Commit 749af556 authored Jun 09, 2021 by Thomas Gleixner Committed by Sasha Levin Jun 30, 2021

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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent fab7d0d5

arch/x86/kernel/fpu/signal.c

+13 −5

Original line number	Diff line number	Diff line
		@@ -262,15 +262,23 @@ static int __fpu__restore_sig(void __user buf, void __user buf_fx, int size)
		return 0;
		}

		if (!access_ok(VERIFY_READ, buf, size))
		if (!access_ok(VERIFY_READ, buf, size)) {
		fpu__clear(fpu);
		return -EACCES;
		}

		fpu__activate_curr(fpu);

		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)) {
		int ret = fpregs_soft_set(current, NULL, 0,
		sizeof(struct user_i387_ia32_struct),
		NULL, buf);

		if (ret)
		fpu__clear(fpu);

		return ret != 0;
		}

		if (use_xsave()) {
		struct _fpx_sw_bytes fx_sw_user;