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authorTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>2011-05-07 16:35:38 +0900
committerAvi Kivity <avi@redhat.com>2011-05-22 08:47:56 -0400
commitfa3d315a4ce2c0891cdde262562e710d95fba19e (patch)
tree79205998f6734b51628f92641124dbe4aaa9882f /virt/kvm/kvm_main.c
parent12cb814f3bb35736420cc6bfc9fed7b6a9d3a828 (diff)
downloadlinaro-lsk-fa3d315a4ce2c0891cdde262562e710d95fba19e.tar.gz
KVM: Validate userspace_addr of memslot when registered
This way, we can avoid checking the user space address many times when we read the guest memory. Although we can do the same for write if we check which slots are writable, we do not care write now: reading the guest memory happens more often than writing. [avi: change VERIFY_READ to VERIFY_WRITE] Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 58146457bf9..ed3c4e7c100 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -648,7 +648,10 @@ int __kvm_set_memory_region(struct kvm *kvm,
goto out;
if (mem->guest_phys_addr & (PAGE_SIZE - 1))
goto out;
- if (user_alloc && (mem->userspace_addr & (PAGE_SIZE - 1)))
+ /* We can read the guest memory with __xxx_user() later on. */
+ if (user_alloc &&
+ ((mem->userspace_addr & (PAGE_SIZE - 1)) ||
+ !access_ok(VERIFY_WRITE, mem->userspace_addr, mem->memory_size)))
goto out;
if (mem->slot >= KVM_MEMORY_SLOTS + KVM_PRIVATE_MEM_SLOTS)
goto out;
@@ -1283,7 +1286,7 @@ int kvm_read_guest_page(struct kvm *kvm, gfn_t gfn, void *data, int offset,
addr = gfn_to_hva(kvm, gfn);
if (kvm_is_error_hva(addr))
return -EFAULT;
- r = copy_from_user(data, (void __user *)addr + offset, len);
+ r = __copy_from_user(data, (void __user *)addr + offset, len);
if (r)
return -EFAULT;
return 0;