[PATCH 4.7 176/184] openrisc: fix copy_from_user()

[Greg Kroah-Hartman]

4.7-stable review patch.  If anyone has any objections, please let me know.

--

From: Al Viro 

commit acb2505d0119033a80c85ac8d02dccae41271667 upstream.

... that should zero on faults.  Also remove the  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...

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman 

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

--- 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
 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;
 }
 

[PATCH 4.7 176/184] openrisc: fix copy_from_user()

[Greg Kroah-Hartman]

4.7-stable review patch.  If anyone has any objections, please let me know.

--

From: Al Viro 

commit acb2505d0119033a80c85ac8d02dccae41271667 upstream.

... that should zero on faults.  Also remove the  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...

Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman 

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

--- 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
 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;
 }