[PATCH v2 09/11] test_user_copy: Check user string accessors
From: James Hogan <hidden>
Date: 2015-08-07 15:23:24
Also in:
lkml
Subsystem:
library code, the rest · Maintainers:
Andrew Morton, Linus Torvalds
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 <redacted> Cc: Kees Cook <redacted> Cc: Andrew Morton <akpm@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