From: Arnd Bergmann Date: Tue, 5 Jan 2021 13:52:45 +0000 (+0100) Subject: staging: vchiq: fix uninitialized variable copy X-Git-Tag: microblaze-v5.13~180^2~115 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=662d82cf39ff60df33b6af6c8da71e900e65350a;p=linux-2.6-microblaze.git staging: vchiq: fix uninitialized variable copy Smatch found a local variable that can get copied to another local variable without an initializion in the error case: drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c:1056 vchiq_get_user_ptr() error: uninitialized symbol 'ptr'. This seems harmless, as the function should normally get inlined, with the output directly written or not. In any case, the uninitialized data is never used after get_user() fails. As Dan mentions, it could still trigger an UBSAN runtime error, and it is of course a bad idea to copy uninitialized variables, so just bail out early. Reported-by: kernel test robot Reported-by: Dan Carpenter Signed-off-by: Arnd Bergmann Link: https://lore.kernel.org/r/20210105135256.1810337-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c index 23f4389cf51d..59e45dc03a97 100644 --- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c +++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c @@ -1052,14 +1052,21 @@ static inline int vchiq_get_user_ptr(void __user **buf, void __user *ubuf, int i compat_uptr_t ptr32; compat_uptr_t __user *uptr = ubuf; ret = get_user(ptr32, uptr + index); + if (ret) + return ret; + *buf = compat_ptr(ptr32); } else { uintptr_t ptr, __user *uptr = ubuf; ret = get_user(ptr, uptr + index); + + if (ret) + return ret; + *buf = (void __user *)ptr; } - return ret; + return 0; } struct vchiq_completion_data32 {