Messages in this thread Patch in this message | | | From | Misono Tomohiro <> | Subject | [PATCH] x86/msr: Filter msr write by X86_IOC_WRMSR_REGS ioctl | Date | Wed, 27 Jan 2021 21:24:56 +0900 |
| |
commit a7e1f67ed29f ("x86/msr: Filter MSR writes") introduces a module parameter to disable writing to msr device file (and add_taint() upon writing). As msr register can be written by X86_IOC_WRMSR_REGS ioctl too, they should be applied to the ioctl as well.
Fixes: a7e1f67ed29f ("x86/msr: Filter MSR writes") Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com> --- Hello,
I just noticed this when I read the code. I'm not sure if anyone uses ioctl interface now, but I tested this by resetting IA32_MPERF by X86_IOC_WRMSR_REGS ioctl.
Thanks,
arch/x86/kernel/msr.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c index 8a67d1fa8dc5..d774618e75b8 100644 --- a/arch/x86/kernel/msr.c +++ b/arch/x86/kernel/msr.c @@ -182,6 +182,10 @@ 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; -- 2.26.2
| |