The patch titled
Subject: lib/test_user_copy.c: check __clear_user()/clear_user()
has been added to the -mm tree. Its filename is
test_user_copy-check-__clear_user-clear_user.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/test_user_copy-check-__clear_user-clear_user.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/test_user_copy-check-__clear_user-clear_user.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 __clear_user()/clear_user()
Add basic success/failure checking of __clear_user() and clear_user(),
which zero an area of user or kernel memory and return the number of bytes
left to clear.
This catches a couple of bugs in the MIPS Enhanced Virtual Memory (EVA)
implementation (which have already been fixed): test_user_copy: legitimate
kernel clear_user failed test_user_copy: legitimate kernel __clear_user
failed
Due to neither function checking the user address limit, and both
resorting to user access unconditionally.
New tests:
- legitimate clear_user
- legitimate __clear_user
- illegal kernel clear_user
- illegal kernel __clear_user
- legitimate kernel clear_user
- legitimate kernel __clear_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 | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff -puN lib/test_user_copy.c~test_user_copy-check-__clear_user-clear_user lib/test_user_copy.c
--- a/lib/test_user_copy.c~test_user_copy-check-__clear_user-clear_user
+++ a/lib/test_user_copy.c
@@ -68,6 +68,8 @@ static int __init test_user_copy_init(vo
"legitimate get_user failed");
ret |= test(put_user(value, (unsigned long __user *)usermem),
"legitimate put_user failed");
+ ret |= test(clear_user(usermem, PAGE_SIZE) != 0,
+ "legitimate clear_user passed");
ret |= test(!access_ok(VERIFY_READ, usermem, PAGE_SIZE * 2),
"legitimate access_ok VERIFY_READ failed");
@@ -81,6 +83,8 @@ static int __init test_user_copy_init(vo
"legitimate __get_user failed");
ret |= test(__put_user(value, (unsigned long __user *)usermem),
"legitimate __put_user failed");
+ ret |= test(__clear_user(usermem, PAGE_SIZE) != 0,
+ "legitimate __clear_user passed");
/* Invalid usage: none of these should succeed. */
ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
@@ -99,6 +103,8 @@ static int __init test_user_copy_init(vo
"illegal get_user passed");
ret |= test(!put_user(value, (unsigned long __user *)kmem),
"illegal put_user passed");
+ ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != PAGE_SIZE,
+ "illegal kernel clear_user passed");
/*
* If unchecked user accesses (__*) on this architecture cannot access
@@ -128,6 +134,8 @@ static int __init test_user_copy_init(vo
"illegal __get_user passed");
ret |= test(!__put_user(value, (unsigned long __user *)kmem),
"illegal __put_user passed");
+ ret |= test(__clear_user((char __user *)kmem, PAGE_SIZE) != PAGE_SIZE,
+ "illegal kernel __clear_user passed");
#endif
/*
@@ -148,6 +156,8 @@ static int __init test_user_copy_init(vo
"legitimate kernel get_user failed");
ret |= test(put_user(value, (unsigned long __user *)kmem),
"legitimate kernel put_user failed");
+ ret |= test(clear_user((char __user *)kmem, PAGE_SIZE) != 0,
+ "legitimate kernel clear_user failed");
ret |= test(!access_ok(VERIFY_READ, (char __user *)kmem, PAGE_SIZE * 2),
"legitimate kernel access_ok VERIFY_READ failed");
@@ -164,6 +174,8 @@ static int __init test_user_copy_init(vo
"legitimate kernel __get_user failed");
ret |= test(__put_user(value, (unsigned long __user *)kmem),
"legitimate kernel __put_user failed");
+ ret |= test(__clear_user((char __user *)kmem, PAGE_SIZE) != 0,
+ "legitimate kernel __clear_user failed");
/* Restore previous address limit. */
set_fs(fs);
_
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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