Re: [net-next 0/4] devlink: add dry run support for flash update

On Fri, 8 Oct 2021 23:58:45 +0000 Keller, Jacob E wrote:

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Doesn't the policy checks prevent any unknown attributes?
Or are unknown attributes silently ignored?  

Did you test it?

DEVLINK_CMD_FLASH_UPDATE has GENL_DONT_VALIDATE_STRICT set.  

Hmm. I did run into an issue while initially testing where
DEVLINK_ATTR_DRY_RUN wasn't in the devlink_nla_policy table and it
rejected the command with an unknown attribute. I had to add the
attribute to the policy table to fix this.

I'm double checking on a different kernel now with the new userspace
to see if I get the same behavior.

Weird.
 

I'm not super familiar with the validation code or what
GENL_DONT_VALIDATE_STRICT means...

Indeed.. I just did a search for GENL_DONT_VALIDATE_STRICT and the
only uses I can find are ones which *set* the flag. Nothing ever
checks it!!

I suspect it got removed at some point.. still digging into exact
history though...

 It's passed by genl_family_rcv_msg_doit() to
genl_family_rcv_msg_attrs_parse() where it chooses the netlink policy.