Re: pf label $nr macro expand reproducable bug

From: Özkan KIRIK <ozkan.kirik_at_gmail.com>
Date: Sat, 2 Oct 2021 20:31:37 +0300
Thank you! I'll try it.

Have a nice day,
Best regards,
Ozkan

On Sat, Oct 2, 2021 at 7:03 PM Kristof Provost <kp_at_freebsd.org> wrote:
>
> On 22 Sep 2021, at 11:47, Özkan KIRIK wrote:
>
> Hi Kristof,
>
> I tried many things and I found the real problem to reproduce the bug.
> Tested with the latest stable/12.
> And also tested with Live CD without installing
> (https://download.freebsd.org/ftp/snapshots/ISO-IMAGES/12.2/FreeBSD-12.2-STABLE-amd64-20210916-r370608-disc1.iso).
> The result is same.
>
> My determination is the problem in the rule optimizer of pf. You can
> see the difference with / without ruleset optimization.
> Without ruleset optimization, $nr macro expanding is true. otherwise false.
>
> if the interface used in the rule, have multiple IP addresses that
> rule optimizer removes lines then the rule number expanding fails. ie:
>
>
> Yeah, that makes sense. It looks like the problem is that we expand the $nr tag before the ruleset optimisation, so we end up using the wrong rule number.
>
> As a first attempt this also seems to work:
>
> diff --git a/sbin/pfctl/parse.y b/sbin/pfctl/parse.y
> index 89d5f330da47..eb38fd9e344e 100644
> --- a/sbin/pfctl/parse.y
> +++ b/sbin/pfctl/parse.y
> _at__at_ -330,14 +330,12 _at__at_ int                filter_consistent(struct pfctl_rule *, int);
>  int             nat_consistent(struct pfctl_rule *);
>  int             rdr_consistent(struct pfctl_rule *);
>  int             process_tabledef(char *, struct table_opts *);
> -void            expand_label_str(char *, size_t, const char *, const char *);
>  void            expand_label_if(const char *, char *, size_t, const char *);
>  void            expand_label_addr(const char *, char *, size_t, u_int8_t,
>                     struct node_host *);
>  void            expand_label_port(const char *, char *, size_t,
>                     struct node_port *);
>  void            expand_label_proto(const char *, char *, size_t, u_int8_t);
> -void            expand_label_nr(const char *, char *, size_t);
>  void            expand_label(char *, size_t, const char *, u_int8_t,
>                     struct node_host *, struct node_port *, struct node_host *,
>                     struct node_port *, u_int8_t);
> _at__at_ -5125,17 +5123,6 _at__at_ expand_label_proto(const char *name, char *label, size_t len, u_int8_t proto)
>         }
>  }
>
> -void
> -expand_label_nr(const char *name, char *label, size_t len)
> -{
> -       char n[11];
> -
> -       if (strstr(label, name) != NULL) {
> -               snprintf(n, sizeof(n), "%u", pf->anchor->match);
> -               expand_label_str(label, len, name, n);
> -       }
> -}
> -
>  void
>  expand_label(char *label, size_t len, const char *ifname, sa_family_t af,
>      struct node_host *src_host, struct node_port *src_port,
> _at__at_ -5148,7 +5135,6 _at__at_ expand_label(char *label, size_t len, const char *ifname, sa_family_t af,
>         expand_label_port("$srcport", label, len, src_port);
>         expand_label_port("$dstport", label, len, dst_port);
>         expand_label_proto("$proto", label, len, proto);
> -       expand_label_nr("$nr", label, len);
>  }
>
>  int
> diff --git a/sbin/pfctl/pfctl.c b/sbin/pfctl/pfctl.c
> index d7bde0012e9b..749d73705f45 100644
> --- a/sbin/pfctl/pfctl.c
> +++ b/sbin/pfctl/pfctl.c
> _at__at_ -1528,6 +1528,15 _at__at_ pfctl_load_ruleset(struct pfctl *pf, char *path, struct pfctl_ruleset *rs,
>
>         while ((r = TAILQ_FIRST(rs->rules[rs_num].active.ptr)) != NULL) {
>                 TAILQ_REMOVE(rs->rules[rs_num].active.ptr, r, entries);
> +               char n[11];
> +               snprintf(n, sizeof(n), "%u", r->nr);
> +               for (int i = 0; i < PF_RULE_MAX_LABEL_COUNT; i++) {
> +                       expand_label_str(r->label[i], PF_RULE_LABEL_SIZE,
> +                           "$nr", n);
> +               }
> +               expand_label_str(r->tagname, PF_TAG_NAME_SIZE, "$nr", n);
> +               expand_label_str(r->match_tagname, PF_TAG_NAME_SIZE, "$nr", n);
> +
>                 if ((error = pfctl_load_rule(pf, path, r, depth)))
>                         goto error;
>                 if (r->anchor) {
> diff --git a/sbin/pfctl/pfctl.h b/sbin/pfctl/pfctl.h
> index 80ef184fa90f..d725341d1cd7 100644
> --- a/sbin/pfctl/pfctl.h
> +++ b/sbin/pfctl/pfctl.h
> _at__at_ -139,5 +139,6 _at__at_ struct pfctl_ruleset        *pf_find_ruleset(const char *);
>  struct pfctl_ruleset   *pf_find_or_create_ruleset(const char *);
>
>  const char *pfctl_proto2name(int);
> +void expand_label_str(char *, size_t, const char *, const char *);
>
>  #endif /* _PFCTL_H_ */
>
> I think I want to restructure that a bit, but this should already work.
>
> Best regards,
> Kristof
Received on Sat Oct 02 2021 - 17:31:37 UTC

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