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![Yann Droneaud](/assets/img/avatar_default.png)
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: Alexander Graf <agraf@suse.de> Signed-off-by: Gleb Natapov <gleb@redhat.com>
150 lines
3.7 KiB
C
150 lines
3.7 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
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* Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
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*/
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/kvm.h>
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#include <linux/kvm_host.h>
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#include <linux/highmem.h>
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#include <linux/gfp.h>
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#include <linux/slab.h>
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#include <linux/hugetlb.h>
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#include <linux/list.h>
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#include <linux/anon_inodes.h>
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#include <asm/tlbflush.h>
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#include <asm/kvm_ppc.h>
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#include <asm/kvm_book3s.h>
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#include <asm/mmu-hash64.h>
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#include <asm/hvcall.h>
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#include <asm/synch.h>
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#include <asm/ppc-opcode.h>
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#include <asm/kvm_host.h>
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#include <asm/udbg.h>
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#define TCES_PER_PAGE (PAGE_SIZE / sizeof(u64))
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static long kvmppc_stt_npages(unsigned long window_size)
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{
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return ALIGN((window_size >> SPAPR_TCE_SHIFT)
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* sizeof(u64), PAGE_SIZE) / PAGE_SIZE;
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}
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static void release_spapr_tce_table(struct kvmppc_spapr_tce_table *stt)
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{
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struct kvm *kvm = stt->kvm;
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int i;
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mutex_lock(&kvm->lock);
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list_del(&stt->list);
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for (i = 0; i < kvmppc_stt_npages(stt->window_size); i++)
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__free_page(stt->pages[i]);
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kfree(stt);
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mutex_unlock(&kvm->lock);
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kvm_put_kvm(kvm);
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}
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static int kvm_spapr_tce_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct kvmppc_spapr_tce_table *stt = vma->vm_file->private_data;
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struct page *page;
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if (vmf->pgoff >= kvmppc_stt_npages(stt->window_size))
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return VM_FAULT_SIGBUS;
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page = stt->pages[vmf->pgoff];
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get_page(page);
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vmf->page = page;
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return 0;
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}
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static const struct vm_operations_struct kvm_spapr_tce_vm_ops = {
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.fault = kvm_spapr_tce_fault,
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};
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static int kvm_spapr_tce_mmap(struct file *file, struct vm_area_struct *vma)
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{
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vma->vm_ops = &kvm_spapr_tce_vm_ops;
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return 0;
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}
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static int kvm_spapr_tce_release(struct inode *inode, struct file *filp)
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{
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struct kvmppc_spapr_tce_table *stt = filp->private_data;
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release_spapr_tce_table(stt);
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return 0;
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}
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static const struct file_operations kvm_spapr_tce_fops = {
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.mmap = kvm_spapr_tce_mmap,
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.release = kvm_spapr_tce_release,
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};
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long kvm_vm_ioctl_create_spapr_tce(struct kvm *kvm,
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struct kvm_create_spapr_tce *args)
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{
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struct kvmppc_spapr_tce_table *stt = NULL;
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long npages;
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int ret = -ENOMEM;
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int i;
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/* Check this LIOBN hasn't been previously allocated */
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list_for_each_entry(stt, &kvm->arch.spapr_tce_tables, list) {
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if (stt->liobn == args->liobn)
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return -EBUSY;
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}
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npages = kvmppc_stt_npages(args->window_size);
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stt = kzalloc(sizeof(*stt) + npages * sizeof(struct page *),
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GFP_KERNEL);
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if (!stt)
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goto fail;
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stt->liobn = args->liobn;
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stt->window_size = args->window_size;
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stt->kvm = kvm;
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for (i = 0; i < npages; i++) {
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stt->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
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if (!stt->pages[i])
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goto fail;
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}
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kvm_get_kvm(kvm);
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mutex_lock(&kvm->lock);
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list_add(&stt->list, &kvm->arch.spapr_tce_tables);
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mutex_unlock(&kvm->lock);
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return anon_inode_getfd("kvm-spapr-tce", &kvm_spapr_tce_fops,
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stt, O_RDWR | O_CLOEXEC);
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fail:
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if (stt) {
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for (i = 0; i < npages; i++)
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if (stt->pages[i])
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__free_page(stt->pages[i]);
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kfree(stt);
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}
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return ret;
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}
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