From: Misono Tomohiro misono.tomohiro@jp.fujitsu.com
[ Upstream commit 02a16aa13574c8526beadfc9ae8cc9b66315fa2d ]
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 misono.tomohiro@jp.fujitsu.com Signed-off-by: Borislav Petkov bp@suse.de Link: https://lkml.kernel.org/r/20210127122456.13939-1-misono.tomohiro@jp.fujitsu.... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/x86/kernel/msr.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index c0d4098106589..79f900ffde4c5 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -184,6 +184,13 @@ 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;