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Filename Latest commit message Latest commit date
Wanpeng Li 3ca9419227 KVM: X86: Fix userspace set invalid CR4
Reported by syzkaller:

	WARNING: CPU: 0 PID: 6544 at /home/kernel/data/kvm/arch/x86/kvm//vmx/vmx.c:4689 handle_desc+0x37/0x40 [kvm_intel]
	CPU: 0 PID: 6544 Comm: a.out Tainted: G           OE     5.3.0-rc4+ #4
	RIP: 0010:handle_desc+0x37/0x40 [kvm_intel]
	Call Trace:
	 vmx_handle_exit+0xbe/0x6b0 [kvm_intel]
	 vcpu_enter_guest+0x4dc/0x18d0 [kvm]
	 kvm_arch_vcpu_ioctl_run+0x407/0x660 [kvm]
	 kvm_vcpu_ioctl+0x3ad/0x690 [kvm]
	 do_vfs_ioctl+0xa2/0x690
	 ksys_ioctl+0x6d/0x80
	 __x64_sys_ioctl+0x1a/0x20
	 do_syscall_64+0x74/0x720
	 entry_SYSCALL_64_after_hwframe+0x49/0xbe

When CR4.UMIP is set, guest should have UMIP cpuid flag. Current
kvm set_sregs function doesn't have such check when userspace inputs
sregs values. SECONDARY_EXEC_DESC is enabled on writes to CR4.UMIP
in vmx_set_cr4 though guest doesn't have UMIP cpuid flag. The testcast
triggers handle_desc warning when executing ltr instruction since
guest architectural CR4 doesn't set UMIP. This patch fixes it by
adding valid CR4 and CPUID combination checking in __set_sregs.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=138efb99600000

Reported-by: syzbot+0f1819555fbdce992df9@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2019-09-26 12:31:31 +02:00
arch KVM: X86: Fix userspace set invalid CR4 2019-09-26 12:31:31 +02:00
block
certs
crypto
Documentation KVM/Hyper-V: Add new KVM capability KVM_CAP_HYPERV_DIRECT_TLBFLUSH 2019-09-24 13:37:13 +02:00
drivers - New Drivers 2019-09-23 19:37:49 -07:00
fs selinux/stable-5.4 PR 20190917 2019-09-23 11:21:04 -07:00
include cpu/SMT: create and export cpu_smt_possible() 2019-09-24 13:37:28 +02:00
init Modules updates for v5.4 2019-09-22 10:34:46 -07:00
ipc
kernel Revert "locking/pvqspinlock: Don't wait if vCPU is preempted" 2019-09-25 10:22:37 +02:00
lib Modules updates for v5.4 2019-09-22 10:34:46 -07:00
LICENSES
mm
net
samples rpmsg updates for v5.4 2019-09-22 10:58:15 -07:00
scripts Modules updates for v5.4 2019-09-22 10:34:46 -07:00
security I have four patches for v5.4. Nothing is major. All but one are in 2019-09-23 14:25:45 -07:00
sound
tools KVM: x86: Check kvm_rebooting in kvm_spurious_fault() 2019-09-25 15:23:33 +02:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS - New Drivers 2019-09-23 19:37:49 -07:00
Makefile Modules updates for v5.4 2019-09-22 10:34:46 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.