kvm: convert kvm.users_count from atomic_t to refcount_t
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This commit is contained in:
parent
bba82fd756
commit
e3736c3eb3
|
@ -26,6 +26,7 @@
|
||||||
#include <linux/context_tracking.h>
|
#include <linux/context_tracking.h>
|
||||||
#include <linux/irqbypass.h>
|
#include <linux/irqbypass.h>
|
||||||
#include <linux/swait.h>
|
#include <linux/swait.h>
|
||||||
|
#include <linux/refcount.h>
|
||||||
#include <asm/signal.h>
|
#include <asm/signal.h>
|
||||||
|
|
||||||
#include <linux/kvm.h>
|
#include <linux/kvm.h>
|
||||||
|
@ -401,7 +402,7 @@ struct kvm {
|
||||||
#endif
|
#endif
|
||||||
struct kvm_vm_stat stat;
|
struct kvm_vm_stat stat;
|
||||||
struct kvm_arch arch;
|
struct kvm_arch arch;
|
||||||
atomic_t users_count;
|
refcount_t users_count;
|
||||||
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
|
#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
|
||||||
struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
|
struct kvm_coalesced_mmio_ring *coalesced_mmio_ring;
|
||||||
spinlock_t ring_lock;
|
spinlock_t ring_lock;
|
||||||
|
|
|
@ -617,7 +617,7 @@ static struct kvm *kvm_create_vm(unsigned long type)
|
||||||
mutex_init(&kvm->lock);
|
mutex_init(&kvm->lock);
|
||||||
mutex_init(&kvm->irq_lock);
|
mutex_init(&kvm->irq_lock);
|
||||||
mutex_init(&kvm->slots_lock);
|
mutex_init(&kvm->slots_lock);
|
||||||
atomic_set(&kvm->users_count, 1);
|
refcount_set(&kvm->users_count, 1);
|
||||||
INIT_LIST_HEAD(&kvm->devices);
|
INIT_LIST_HEAD(&kvm->devices);
|
||||||
|
|
||||||
r = kvm_arch_init_vm(kvm, type);
|
r = kvm_arch_init_vm(kvm, type);
|
||||||
|
@ -747,13 +747,13 @@ static void kvm_destroy_vm(struct kvm *kvm)
|
||||||
|
|
||||||
void kvm_get_kvm(struct kvm *kvm)
|
void kvm_get_kvm(struct kvm *kvm)
|
||||||
{
|
{
|
||||||
atomic_inc(&kvm->users_count);
|
refcount_inc(&kvm->users_count);
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL_GPL(kvm_get_kvm);
|
EXPORT_SYMBOL_GPL(kvm_get_kvm);
|
||||||
|
|
||||||
void kvm_put_kvm(struct kvm *kvm)
|
void kvm_put_kvm(struct kvm *kvm)
|
||||||
{
|
{
|
||||||
if (atomic_dec_and_test(&kvm->users_count))
|
if (refcount_dec_and_test(&kvm->users_count))
|
||||||
kvm_destroy_vm(kvm);
|
kvm_destroy_vm(kvm);
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL_GPL(kvm_put_kvm);
|
EXPORT_SYMBOL_GPL(kvm_put_kvm);
|
||||||
|
@ -3639,7 +3639,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file,
|
||||||
* To avoid the race between open and the removal of the debugfs
|
* To avoid the race between open and the removal of the debugfs
|
||||||
* directory we test against the users count.
|
* directory we test against the users count.
|
||||||
*/
|
*/
|
||||||
if (!atomic_add_unless(&stat_data->kvm->users_count, 1, 0))
|
if (!refcount_inc_not_zero(&stat_data->kvm->users_count))
|
||||||
return -ENOENT;
|
return -ENOENT;
|
||||||
|
|
||||||
if (simple_attr_open(inode, file, get, set, fmt)) {
|
if (simple_attr_open(inode, file, get, set, fmt)) {
|
||||||
|
|
Loading…
Reference in a new issue