Re: ABI Breakage - nftnl_rule_parse_attr_cb

[Florian Westphal <fw@strlen.de>]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> On Wed, Jun 22, 2022 at 09:24:25AM -0400, Kiernan George wrote:
> > This is the relevant line where I build my header:
> > nlh = nftnl_rule_nlmsg_build_hdr(mnl_nlmsg_batch_current(batch),
> > NFT_MSG_NEWRULE, family, NLM_F_APPEND | NLM_F_EXCL | NLM_F_CREATE |
> > NLM_F_ECHO | NLM_F_ACK, seq++);
> > 
> > If I remove NLM_F_ECHO, it fixes my issue, but I would prefer to keep
> > this unless there is a better way to get the created rule's handle. I
> > also set the handle directly:
> > mnl_attr_put_u64(nlh, NFTNL_RULE_POSITION, htobe64(handle));
> 
> Makes no sense. Flags are irrelevant for the ABI breakage you are
> reporting. Send us a reproducer.

Probably corrupted or too-small receive buffer w. garbage fed into
netlink parser.

Impossible to say without reproducer.