x86/fpu: Fix __user annotations (89833fab) · Commits · 戴 / test

In save_xstate_epilog(), use __user when type-casting userspace pointers. In setup_sigcontext() and x32_setup_rt_frame(), cast the userspace pointers to 'unsigned long __user *' before writing into them. These pointers are originally '__u32 __user *' or '__u64 __user *', causing sparse to complain when a userspace pointer is written into them. The casts are okay because the pointers always point to pointer-sized values. Thanks to Luc Van Oostenryck and Al Viro for explaining this to me. Signed-off-by:

Jann Horn <jannh@google.com> Signed-off-by:

Borislav Petkov <bp@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mukesh Ojha <mojha@codeaurora.org> Cc: Qiaowei Ren <qiaowei.ren@intel.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190329214652.258477-3-jannh@google.com

arch/x86/kernel/fpu/signal.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -92,13 +92,13 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
		return err;

		err \|= __put_user(FP_XSTATE_MAGIC2,
		(__u32 *)(buf + fpu_user_xstate_size));
		(__u32 __user *)(buf + fpu_user_xstate_size));

		/*
		* Read the xfeatures which we copied (directly from the cpu or
		* from the state in task struct) to the user buffers.
		*/
		err \|= __get_user(xfeatures, (__u32 *)&x->header.xfeatures);
		err \|= __get_user(xfeatures, (__u32 __user *)&x->header.xfeatures);

		/*
		* For legacy compatible, we always set FP/SSE bits in the bit
		@@ -113,7 +113,7 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame)
		*/
		xfeatures \|= XFEATURE_MASK_FPSSE;

		err \|= __put_user(xfeatures, (__u32 *)&x->header.xfeatures);
		err \|= __put_user(xfeatures, (__u32 __user *)&x->header.xfeatures);

		return err;
		}

arch/x86/kernel/signal.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -206,7 +206,7 @@ int setup_sigcontext(struct sigcontext __user sc, void __user fpstate,
		put_user_ex(regs->ss, &sc->ss);
		#endif /* CONFIG_X86_32 */

		put_user_ex(fpstate, &sc->fpstate);
		put_user_ex(fpstate, (unsigned long __user *)&sc->fpstate);

		/* non-iBCS2 extensions.. */
		put_user_ex(mask, &sc->oldmask);
		@@ -569,7 +569,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
		restorer = NULL;
		err \|= -EFAULT;
		}
		put_user_ex(restorer, &frame->pretcode);
		put_user_ex(restorer, (unsigned long __user *)&frame->pretcode);
		} put_user_catch(err);

		err \|= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,

Admin message