[PATCH] uaccess: Add missing __must_check attributes
From: Kees Cook
Date: Wed Aug 28 2019 - 13:36:59 EST
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.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/linux/thread_info.h | 2 +-
include/linux/uaccess.h | 21 +++++++++++----------
2 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index 8d8821b3689a..659a4400517b 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -134,7 +134,7 @@ static inline void copy_overflow(int size, unsigned long count)
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 34a038563d97..70bbdc38dc37 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 @@ __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n)
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 @@ __copy_from_user(void *to, const void __user *from, unsigned long n)
* 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 @@ __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n)
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 @@ __copy_to_user(void __user *to, const void *from, unsigned long n)
}
#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 @@ _copy_from_user(void *to, const void __user *from, unsigned long n)
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 @@ _copy_to_user(void __user *to, const void *from, unsigned long n)
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 @@ static inline bool pagefault_disabled(void)
#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);
}
--
2.17.1
--
Kees Cook