uaccess: add missing __must_check attributes
The usercopy implementation comments describe that callers of the
copy_*_user() family of functions must always have their return values
checked. This can be enforced at compile time with __must_check, so add
it where needed.
Link: http://lkml.kernel.org/r/201908251609.ADAD5CAAC1@keescook
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 8d8821b..659a440 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -134,7 +134,7 @@
WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
}
-static __always_inline bool
+static __always_inline __must_check bool
check_copy_size(const void *addr, size_t bytes, bool is_source)
{
int sz = __compiletime_object_size(addr);
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index 34a0385..70bbdc3 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -55,7 +55,7 @@
* as usual) and both source and destination can trigger faults.
*/
-static __always_inline unsigned long
+static __always_inline __must_check unsigned long
__copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
{
kasan_check_write(to, n);
@@ -63,7 +63,7 @@
return raw_copy_from_user(to, from, n);
}
-static __always_inline unsigned long
+static __always_inline __must_check unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_fault();
@@ -85,7 +85,7 @@
* The caller should also make sure he pins the user space address
* so that we don't result in page fault and sleep.
*/
-static __always_inline unsigned long
+static __always_inline __must_check unsigned long
__copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
{
kasan_check_read(from, n);
@@ -93,7 +93,7 @@
return raw_copy_to_user(to, from, n);
}
-static __always_inline unsigned long
+static __always_inline __must_check unsigned long
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
@@ -103,7 +103,7 @@
}
#ifdef INLINE_COPY_FROM_USER
-static inline unsigned long
+static inline __must_check unsigned long
_copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
@@ -117,12 +117,12 @@
return res;
}
#else
-extern unsigned long
+extern __must_check unsigned long
_copy_from_user(void *, const void __user *, unsigned long);
#endif
#ifdef INLINE_COPY_TO_USER
-static inline unsigned long
+static inline __must_check unsigned long
_copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
@@ -133,7 +133,7 @@
return n;
}
#else
-extern unsigned long
+extern __must_check unsigned long
_copy_to_user(void __user *, const void *, unsigned long);
#endif
@@ -222,8 +222,9 @@
#ifndef ARCH_HAS_NOCACHE_UACCESS
-static inline unsigned long __copy_from_user_inatomic_nocache(void *to,
- const void __user *from, unsigned long n)
+static inline __must_check unsigned long
+__copy_from_user_inatomic_nocache(void *to, const void __user *from,
+ unsigned long n)
{
return __copy_from_user_inatomic(to, from, n);
}