[Qemu-devel] [PATCH] block/vpc: check that the image has not been truncated

[Qemu-devel] [PATCH] block/vpc: check that the image has not been truncated

[Peter Lieven]

this adds a check that a dynamic VHD file has not been
accidently truncated (e.g. during transfer or upload).

Signed-off-by: Peter Lieven <pl@kamp.de>
---
 block/vpc.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/block/vpc.c b/block/vpc.c
index 1acc1d4..921364e 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -269,6 +269,13 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
             }
         }
 
+        if (s->free_data_block_offset > bdrv_getlength(bs->file)) {
+            ret = -EINVAL;
+            fprintf(stderr, "block-vpc: free_data_block_offset points after"
+                            "the end of file. the image has been truncated.\n");
+            goto fail;
+        }
+
         s->last_bitmap_offset = (int64_t) -1;
 
 #ifdef CACHE
-- 
1.7.9.5

Re: [Qemu-devel] [PATCH] block/vpc: check that the image has not been truncated

[Eric Blake]

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On 10/22/2013 07:43 AM, Peter Lieven wrote:
> this adds a check that a dynamic VHD file has not been
> accidently truncated (e.g. during transfer or upload).
> 
> Signed-off-by: Peter Lieven <pl@kamp.de>
> ---
>  block/vpc.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/block/vpc.c b/block/vpc.c
> index 1acc1d4..921364e 100644
> --- a/block/vpc.c
> +++ b/block/vpc.c
> @@ -269,6 +269,13 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
>              }
>          }
>  
> +        if (s->free_data_block_offset > bdrv_getlength(bs->file)) {
> +            ret = -EINVAL;
> +            fprintf(stderr, "block-vpc: free_data_block_offset points after"
> +                            "the end of file. the image has been truncated.\n");

Why fprintf() instead of using the errp argument?

Also, s/afterthe/after the/; s/file\. the/file. The/

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [PATCH] block/vpc: check that the image has not been truncated

[Peter Lieven]

On 22.10.2013 08:59, Eric Blake wrote:
> On 10/22/2013 07:43 AM, Peter Lieven wrote:
>> this adds a check that a dynamic VHD file has not been
>> accidently truncated (e.g. during transfer or upload).
>>
>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> ---
>>   block/vpc.c |    7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/block/vpc.c b/block/vpc.c
>> index 1acc1d4..921364e 100644
>> --- a/block/vpc.c
>> +++ b/block/vpc.c
>> @@ -269,6 +269,13 @@ static int vpc_open(BlockDriverState *bs, QDict *options, int flags,
>>               }
>>           }
>>   
>> +        if (s->free_data_block_offset > bdrv_getlength(bs->file)) {
>> +            ret = -EINVAL;
>> +            fprintf(stderr, "block-vpc: free_data_block_offset points after"
>> +                            "the end of file. the image has been truncated.\n");
> Why fprintf() instead of using the errp argument?
wasn't aware. a few lines earlier fprintf(stderr, ...) was used.

if the others are otherwise happy with the patch I will send a v2.

Peter