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Wanpeng Li ffb01e7373 KVM: LAPIC: Fix pv ipis use-before-initialization
commit 38ab012f10 upstream.

Reported by syzkaller:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000014
 PGD 800000040410c067 P4D 800000040410c067 PUD 40410d067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP PTI
 CPU: 3 PID: 2567 Comm: poc Tainted: G           OE     4.19.0-rc5 #16
 RIP: 0010:kvm_pv_send_ipi+0x94/0x350 [kvm]
 Call Trace:
  kvm_emulate_hypercall+0x3cc/0x700 [kvm]
  handle_vmcall+0xe/0x10 [kvm_intel]
  vmx_handle_exit+0xc1/0x11b0 [kvm_intel]
  vcpu_enter_guest+0x9fb/0x1910 [kvm]
  kvm_arch_vcpu_ioctl_run+0x35c/0x610 [kvm]
  kvm_vcpu_ioctl+0x3e9/0x6d0 [kvm]
  do_vfs_ioctl+0xa5/0x690
  ksys_ioctl+0x6d/0x80
  __x64_sys_ioctl+0x1a/0x20
  do_syscall_64+0x83/0x6e0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

The reason is that the apic map has not yet been initialized, the testcase
triggers pv_send_ipi interface by vmcall which results in kvm->arch.apic_map
is dereferenced. This patch fixes it by checking whether or not apic map is
NULL and bailing out immediately if that is the case.

Fixes: 4180bf1b65 (KVM: X86: Implement "send IPI" hypercall)
Reported-by: Wei Wu <ww9210@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Wei Wu <ww9210@gmail.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-05 19:32:05 +01:00
arch KVM: LAPIC: Fix pv ipis use-before-initialization 2018-12-05 19:32:05 +01:00
block block: copy ioprio in __bio_clone_fast() and bounce 2018-12-01 09:37:32 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: simd - correctly take reqsize of wrapped skcipher into account 2018-12-01 09:37:32 +01:00
Documentation x86/speculation: Provide IBPB always command line options 2018-12-05 19:32:04 +01:00
drivers net: phy: add workaround for issue where PHY driver doesn't bind to the device 2018-12-05 19:32:00 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas 2018-12-05 19:32:04 +01:00
include x86/speculation: Add prctl() control for indirect branch speculation 2018-12-05 19:32:04 +01:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS 2018-12-05 19:32:03 +01:00
lib lib/raid6: Fix arm64 test build 2018-11-27 16:13:05 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm userfaultfd: shmem/hugetlbfs: only allow to register VM_MAYWRITE vmas 2018-12-05 19:32:04 +01:00
net tipc: fix lockdep warning during node delete 2018-12-05 19:32:00 +01:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support 2018-12-05 19:32:01 +01:00
security selinux: Add __GFP_NOWARN to allocation at str_read() 2018-12-01 09:37:27 +01:00
sound ALSA: oss: Use kvzalloc() for local buffer allocations 2018-12-01 09:37:25 +01:00
tools x86/speculation: Add prctl() control for indirect branch speculation 2018-12-05 19:32:04 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add Sasha as a stable branch maintainer 2018-12-01 09:37:25 +01:00
Makefile Linux 4.19.6 2018-12-01 09:37:35 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.