From: Misono Tomohiro <misono.tomohiro@xxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Link: https://lkml.kernel.org/r/20210127122456.13939-1-misono.tomohiro@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 8a67d1fa8dc58..ed8ac6bcbafb2 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;
--
2.27.0
