Commit 145e9e0d authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Borislav Petkov
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x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values 



There is no benefit from accepting and silently changing an invalid MXCSR
value supplied via ptrace().  Instead, return -EINVAL on invalid input.

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.613614842@linutronix.de
parent 6164331d

arch/x86/kernel/fpu/regset.c

+3 −2
Original line number Diff line number Diff line
@@ -63,8 +63,9 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset, 
	if (ret)

		return ret;



	/* Mask invalid MXCSR bits (for historical reasons). */

	newstate.mxcsr &= mxcsr_feature_mask;

	/* Do not allow an invalid MXCSR value. */

	if (newstate.mxcsr & ~mxcsr_feature_mask)

		return -EINVAL;



	fpu__prepare_write(fpu);