The patch titled
Subject: lib/test_user_copy.c: check user string accessors
has been added to the -mm tree. Its filename is
test_user_copy-check-user-string-accessors.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/test_user_copy-check-user-string-accessors.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/test_user_copy-check-user-string-accessors.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: James Hogan <james.hogan@xxxxxxxxxx>
Subject: lib/test_user_copy.c: check user string accessors
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()/strlen_user() with a legitimate user address, an
illegal kernel address, and a legitimate kernel address.
This caught a bug in the MIPS Enhanced Virtual Memory (EVA)
implementation:
test_user_copy: illegal strlen_user passed
Due to strlen_user() accidentally always using normal kernel loads, and
the EVA user/kernel address ranges overlapping.
New tests:
- legitimate strncpy_from_user
- legitimate strnlen_user
- legitimate strlen_user
- illegal all-kernel strncpy_from_user
- illegal reversed strncpy_from_user
- illegal strnlen_user
- illegal strlen_user
- legitimate all-kernel strncpy_from_user
- legitimate kernel strnlen_user
- legitimate kernel strlen_user
Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/test_user_copy.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff -puN lib/test_user_copy.c~test_user_copy-check-user-string-accessors lib/test_user_copy.c
--- a/lib/test_user_copy.c~test_user_copy-check-user-string-accessors
+++ a/lib/test_user_copy.c
@@ -72,6 +72,12 @@ static int __init test_user_copy_init(vo
"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(strlen_user(usermem) == 0,
+ "legitimate strlen_user failed");
ret |= test(!access_ok(VERIFY_READ, usermem, PAGE_SIZE * 2),
"legitimate access_ok VERIFY_READ failed");
@@ -122,6 +128,16 @@ static int __init test_user_copy_init(vo
"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");
+ ret |= test(strlen_user((char __user *)kmem) != 0,
+ "illegal strlen_user passed");
/*
* If unchecked user accesses (__*) on this architecture cannot access
@@ -201,6 +217,13 @@ static int __init test_user_copy_init(vo
"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(strlen_user((char __user *)kmem) == 0,
+ "legitimate kernel strlen_user failed");
ret |= test(!access_ok(VERIFY_READ, (char __user *)kmem, PAGE_SIZE * 2),
"legitimate kernel access_ok VERIFY_READ failed");
_
Patches currently in -mm which might be from james.hogan@xxxxxxxxxx are
test_user_copy-check-legit-kernel-accesses.patch
test_user_copy-check-unchecked-accessors.patch
test_user_copy-check-__clear_user-clear_user.patch
test_user_copy-check-__copy_in_user-copy_in_user.patch
test_user_copy-check-__copy_tofrom_user_inatomic.patch
test_user_copy-check-user-string-accessors.patch
test_user_copy-check-user-checksum-functions.patch
linux-next.patch
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