Jann Horn 0c42df1f9f kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974) ... commit cfa3938117 upstream. kvm_ioctl_create_device() does the following: 1. creates a device that holds a reference to the VM object (with a borrowed reference, the VM's refcount has not been bumped yet) 2. initializes the device 3. transfers the reference to the device to the caller's file descriptor table 4. calls kvm_get_kvm() to turn the borrowed reference to the VM into a real reference The ownership transfer in step 3 must not happen before the reference to the VM becomes a proper, non-borrowed reference, which only happens in step 4. After step 3, an attacker can close the file descriptor and drop the borrowed reference, which can cause the refcount of the kvm object to drop to zero. This means that we need to grab a reference for the device before anon_inode_getfd(), otherwise the VM can disappear from under us. Fixes: 852b6d57dc ("kvm: add device control API") Cc: stable@kernel.org Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2019-02-12 19:45:01 +01:00
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kvm	kvm: fix kvm_ioctl_create_device() reference counting (CVE-2019-6974)	2019-02-12 19:45:01 +01:00
lib	KVM: eventfd: fix NULL deref irqbypass consumer	2017-01-19 20:17:59 +01:00
Makefile	virt: Add virt directory to the top Makefile	2015-10-01 15:06:44 +02:00