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Commit 55cfd22f authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Sasha Levin
Browse files

x86/fpu: Reset state for all signal restore failures 



commit efa165504943f2128d50f63de0c02faf6dcceb0d upstream.

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


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7f9745ab

arch/x86/kernel/fpu/signal.c

+20 −11
Original line number Diff line number Diff line
@@ -272,6 +272,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
	int state_size = fpu_kernel_xstate_size;

	u64 xfeatures = 0;

	int fx_only = 0;

	int ret = 0;



	ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) ||

			 IS_ENABLED(CONFIG_IA32_EMULATION));
@@ -281,15 +282,21 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		return 0;

	}



	if (!access_ok(VERIFY_READ, buf, size))

		return -EACCES;

	if (!access_ok(VERIFY_READ, buf, size)) {

		ret = -EACCES;

		goto out_err;

	}



	fpu__initialize(fpu);



	if (!static_cpu_has(X86_FEATURE_FPU))

		return fpregs_soft_set(current, NULL,

	if (!static_cpu_has(X86_FEATURE_FPU)) {

		ret = fpregs_soft_set(current, NULL,

				      0, sizeof(struct user_i387_ia32_struct),

				      NULL, buf) != 0;

		if (ret)

			goto out_err;

		return 0;

	}



	if (use_xsave()) {

		struct _fpx_sw_bytes fx_sw_user;
@@ -349,6 +356,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		fpu__restore(fpu);

		local_bh_enable();



		/* Failure is already handled */

		return err;

	} else {

		/*
@@ -356,13 +364,14 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		 * state to the registers directly (with exceptions handled).

		 */

		user_fpu_begin();

		if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) {

			fpu__clear(fpu);

			return -1;

		}

		if (!copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only))

			return 0;

		ret = -1;

	}



	return 0;

out_err:

	fpu__clear(fpu);

	return ret;

}



static inline int xstate_sigframe_size(void)