On 05.03.21 14:22, Ian Jackson wrote:
> Julien Grall writes ("[PATCH for-4.15] tools/xenstored: liveupdate: Increase the maximum number of parameters"):
>> From: Julien Grall <jgrall@amazon.com>
>>
>> The longest possible command line for LiveUpdate is:
>>
>>    liveupdate -s -t <timeout> -F
>>
>> This is 5 parameters. However, the maximum is currently specified to 4.
>> This means the some of the parameters will get ignored.
> 
> Why are the extra parameters ignored rather than treated as errors ?
> This seems like an invitation to making code with bad behaviour
> (perhaps bad security-relevant behaviour).
> 
> CC Juergen who seems to have written the code...

This is the max number of 0 delimited string parameters. Especially the
stubdom case needs a binary blob (with length, of course) as parameter,
and the number of 0 bytes in this data is just limited by the allowed
payload length.

See the comment in line 111 of xenstored_control.c.


Juergen