* [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute
@ 2007-02-12 22:46 Pablo Neira Ayuso
2007-02-13 11:05 ` Patrick McHardy
0 siblings, 1 reply; 5+ messages in thread
From: Pablo Neira Ayuso @ 2007-02-12 22:46 UTC (permalink / raw)
To: Netfilter Development Mailinglist; +Cc: Patrick McHardy
[-- Attachment #1: Type: text/plain, Size: 452 bytes --]
Use nfattr_parse to parse attributes, this patch also modifies the
default behaviour since unknown attributes will be ignored instead of
returning EINVAL. This ensure backward compatibility: new libraries with
new attributes and old kernels can work.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
--
The dawn of the fourth age of Linux firewalling is coming; a time of
great struggle and heroic deeds -- J.Kadlecsik got inspired by J.Morris
[-- Attachment #2: 05.patch --]
[-- Type: text/plain, Size: 1588 bytes --]
[PATCH] parse attributes with nfattr_parse in nfnetlink_check_attribute
Use nfattr_parse to parse attributes, this patch also modifies the default
behaviour since unknown attributes will be ignored instead of returning
EINVAL. This ensure backward compatibility: new libraries with new
attributes and old kernels can work.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Index: net-2.6.git/net/netfilter/nfnetlink.c
===================================================================
--- net-2.6.git.orig/net/netfilter/nfnetlink.c 2007-01-19 19:37:01.000000000 +0100
+++ net-2.6.git/net/netfilter/nfnetlink.c 2007-01-19 19:48:18.000000000 +0100
@@ -128,26 +128,14 @@ nfnetlink_check_attributes(struct nfnetl
struct nlmsghdr *nlh, struct nfattr *cda[])
{
int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
- u_int16_t attr_count;
u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
-
- attr_count = subsys->cb[cb_id].attr_count;
- memset(cda, 0, sizeof(struct nfattr *) * attr_count);
+ u_int16_t attr_count = subsys->cb[cb_id].attr_count;
/* check attribute lengths. */
if (likely(nlh->nlmsg_len > min_len)) {
struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
-
- while (NFA_OK(attr, attrlen)) {
- unsigned flavor = NFA_TYPE(attr);
- if (flavor) {
- if (flavor > attr_count)
- return -EINVAL;
- cda[flavor - 1] = attr;
- }
- attr = NFA_NEXT(attr, attrlen);
- }
+ nfattr_parse(cda, attr_count, attr, attrlen);
}
/* implicit: if nlmsg_len == min_len, we return 0, and an empty
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute
2007-02-12 22:46 [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute Pablo Neira Ayuso
@ 2007-02-13 11:05 ` Patrick McHardy
2007-03-06 21:45 ` Thomas Graf
0 siblings, 1 reply; 5+ messages in thread
From: Patrick McHardy @ 2007-02-13 11:05 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: Netfilter Development Mailinglist
Pablo Neira Ayuso wrote:
> [PATCH] parse attributes with nfattr_parse in nfnetlink_check_attribute
>
> Use nfattr_parse to parse attributes, this patch also modifies the default
> behaviour since unknown attributes will be ignored instead of returning
> EINVAL. This ensure backward compatibility: new libraries with new
> attributes and old kernels can work.
Currently other netlink subsystems return errors for the first level
of attributes and accept unknown attributes on deeper levels. I'm
not sure which I prefer, ignoring unknown attributes makes it
impossible for userspace to know that something isn't going to have
any effect, returning an error makes it harder to support new features.
I know Thomas had intentions of increasing consistency in this area,
I'm just not sure in which direction :)
Thomas, what do you think of this patch?
>
> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
>
> Index: net-2.6.git/net/netfilter/nfnetlink.c
> ===================================================================
> --- net-2.6.git.orig/net/netfilter/nfnetlink.c 2007-01-19 19:37:01.000000000 +0100
> +++ net-2.6.git/net/netfilter/nfnetlink.c 2007-01-19 19:48:18.000000000 +0100
> @@ -128,26 +128,14 @@ nfnetlink_check_attributes(struct nfnetl
> struct nlmsghdr *nlh, struct nfattr *cda[])
> {
> int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
> - u_int16_t attr_count;
> u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
> -
> - attr_count = subsys->cb[cb_id].attr_count;
> - memset(cda, 0, sizeof(struct nfattr *) * attr_count);
> + u_int16_t attr_count = subsys->cb[cb_id].attr_count;
>
> /* check attribute lengths. */
> if (likely(nlh->nlmsg_len > min_len)) {
> struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
> int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
> -
> - while (NFA_OK(attr, attrlen)) {
> - unsigned flavor = NFA_TYPE(attr);
> - if (flavor) {
> - if (flavor > attr_count)
> - return -EINVAL;
> - cda[flavor - 1] = attr;
> - }
> - attr = NFA_NEXT(attr, attrlen);
> - }
> + nfattr_parse(cda, attr_count, attr, attrlen);
> }
>
> /* implicit: if nlmsg_len == min_len, we return 0, and an empty
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute
2007-02-13 11:05 ` Patrick McHardy
@ 2007-03-06 21:45 ` Thomas Graf
2007-03-07 10:43 ` Pablo Neira Ayuso
0 siblings, 1 reply; 5+ messages in thread
From: Thomas Graf @ 2007-03-06 21:45 UTC (permalink / raw)
To: Patrick McHardy; +Cc: Netfilter Development Mailinglist, Pablo Neira Ayuso
* Patrick McHardy <kaber@trash.net> 2007-02-13 12:05
> Pablo Neira Ayuso wrote:
> > [PATCH] parse attributes with nfattr_parse in nfnetlink_check_attribute
> >
> > Use nfattr_parse to parse attributes, this patch also modifies the default
> > behaviour since unknown attributes will be ignored instead of returning
> > EINVAL. This ensure backward compatibility: new libraries with new
> > attributes and old kernels can work.
>
> Currently other netlink subsystems return errors for the first level
> of attributes and accept unknown attributes on deeper levels. I'm
> not sure which I prefer, ignoring unknown attributes makes it
> impossible for userspace to know that something isn't going to have
> any effect, returning an error makes it harder to support new features.
>
> I know Thomas had intentions of increasing consistency in this area,
> I'm just not sure in which direction :)
>
> Thomas, what do you think of this patch?
I believe that all unknown attributes should be ignored so recent
userspace code can function on older kernels. That's the way I'm
working towards.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute
2007-03-06 21:45 ` Thomas Graf
@ 2007-03-07 10:43 ` Pablo Neira Ayuso
2007-03-14 8:23 ` Patrick McHardy
0 siblings, 1 reply; 5+ messages in thread
From: Pablo Neira Ayuso @ 2007-03-07 10:43 UTC (permalink / raw)
To: Thomas Graf; +Cc: Netfilter Development Mailinglist, Patrick McHardy
Thomas Graf wrote:
> * Patrick McHardy <kaber@trash.net> 2007-02-13 12:05
>> Pablo Neira Ayuso wrote:
>> Currently other netlink subsystems return errors for the first level
>> of attributes and accept unknown attributes on deeper levels. I'm
>> not sure which I prefer, ignoring unknown attributes makes it
>> impossible for userspace to know that something isn't going to have
>> any effect, returning an error makes it harder to support new features.
>>
>> I know Thomas had intentions of increasing consistency in this area,
>> I'm just not sure in which direction :)
>>
>> Thomas, what do you think of this patch?
>
> I believe that all unknown attributes should be ignored so recent
> userspace code can function on older kernels. That's the way I'm
> working towards.
Then I'll resend the patch if nobody objects anymore ;)
--
The dawn of the fourth age of Linux firewalling is coming; a time of
great struggle and heroic deeds -- J.Kadlecsik got inspired by J.Morris
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute
2007-03-07 10:43 ` Pablo Neira Ayuso
@ 2007-03-14 8:23 ` Patrick McHardy
0 siblings, 0 replies; 5+ messages in thread
From: Patrick McHardy @ 2007-03-14 8:23 UTC (permalink / raw)
To: Pablo Neira Ayuso; +Cc: Netfilter Development Mailinglist
Pablo Neira Ayuso wrote:
> Thomas Graf wrote:
>
>>* Patrick McHardy <kaber@trash.net> 2007-02-13 12:05
>>´
>>>Thomas, what do you think of this patch?
>>
>>I believe that all unknown attributes should be ignored so recent
>>userspace code can function on older kernels. That's the way I'm
>>working towards.
>
>
> Then I'll resend the patch if nobody objects anymore ;)
Don't bother, I've applied the patch you sent. Thanks everybody.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2007-03-14 8:23 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2007-02-12 22:46 [PATCH 4/7 parse attributes with nfattr_parse in nfnetlink_check_attribute Pablo Neira Ayuso
2007-02-13 11:05 ` Patrick McHardy
2007-03-06 21:45 ` Thomas Graf
2007-03-07 10:43 ` Pablo Neira Ayuso
2007-03-14 8:23 ` Patrick McHardy
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.