From 12a52ff9cc9944345204d3e429dd4414448fbcd2 Mon Sep 17 00:00:00 2001 From: Serhey Popovych Date: Wed, 7 Mar 2018 11:10:43 +0200 Subject: xtables: Fix rules print/save after iptables update Updating iptables from 1.4.x to 1.6.x brokes rules print/save output and causes rules load after reboot to fail. Here is example from iptables-save(8) output after update: -A CHAIN1 -m set [unsupported revision] -j DROP -A CHAIN1 -m set [unsupported revision] -j DROP Similar output could be obtained via iptables -L CHAIN1. While issue reproduced with xt_set match it is not specific to any match or target module: it is related on how xtables handles revisions. In this particular case we have following situation: 1) Kernel supports revisions from 1 to 4. 2) Rules configured with iptables 1.4.x supporting only revisions from 1 to 3. Choosen highest possible revision 3. 3) Rules printed/saved with iptables 1.6.x supporting revisions from 1 to 4. 4) Xtables registers matches/targets with highest supported revision by the kernel. This is 4 in our case after update to iptables 1.6.x. 5) When printing/saving kernel submits match/target with revision it is configured (3), while iptables thinks that rules configured with highest supported (4). That's causes revision mismatch in during print and "[unsupported revision]" output. To fix this issue we now store all supported by kernel and xtables revisions in xt_matches/xt_targets list sorted in descending order. Introduce helper routines to find match/target with given revision and use them to find right revision to print submitted by kernel entry. Signed-off-by: Serhey Popovych Signed-off-by: Florian Westphal --- iptables/iptables.c | 66 ++++++++++++++++++++++++++++++++++------------------- 1 file changed, 43 insertions(+), 23 deletions(-) (limited to 'iptables/iptables.c') diff --git a/iptables/iptables.c b/iptables/iptables.c index 69d19fec..acacf182 100644 --- a/iptables/iptables.c +++ b/iptables/iptables.c @@ -502,19 +502,23 @@ print_match(const struct xt_entry_match *m, const struct ipt_ip *ip, int numeric) { - const struct xtables_match *match = - xtables_find_match(m->u.user.name, XTF_TRY_LOAD, NULL); + const char *name = m->u.user.name; + const int revision = m->u.user.revision; + struct xtables_match *match, *mt; + match = xtables_find_match(name, XTF_TRY_LOAD, NULL); if (match) { - if (match->print && m->u.user.revision == match->revision) - match->print(ip, m, numeric); + mt = xtables_find_match_revision(name, XTF_TRY_LOAD, + match, revision); + if (mt && mt->print) + mt->print(ip, m, numeric); else if (match->print) printf("%s%s ", match->name, unsupported_rev); else printf("%s ", match->name); } else { - if (m->u.user.name[0]) - printf("UNKNOWN match `%s' ", m->u.user.name); + if (name[0]) + printf("UNKNOWN match `%s' ", name); } /* Don't stop iterating. */ return 0; @@ -528,7 +532,7 @@ print_firewall(const struct ipt_entry *fw, unsigned int format, struct xtc_handle *const handle) { - const struct xtables_target *target = NULL; + struct xtables_target *target, *tg; const struct xt_entry_target *t; uint8_t flags; char buf[BUFSIZ]; @@ -635,9 +639,13 @@ print_firewall(const struct ipt_entry *fw, IPT_MATCH_ITERATE(fw, print_match, &fw->ip, format & FMT_NUMERIC); if (target) { - if (target->print && t->u.user.revision == target->revision) + const int revision = t->u.user.revision; + + tg = xtables_find_target_revision(targname, XTF_TRY_LOAD, + target, revision); + if (tg && tg->print) /* Print the target information. */ - target->print(&fw->ip, t, format & FMT_NUMERIC); + tg->print(&fw->ip, t, format & FMT_NUMERIC); else if (target->print) printf(" %s%s", target->name, unsupported_rev); } else if (t->u.target_size != sizeof(*t)) @@ -1025,23 +1033,28 @@ print_iface(char letter, const char *iface, const unsigned char *mask, static int print_match_save(const struct xt_entry_match *e, const struct ipt_ip *ip) { - const struct xtables_match *match = - xtables_find_match(e->u.user.name, XTF_TRY_LOAD, NULL); + const char *name = e->u.user.name; + const int revision = e->u.user.revision; + struct xtables_match *match, *mt, *mt2; + match = xtables_find_match(name, XTF_TRY_LOAD, NULL); if (match) { - printf(" -m %s", - match->alias ? match->alias(e) : e->u.user.name); + mt = mt2 = xtables_find_match_revision(name, XTF_TRY_LOAD, + match, revision); + if (!mt2) + mt2 = match; + printf(" -m %s", mt2->alias ? mt2->alias(e) : name); /* some matches don't provide a save function */ - if (match->save && e->u.user.revision == match->revision) - match->save(ip, e); + if (mt && mt->save) + mt->save(ip, e); else if (match->save) printf(unsupported_rev); } else { if (e->u.match_size) { fprintf(stderr, "Can't find library for match `%s'\n", - e->u.user.name); + name); exit(1); } } @@ -1125,18 +1138,25 @@ void print_rule4(const struct ipt_entry *e, target_name = iptc_get_target(e, h); t = ipt_get_target((struct ipt_entry *)e); if (t->u.user.name[0]) { - const struct xtables_target *target = - xtables_find_target(t->u.user.name, XTF_TRY_LOAD); + const char *name = t->u.user.name; + const int revision = t->u.user.revision; + struct xtables_target *target, *tg, *tg2; + target = xtables_find_target(name, XTF_TRY_LOAD); if (!target) { fprintf(stderr, "Can't find library for target `%s'\n", - t->u.user.name); + name); exit(1); } - printf(" -j %s", target->alias ? target->alias(t) : target_name); - if (target->save && t->u.user.revision == target->revision) - target->save(&e->ip, t); + tg = tg2 = xtables_find_target_revision(name, XTF_TRY_LOAD, + target, revision); + if (!tg2) + tg2 = target; + printf(" -j %s", tg2->alias ? tg2->alias(t) : target_name); + + if (tg && tg->save) + tg->save(&e->ip, t); else if (target->save) printf(unsupported_rev); else { @@ -1147,7 +1167,7 @@ void print_rule4(const struct ipt_entry *e, sizeof(struct xt_entry_target)) { fprintf(stderr, "Target `%s' is missing " "save function\n", - t->u.user.name); + name); exit(1); } } -- cgit v1.2.3