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KVM: add missing compat KVM_CLEAR_DIRTY_LOG 

commit 8750f9bbda115f3f79bfe43be85551ee5e12b6ff upstream.

The arguments to the KVM_CLEAR_DIRTY_LOG ioctl include a pointer,
therefore it needs a compat ioctl implementation.  Otherwise,
32-bit userspace fails to invoke it on 64-bit kernels; for x86
it might work fine by chance if the padding is zero, but not
on big-endian architectures.

Reported-by: Thomas Sattler
Cc: stable@vger.kernel.org
Fixes: 2a31b9db15 ("kvm: introduce manual dirty log reprotect")
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Paolo Bonzini 2021-07-27 08:43:10 -04:00 committed by Greg Kroah-Hartman
parent 7a94dfe5e2
commit 9bd1092148
1 changed files with 28 additions and 0 deletions
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28
virt/kvm/kvm_main.c
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@ -3570,6 +3570,16 @@ struct compat_kvm_dirty_log {
};
};
struct compat_kvm_clear_dirty_log {
__u32 slot;
__u32 num_pages;
__u64 first_page;
union {
compat_uptr_t dirty_bitmap; /* one bit per page */
__u64 padding2;
};
};
static long kvm_vm_compat_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@ -3579,6 +3589,24 @@ static long kvm_vm_compat_ioctl(struct file *filp,
if (kvm->mm != current->mm)
return -EIO;
switch (ioctl) {
#ifdef CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT
case KVM_CLEAR_DIRTY_LOG: {
struct compat_kvm_clear_dirty_log compat_log;
struct kvm_clear_dirty_log log;
if (copy_from_user(&compat_log, (void __user *)arg,
sizeof(compat_log)))
return -EFAULT;
log.slot = compat_log.slot;
log.num_pages = compat_log.num_pages;
log.first_page = compat_log.first_page;
log.padding2 = compat_log.padding2;
log.dirty_bitmap = compat_ptr(compat_log.dirty_bitmap);
r = kvm_vm_ioctl_clear_dirty_log(kvm, &log);
break;
}
#endif
case KVM_GET_DIRTY_LOG: {
struct compat_kvm_dirty_log compat_log;
struct kvm_dirty_log log;