diff options
| author | Peter Gonda <pgonda@google.com> | 2023-02-07 09:13:54 -0800 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-02-07 14:36:45 -0800 |
| commit | f94f053aa3a5d6ff17951870483d9eb9e13de2e2 (patch) | |
| tree | 76fd11933ff8509d5dd242175e5fbf6e5d754588 /arch/x86/kvm/svm | |
| parent | 32e69f232db4ca11f26e5961daeff93906ce232f (diff) | |
KVM: SVM: Fix potential overflow in SEV's send|receive_update_data()
KVM_SEV_SEND_UPDATE_DATA and KVM_SEV_RECEIVE_UPDATE_DATA have an integer
overflow issue. Params.guest_len and offset are both 32 bits wide, with a
large params.guest_len the check to confirm a page boundary is not
crossed can falsely pass:
/* Check if we are crossing the page boundary *
offset = params.guest_uaddr & (PAGE_SIZE - 1);
if ((params.guest_len + offset > PAGE_SIZE))
Add an additional check to confirm that params.guest_len itself is not
greater than PAGE_SIZE.
Note, this isn't a security concern as overflow can happen if and only if
params.guest_len is greater than 0xfffff000, and the FW spec says these
commands fail with lengths greater than 16KB, i.e. the PSP will detect
KVM's goof.
Fixes: 15fb7de1a7f5 ("KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command")
Fixes: d3d1af85e2c7 ("KVM: SVM: Add KVM_SEND_UPDATE_DATA command")
Reported-by: Andy Nguyen <theflow@google.com>
Suggested-by: Thomas Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Peter Gonda <pgonda@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org
Cc: stable@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://lore.kernel.org/r/20230207171354.4012821-1-pgonda@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/svm')
| -rw-r--r-- | arch/x86/kvm/svm/sev.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index a5e4c5ef7c9e..c25aeb550cd9 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -1294,7 +1294,7 @@ static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp) /* Check if we are crossing the page boundary */ offset = params.guest_uaddr & (PAGE_SIZE - 1); - if ((params.guest_len + offset > PAGE_SIZE)) + if (params.guest_len > PAGE_SIZE || (params.guest_len + offset) > PAGE_SIZE) return -EINVAL; /* Pin guest memory */ @@ -1474,7 +1474,7 @@ static int sev_receive_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp) /* Check if we are crossing the page boundary */ offset = params.guest_uaddr & (PAGE_SIZE - 1); - if ((params.guest_len + offset > PAGE_SIZE)) + if (params.guest_len > PAGE_SIZE || (params.guest_len + offset) > PAGE_SIZE) return -EINVAL; hdr = psp_copy_user_blob(params.hdr_uaddr, params.hdr_len); |