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 --- libxtables/xtables.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'libxtables/xtables.c') diff --git a/libxtables/xtables.c b/libxtables/xtables.c index ebdcc512..c5e86f38 100644 --- a/libxtables/xtables.c +++ b/libxtables/xtables.c @@ -709,6 +709,27 @@ xtables_find_match(const char *name, enum xtables_tryload tryload, return ptr; } +struct xtables_match * +xtables_find_match_revision(const char *name, enum xtables_tryload tryload, + struct xtables_match *match, int revision) +{ + if (!match) { + match = xtables_find_match(name, tryload, NULL); + if (!match) + return NULL; + } + + while (1) { + if (match->revision == revision) + return match; + match = match->next; + if (!match) + return NULL; + if (!extension_cmp(name, match->name, match->family)) + return NULL; + } +} + struct xtables_target * xtables_find_target(const char *name, enum xtables_tryload tryload) { @@ -769,6 +790,27 @@ xtables_find_target(const char *name, enum xtables_tryload tryload) return ptr; } +struct xtables_target * +xtables_find_target_revision(const char *name, enum xtables_tryload tryload, + struct xtables_target *target, int revision) +{ + if (!target) { + target = xtables_find_target(name, tryload); + if (!target) + return NULL; + } + + while (1) { + if (target->revision == revision) + return target; + target = target->next; + if (!target) + return NULL; + if (!extension_cmp(name, target->name, target->family)) + return NULL; + } +} + int xtables_compatible_revision(const char *name, uint8_t revision, int opt) { struct xt_get_revision rev; -- cgit v1.2.3