Merge branch 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull uaccess fixes from Al Viro:
 "Fixes for broken uaccess primitives - mostly lack of proper zeroing
  in copy_from_user()/get_user()/__get_user(), but for several
  architectures there's more (broken clear_user() on frv and
  strncpy_from_user() on hexagon)"

* 'uaccess-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (28 commits)
  avr32: fix copy_from_user()
  microblaze: fix __get_user()
  microblaze: fix copy_from_user()
  m32r: fix __get_user()
  blackfin: fix copy_from_user()
  sparc32: fix copy_from_user()
  sh: fix copy_from_user()
  sh64: failing __get_user() should zero
  score: fix copy_from_user() and friends
  score: fix __get_user/get_user
  s390: get_user() should zero on failure
  ppc32: fix copy_from_user()
  parisc: fix copy_from_user()
  openrisc: fix copy_from_user()
  nios2: fix __get_user()
  nios2: copy_from_user() should zero the tail of destination
  mn10300: copy_from_user() should zero on access_ok() failure...
  mn10300: failing __get_user() and get_user() should zero
  mips: copy_from_user() must zero the destination on access_ok() failure
  ARC: uaccess: get_user to zero out dest in cause of fault
  ...

1 files changed, 11 insertions, 24 deletions

diff --git a/arch/openrisc/include/asm/uaccess.h b/arch/openrisc/include/asm/uaccess.h
index a6bd07ca3d6c..cbad29b5a131 100644
--- a/arch/openrisc/include/asm/uaccess.h
+++ b/arch/openrisc/include/asm/uaccess.h
@@ -273,28 +273,20 @@ __copy_tofrom_user(void *to, const void *from, unsigned long size);
 static inline unsigned long
 copy_from_user(void *to, const void *from, unsigned long n)
 {
-	unsigned long over;
-
-	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;
+	unsigned long res = 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 *addr, unsigned long size);
 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;
 }