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 <serhe.popovych@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/include/xtables.h b/include/xtables.h
index 304828a67eebcfe4b3eeba5b0c2e55b962e04520..743906bf1ffefe6be9f0ef367118e9e092faf64f 100644 (file)
--- a/include/xtables.h
+++ b/include/xtables.h
@@ -464,8 +464,14 @@ extern struct option *xtables_merge_options(struct option *origopts,
 extern int xtables_init_all(struct xtables_globals *xtp, uint8_t nfproto);
 extern struct xtables_match *xtables_find_match(const char *name,
        enum xtables_tryload, struct xtables_rule_match **match);
+extern struct xtables_match *xtables_find_match_revision(const char *name,
+       enum xtables_tryload tryload, struct xtables_match *match,
+       int revision);
 extern struct xtables_target *xtables_find_target(const char *name,
        enum xtables_tryload);
+struct xtables_target *xtables_find_target_revision(const char *name,
+       enum xtables_tryload tryload, struct xtables_target *target,
+       int revision);
 extern int xtables_compatible_revision(const char *name, uint8_t revision,
                                       int opt);
 

diff --git a/iptables/ip6tables.c b/iptables/ip6tables.c
index 49bd006fb22f67577658fa850f5597d19566a08a..6954c25228d53c68c8203073d7df99c1bc9f6b70 100644 (file)
--- a/iptables/ip6tables.c
+++ b/iptables/ip6tables.c
@@ -518,19 +518,23 @@ print_match(const struct xt_entry_match *m,
            const struct ip6t_ip6 *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;
@@ -544,7 +548,7 @@ print_firewall(const struct ip6t_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;
        char buf[BUFSIZ];
 
@@ -651,9 +655,13 @@ print_firewall(const struct ip6t_entry *fw,
        IP6T_MATCH_ITERATE(fw, print_match, &fw->ipv6, 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->ipv6, t, format & FMT_NUMERIC);
+                       tg->print(&fw->ipv6, t, format & FMT_NUMERIC);
                else if (target->print)
                        printf(" %s%s", target->name, unsupported_rev);
        } else if (t->u.target_size != sizeof(*t))
@@ -1035,23 +1043,28 @@ static void print_proto(uint16_t proto, int invert)
 static int print_match_save(const struct xt_entry_match *e,
                        const struct ip6t_ip6 *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);
                }
        }
@@ -1136,18 +1149,25 @@ void print_rule6(const struct ip6t_entry *e,
        target_name = ip6tc_get_target(e, h);
        t = ip6t_get_target((struct ip6t_entry *)e);
        if (t->u.user.name[0]) {
-               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->ipv6, 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->ipv6, t);
                else if (target->save)
                        printf(unsupported_rev);
                else {
@@ -1158,7 +1178,7 @@ void print_rule6(const struct ip6t_entry *e,
                            sizeof(struct xt_entry_target)) {
                                fprintf(stderr, "Target `%s' is missing "
                                                "save function\n",
-                                       t->u.user.name);
+                                       name);
                                exit(1);
                        }
                }

diff --git a/iptables/iptables.c b/iptables/iptables.c
index 69d19feca1c22a89d551b29247199d890466e82a..acacf182a8343bed6adb0e611076ba6d6b5de5a8 100644 (file)
--- 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);
                        }
                }

diff --git a/libxtables/xtables.c b/libxtables/xtables.c
index ebdcc512fd711af0549f3467ed4788d9c4b7a484..c5e86f389d473ffb7b56672be5e5322641fb2852 100644 (file)
--- 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;