[ Upstream commit a0fe2c6479aab5723239b315ef1b552673f434a3 ]
Use parentheses around uses of the argument in u64_to_user_ptr() to ensure that the cast doesn't apply to part of the argument.
There are existing uses of the macro of the form
u64_to_user_ptr(A + B)
which expands to
(void __user *)(uintptr_t)A + B
(the cast applies to the first operand of the addition, the addition is a pointer addition). This happens to still work as intended, the semantic difference doesn't cause a difference in behavior.
But I want to use u64_to_user_ptr() with a ternary operator in the argument, like so:
u64_to_user_ptr(A ? B : C)
This currently doesn't work as intended.
Signed-off-by: Jann Horn jannh@google.com Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Mukesh Ojha mojha@codeaurora.org Cc: Andrei Vagin avagin@openvz.org Cc: Andrew Morton akpm@linux-foundation.org Cc: Dan Carpenter dan.carpenter@oracle.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@kernel.org Cc: Jani Nikula jani.nikula@intel.com Cc: Kees Cook keescook@chromium.org Cc: Masahiro Yamada yamada.masahiro@socionext.com Cc: NeilBrown neilb@suse.com Cc: Peter Zijlstra peterz@infradead.org Cc: Qiaowei Ren qiaowei.ren@intel.com Cc: Thomas Gleixner tglx@linutronix.de Cc: x86-ml x86@kernel.org Link: https://lkml.kernel.org/r/20190329214652.258477-1-jannh@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/kernel.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 61054f12be7cf..d83fc669eeac7 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -55,8 +55,8 @@
#define u64_to_user_ptr(x) ( \ { \ - typecheck(u64, x); \ - (void __user *)(uintptr_t)x; \ + typecheck(u64, (x)); \ + (void __user *)(uintptr_t)(x); \ } \ )