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

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

openrisc: 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:
openrisc-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 <[email protected]> know about it.

From: Al Viro <[email protected]>
Date: Sat, 20 Aug 2016 17:05:21 -0400
Subject: openrisc: fix copy_from_user()

From: Al Viro <[email protected]>

commit acb2505d0119033a80c85ac8d02dccae41271667 upstream.

... that should zero on faults. Also remove the <censored> helpful logics wrt range truncation copied from ppc32. Where it had ever been needed only in case of copy_from_user() *and* had not been merged into the mainline until a month after the need had disappeared. A decade before openrisc went into mainline, I might add...

---
 arch/openrisc/include/asm/uaccess.h |   33 ++++++++++-----------------------
 1 file changed, 10 insertions(+), 23 deletions(-)

@@ -273,28 +273,20 @@ __copy_tofrom_user(void *to, const void
 static inline unsigned long
 copy_from_user(void *to, const void *from, unsigned long n)
 {
-	unsigned long over;
+	unsigned long res = n;
 
-	if (access_ok(VERIFY_READ, from, n))
-		return __copy_tofrom_user(to, from, n);
-	if ((unsigned long)from < TASK_SIZE) {
-		over = (unsigned long)from + n - TASK_SIZE;
-		return __copy_tofrom_user(to, from, n - over) + over;
-	}
-	return n;
+	if (likely(access_ok(VERIFY_READ, from, n)))
+		n = __copy_tofrom_user(to, from, n);
+	if (unlikely(res))
+		memset(to + (n - res), 0, res);
+	return res;
 }
 
 static inline unsigned long
 copy_to_user(void *to, const void *from, unsigned long n)
 {
-	unsigned long over;
-
-	if (access_ok(VERIFY_WRITE, to, n))
-		return __copy_tofrom_user(to, from, n);
-	if ((unsigned long)to < TASK_SIZE) {
-		over = (unsigned long)to + n - TASK_SIZE;
-		return __copy_tofrom_user(to, from, n - over) + over;
-	}
+	if (likely(access_ok(VERIFY_WRITE, to, n)))
+		n = __copy_tofrom_user(to, from, n);
 	return n;
 }
 

@@ -303,13 +295,8 @@ extern unsigned long __clear_user(void *
 static inline __must_check unsigned long
 clear_user(void *addr, unsigned long size)
 {
-
-	if (access_ok(VERIFY_WRITE, addr, size))
-		return __clear_user(addr, size);
-	if ((unsigned long)addr < TASK_SIZE) {
-		unsigned long over = (unsigned long)addr + size - TASK_SIZE;
-		return __clear_user(addr, size - over) + over;
-	}
+	if (likely(access_ok(VERIFY_WRITE, addr, size)))
+		size = __clear_user(addr, size);
 	return size;
 }
 

Patches currently in stable-queue which might be from [email protected] 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