
+ PAGE_SIZE) < 0,
+ "legitimate all-kernel strncpy_from_user failed");
+ ret |= test(strnlen_user((char __user *)kmem, PAGE_SIZE) == 0,
+ "legitimate kernel strnlen_user failed");
ret |= test(!access_ok(VERIFY_READ, (char __user *)kmem, PAGE_SIZE * 2),
"legitimate kernel access_ok VERIFY_READ failed");
--
2.3.6
--
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