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Groups > linux.kernel > #1200934

[PATCH 4/7] test_user_copy: Check __copy_in_user()/copy_in_user()

From James Hogan <james.hogan@imgtec.com>
Newsgroups linux.kernel
Subject [PATCH 4/7] test_user_copy: Check __copy_in_user()/copy_in_user()
Date 2015-08-05 18:00 +0200
Message-ID <pU9gK-5S2-25@gated-at.bofh.it> (permalink)
References <pU974-5Ga-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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Add basic success/failure checking of copy_in_user() which copies data
from userspace to userspace (or kernel to kernel), and its unchecking
cousin __copy_in_user() which assumes that access_ok() has already been
used as appropriate.

The following cases are checked:
- __copy_in_user/copy_in_user from user to user should succeed.
- __copy_in_user/copy_in_user involving 1 or 2 kernel pointers should
  not succeed.
- __copy_in_user/copy_in_user from kernel to kernel should succeed when
  user address limit is set for kernel accesses.

New tests:
- legitimate copy_in_user
- legitimate __copy_in_user
- illegal all-kernel copy_in_user
- illegal copy_in_user to kernel
- illegal copy_in_user from kernel
- illegal all-kernel __copy_in_user
- illegal __copy_in_user to kernel
- illegal __copy_in_user from kernel
- legitimate all-kernel copy_in_user
- legitimate all-kernel __copy_in_user

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 lib/test_user_copy.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c
index 4ec2cfa916c1..310e796beef6 100644
--- a/lib/test_user_copy.c
+++ b/lib/test_user_copy.c
@@ -64,6 +64,8 @@ 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(copy_in_user(usermem, usermem + PAGE_SIZE, PAGE_SIZE),
+		    "legitimate copy_in_user failed");
 	ret |= test(get_user(value, (unsigned long __user *)usermem),
 		    "legitimate get_user failed");
 	ret |= test(put_user(value, (unsigned long __user *)usermem),
@@ -79,6 +81,8 @@ 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(__copy_in_user(usermem, usermem + PAGE_SIZE, PAGE_SIZE),
+		    "legitimate __copy_in_user failed");
 	ret |= test(__get_user(value, (unsigned long __user *)usermem),
 		    "legitimate __get_user failed");
 	ret |= test(__put_user(value, (unsigned long __user *)usermem),
@@ -99,6 +103,15 @@ static int __init test_user_copy_init(void)
 	ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
 				  PAGE_SIZE),
 		    "illegal reversed copy_to_user passed");
+	ret |= test(!copy_in_user((char __user *)kmem,
+				  (char __user *)(kmem + PAGE_SIZE), PAGE_SIZE),
+		    "illegal all-kernel copy_in_user passed");
+	ret |= test(!copy_in_user((char __user *)kmem, usermem,
+				  PAGE_SIZE),
+		    "illegal copy_in_user to kernel passed");
+	ret |= test(!copy_in_user(usermem, (char __user *)kmem,
+				  PAGE_SIZE),
+		    "illegal copy_in_user from kernel passed");
 	ret |= test(!get_user(value, (unsigned long __user *)kmem),
 		    "illegal get_user passed");
 	ret |= test(!put_user(value, (unsigned long __user *)kmem),
@@ -130,6 +143,16 @@ static int __init test_user_copy_init(void)
 	ret |= test(!__copy_to_user((char __user *)kmem, bad_usermem,
 				    PAGE_SIZE),
 		    "illegal reversed __copy_to_user passed");
+	ret |= test(!__copy_in_user((char __user *)kmem,
+				    (char __user *)(kmem + PAGE_SIZE),
+				    PAGE_SIZE),
+		    "illegal all-kernel __copy_in_user passed");
+	ret |= test(!__copy_in_user((char __user *)kmem, usermem,
+				    PAGE_SIZE),
+		    "illegal __copy_in_user to kernel passed");
+	ret |= test(!__copy_in_user(usermem, (char __user *)kmem,
+				    PAGE_SIZE),
+		    "illegal __copy_in_user from kernel passed");
 	ret |= test(!__get_user(value, (unsigned long __user *)kmem),
 		    "illegal __get_user passed");
 	ret |= test(!__put_user(value, (unsigned long __user *)kmem),
@@ -152,6 +175,9 @@ static int __init test_user_copy_init(void)
 	ret |= test(copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
 				 PAGE_SIZE),
 		    "legitimate all-kernel copy_to_user failed");
+	ret |= test(copy_in_user((char __user *)kmem,
+				 (char __user *)(kmem + PAGE_SIZE), PAGE_SIZE),
+		    "legitimate all-kernel copy_in_user failed");
 	ret |= test(get_user(value, (unsigned long __user *)kmem),
 		    "legitimate kernel get_user failed");
 	ret |= test(put_user(value, (unsigned long __user *)kmem),
@@ -170,6 +196,10 @@ static int __init test_user_copy_init(void)
 	ret |= test(__copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
 				   PAGE_SIZE),
 		    "legitimate all-kernel __copy_to_user failed");
+	ret |= test(__copy_in_user((char __user *)kmem,
+				   (char __user *)(kmem + PAGE_SIZE),
+				   PAGE_SIZE),
+		    "legitimate all-kernel __copy_in_user failed");
 	ret |= test(__get_user(value, (unsigned long __user *)kmem),
 		    "legitimate kernel __get_user failed");
 	ret |= test(__put_user(value, (unsigned long __user *)kmem),
-- 
2.3.6

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Thread

[PATCH 0/7] test_user_copy improvements James Hogan <james.hogan@imgtec.com> - 2015-08-05 17:50 +0200
  [PATCH 7/7] test_user_copy: Check user checksum functions James Hogan <james.hogan@imgtec.com> - 2015-08-05 17:50 +0200
  [PATCH 2/7] test_user_copy: Check unchecked accessors James Hogan <james.hogan@imgtec.com> - 2015-08-05 17:50 +0200
  [PATCH 3/7] test_user_copy: Check __clear_user()/clear_user() James Hogan <james.hogan@imgtec.com> - 2015-08-05 18:00 +0200
  [PATCH 1/7] test_user_copy: Check legit kernel accesses James Hogan <james.hogan@imgtec.com> - 2015-08-05 18:00 +0200
  [PATCH 6/7] test_user_copy: Check user string accessors James Hogan <james.hogan@imgtec.com> - 2015-08-05 18:00 +0200
  [PATCH 4/7] test_user_copy: Check __copy_in_user()/copy_in_user() James Hogan <james.hogan@imgtec.com> - 2015-08-05 18:00 +0200
  [PATCH 5/7] test_user_copy: Check __copy_{to,from}_user_inatomic() James Hogan <james.hogan@imgtec.com> - 2015-08-05 18:00 +0200
  Re: [PATCH 0/7] test_user_copy improvements Kees Cook <keescook@chromium.org> - 2015-08-05 22:30 +0200
    Re: [PATCH 0/7] test_user_copy improvements James Hogan <james.hogan@imgtec.com> - 2015-08-06 18:30 +0200
  Re: [PATCH 0/7] test_user_copy improvements Guenter Roeck <linux@roeck-us.net> - 2015-08-06 12:00 +0200
    Re: [PATCH 0/7] test_user_copy improvements James Hogan <james.hogan@imgtec.com> - 2015-08-06 12:10 +0200
  Re: [PATCH 0/7] test_user_copy improvements James Hogan <james.hogan@imgtec.com> - 2015-08-06 17:10 +0200

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