From 0ede5bfc57b8910f6436a23955422fae109636c2 Mon Sep 17 00:00:00 2001 From: Dmitry Vyukov Date: Mon, 25 Apr 2022 08:07:36 +0200 Subject: dashboard/config/linux: disable MSR writes Randomly changing MSRs can have unpredictable results. We tried to protect from writes on descriptions level, but it does not work well, the fuzzer has figured out: 03:37:28 executing program 3: syz_open_dev$MSR(&(0x7f0000000040), 0x0, 0x0) r0 = syz_open_procfs(0x0, &(0x7f0000000180)='fd/3\x00') pwritev(r0, ...) Fortunately there is a command line argument that disables all writes. Use it instead. Note: older kernels will need: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a7e1f67ed29f https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=02a16aa13574 --- sys/linux/dev_msr.txt | 2 -- 1 file changed, 2 deletions(-) (limited to 'sys/linux/dev_msr.txt') diff --git a/sys/linux/dev_msr.txt b/sys/linux/dev_msr.txt index 07a3d3554..f3ae87664 100644 --- a/sys/linux/dev_msr.txt +++ b/sys/linux/dev_msr.txt @@ -11,5 +11,3 @@ syz_open_dev$MSR(dev ptr[in, string["/dev/cpu/#/msr"]], id intptr, flags const[O read$msr(fd fd_msr, buf buffer[out], count len[buf]) ioctl$X86_IOC_RDMSR_REGS(fd fd_msr, cmd const[X86_IOC_RDMSR_REGS], arg ptr[in, array[int32, 8]]) -# Disallow writing to MSRs -_ = X86_IOC_WRMSR_REGS -- cgit mrf-deployment