user/sven/linux.git, branch v4.9.319

Linux 4.9.319

2022-06-16T11:00:52Z

Link: https://lore.kernel.org/r/20220614183722.061550591@linuxfoundation.org Tested-by: Florian Fainelli Tested-by: Shuah Khan Tested-by: Guenter Roeck Tested-by: Linux Kernel Functional Testing Tested-by: Jon Hunter Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Print SMT warning

2022-06-16T11:00:52Z

commit 1dc6ff02c8bf77d71b9b5d11cbc9df77cfb28626 upstream Similar to MDS and TAA, print a warning if SMT is enabled for the MMIO Stale Data vulnerability. Signed-off-by: Josh Poimboeuf Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

KVM: x86/speculation: Disable Fill buffer clear within guests

2022-06-16T11:00:52Z

commit 027bbb884be006b05d9c577d6401686053aa789e upstream The enumeration of MD_CLEAR in CPUID(EAX=7,ECX=0).EDX{bit 10} is not an accurate indicator on all CPUs of whether the VERW instruction will overwrite fill buffers. FB_CLEAR enumeration in IA32_ARCH_CAPABILITIES{bit 17} covers the case of CPUs that are not vulnerable to MDS/TAA, indicating that microcode does overwrite fill buffers. Guests running in VMM environments may not be aware of all the capabilities/vulnerabilities of the host CPU. Specifically, a guest may apply MDS/TAA mitigations when a virtual CPU is enumerated as vulnerable to MDS/TAA even when the physical CPU is not. On CPUs that enumerate FB_CLEAR_CTRL the VMM may set FB_CLEAR_DIS to skip overwriting of fill buffers by the VERW instruction. This is done by setting FB_CLEAR_DIS during VMENTER and resetting on VMEXIT. For guests that enumerate FB_CLEAR (explicitly asking for fill buffer clear capability) the VMM will not use FB_CLEAR_DIS. Irrespective of guest state, host overwrites CPU buffers before VMENTER to protect itself from an MMIO capable guest, as part of mitigation for MMIO Stale Data vulnerabilities. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner [cascardo: arch/x86/kvm/vmx.c has been split and context adjustment at vmx_vcpu_run] [cascardo: moved functions so they are after struct vcpu_vmx definition] [cascardo: fb_clear is disabled/enabled around __vmx_vcpu_run] [cascardo: conflict context fixups] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Reuse SRBDS mitigation for SBDS

2022-06-16T11:00:52Z

commit a992b8a4682f119ae035a01b40d4d0665c4a2875 upstream The Shared Buffers Data Sampling (SBDS) variant of Processor MMIO Stale Data vulnerabilities may expose RDRAND, RDSEED and SGX EGETKEY data. Mitigation for this is added by a microcode update. As some of the implications of SBDS are similar to SRBDS, SRBDS mitigation infrastructure can be leveraged by SBDS. Set X86_BUG_SRBDS and use SRBDS mitigation. Mitigation is enabled by default; use srbds=off to opt-out. Mitigation status can be checked from below file: /sys/devices/system/cpu/vulnerabilities/srbds Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner [cascardo: adjust for processor model names] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/srbds: Update SRBDS mitigation selection

2022-06-16T11:00:52Z

commit 22cac9c677c95f3ac5c9244f8ca0afdc7c8afb19 upstream Currently, Linux disables SRBDS mitigation on CPUs not affected by MDS and have the TSX feature disabled. On such CPUs, secrets cannot be extracted from CPU fill buffers using MDS or TAA. Without SRBDS mitigation, Processor MMIO Stale Data vulnerabilities can be used to extract RDRAND, RDSEED, and EGETKEY data. Do not disable SRBDS mitigation by default when CPU is also affected by Processor MMIO Stale Data vulnerabilities. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Add sysfs reporting for Processor MMIO Stale Data

2022-06-16T11:00:52Z

commit 8d50cdf8b8341770bc6367bce40c0c1bb0e1d5b3 upstream Add the sysfs reporting file for Processor MMIO Stale Data vulnerability. It exposes the vulnerability and mitigation state similar to the existing files for the other hardware vulnerabilities. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Enable CPU Fill buffer clearing on idle

2022-06-16T11:00:52Z

commit 99a83db5a605137424e1efe29dc0573d6a5b6316 upstream When the CPU is affected by Processor MMIO Stale Data vulnerabilities, Fill Buffer Stale Data Propagator (FBSDP) can propagate stale data out of Fill buffer to uncore buffer when CPU goes idle. Stale data can then be exploited with other variants using MMIO operations. Mitigate it by clearing the Fill buffer before entering idle state. Signed-off-by: Pawan Gupta Signed-off-by: Thomas Gleixner Co-developed-by: Josh Poimboeuf Signed-off-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/bugs: Group MDS, TAA & Processor MMIO Stale Data mitigations

2022-06-16T11:00:52Z

commit e5925fb867290ee924fcf2fe3ca887b792714366 upstream MDS, TAA and Processor MMIO Stale Data mitigations rely on clearing CPU buffers. Moreover, status of these mitigations affects each other. During boot, it is important to maintain the order in which these mitigations are selected. This is especially true for md_clear_update_mitigation() that needs to be called after MDS, TAA and Processor MMIO Stale Data mitigation selection is done. Introduce md_clear_select_mitigation(), and select all these mitigations from there. This reflects relationships between these mitigations and ensures proper ordering. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation/mmio: Add mitigation for Processor MMIO Stale Data

2022-06-16T11:00:51Z

commit 8cb861e9e3c9a55099ad3d08e1a3b653d29c33ca upstream Processor MMIO Stale Data is a class of vulnerabilities that may expose data after an MMIO operation. For details please refer to Documentation/admin-guide/hw-vuln/processor_mmio_stale_data.rst. These vulnerabilities are broadly categorized as: Device Register Partial Write (DRPW): Some endpoint MMIO registers incorrectly handle writes that are smaller than the register size. Instead of aborting the write or only copying the correct subset of bytes (for example, 2 bytes for a 2-byte write), more bytes than specified by the write transaction may be written to the register. On some processors, this may expose stale data from the fill buffers of the core that created the write transaction. Shared Buffers Data Sampling (SBDS): After propagators may have moved data around the uncore and copied stale data into client core fill buffers, processors affected by MFBDS can leak data from the fill buffer. Shared Buffers Data Read (SBDR): It is similar to Shared Buffer Data Sampling (SBDS) except that the data is directly read into the architectural software-visible state. An attacker can use these vulnerabilities to extract data from CPU fill buffers using MDS and TAA methods. Mitigate it by clearing the CPU fill buffers using the VERW instruction before returning to a user or a guest. On CPUs not affected by MDS and TAA, user application cannot sample data from CPU fill buffers using MDS or TAA. A guest with MMIO access can still use DRPW or SBDR to extract data architecturally. Mitigate it with VERW instruction to clear fill buffers before VMENTER for MMIO capable guests. Add a kernel parameter mmio_stale_data={off|full|full,nosmt} to control the mitigation. Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner [cascardo: arch/x86/kvm/vmx.c has been moved] Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/speculation: Add a common function for MD_CLEAR mitigation update

2022-06-16T11:00:51Z

commit f52ea6c26953fed339aa4eae717ee5c2133c7ff2 upstream Processor MMIO Stale Data mitigation uses similar mitigation as MDS and TAA. In preparation for adding its mitigation, add a common function to update all mitigations that depend on MD_CLEAR. [ bp: Add a newline in md_clear_update_mitigation() to separate statements better. ] Signed-off-by: Pawan Gupta Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman