forecast: Fix alignment when adding rules
authorTobias Brunner <tobias@strongswan.org>
Mon, 30 Nov 2015 15:30:22 +0000 (16:30 +0100)
committerTobias Brunner <tobias@strongswan.org>
Thu, 3 Mar 2016 16:20:37 +0000 (17:20 +0100)
Basically the same issue as with the connmark plugin.

Fixes #1212.

src/libcharon/plugins/forecast/forecast_listener.c

index 63a8cb1..7e93617 100644 (file)
@@ -1,4 +1,7 @@
 /*
+ * Copyright (C) 2015 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
  * Copyright (C) 2010-2014 Martin Willi
  * Copyright (C) 2010-2014 revosec AG
  *
 #include <collections/hashtable.h>
 #include <threading/rwlock.h>
 
+/**
+ * Add a struct at the current position in the buffer
+ */
+#define ADD_STRUCT(pos, st, ...) ({\
+       typeof(pos) _cur = pos; pos += XT_ALIGN(sizeof(st));\
+       *(st*)_cur = (st){ __VA_ARGS__ };\
+       (st*)_cur;\
+})
+
 typedef struct private_forecast_listener_t private_forecast_listener_t;
 
 /**
@@ -164,60 +176,60 @@ static bool manage_rule(struct iptc_handle *ipth, const char *chain,
 static bool manage_pre_esp_in_udp(struct iptc_handle *ipth,
                                                                  entry_t *entry, bool add)
 {
-       struct {
-               struct ipt_entry e;
-               struct ipt_entry_match m;
-               struct xt_udp udp;
-               struct ipt_entry_target t;
-               struct xt_mark_tginfo2 tm;
-       } ipt = {
-               .e  = {
-                       .target_offset = XT_ALIGN(sizeof(ipt.e) + sizeof(ipt.m) +
-                                                                         sizeof(ipt.udp)),
-                       .next_offset = sizeof(ipt),
-                       .ip = {
-                               .proto = IPPROTO_UDP,
-                       },
+       u_int16_t match_size    = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                                                         XT_ALIGN(sizeof(struct xt_udp));
+       u_int16_t target_offset = XT_ALIGN(sizeof(struct ipt_entry)) + match_size;
+       u_int16_t target_size   = XT_ALIGN(sizeof(struct ipt_entry_target)) +
+                                                         XT_ALIGN(sizeof(struct xt_mark_tginfo2));
+       u_int16_t entry_size    = target_offset + target_size;
+       u_char ipt[entry_size], *pos = ipt;
+       struct ipt_entry *e;
+
+       memset(ipt, 0, sizeof(ipt));
+       e = ADD_STRUCT(pos, struct ipt_entry,
+               .target_offset = target_offset,
+               .next_offset = entry_size,
+               .ip = {
+                       .proto = IPPROTO_UDP,
                },
-               .m = {
-                       .u = {
-                               .user = {
-                                       .match_size = XT_ALIGN(sizeof(ipt.m) + sizeof(ipt.udp)),
-                                       .name = "udp",
-                               },
+       );
+       if (!host2in(entry->lhost, &e->ip.dst, &e->ip.dmsk) ||
+               !host2in(entry->rhost, &e->ip.src, &e->ip.smsk))
+       {
+               return FALSE;
+       }
+       ADD_STRUCT(pos, struct ipt_entry_match,
+               .u = {
+                       .user = {
+                               .match_size = match_size,
+                               .name = "udp",
                        },
                },
-               .udp = {
-                       .spts = {
-                               entry->rhost->get_port(entry->rhost),
-                               entry->rhost->get_port(entry->lhost)
-                       },
-                       .dpts = {
-                               entry->lhost->get_port(entry->lhost),
-                               entry->lhost->get_port(entry->lhost)
-                       },
+       );
+       ADD_STRUCT(pos, struct xt_udp,
+               .spts = {
+                       entry->rhost->get_port(entry->rhost),
+                       entry->rhost->get_port(entry->lhost)
                },
-               .t = {
-                       .u = {
-                               .user = {
-                                       .target_size = XT_ALIGN(sizeof(ipt.t) + sizeof(ipt.tm)),
-                                       .name = "MARK",
-                                       .revision = 2,
-                               },
-                       },
+               .dpts = {
+                       entry->lhost->get_port(entry->lhost),
+                       entry->lhost->get_port(entry->lhost)
                },
-               .tm = {
-                       .mark = entry->mark,
-                       .mask = ~0,
+       );
+       ADD_STRUCT(pos, struct ipt_entry_target,
+               .u = {
+                       .user = {
+                               .target_size = target_size,
+                               .name = "MARK",
+                               .revision = 2,
+                       },
                },
-       };
-
-       if (!host2in(entry->lhost, &ipt.e.ip.dst, &ipt.e.ip.dmsk) ||
-               !host2in(entry->rhost, &ipt.e.ip.src, &ipt.e.ip.smsk))
-       {
-               return FALSE;
-       }
-       return manage_rule(ipth, "PREROUTING", add, &ipt.e);
+       );
+       ADD_STRUCT(pos, struct xt_mark_tginfo2,
+               .mark = entry->mark,
+               .mask = ~0,
+       );
+       return manage_rule(ipth, "PREROUTING", add, e);
 }
 
 /**
@@ -225,53 +237,53 @@ static bool manage_pre_esp_in_udp(struct iptc_handle *ipth,
  */
 static bool manage_pre_esp(struct iptc_handle *ipth, entry_t *entry, bool add)
 {
-       struct {
-               struct ipt_entry e;
-               struct ipt_entry_match m;
-               struct xt_esp esp;
-               struct ipt_entry_target t;
-               struct xt_mark_tginfo2 tm;
-       } ipt = {
-               .e  = {
-                       .target_offset = XT_ALIGN(sizeof(ipt.e) + sizeof(ipt.m) +
-                                                                         sizeof(ipt.esp)),
-                       .next_offset = sizeof(ipt),
-                       .ip = {
-                               .proto = IPPROTO_ESP,
-                       },
+       u_int16_t match_size    = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                                                         XT_ALIGN(sizeof(struct xt_esp));
+       u_int16_t target_offset = XT_ALIGN(sizeof(struct ipt_entry)) + match_size;
+       u_int16_t target_size   = XT_ALIGN(sizeof(struct ipt_entry_target)) +
+                                                         XT_ALIGN(sizeof(struct xt_mark_tginfo2));
+       u_int16_t entry_size    = target_offset + target_size;
+       u_char ipt[entry_size], *pos = ipt;
+       struct ipt_entry *e;
+
+       memset(ipt, 0, sizeof(ipt));
+       e = ADD_STRUCT(pos, struct ipt_entry,
+               .target_offset = target_offset,
+               .next_offset = entry_size,
+               .ip = {
+                       .proto = IPPROTO_ESP,
                },
-               .m = {
-                       .u = {
-                               .user = {
-                                       .match_size = XT_ALIGN(sizeof(ipt.m) + sizeof(ipt.esp)),
-                                       .name = "esp",
-                               },
+       );
+       if (!host2in(entry->lhost, &e->ip.dst, &e->ip.dmsk) ||
+               !host2in(entry->rhost, &e->ip.src, &e->ip.smsk))
+       {
+               return FALSE;
+       }
+       ADD_STRUCT(pos, struct ipt_entry_match,
+               .u = {
+                       .user = {
+                               .match_size = match_size,
+                               .name = "esp",
                        },
                },
-               .esp = {
-                       .spis = { htonl(entry->spi), htonl(entry->spi) },
-               },
-               .t = {
-                       .u = {
-                               .user = {
-                                       .target_size = XT_ALIGN(sizeof(ipt.t) + sizeof(ipt.tm)),
-                                       .name = "MARK",
-                                       .revision = 2,
-                               },
+       );
+       ADD_STRUCT(pos, struct xt_esp,
+               .spis = { htonl(entry->spi), htonl(entry->spi) },
+       );
+       ADD_STRUCT(pos, struct ipt_entry_target,
+               .u = {
+                       .user = {
+                               .target_size = target_size,
+                               .name = "MARK",
+                               .revision = 2,
                        },
                },
-               .tm = {
-                       .mark = entry->mark,
-                       .mask = ~0,
-               },
-       };
-
-       if (!host2in(entry->lhost, &ipt.e.ip.dst, &ipt.e.ip.dmsk) ||
-               !host2in(entry->rhost, &ipt.e.ip.src, &ipt.e.ip.smsk))
-       {
-               return FALSE;
-       }
-       return manage_rule(ipth, "PREROUTING", add, &ipt.e);
+       );
+       ADD_STRUCT(pos, struct xt_mark_tginfo2,
+               .mark = entry->mark,
+               .mask = ~0,
+       );
+       return manage_rule(ipth, "PREROUTING", add, e);
 }
 
 /**
@@ -291,45 +303,52 @@ static bool manage_pre(struct iptc_handle *ipth, entry_t *entry, bool add)
  */
 static bool manage_out(struct iptc_handle *ipth, entry_t *entry, bool add)
 {
-       struct {
-               struct ipt_entry e;
-               struct ipt_entry_target t;
-               struct xt_mark_tginfo2 m;
-       } ipt = {
-               .e  = {
-                       .target_offset = XT_ALIGN(sizeof(ipt.e)),
-                       .next_offset = sizeof(ipt),
-               },
-               .t = {
-                       .u.user.target_size = XT_ALIGN(sizeof(ipt.t) + sizeof(ipt.m)),
-                       .u.user.name = "MARK",
-                       .u.user.revision = 2,
-               },
-               .m = {
-                       .mark = entry->mark,
-                       .mask = ~0,
+       u_int16_t target_offset = XT_ALIGN(sizeof(struct ipt_entry));
+       u_int16_t target_size   = XT_ALIGN(sizeof(struct ipt_entry_target)) +
+                                                         XT_ALIGN(sizeof(struct xt_mark_tginfo2));
+       u_int16_t entry_size    = target_offset + target_size;
+       u_char ipt[entry_size], *pos = ipt;
+       struct ipt_entry *e;
+
+       memset(ipt, 0, sizeof(ipt));
+       e = ADD_STRUCT(pos, struct ipt_entry,
+               .target_offset = target_offset,
+               .next_offset = entry_size,
+       );
+       ADD_STRUCT(pos, struct ipt_entry_target,
+               .u = {
+                       .user = {
+                               .target_size = target_size,
+                               .name = "MARK",
+                               .revision = 2,
+                       },
                },
-       };
+       );
+       ADD_STRUCT(pos, struct xt_mark_tginfo2,
+               .mark = entry->mark,
+               .mask = ~0,
+       );
+
        enumerator_t *enumerator;
        traffic_selector_t *ts;
 
        enumerator = array_create_enumerator(entry->rts);
        while (enumerator->enumerate(enumerator, &ts))
        {
-               if (!ts2in(ts, &ipt.e.ip.dst, &ipt.e.ip.dmsk))
+               if (!ts2in(ts, &e->ip.dst, &e->ip.dmsk))
                {
                        continue;
                }
-               if (ipt.e.ip.dst.s_addr == 0xffffffff ||
-                       ipt.e.ip.dst.s_addr == entry->broadcast ||
-                       memeq(&ipt.e.ip.dst.s_addr, "\xe0", 1))
+               if (e->ip.dst.s_addr == 0xffffffff ||
+                       e->ip.dst.s_addr == entry->broadcast ||
+                       memeq(&e->ip.dst.s_addr, "\xe0", 1))
                {
                        /* skip broadcast/multicast selectors, they are shared and the mark
                         * is set by the socket we use for reinjection */
                        continue;
                }
-               if (!manage_rule(ipth, "PREROUTING", add, &ipt.e) ||
-                       !manage_rule(ipth, "OUTPUT", add, &ipt.e))
+               if (!manage_rule(ipth, "PREROUTING", add, e) ||
+                       !manage_rule(ipth, "OUTPUT", add, e))
                {
                        enumerator->destroy(enumerator);
                        return FALSE;