Re: [PATCH 1/2] kvm: use anon_inode_getfd() with O_CLOEXEC flag

[Paolo Bonzini <pbonzini@redhat.com>]

Il 24/08/2013 22:14, Yann Droneaud ha scritto:
> KVM uses anon_inode_get() to allocate file descriptors as part
> of some of its ioctls. But those ioctls are lacking a flag argument
> allowing userspace to choose options for the newly opened file descriptor.
> 
> In such case it's advised to use O_CLOEXEC by default so that
> userspace is allowed to choose, without race, if the file descriptor
> is going to be inherited across exec().
> 
> This patch set O_CLOEXEC flag on all file descriptors created
> with anon_inode_getfd() to not leak file descriptors across exec().
> 
> Signed-off-by: Yann Droneaud <ydroneaud@opteya.com>
> Link: http://lkml.kernel.org/r/cover.1377372576.git.ydroneaud@opteya.com

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

> ---
>  virt/kvm/kvm_main.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 89f74d1..d65cc0c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -1896,7 +1896,7 @@ static struct file_operations kvm_vcpu_fops = {
>   */
>  static int create_vcpu_fd(struct kvm_vcpu *vcpu)
>  {
> -	return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR);
> +	return anon_inode_getfd("kvm-vcpu", &kvm_vcpu_fops, vcpu, O_RDWR | O_CLOEXEC);
>  }
>  
>  /*
> @@ -2306,7 +2306,7 @@ static int kvm_ioctl_create_device(struct kvm *kvm,
>  		return ret;
>  	}
>  
> -	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR);
> +	ret = anon_inode_getfd(ops->name, &kvm_device_fops, dev, O_RDWR | O_CLOEXEC);
>  	if (ret < 0) {
>  		ops->destroy(dev);
>  		return ret;
> @@ -2590,7 +2590,7 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
>  		return r;
>  	}
>  #endif
> -	r = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
> +	r = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR | O_CLOEXEC);
>  	if (r < 0)
>  		kvm_put_kvm(kvm);
>  
>