Commit cdcec1b7 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu/signal: Sanitize copy_user_to_fpregs_zeroing() 



Now that user_xfeatures is correctly set when xsave is enabled, remove
the duplicated initialization of components.

Rename the function while at it.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121457.377341297@linutronix.de
parent 1258a8c8

arch/x86/kernel/fpu/signal.c

+15 −21
Original line number Diff line number Diff line
@@ -251,34 +251,28 @@ sanitize_restored_user_xstate(union fpregs_state *state, 
}



/*

 * Restore the extended state if present. Otherwise, restore the FP/SSE state.

 * Restore the FPU state directly from the userspace signal frame.

 */

static int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only)

static int restore_fpregs_from_user(void __user *buf, u64 xrestore, bool fx_only)

{

	u64 init_bv;

	int r;



	if (use_xsave()) {

		if (fx_only) {

			init_bv = xfeatures_mask_uabi() & ~XFEATURE_MASK_FPSSE;

		u64 init_bv = xfeatures_mask_uabi() & ~xrestore;

		int ret;



			r = fxrstor_from_user_sigframe(buf);

			if (!r)

				os_xrstor(&init_fpstate.xsave, init_bv);

			return r;

		} else {

			init_bv = xfeatures_mask_uabi() & ~xbv;

		if (likely(!fx_only))

			ret = xrstor_from_user_sigframe(buf, xrestore);

		else

			ret = fxrstor_from_user_sigframe(buf);



			r = xrstor_from_user_sigframe(buf, xbv);

			if (!r && unlikely(init_bv))

		if (!ret && unlikely(init_bv))

			os_xrstor(&init_fpstate.xsave, init_bv);

			return r;

		}

		return ret;

	} else if (use_fxsr()) {

		return fxrstor_from_user_sigframe(buf);

	} else

	} else {

		return frstor_from_user_sigframe(buf);

	}

}



static int __fpu_restore_sig(void __user *buf, void __user *buf_fx,

			     bool ia32_fxstate)
@@ -314,7 +308,7 @@ static int __fpu_restore_sig(void __user *buf, void __user *buf_fx, 
		 */

		fpregs_lock();

		pagefault_disable();

		ret = copy_user_to_fpregs_zeroing(buf_fx, user_xfeatures, fx_only);

		ret = restore_fpregs_from_user(buf_fx, user_xfeatures, fx_only);

		pagefault_enable();

		if (!ret) {