Re: [PULL 03/16] net: validate that ids are well formed

[Jason Wang <jasowang@redhat.com>]

On 2021/3/12 4:44 下午, Paolo Bonzini wrote:
> On 12/03/21 07:16, Jason Wang wrote:
>> From: Paolo Bonzini <pbonzini@redhat.com>
>>
>> When a network or network device is created from the command line or 
>> HMP,
>> QemuOpts ensures that the id passes the id_wellformed check. However,
>> QMP skips this:
>>
>>     $ qemu-system-x86_64 -qmp stdio -S -nic user,id=123/456
>>     qemu-system-x86_64: -nic user,id=123/456: Parameter id expects an 
>> identifier
>>     Identifiers consist of letters, digits, -, ., _, starting with a 
>> letter.
>>
>>     $ qemu-system-x86_64 -qmp stdio -S
>>     {"execute":"qmp_capabilities"}
>>     {"return": {}}
>>     {"execute":"netdev_add", "arguments": {"type": "user", "id": 
>> "123/456"}}
>>     {"return": {}}
>>
>> After:
>>
>>     $ qemu-system-x86_64 -qmp stdio -S
>>     {"execute":"qmp_capabilities"}
>>     {"return": {}}
>>     {"execute":"netdev_add", "arguments": {"type": "user", "id": 
>> "123/456"}}
>>     {"error": {"class": "GenericError", "desc": "Parameter "id" 
>> expects an identifier"}}
>>
>> Validity checks should be performed always at the bottom of the call 
>> chain,
>> because QMP skips all the steps above.  Do this for the network 
>> subsystem.
>>
>> Cc: Jason Wang <jasowang@redhat.com>
>> Reviewed-by: Eric Blake <eblake@redhat.com>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>   net/net.c | 12 ++++++++++++
>>   1 file changed, 12 insertions(+)
>>
>> diff --git a/net/net.c b/net/net.c
>> index 9c784da..d36729f 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -44,6 +44,7 @@
>>   #include "qemu/cutils.h"
>>   #include "qemu/config-file.h"
>>   #include "qemu/ctype.h"
>> +#include "qemu/id.h"
>>   #include "qemu/iov.h"
>>   #include "qemu/qemu-print.h"
>>   #include "qemu/main-loop.h"
>> @@ -1011,6 +1012,17 @@ static int net_client_init1(const Netdev 
>> *netdev, bool is_netdev, Error **errp)
>>           }
>>       }
>>   +    /*
>> +     * The id for -net has already been checked by QemuOpts and
>> +     * could be automatically generated, in which case it is not
>> +     * well-formed by design.  HMP and QMP only call us with
>> +     * is_netdev == true.
>> +     */
>> +    if (is_netdev && !id_wellformed(netdev->id)) {
>> +        error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "id", "an 
>> identifier");
>> +        return -1;
>> +    }
>> +
>>       nc = qemu_find_netdev(netdev->id);
>>       if (nc) {
>>           error_setg(errp, "Duplicate ID '%s'", netdev->id);
>>
>
> Sorry, I sent v2 yesterday.  This patch passed the tests at the time 
> it was submitted, but now fails (because it does not work with -nic).


I don't see that. But I add a fixup in the pull request:

https://lists.gnu.org/archive/html/qemu-devel/2021-03/msg04237.html

If it doesn't make sense, I will drop this and send a new pull request 
next week.

THanks


>
> Paolo
>
>