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| author | Paolo Bonzini <pbonzini@redhat.com> | 2019-04-17 15:28:44 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-04-30 21:32:19 +0200 |
| commit | 65c4189de8c1d995f6bc2cc96b22206405466b53 (patch) | |
| tree | 458839f13a2c760594db18f48c52cd9d1b267829 /virt | |
| parent | KVM: VMX: Skip delta_tsc shift-and-divide if the dividend is zero (diff) | |
| download | linux-65c4189de8c1d995f6bc2cc96b22206405466b53.tar.xz linux-65c4189de8c1d995f6bc2cc96b22206405466b53.zip | |
KVM: fix KVM_CLEAR_DIRTY_LOG for memory slots of unaligned size
If a memory slot's size is not a multiple of 64 pages (256K), then
the KVM_CLEAR_DIRTY_LOG API is unusable: clearing the final 64 pages
either requires the requested page range to go beyond memslot->npages,
or requires log->num_pages to be unaligned, and kvm_clear_dirty_log_protect
requires log->num_pages to be both in range and aligned.
To allow this case, allow log->num_pages not to be a multiple of 64 if
it ends exactly on the last page of the slot.
Reported-by: Peter Xu <peterx@redhat.com>
Fixes: 98938aa8edd6 ("KVM: validate userspace input in kvm_clear_dirty_log_protect()", 2019-01-02)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 71ac0de892dc..e9ca417b9ae9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1240,7 +1240,7 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm, if (as_id >= KVM_ADDRESS_SPACE_NUM || id >= KVM_USER_MEM_SLOTS) return -EINVAL; - if ((log->first_page & 63) || (log->num_pages & 63)) + if (log->first_page & 63) return -EINVAL; slots = __kvm_memslots(kvm, as_id); @@ -1253,8 +1253,9 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm, n = kvm_dirty_bitmap_bytes(memslot); if (log->first_page > memslot->npages || - log->num_pages > memslot->npages - log->first_page) - return -EINVAL; + log->num_pages > memslot->npages - log->first_page || + (log->num_pages < memslot->npages - log->first_page && (log->num_pages & 63))) + return -EINVAL; *flush = false; dirty_bitmap_buffer = kvm_second_dirty_bitmap(memslot); |