From 02a16aa13574c8526beadfc9ae8cc9b66315fa2d Mon Sep 17 00:00:00 2001 From: Misono Tomohiro Date: Wed, 27 Jan 2021 21:24:56 +0900 Subject: x86/MSR: Filter MSR writes through X86_IOC_WRMSR_REGS ioctl too Commit a7e1f67ed29f ("x86/msr: Filter MSR writes") introduced a module parameter to disable writing to the MSR device file and tainted the kernel upon writing. As MSR registers can be written by the X86_IOC_WRMSR_REGS ioctl too, the same filtering and tainting should be applied to the ioctl as well. [ bp: Massage commit message and space out statements. ] Fixes: a7e1f67ed29f ("x86/msr: Filter MSR writes") Signed-off-by: Misono Tomohiro Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210127122456.13939-1-misono.tomohiro@jp.fujitsu.com --- arch/x86/kernel/msr.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'arch') diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index 8a67d1fa8dc5..ed8ac6bcbafb 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -182,6 +182,13 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg) err = security_locked_down(LOCKDOWN_MSR); if (err) break; + + err = filter_write(regs[1]); + if (err) + return err; + + add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_STILL_OK); + err = wrmsr_safe_regs_on_cpu(cpu, regs); if (err) break; -- cgit v1.2.3-59-g8ed1b