Re: [Qemu-devel] [PATCH v3 03/12] VMDK: probe for monolithicFlat images

[Stefan Hajnoczi]

On Mon, Jun 27, 2011 at 6:11 AM, Fam Zheng <address@hidden> wrote:
> On Mon, Jun 27, 2011 at 12:43 PM, Stefan Hajnoczi <address@hidden> wrote:
>> On Mon, Jun 27, 2011 at 4:48 AM, Fam Zheng <address@hidden> wrote:
>>> +            if (strncmp("version=1\n", p, strlen("version=1\n")) == 0 ||
>>> +                strncmp("version=1\r\n", p, strlen("version=1\r\n")) == 0 
>>> ||
>>> +                strncmp("version=2\n", p, strlen("version=2\n")) == 0 ||
>>> +                strncmp("version=2\r\n", p, strlen("version=2\r\n")) == 0) 
>>> {
>>> +                return 100;
>>> +            }
>>
>> If p == end - 1 then this will run off the end of the buffer.  You need to 
>> use:
>>
>> strncmp("version=1\n", p, end - p);
>>
>
> Won't work if (p == end -1 and *p == 'v'), how about check if end - p
> is big enough first?

Yes, good point.  Only compare if there is enough space for the matching string:

remaining = end - p;
if (remaining < strlen("version=X\n")) {
    continue;
}
if (strncmp("version=1\n", p, remaining) == 0 ||
    strncmp("version=2\n", p, remaining) == 0) {
    return 100;
}

if (remaining < strlen("version=X\r\n")) {
    continue;
}
if (strncmp("version=1\r\n", p, remaining) == 0 ||
    strncmp("version=2\r\n", p, remaining) == 0) {
    return 100;
}

Stefan