Patch "alpha: fix copy_from_user()" has been added to the 4.4-stable tree

Patch "alpha: fix copy_from_user()" has been added to the 4.4-stable tree

[gregkh]

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

    alpha: fix copy_from_user()

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:
     alpha-fix-copy_from_user.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 2561d309dfd1555e781484af757ed0115035ddb3 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Wed, 17 Aug 2016 16:02:32 -0400
Subject: alpha: fix copy_from_user()

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

commit 2561d309dfd1555e781484af757ed0115035ddb3 upstream.

it should clear the destination even when access_ok() fails.

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

---
 arch/alpha/include/asm/uaccess.h |   19 ++++++++-----------
 1 file changed, 8 insertions(+), 11 deletions(-)

--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -371,14 +371,6 @@ __copy_tofrom_user_nocheck(void *to, con
 	return __cu_len;
 }
 
-extern inline long
-__copy_tofrom_user(void *to, const void *from, long len, const void __user *validate)
-{
-	if (__access_ok((unsigned long)validate, len, get_fs()))
-		len = __copy_tofrom_user_nocheck(to, from, len);
-	return len;
-}
-
 #define __copy_to_user(to, from, n)					\
 ({									\
 	__chk_user_ptr(to);						\
@@ -393,17 +385,22 @@ __copy_tofrom_user(void *to, const void
 #define __copy_to_user_inatomic __copy_to_user
 #define __copy_from_user_inatomic __copy_from_user
 
-
 extern inline long
 copy_to_user(void __user *to, const void *from, long n)
 {
-	return __copy_tofrom_user((__force void *)to, from, n, to);
+	if (likely(__access_ok((unsigned long)to, n, get_fs())))
+		n = __copy_tofrom_user_nocheck((__force void *)to, from, n);
+	return n;
 }
 
 extern inline long
 copy_from_user(void *to, const void __user *from, long n)
 {
-	return __copy_tofrom_user(to, (__force void *)from, n, from);
+	if (likely(__access_ok((unsigned long)from, n, get_fs())))
+		n = __copy_tofrom_user_nocheck(to, (__force void *)from, n);
+	else
+		memset(to, 0, n);
+	return n;
 }
 
 extern void __do_clear_user(void);


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