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Filename Latest commit message Latest commit date
Liran Alon 7f9ad1dfa3 KVM: nVMX: Fix kernel info-leak when enabling KVM_CAP_HYPERV_ENLIGHTENED_VMCS more than once
Consider the case that userspace enables KVM_CAP_HYPERV_ENLIGHTENED_VMCS twice:
1) kvm_vcpu_ioctl_enable_cap() is called to enable
KVM_CAP_HYPERV_ENLIGHTENED_VMCS which calls nested_enable_evmcs().
2) nested_enable_evmcs() sets enlightened_vmcs_enabled to true and fills
vmcs_version which is then copied to userspace.
3) kvm_vcpu_ioctl_enable_cap() is called again to enable
KVM_CAP_HYPERV_ENLIGHTENED_VMCS which calls nested_enable_evmcs().
4) This time nested_enable_evmcs() just returns 0 as
enlightened_vmcs_enabled is already true. *Without filling
vmcs_version*.
5) kvm_vcpu_ioctl_enable_cap() continues as usual and copies
*uninitialized* vmcs_version to userspace which leads to kernel info-leak.

Fix this issue by simply changing nested_enable_evmcs() to always fill
vmcs_version output argument. Even when enlightened_vmcs_enabled is
already set to true.

Note that SVM's nested_enable_evmcs() should not be modified because it
always returns a non-zero value (-ENODEV) which results in
kvm_vcpu_ioctl_enable_cap() skipping the copy of vmcs_version to
userspace (as it should).

Fixes: 57b119da35 ("KVM: nVMX: add KVM_CAP_HYPERV_ENLIGHTENED_VMCS capability")
Reported-by: syzbot+cfbc368e283d381f8cef@syzkaller.appspotmail.com
Reviewed-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2018-11-27 12:49:46 +01:00
arch KVM: nVMX: Fix kernel info-leak when enabling KVM_CAP_HYPERV_ENLIGHTENED_VMCS more than once 2018-11-27 12:49:46 +01:00
block SCSI: fix queue cleanup race before queue initialization is done 2018-11-14 08:19:10 -07:00
certs
crypto crypto: user - Zeroize whole structure given to user space 2018-11-09 17:35:43 +08:00
Documentation Power management updates for 4.20-rc3 2018-11-14 15:33:45 -06:00
drivers libnvdimm 4.20-rc3 2018-11-18 12:21:09 -08:00
firmware
fs ocfs2: free up write context when direct IO failed 2018-11-18 10:15:09 -08:00
include Merge branch 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-11-18 10:52:26 -08:00
init
ipc
kernel Merge branch 'akpm' (patches from Andrew) 2018-11-18 11:31:26 -08:00
lib lib/ubsan.c: don't mark __ubsan_handle_builtin_unreachable as noreturn 2018-11-18 10:15:10 -08:00
LICENSES
mm mm/memblock.c: fix a typo in __next_mem_pfn_range() comments 2018-11-18 10:15:10 -08:00
net NFS client bugfixes for Linux 4.20 2018-11-15 10:59:37 -06:00
samples
scripts scripts/spdxcheck.py: make python3 compliant 2018-11-18 10:15:10 -08:00
security selinux/stable-4.20 PR 20181115 2018-11-15 11:26:09 -06:00
sound
tools libnvdimm 4.20-rc3 2018-11-18 12:21:09 -08:00
usr
virt
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS MAINTAINERS: update OMAP MMC entry 2018-11-18 10:15:09 -08:00
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: update OMAP MMC entry 2018-11-18 10:15:09 -08:00
Makefile Linux 4.20-rc3 2018-11-18 13:33:44 -08:00
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.