| Message ID | 1487588781-15123-5-git-send-email-elena.reshetova@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 20/02/2017 12:06, Elena Reshetova wrote: > 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> Looks good, will apply after the merge window. Paolo > --- > include/linux/kvm_host.h | 3 ++- > virt/kvm/kvm_main.c | 8 ++++---- > 2 files changed, 6 insertions(+), 5 deletions(-) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index cda457b..7fa05a5 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -26,6 +26,7 @@ > #include <linux/context_tracking.h> > #include <linux/irqbypass.h> > #include <linux/swait.h> > +#include <linux/refcount.h> > #include <asm/signal.h> > > #include <linux/kvm.h> > @@ -402,7 +403,7 @@ struct kvm { > #endif > struct kvm_vm_stat stat; > struct kvm_arch arch; > - atomic_t users_count; > + refcount_t users_count; > #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET > struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; > spinlock_t ring_lock; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index dcd1c12..6ae5775 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -622,7 +622,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > mutex_init(&kvm->lock); > mutex_init(&kvm->irq_lock); > mutex_init(&kvm->slots_lock); > - atomic_set(&kvm->users_count, 1); > + refcount_set(&kvm->users_count, 1); > INIT_LIST_HEAD(&kvm->devices); > > r = kvm_arch_init_vm(kvm, type); > @@ -745,13 +745,13 @@ static void kvm_destroy_vm(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); > > 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); > } > EXPORT_SYMBOL_GPL(kvm_put_kvm); > @@ -3640,7 +3640,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, > * To avoid the race between open and the removal of the debugfs > * 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; > > if (simple_attr_open(inode, file, get, set, fmt)) { >
> On 20/02/2017 12:06, Elena Reshetova wrote: > > 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> > > Looks good, will apply after the merge window. > > Paolo Thank you very much! Best Regards, Elena. > > > --- > > include/linux/kvm_host.h | 3 ++- > > virt/kvm/kvm_main.c | 8 ++++---- > > 2 files changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > > index cda457b..7fa05a5 100644 > > --- a/include/linux/kvm_host.h > > +++ b/include/linux/kvm_host.h > > @@ -26,6 +26,7 @@ > > #include <linux/context_tracking.h> > > #include <linux/irqbypass.h> > > #include <linux/swait.h> > > +#include <linux/refcount.h> > > #include <asm/signal.h> > > > > #include <linux/kvm.h> > > @@ -402,7 +403,7 @@ struct kvm { > > #endif > > struct kvm_vm_stat stat; > > struct kvm_arch arch; > > - atomic_t users_count; > > + refcount_t users_count; > > #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET > > struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; > > spinlock_t ring_lock; > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > index dcd1c12..6ae5775 100644 > > --- a/virt/kvm/kvm_main.c > > +++ b/virt/kvm/kvm_main.c > > @@ -622,7 +622,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > > mutex_init(&kvm->lock); > > mutex_init(&kvm->irq_lock); > > mutex_init(&kvm->slots_lock); > > - atomic_set(&kvm->users_count, 1); > > + refcount_set(&kvm->users_count, 1); > > INIT_LIST_HEAD(&kvm->devices); > > > > r = kvm_arch_init_vm(kvm, type); > > @@ -745,13 +745,13 @@ static void kvm_destroy_vm(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); > > > > 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); > > } > > EXPORT_SYMBOL_GPL(kvm_put_kvm); > > @@ -3640,7 +3640,7 @@ static int kvm_debugfs_open(struct inode *inode, > struct file *file, > > * To avoid the race between open and the removal of the debugfs > > * 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; > > > > if (simple_attr_open(inode, file, get, set, fmt)) { > >
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index cda457b..7fa05a5 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -26,6 +26,7 @@ #include <linux/context_tracking.h> #include <linux/irqbypass.h> #include <linux/swait.h> +#include <linux/refcount.h> #include <asm/signal.h> #include <linux/kvm.h> @@ -402,7 +403,7 @@ struct kvm { #endif struct kvm_vm_stat stat; struct kvm_arch arch; - atomic_t users_count; + refcount_t users_count; #ifdef KVM_COALESCED_MMIO_PAGE_OFFSET struct kvm_coalesced_mmio_ring *coalesced_mmio_ring; spinlock_t ring_lock; diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index dcd1c12..6ae5775 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -622,7 +622,7 @@ static struct kvm *kvm_create_vm(unsigned long type) mutex_init(&kvm->lock); mutex_init(&kvm->irq_lock); mutex_init(&kvm->slots_lock); - atomic_set(&kvm->users_count, 1); + refcount_set(&kvm->users_count, 1); INIT_LIST_HEAD(&kvm->devices); r = kvm_arch_init_vm(kvm, type); @@ -745,13 +745,13 @@ static void kvm_destroy_vm(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); 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); } EXPORT_SYMBOL_GPL(kvm_put_kvm); @@ -3640,7 +3640,7 @@ static int kvm_debugfs_open(struct inode *inode, struct file *file, * To avoid the race between open and the removal of the debugfs * 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; if (simple_attr_open(inode, file, get, set, fmt)) {