Commit efa16550 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu: Reset state for all signal restore failures 



If access_ok() or fpregs_soft_set() fails in __fpu__restore_sig() then the
function just returns but does not clear the FPU state as it does for all
other fatal failures.

Clear the FPU state for these failures as well.

Fixes: 72a671ce ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de
parent 510b80a6

arch/x86/kernel/fpu/signal.c

+15 −11
Original line number Diff line number Diff line
@@ -307,13 +307,17 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		return 0;

	}



	if (!access_ok(buf, size))

		return -EACCES;

	if (!access_ok(buf, size)) {

		ret = -EACCES;

		goto out;

	}



	if (!static_cpu_has(X86_FEATURE_FPU))

		return fpregs_soft_set(current, NULL,

				       0, sizeof(struct user_i387_ia32_struct),

				       NULL, buf) != 0;

	if (!static_cpu_has(X86_FEATURE_FPU)) {

		ret = fpregs_soft_set(current, NULL, 0,

				      sizeof(struct user_i387_ia32_struct),

				      NULL, buf);

		goto out;

	}



	if (use_xsave()) {

		struct _fpx_sw_bytes fx_sw_user;
@@ -396,7 +400,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		 */

		ret = __copy_from_user(&env, buf, sizeof(env));

		if (ret)

			goto err_out;

			goto out;

		envp = &env;

	}
@@ -426,7 +430,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 


		ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx);

		if (ret)

			goto err_out;

			goto out;



		sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,

					      fx_only);
@@ -446,7 +450,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		ret = __copy_from_user(&fpu->state.fxsave, buf_fx, state_size);

		if (ret) {

			ret = -EFAULT;

			goto err_out;

			goto out;

		}



		sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,
@@ -464,7 +468,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
	} else {

		ret = __copy_from_user(&fpu->state.fsave, buf_fx, state_size);

		if (ret)

			goto err_out;

			goto out;



		fpregs_lock();

		ret = copy_kernel_to_fregs_err(&fpu->state.fsave);
@@ -475,7 +479,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		fpregs_deactivate(fpu);

	fpregs_unlock();



err_out:

out:

	if (ret)

		fpu__clear_user_states(fpu);

	return ret;