iptables: fix regression with unintended free in need_protomatch
[project/firewall3.git] / iptables.c
index f8d4d46ec7717fca1f38f77c23092342b576e3c6..d03d1dd2933e8000712a0696c4e0d60fa6142347 100644 (file)
@@ -55,6 +55,8 @@
 
 #include "iptables.h"
 
+#define XT_LOCK_NAME "/var/run/xtables.lock"
+static int xt_lock_fd = -1;
 
 struct fw3_ipt_rule {
        struct fw3_ipt_handle *h;
@@ -139,12 +141,11 @@ void
 get_kernel_version(void)
 {
        static struct utsname uts;
-       int x = 0, y = 0, z = 0;
+       int x = 3, y = 0, z = 0;
 
-       if (uname(&uts) == -1)
-               sprintf(uts.release, "3.0.0");
+       if (uname(&uts) != -1)
+               sscanf(uts.release, "%d.%d.%d", &x, &y, &z);
 
-       sscanf(uts.release, "%d.%d.%d", &x, &y, &z);
        kernel_version = 0x10000 * x + 0x100 * y + z;
 }
 
@@ -168,6 +169,11 @@ fw3_ipt_open(enum fw3_family family, enum fw3_table table)
 
        xtables_init();
 
+       while (!fw3_lock_path(&xt_lock_fd, XT_LOCK_NAME)) {
+               warn("Currently busy xtables.lock - wait 1 second");
+               sleep(1);
+       }
+
        if (family == FW3_FAMILY_V6)
        {
 #ifndef DISABLE_IPV6
@@ -192,6 +198,7 @@ fw3_ipt_open(enum fw3_family family, enum fw3_table table)
        if (!h->handle)
        {
                free(h);
+               fw3_unlock_path(&xt_lock_fd, XT_LOCK_NAME);
                return NULL;
        }
 
@@ -321,9 +328,61 @@ delete_rules(struct fw3_ipt_handle *h, const char *target)
        }
 }
 
+static bool
+is_referenced(struct fw3_ipt_handle *h, const char *target)
+{
+       const struct ipt_entry *e;
+       const char *chain;
+       const char *t;
+
+#ifndef DISABLE_IPV6
+       if (h->family == FW3_FAMILY_V6)
+       {
+               for (chain = ip6tc_first_chain(h->handle);
+                    chain != NULL;
+                    chain = ip6tc_next_chain(h->handle))
+               {
+                       const struct ip6t_entry *e6;
+                       for (e6 = ip6tc_first_rule(chain, h->handle);
+                            e6 != NULL;
+                            e6 = ip6tc_next_rule(e6, h->handle))
+                       {
+                               t = ip6tc_get_target(e6, h->handle);
+
+                               if (*t && !strcmp(t, target))
+                                       return true;
+                       }
+               }
+       }
+       else
+#endif
+       {
+               for (chain = iptc_first_chain(h->handle);
+                    chain != NULL;
+                    chain = iptc_next_chain(h->handle))
+               {
+                       for (e = iptc_first_rule(chain, h->handle);
+                            e != NULL;
+                            e = iptc_next_rule(e, h->handle))
+                       {
+                               t = iptc_get_target(e, h->handle);
+
+                               if (*t && !strcmp(t, target))
+                                       return true;
+                       }
+               }
+       }
+
+       return false;
+}
+
 void
-fw3_ipt_delete_chain(struct fw3_ipt_handle *h, const char *chain)
+fw3_ipt_delete_chain(struct fw3_ipt_handle *h, bool if_unused,
+                     const char *chain)
 {
+       if (if_unused && is_referenced(h, chain))
+               return;
+
        delete_rules(h, chain);
 
        if (fw3_pr_debug)
@@ -417,20 +476,29 @@ fw3_ipt_delete_id_rules(struct fw3_ipt_handle *h, const char *chain)
        }
 }
 
-void
-fw3_ipt_create_chain(struct fw3_ipt_handle *h, const char *fmt, ...)
+
+static bool
+is_chain(struct fw3_ipt_handle *h, const char *name)
 {
-       char buf[32];
-       va_list ap;
+#ifndef DISABLE_IPV6
+       if (h->family == FW3_FAMILY_V6)
+               return ip6tc_is_chain(name, h->handle);
+       else
+#endif
+               return iptc_is_chain(name, h->handle);
+}
 
-       va_start(ap, fmt);
-       vsnprintf(buf, sizeof(buf) - 1, fmt, ap);
-       va_end(ap);
+void
+fw3_ipt_create_chain(struct fw3_ipt_handle *h, bool ignore_existing,
+                     const char *chain)
+{
+       if (ignore_existing && is_chain(h, chain))
+               return;
 
        if (fw3_pr_debug)
-               debug(h, "-N %s\n", buf);
+               debug(h, "-N %s\n", chain);
 
-       iptc_create_chain(buf, h->handle);
+       iptc_create_chain(chain, h->handle);
 }
 
 void
@@ -506,7 +574,7 @@ fw3_ipt_gc(struct fw3_ipt_handle *h)
                                if (!chain_is_empty(h, chain))
                                        continue;
 
-                               fw3_ipt_delete_chain(h, chain);
+                               fw3_ipt_delete_chain(h, false, chain);
                                found = true;
                                break;
                        }
@@ -529,7 +597,7 @@ fw3_ipt_gc(struct fw3_ipt_handle *h)
 
                                warn("D=%s\n", chain);
 
-                               fw3_ipt_delete_chain(h, chain);
+                               fw3_ipt_delete_chain(h, false, chain);
                                found = true;
                                break;
                        }
@@ -561,6 +629,7 @@ fw3_ipt_commit(struct fw3_ipt_handle *h)
 void
 fw3_ipt_close(struct fw3_ipt_handle *h)
 {
+       fw3_unlock_path(&xt_lock_fd, XT_LOCK_NAME);
        free(h);
 }
 
@@ -579,17 +648,6 @@ fw3_ipt_rule_new(struct fw3_ipt_handle *h)
 }
 
 
-static bool
-is_chain(struct fw3_ipt_handle *h, const char *name)
-{
-#ifndef DISABLE_IPV6
-       if (h->family == FW3_FAMILY_V6)
-               return ip6tc_is_chain(name, h->handle);
-       else
-#endif
-               return iptc_is_chain(name, h->handle);
-}
-
 static char *
 get_protoname(struct fw3_ipt_rule *r)
 {
@@ -651,12 +709,18 @@ init_match(struct fw3_ipt_rule *r, struct xtables_match *m, bool no_clone)
 static bool
 need_protomatch(struct fw3_ipt_rule *r, const char *pname)
 {
+       struct xtables_match *match;
+
        if (!pname)
                return false;
 
-       if (!xtables_find_match(pname, XTF_DONT_LOAD, NULL))
+       match = xtables_find_match(pname, XTF_DONT_LOAD, NULL);
+       if (!match)
                return true;
 
+       /* Free any kind of clone from xtables_find_match */
+       if (match == match->next)
+               free(match);
        return !r->protocol_loaded;
 }
 
@@ -886,7 +950,7 @@ void
 fw3_ipt_rule_sport_dport(struct fw3_ipt_rule *r,
                          struct fw3_port *sp, struct fw3_port *dp)
 {
-       char buf[sizeof("65535:65535\0")];
+       char buf[sizeof("65535:65535")];
 
        if ((!sp || !sp->set) && (!dp || !dp->set))
                return;
@@ -897,9 +961,9 @@ fw3_ipt_rule_sport_dport(struct fw3_ipt_rule *r,
        if (sp && sp->set)
        {
                if (sp->port_min == sp->port_max)
-                       sprintf(buf, "%u", sp->port_min);
+                       snprintf(buf, sizeof(buf), "%u", sp->port_min);
                else
-                       sprintf(buf, "%u:%u", sp->port_min, sp->port_max);
+                       snprintf(buf, sizeof(buf), "%u:%u", sp->port_min, sp->port_max);
 
                fw3_ipt_rule_addarg(r, sp->invert, "--sport", buf);
        }
@@ -907,9 +971,9 @@ fw3_ipt_rule_sport_dport(struct fw3_ipt_rule *r,
        if (dp && dp->set)
        {
                if (dp->port_min == dp->port_max)
-                       sprintf(buf, "%u", dp->port_min);
+                       snprintf(buf, sizeof(buf), "%u", dp->port_min);
                else
-                       sprintf(buf, "%u:%u", dp->port_min, dp->port_max);
+                       snprintf(buf, sizeof(buf), "%u:%u", dp->port_min, dp->port_max);
 
                fw3_ipt_rule_addarg(r, dp->invert, "--dport", buf);
        }
@@ -918,9 +982,10 @@ fw3_ipt_rule_sport_dport(struct fw3_ipt_rule *r,
 void
 fw3_ipt_rule_device(struct fw3_ipt_rule *r, const char *device, bool out)
 {
+       struct fw3_device dev = { .any = false };
+
        if (device) {
-               struct fw3_device dev = { .any = false };
-               strncpy(dev.name, device, sizeof(dev.name) - 1);
+               snprintf(dev.name, sizeof(dev.name), "%s", device);
                fw3_ipt_rule_in_out(r, (out) ? NULL : &dev, (out) ? &dev : NULL);
        }
 }
@@ -928,14 +993,14 @@ fw3_ipt_rule_device(struct fw3_ipt_rule *r, const char *device, bool out)
 void
 fw3_ipt_rule_mac(struct fw3_ipt_rule *r, struct fw3_mac *mac)
 {
-       char buf[sizeof("ff:ff:ff:ff:ff:ff\0")];
+       char buf[sizeof("ff:ff:ff:ff:ff:ff")];
        uint8_t *addr = mac->mac.ether_addr_octet;
 
        if (!mac)
                return;
 
-       sprintf(buf, "%02x:%02x:%02x:%02x:%02x:%02x",
-               addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
+       snprintf(buf, sizeof(buf), "%02x:%02x:%02x:%02x:%02x:%02x",
+                addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
 
        fw3_ipt_rule_addarg(r, false, "-m", "mac");
        fw3_ipt_rule_addarg(r, mac->invert, "--mac-source", buf);
@@ -944,7 +1009,7 @@ fw3_ipt_rule_mac(struct fw3_ipt_rule *r, struct fw3_mac *mac)
 void
 fw3_ipt_rule_icmptype(struct fw3_ipt_rule *r, struct fw3_icmptype *icmp)
 {
-       char buf[sizeof("255/255\0")];
+       char buf[sizeof("255/255")];
 
        if (!icmp)
                return;
@@ -953,9 +1018,9 @@ fw3_ipt_rule_icmptype(struct fw3_ipt_rule *r, struct fw3_icmptype *icmp)
        if (r->h->family == FW3_FAMILY_V6)
        {
                if (icmp->code6_min == 0 && icmp->code6_max == 0xFF)
-                       sprintf(buf, "%u", icmp->type6);
+                       snprintf(buf, sizeof(buf), "%u", icmp->type6);
                else
-                       sprintf(buf, "%u/%u", icmp->type6, icmp->code6_min);
+                       snprintf(buf, sizeof(buf), "%u/%u", icmp->type6, icmp->code6_min);
 
                fw3_ipt_rule_addarg(r, icmp->invert, "--icmpv6-type", buf);
        }
@@ -963,9 +1028,9 @@ fw3_ipt_rule_icmptype(struct fw3_ipt_rule *r, struct fw3_icmptype *icmp)
 #endif
        {
                if (icmp->code_min == 0 && icmp->code_max == 0xFF)
-                       sprintf(buf, "%u", icmp->type);
+                       snprintf(buf, sizeof(buf), "%u", icmp->type);
                else
-                       sprintf(buf, "%u/%u", icmp->type, icmp->code_min);
+                       snprintf(buf, sizeof(buf), "%u/%u", icmp->type, icmp->code_min);
 
                fw3_ipt_rule_addarg(r, icmp->invert, "--icmp-type", buf);
        }
@@ -974,19 +1039,19 @@ fw3_ipt_rule_icmptype(struct fw3_ipt_rule *r, struct fw3_icmptype *icmp)
 void
 fw3_ipt_rule_limit(struct fw3_ipt_rule *r, struct fw3_limit *limit)
 {
-       char buf[sizeof("-4294967296/second\0")];
+       char buf[sizeof("-4294967296/second")];
 
        if (!limit || limit->rate <= 0)
                return;
 
        fw3_ipt_rule_addarg(r, false, "-m", "limit");
 
-       sprintf(buf, "%u/%s", limit->rate, fw3_limit_units[limit->unit]);
+       snprintf(buf, sizeof(buf), "%u/%s", limit->rate, fw3_limit_units[limit->unit]);
        fw3_ipt_rule_addarg(r, limit->invert, "--limit", buf);
 
        if (limit->burst > 0)
        {
-               sprintf(buf, "%u", limit->burst);
+               snprintf(buf, sizeof(buf), "%u", limit->burst);
                fw3_ipt_rule_addarg(r, limit->invert, "--limit-burst", buf);
        }
 }
@@ -994,9 +1059,10 @@ fw3_ipt_rule_limit(struct fw3_ipt_rule *r, struct fw3_limit *limit)
 void
 fw3_ipt_rule_ipset(struct fw3_ipt_rule *r, struct fw3_setmatch *match)
 {
-       char buf[sizeof("dst,dst,dst\0")];
+       char buf[sizeof("dst,dst,dst")];
        char *p = buf;
-       int i = 0;
+       int i = 0, len;
+       size_t rem = sizeof(buf);
 
        struct fw3_ipset *set;
        struct fw3_ipset_datatype *type;
@@ -1010,10 +1076,23 @@ fw3_ipt_rule_ipset(struct fw3_ipt_rule *r, struct fw3_setmatch *match)
                if (i >= 3)
                        break;
 
-               if (p > buf)
+               if (p > buf) {
+                       if (rem <= 1)
+                               break;
+
                        *p++ = ',';
+                       *p = 0;
+                       rem--;
+               }
+
+               len = snprintf(p, rem, "%s", match->dir[i] ? match->dir[i] : type->dir);
+
+               if (len < 0 || len >= rem)
+                       break;
+
+               rem -= len;
+               p += len;
 
-               p += sprintf(p, "%s", match->dir[i] ? match->dir[i] : type->dir);
                i++;
        }
 
@@ -1038,15 +1117,17 @@ fw3_ipt_rule_helper(struct fw3_ipt_rule *r, struct fw3_cthelpermatch *match)
 void
 fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 {
-       int i;
+       int i, len;
        struct tm empty = { 0 };
 
-       char buf[84]; /* sizeof("1,2,3,...,30,31\0") */
+       char buf[84]; /* sizeof("1,2,3,...,30,31") */
        char *p;
 
        bool d1 = memcmp(&time->datestart, &empty, sizeof(empty));
        bool d2 = memcmp(&time->datestop, &empty, sizeof(empty));
 
+       size_t rem;
+
        if (!d1 && !d2 && !time->timestart && !time->timestop &&
            !(time->monthdays & 0xFFFFFFFE) && !(time->weekdays & 0xFE))
        {
@@ -1072,7 +1153,7 @@ fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 
        if (time->timestart)
        {
-               sprintf(buf, "%02d:%02d:%02d",
+               snprintf(buf, sizeof(buf), "%02d:%02d:%02d",
                        time->timestart / 3600,
                        time->timestart % 3600 / 60,
                        time->timestart % 60);
@@ -1082,7 +1163,7 @@ fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 
        if (time->timestop)
        {
-               sprintf(buf, "%02d:%02d:%02d",
+               snprintf(buf, sizeof(buf), "%02d:%02d:%02d",
                        time->timestop / 3600,
                        time->timestop % 3600 / 60,
                        time->timestop % 60);
@@ -1092,14 +1173,26 @@ fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 
        if (time->monthdays & 0xFFFFFFFE)
        {
-               for (i = 1, p = buf; i < 32; i++)
+               for (i = 1, p = buf, rem = sizeof(buf); i < 32; i++)
                {
                        if (fw3_hasbit(time->monthdays, i))
                        {
-                               if (p > buf)
+                               if (p > buf) {
+                                       if (rem <= 1)
+                                               break;
+
                                        *p++ = ',';
+                                       *p = 0;
+                                       rem--;
+                               }
 
-                               p += sprintf(p, "%u", i);
+                               len = snprintf(p, rem, "%u", i);
+
+                               if (len < 0 || len >= rem)
+                                       break;
+
+                               rem -= len;
+                               p += len;
                        }
                }
 
@@ -1108,14 +1201,26 @@ fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 
        if (time->weekdays & 0xFE)
        {
-               for (i = 1, p = buf; i < 8; i++)
+               for (i = 1, p = buf, rem = sizeof(buf); i < 8; i++)
                {
                        if (fw3_hasbit(time->weekdays, i))
                        {
-                               if (p > buf)
+                               if (p > buf) {
+                                       if (rem <= 1)
+                                               break;
+
                                        *p++ = ',';
+                                       *p = 0;
+                                       rem--;
+                               }
 
-                               p += sprintf(p, "%u", i);
+                               len = snprintf(p, rem, "%u", i);
+
+                               if (len < 0 || len >= rem)
+                                       break;
+
+                               rem -= len;
+                               p += len;
                        }
                }
 
@@ -1126,20 +1231,34 @@ fw3_ipt_rule_time(struct fw3_ipt_rule *r, struct fw3_time *time)
 void
 fw3_ipt_rule_mark(struct fw3_ipt_rule *r, struct fw3_mark *mark)
 {
-       char buf[sizeof("0xFFFFFFFF/0xFFFFFFFF\0")];
+       char buf[sizeof("0xFFFFFFFF/0xFFFFFFFF")];
 
        if (!mark || !mark->set)
                return;
 
        if (mark->mask < 0xFFFFFFFF)
-               sprintf(buf, "0x%x/0x%x", mark->mark, mark->mask);
+               snprintf(buf, sizeof(buf), "0x%x/0x%x", mark->mark, mark->mask);
        else
-               sprintf(buf, "0x%x", mark->mark);
+               snprintf(buf, sizeof(buf), "0x%x", mark->mark);
 
        fw3_ipt_rule_addarg(r, false, "-m", "mark");
        fw3_ipt_rule_addarg(r, mark->invert, "--mark", buf);
 }
 
+void
+fw3_ipt_rule_dscp(struct fw3_ipt_rule *r, struct fw3_dscp *dscp)
+{
+       char buf[sizeof("0xFF")];
+
+       if (!dscp || !dscp->set)
+               return;
+
+       snprintf(buf, sizeof(buf), "0x%x", dscp->dscp);
+
+       fw3_ipt_rule_addarg(r, false, "-m", "dscp");
+       fw3_ipt_rule_addarg(r, dscp->invert, "--dscp", buf);
+}
+
 void
 fw3_ipt_rule_comment(struct fw3_ipt_rule *r, const char *fmt, ...)
 {
@@ -1150,7 +1269,7 @@ fw3_ipt_rule_comment(struct fw3_ipt_rule *r, const char *fmt, ...)
                return;
 
        va_start(ap, fmt);
-       vsnprintf(buf, sizeof(buf) - 1, fmt, ap);
+       vsnprintf(buf, sizeof(buf), fmt, ap);
        va_end(ap);
 
        fw3_ipt_rule_addarg(r, false, "-m", "comment");
@@ -1243,7 +1362,7 @@ static void
 rule_print4(struct ipt_entry *e)
 {
        struct in_addr in_zero = { 0 };
-       char buf1[sizeof("255.255.255.255\0")], buf2[sizeof("255.255.255.255\0")];
+       char buf1[sizeof("255.255.255.255")], buf2[sizeof("255.255.255.255")];
        char *pname;
 
        if (e->ip.proto)