Patch "asm-generic: make get_user() clear the destination on errors" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    asm-generic: make get_user() clear the destination on errors

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     asm-generic-make-get_user-clear-the-destination-on-errors.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 17 Aug 2016 23:19:01 -0400
Subject: asm-generic: make get_user() clear the destination on errors

From: Al Viro <viro@zeniv.linux.org.uk>

commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream.

both for access_ok() failures and for faults halfway through

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/asm-generic/uaccess.h |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h
@@ -230,14 +230,18 @@ extern int __put_user_bad(void) __attrib
 	might_fault();						\
 	access_ok(VERIFY_READ, __p, sizeof(*ptr)) ?		\
 		__get_user((x), (__typeof__(*(ptr)) *)__p) :	\
-		-EFAULT;					\
+		((x) = (__typeof__(*(ptr)))0,-EFAULT);		\
 })
 
 #ifndef __get_user_fn
 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
 {
-	size = __copy_from_user(x, ptr, size);
-	return size ? -EFAULT : size;
+	size_t n = __copy_from_user(x, ptr, size);
+	if (unlikely(n)) {
+		memset(x + (size - n), 0, n);
+		return -EFAULT;
+	}
+	return 0;
 }
 
 #define __get_user_fn(sz, u, k)	__get_user_fn(sz, u, k)


Patches currently in stable-queue which might be from viro@zeniv.linux.org.uk are

queue-4.4/nios2-copy_from_user-should-zero-the-tail-of-destination.patch
queue-4.4/m32r-fix-__get_user.patch
queue-4.4/microblaze-fix-copy_from_user.patch
queue-4.4/cris-buggered-copy_from_user-copy_to_user-clear_user.patch
queue-4.4/asm-generic-make-copy_from_user-zero-the-destination-properly.patch
queue-4.4/metag-copy_from_user-should-zero-the-destination-on-access_ok-failure.patch
queue-4.4/score-fix-__get_user-get_user.patch
queue-4.4/parisc-fix-copy_from_user.patch
queue-4.4/mips-copy_from_user-must-zero-the-destination-on-access_ok-failure.patch
queue-4.4/alpha-fix-copy_from_user.patch
queue-4.4/mn10300-failing-__get_user-and-get_user-should-zero.patch
queue-4.4/openrisc-fix-copy_from_user.patch
queue-4.4/avr32-fix-copy_from_user.patch
queue-4.4/score-fix-copy_from_user-and-friends.patch
queue-4.4/sh64-failing-__get_user-should-zero.patch
queue-4.4/arc-uaccess-get_user-to-zero-out-dest-in-cause-of-fault.patch
queue-4.4/hexagon-fix-strncpy_from_user-error-return.patch
queue-4.4/frv-fix-clear_user.patch
queue-4.4/fix-minor-infoleak-in-get_user_ex.patch
queue-4.4/asm-generic-make-get_user-clear-the-destination-on-errors.patch
queue-4.4/mn10300-copy_from_user-should-zero-on-access_ok-failure.patch
queue-4.4/s390-get_user-should-zero-on-failure.patch
queue-4.4/microblaze-fix-__get_user.patch
queue-4.4/blackfin-fix-copy_from_user.patch
queue-4.4/fix-iov_iter_fault_in_readable.patch
queue-4.4/nios2-fix-__get_user.patch
queue-4.4/sh-fix-copy_from_user.patch