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[PATCH] hw/pvrdma: Protect against buggy or malicious guest driver

Yuval Shaia posted 1 patch 2 years, 1 month ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20220321131143.31210-1-yuval.shaia.ml@gmail.com
Maintainers: Yuval Shaia <yuval.shaia.ml@gmail.com>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
There is a newer version of this series
hw/rdma/vmw/pvrdma_cmd.c  | 6 ++++++
hw/rdma/vmw/pvrdma_main.c | 9 +++++----
2 files changed, 11 insertions(+), 4 deletions(-)
[PATCH] hw/pvrdma: Protect against buggy or malicious guest driver
Posted by Yuval Shaia 2 years, 1 month ago 
Guest driver might execute HW commands when shared buffers are not yet
allocated.
This might happen on purpose (malicious guest) or because some other
guest/host address mapping.
We need to protect againts such case.

Reported-by: Mauro Matteo Cascella <mcascell@redhat.com>
Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
---
 hw/rdma/vmw/pvrdma_cmd.c  | 6 ++++++
 hw/rdma/vmw/pvrdma_main.c | 9 +++++----
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
index da7ddfa548..89db963c46 100644
--- a/hw/rdma/vmw/pvrdma_cmd.c
+++ b/hw/rdma/vmw/pvrdma_cmd.c
@@ -796,6 +796,12 @@ int pvrdma_exec_cmd(PVRDMADev *dev)
 
     dsr_info = &dev->dsr_info;
 
+    if (!dsr_info->dsr) {
+            /* Buggy or malicious guest driver */
+            rdma_error_report("Exec command without dsr, req or rsp buffers");
+            goto out;
+    }
+
     if (dsr_info->req->hdr.cmd >= sizeof(cmd_handlers) /
                       sizeof(struct cmd_handler)) {
         rdma_error_report("Unsupported command");
diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
index 91206dbb8e..aae382af59 100644
--- a/hw/rdma/vmw/pvrdma_main.c
+++ b/hw/rdma/vmw/pvrdma_main.c
@@ -159,13 +159,13 @@ static void free_dsr(PVRDMADev *dev)
     free_dev_ring(pci_dev, &dev->dsr_info.cq, dev->dsr_info.cq_ring_state);
 
     rdma_pci_dma_unmap(pci_dev, dev->dsr_info.req,
-                         sizeof(union pvrdma_cmd_req));
+                       sizeof(union pvrdma_cmd_req));
 
     rdma_pci_dma_unmap(pci_dev, dev->dsr_info.rsp,
-                         sizeof(union pvrdma_cmd_resp));
+                       sizeof(union pvrdma_cmd_resp));
 
     rdma_pci_dma_unmap(pci_dev, dev->dsr_info.dsr,
-                         sizeof(struct pvrdma_device_shared_region));
+                       sizeof(struct pvrdma_device_shared_region));
 
     dev->dsr_info.dsr = NULL;
 }
@@ -249,7 +249,8 @@ static void init_dsr_dev_caps(PVRDMADev *dev)
 {
     struct pvrdma_device_shared_region *dsr;
 
-    if (dev->dsr_info.dsr == NULL) {
+    if (!dev->dsr_info.dsr) {
+        /* Buggy or malicious guest driver */
         rdma_error_report("Can't initialized DSR");
         return;
     }
-- 
2.20.1
Re: [PATCH] hw/pvrdma: Protect against buggy or malicious guest driver
Posted by Marcel Apfelbaum 2 years, 1 month ago 
Hi Yuval

On Mon, Mar 21, 2022 at 2:11 PM Yuval Shaia <yuval.shaia.ml@gmail.com> wrote:
>
> Guest driver might execute HW commands when shared buffers are not yet
> allocated.
> This might happen on purpose (malicious guest) or because some other
> guest/host address mapping.
> We need to protect againts such case.
>
> Reported-by: Mauro Matteo Cascella <mcascell@redhat.com>
> Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
> ---
>  hw/rdma/vmw/pvrdma_cmd.c  | 6 ++++++
>  hw/rdma/vmw/pvrdma_main.c | 9 +++++----
>  2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
> index da7ddfa548..89db963c46 100644
> --- a/hw/rdma/vmw/pvrdma_cmd.c
> +++ b/hw/rdma/vmw/pvrdma_cmd.c
> @@ -796,6 +796,12 @@ int pvrdma_exec_cmd(PVRDMADev *dev)
>
>      dsr_info = &dev->dsr_info;
>
> +    if (!dsr_info->dsr) {
> +            /* Buggy or malicious guest driver */
> +            rdma_error_report("Exec command without dsr, req or rsp buffers");
> +            goto out;
> +    }
> +
>      if (dsr_info->req->hdr.cmd >= sizeof(cmd_handlers) /
>                        sizeof(struct cmd_handler)) {
>          rdma_error_report("Unsupported command");
> diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
> index 91206dbb8e..aae382af59 100644
> --- a/hw/rdma/vmw/pvrdma_main.c
> +++ b/hw/rdma/vmw/pvrdma_main.c
> @@ -159,13 +159,13 @@ static void free_dsr(PVRDMADev *dev)
>      free_dev_ring(pci_dev, &dev->dsr_info.cq, dev->dsr_info.cq_ring_state);
>
>      rdma_pci_dma_unmap(pci_dev, dev->dsr_info.req,
> -                         sizeof(union pvrdma_cmd_req));
> +                       sizeof(union pvrdma_cmd_req));
>
>      rdma_pci_dma_unmap(pci_dev, dev->dsr_info.rsp,
> -                         sizeof(union pvrdma_cmd_resp));
> +                       sizeof(union pvrdma_cmd_resp));
>
>      rdma_pci_dma_unmap(pci_dev, dev->dsr_info.dsr,
> -                         sizeof(struct pvrdma_device_shared_region));
> +                       sizeof(struct pvrdma_device_shared_region));
>

Nit: the above changes are not related to the patch, maybe drop them?

Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>

Thanks,
Marcel

>      dev->dsr_info.dsr = NULL;
>  }
> @@ -249,7 +249,8 @@ static void init_dsr_dev_caps(PVRDMADev *dev)
>  {
>      struct pvrdma_device_shared_region *dsr;
>
> -    if (dev->dsr_info.dsr == NULL) {
> +    if (!dev->dsr_info.dsr) {
> +        /* Buggy or malicious guest driver */
>          rdma_error_report("Can't initialized DSR");
>          return;
>      }
> --
> 2.20.1
>
Re: [PATCH-for-7.0] hw/pvrdma: Protect against buggy or malicious guest driver
Posted by Philippe Mathieu-Daudé 2 years, 1 month ago 
On 22/3/22 13:27, Marcel Apfelbaum wrote:
> Hi Yuval
> 
> On Mon, Mar 21, 2022 at 2:11 PM Yuval Shaia <yuval.shaia.ml@gmail.com> wrote:
>>
>> Guest driver might execute HW commands when shared buffers are not yet
>> allocated.
>> This might happen on purpose (malicious guest) or because some other
>> guest/host address mapping.
>> We need to protect againts such case.
>>

Fixes: CVE-2022-1050

>> Reported-by: Mauro Matteo Cascella <mcascell@redhat.com>
>> Signed-off-by: Yuval Shaia <yuval.shaia.ml@gmail.com>
>> ---
>>   hw/rdma/vmw/pvrdma_cmd.c  | 6 ++++++
>>   hw/rdma/vmw/pvrdma_main.c | 9 +++++----
>>   2 files changed, 11 insertions(+), 4 deletions(-)
>>
>> diff --git a/hw/rdma/vmw/pvrdma_cmd.c b/hw/rdma/vmw/pvrdma_cmd.c
>> index da7ddfa548..89db963c46 100644
>> --- a/hw/rdma/vmw/pvrdma_cmd.c
>> +++ b/hw/rdma/vmw/pvrdma_cmd.c
>> @@ -796,6 +796,12 @@ int pvrdma_exec_cmd(PVRDMADev *dev)
>>
>>       dsr_info = &dev->dsr_info;
>>
>> +    if (!dsr_info->dsr) {
>> +            /* Buggy or malicious guest driver */
>> +            rdma_error_report("Exec command without dsr, req or rsp buffers");
>> +            goto out;
>> +    }
>> +
>>       if (dsr_info->req->hdr.cmd >= sizeof(cmd_handlers) /
>>                         sizeof(struct cmd_handler)) {
>>           rdma_error_report("Unsupported command");
>> diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
>> index 91206dbb8e..aae382af59 100644
>> --- a/hw/rdma/vmw/pvrdma_main.c
>> +++ b/hw/rdma/vmw/pvrdma_main.c
>> @@ -159,13 +159,13 @@ static void free_dsr(PVRDMADev *dev)
>>       free_dev_ring(pci_dev, &dev->dsr_info.cq, dev->dsr_info.cq_ring_state);
>>
>>       rdma_pci_dma_unmap(pci_dev, dev->dsr_info.req,
>> -                         sizeof(union pvrdma_cmd_req));
>> +                       sizeof(union pvrdma_cmd_req));
>>
>>       rdma_pci_dma_unmap(pci_dev, dev->dsr_info.rsp,
>> -                         sizeof(union pvrdma_cmd_resp));
>> +                       sizeof(union pvrdma_cmd_resp));
>>
>>       rdma_pci_dma_unmap(pci_dev, dev->dsr_info.dsr,
>> -                         sizeof(struct pvrdma_device_shared_region));
>> +                       sizeof(struct pvrdma_device_shared_region));
>>
> 
> Nit: the above changes are not related to the patch, maybe drop them?

Yes please.

> 
> Reviewed-by: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
> 
> Thanks,
> Marcel
> 
>>       dev->dsr_info.dsr = NULL;
>>   }
>> @@ -249,7 +249,8 @@ static void init_dsr_dev_caps(PVRDMADev *dev)
>>   {
>>       struct pvrdma_device_shared_region *dsr;
>>
>> -    if (dev->dsr_info.dsr == NULL) {
>> +    if (!dev->dsr_info.dsr) {
>> +        /* Buggy or malicious guest driver */
>>           rdma_error_report("Can't initialized DSR");
>>           return;
>>       }
>> --
>> 2.20.1
>>
>

Patchew 2.1-devel-0870f84

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