kernel.git/arch/x86/kvm, branch linux-3.17.y

KVM: x86: Don't report guest userspace emulation error to userspace

2014-11-21T17:23:15Z

commit a2b9e6c1a35afcc0973acb72e591c714e78885ff upstream. Commit fc3a9157d314 ("KVM: X86: Don't report L2 emulation failures to user-space") disabled the reporting of L2 (nested guest) emulation failures to userspace due to race-condition between a vmexit and the instruction emulator. The same rational applies also to userspace applications that are permitted by the guest OS to access MMIO area or perform PIO. This patch extends the current behavior - of injecting a #UD instead of reporting it to userspace - also for guest userspace code. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Fix uninitialized op->type for some immediate values

2014-11-21T17:23:09Z

commit d29b9d7ed76c0b961603ca692b8a562556a20212 upstream. The emulator could reuse an op->type from a previous instruction for some immediate values. If it mistakenly considers the operands as memory operands, it will performs a memory read and overwrite op->val. Consider for instance the ROR instruction - src2 (the number of times) would be read from memory instead of being used as immediate. Mark every immediate operand as such to avoid this problem. Fixes: c44b4c6ab80eef3a9c52c7b3f0c632942e6489aa Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Fix far-jump to non-canonical check

2014-11-14T18:10:41Z

commit 7e46dddd6f6cd5dbf3c7bd04a7e75d19475ac9f2 upstream. Commit d1442d85cc30 ("KVM: x86: Handle errors when RIP is set during far jumps") introduced a bug that caused the fix to be incomplete. Due to incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may not trigger #GP. As we know, this imposes a security problem. In addition, the condition for two warnings was incorrect. Fixes: d1442d85cc30ea75f7d399474ca738e0bc96f715 Reported-by: Dan Carpenter Signed-off-by: Nadav Amit [Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo] Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

kvm: vmx: handle invvpid vm exit gracefully

2014-11-14T18:10:29Z

commit a642fc305053cc1c6e47e4f4df327895747ab485 upstream. On systems with invvpid instruction support (corresponding bit in IA32_VMX_EPT_VPID_CAP MSR is set) guest invocation of invvpid causes vm exit, which is currently not handled and results in propagation of unknown exit to userspace. Fix this by installing an invvpid vm exit handler. This is CVE-2014-3646. Signed-off-by: Petr Matousek Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Handle errors when RIP is set during far jumps

2014-11-14T18:10:28Z

commit d1442d85cc30ea75f7d399474ca738e0bc96f715 upstream. Far jmp/call/ret may fault while loading a new RIP. Currently KVM does not handle this case, and may result in failed vm-entry once the assignment is done. The tricky part of doing so is that loading the new CS affects the VMCS/VMCB state, so if we fail during loading the new RIP, we are left in unconsistent state. Therefore, this patch saves on 64-bit the old CS descriptor and restores it if loading RIP failed. This fixes CVE-2014-3647. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Emulator fixes for eip canonical checks on near branches

2014-11-14T18:10:28Z

commit 234f3ce485d54017f15cf5e0699cff4100121601 upstream. Before changing rip (during jmp, call, ret, etc.) the target should be asserted to be canonical one, as real CPUs do. During sysret, both target rsp and rip should be canonical. If any of these values is noncanonical, a #GP exception should occur. The exception to this rule are syscall and sysenter instructions in which the assigned rip is checked during the assignment to the relevant MSRs. This patch fixes the emulator to behave as real CPUs do for near branches. Far branches are handled by the next patch. This fixes CVE-2014-3647. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Fix wrong masking on relative jump/call

2014-11-14T18:10:28Z

commit 05c83ec9b73c8124555b706f6af777b10adf0862 upstream. Relative jumps and calls do the masking according to the operand size, and not according to the address size as the KVM emulator does today. This patch fixes KVM behavior. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

kvm: x86: don't kill guest on unknown exit reason

2014-11-14T18:10:28Z

commit 2bc19dc3754fc066c43799659f0d848631c44cfe upstream. KVM_EXIT_UNKNOWN is a kvm bug, we don't really know whether it was triggered by a priveledged application. Let's not kill the guest: WARN and inject #UD instead. Signed-off-by: Michael S. Tsirkin Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Check non-canonical addresses upon WRMSR

2014-11-14T18:10:28Z

commit 854e8bb1aa06c578c2c9145fa6bfe3680ef63b23 upstream. Upon WRMSR, the CPU should inject #GP if a non-canonical value (address) is written to certain MSRs. The behavior is "almost" identical for AMD and Intel (ignoring MSRs that are not implemented in either architecture since they would anyhow #GP). However, IA32_SYSENTER_ESP and IA32_SYSENTER_EIP cause #GP if non-canonical address is written on Intel but not on AMD (which ignores the top 32-bits). Accordingly, this patch injects a #GP on the MSRs which behave identically on Intel and AMD. To eliminate the differences between the architecutres, the value which is written to IA32_SYSENTER_ESP and IA32_SYSENTER_EIP is turned to canonical value before writing instead of injecting a #GP. Some references from Intel and AMD manuals: According to Intel SDM description of WRMSR instruction #GP is expected on WRMSR "If the source register contains a non-canonical address and ECX specifies one of the following MSRs: IA32_DS_AREA, IA32_FS_BASE, IA32_GS_BASE, IA32_KERNEL_GS_BASE, IA32_LSTAR, IA32_SYSENTER_EIP, IA32_SYSENTER_ESP." According to AMD manual instruction manual: LSTAR/CSTAR (SYSCALL): "The WRMSR instruction loads the target RIP into the LSTAR and CSTAR registers. If an RIP written by WRMSR is not in canonical form, a general-protection exception (#GP) occurs." IA32_GS_BASE and IA32_FS_BASE (WRFSBASE/WRGSBASE): "The address written to the base field must be in canonical form or a #GP fault will occur." IA32_KERNEL_GS_BASE (SWAPGS): "The address stored in the KernelGSbase MSR must be in canonical form." This patch fixes CVE-2014-3610. Signed-off-by: Nadav Amit Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

KVM: x86: Improve thread safety in pit

2014-11-14T18:10:28Z

commit 2febc839133280d5a5e8e1179c94ea674489dae2 upstream. There's a race condition in the PIT emulation code in KVM. In __kvm_migrate_pit_timer the pit_timer object is accessed without synchronization. If the race condition occurs at the wrong time this can crash the host kernel. This fixes CVE-2014-3611. Signed-off-by: Andrew Honig Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman