Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 392 insertions, 0 deletions

diff --git a/src/shared/firewall-util-iptables.c b/src/shared/firewall-util-iptables.c
new file mode 100644
index 0000000..b70b740
--- /dev/null
+++ b/src/shared/firewall-util-iptables.c
@@ -0,0 +1,392 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+/* Temporary work-around for broken glibc vs. linux kernel header definitions
+ * This is already fixed upstream, remove this when distributions have updated.
+ */
+#define _NET_IF_H 1
+
+#include <arpa/inet.h>
+#include <endian.h>
+#include <errno.h>
+#include <stddef.h>
+#include <string.h>
+#include <net/if.h>
+#ifndef IFNAMSIZ
+#define IFNAMSIZ 16
+#endif
+#include <linux/if.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter/nf_nat.h>
+#include <linux/netfilter/xt_addrtype.h>
+#include <libiptc/libiptc.h>
+
+#include "alloc-util.h"
+#include "dlfcn-util.h"
+#include "firewall-util.h"
+#include "firewall-util-private.h"
+#include "in-addr-util.h"
+#include "macro.h"
+#include "socket-util.h"
+
+static DLSYM_FUNCTION(iptc_check_entry);
+static DLSYM_FUNCTION(iptc_commit);
+static DLSYM_FUNCTION(iptc_delete_entry);
+static DLSYM_FUNCTION(iptc_free);
+static DLSYM_FUNCTION(iptc_init);
+static DLSYM_FUNCTION(iptc_insert_entry);
+static DLSYM_FUNCTION(iptc_strerror);
+
+static void *iptc_dl = NULL;
+
+DEFINE_TRIVIAL_CLEANUP_FUNC_FULL(struct xtc_handle*, sym_iptc_free, NULL);
+
+static int entry_fill_basics(
+                struct ipt_entry *entry,
+                int protocol,
+                const char *in_interface,
+                const union in_addr_union *source,
+                unsigned source_prefixlen,
+                const char *out_interface,
+                const union in_addr_union *destination,
+                unsigned destination_prefixlen) {
+
+        assert(entry);
+
+        if (out_interface && !ifname_valid(out_interface))
+                return -EINVAL;
+        if (in_interface && !ifname_valid(in_interface))
+                return -EINVAL;
+
+        entry->ip.proto = protocol;
+
+        if (in_interface) {
+                size_t l;
+
+                l = strlen(in_interface);
+                assert(l < sizeof entry->ip.iniface);
+                assert(l < sizeof entry->ip.iniface_mask);
+
+                strcpy(entry->ip.iniface, in_interface);
+                memset(entry->ip.iniface_mask, 0xFF, l + 1);
+        }
+        if (source) {
+                entry->ip.src = source->in;
+                in4_addr_prefixlen_to_netmask(&entry->ip.smsk, source_prefixlen);
+        }
+
+        if (out_interface) {
+                size_t l = strlen(out_interface);
+                assert(l < sizeof entry->ip.outiface);
+                assert(l < sizeof entry->ip.outiface_mask);
+
+                strcpy(entry->ip.outiface, out_interface);
+                memset(entry->ip.outiface_mask, 0xFF, l + 1);
+        }
+        if (destination) {
+                entry->ip.dst = destination->in;
+                in4_addr_prefixlen_to_netmask(&entry->ip.dmsk, destination_prefixlen);
+        }
+
+        return 0;
+}
+
+int fw_iptables_add_masquerade(
+                bool add,
+                int af,
+                const union in_addr_union *source,
+                unsigned source_prefixlen) {
+
+        static const xt_chainlabel chain = "POSTROUTING";
+        _cleanup_(sym_iptc_freep) struct xtc_handle *h = NULL;
+        struct ipt_entry *entry, *mask;
+        struct ipt_entry_target *t;
+        size_t sz;
+        struct nf_nat_ipv4_multi_range_compat *mr;
+        int r, protocol = 0;
+        const char *out_interface = NULL;
+        const union in_addr_union *destination = NULL;
+        unsigned destination_prefixlen = 0;
+
+        if (af != AF_INET)
+                return -EOPNOTSUPP;
+
+        if (!source || source_prefixlen == 0)
+                return -EINVAL;
+
+        r = fw_iptables_init_nat(&h);
+        if (r < 0)
+                return r;
+
+        sz = XT_ALIGN(sizeof(struct ipt_entry)) +
+             XT_ALIGN(sizeof(struct ipt_entry_target)) +
+             XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+
+        /* Put together the entry we want to add or remove */
+        entry = alloca0(sz);
+        entry->next_offset = sz;
+        entry->target_offset = XT_ALIGN(sizeof(struct ipt_entry));
+        r = entry_fill_basics(entry, protocol, NULL, source, source_prefixlen, out_interface, destination, destination_prefixlen);
+        if (r < 0)
+                return r;
+
+        /* Fill in target part */
+        t = ipt_get_target(entry);
+        t->u.target_size =
+                XT_ALIGN(sizeof(struct ipt_entry_target)) +
+                XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+        strncpy(t->u.user.name, "MASQUERADE", sizeof(t->u.user.name));
+        mr = (struct nf_nat_ipv4_multi_range_compat*) t->data;
+        mr->rangesize = 1;
+
+        /* Create a search mask entry */
+        mask = alloca_safe(sz);
+        memset(mask, 0xFF, sz);
+
+        if (add) {
+                if (sym_iptc_check_entry(chain, entry, (unsigned char*) mask, h))
+                        return 0;
+                if (errno != ENOENT) /* if other error than not existing yet, fail */
+                        return -errno;
+
+                if (!sym_iptc_insert_entry(chain, entry, 0, h))
+                        return -errno;
+        } else {
+                if (!sym_iptc_delete_entry(chain, entry, (unsigned char*) mask, h)) {
+                        if (errno == ENOENT) /* if it's already gone, all is good! */
+                                return 0;
+
+                        return -errno;
+                }
+        }
+
+        if (!sym_iptc_commit(h))
+                return -errno;
+
+        return 0;
+}
+
+int fw_iptables_add_local_dnat(
+                bool add,
+                int af,
+                int protocol,
+                uint16_t local_port,
+                const union in_addr_union *remote,
+                uint16_t remote_port,
+                const union in_addr_union *previous_remote) {
+
+        static const xt_chainlabel chain_pre = "PREROUTING", chain_output = "OUTPUT";
+        _cleanup_(sym_iptc_freep) struct xtc_handle *h = NULL;
+        struct ipt_entry *entry, *mask;
+        struct ipt_entry_target *t;
+        struct ipt_entry_match *m;
+        struct xt_addrtype_info_v1 *at;
+        struct nf_nat_ipv4_multi_range_compat *mr;
+        size_t sz, msz;
+        int r;
+        const char *in_interface = NULL;
+        const union in_addr_union *source = NULL;
+        unsigned source_prefixlen = 0;
+        const union in_addr_union *destination = NULL;
+        unsigned destination_prefixlen = 0;
+
+        assert(add || !previous_remote);
+
+        if (af != AF_INET)
+                return -EOPNOTSUPP;
+
+        if (!IN_SET(protocol, IPPROTO_TCP, IPPROTO_UDP))
+                return -EOPNOTSUPP;
+
+        if (local_port <= 0)
+                return -EINVAL;
+
+        if (remote_port <= 0)
+                return -EINVAL;
+
+        r = fw_iptables_init_nat(&h);
+        if (r < 0)
+                return r;
+
+        sz = XT_ALIGN(sizeof(struct ipt_entry)) +
+             XT_ALIGN(sizeof(struct ipt_entry_match)) +
+             XT_ALIGN(sizeof(struct xt_addrtype_info_v1)) +
+             XT_ALIGN(sizeof(struct ipt_entry_target)) +
+             XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+
+        if (protocol == IPPROTO_TCP)
+                msz = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                      XT_ALIGN(sizeof(struct xt_tcp));
+        else
+                msz = XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                      XT_ALIGN(sizeof(struct xt_udp));
+
+        sz += msz;
+
+        /* Fill in basic part */
+        entry = alloca0(sz);
+        entry->next_offset = sz;
+        entry->target_offset =
+                XT_ALIGN(sizeof(struct ipt_entry)) +
+                XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                XT_ALIGN(sizeof(struct xt_addrtype_info_v1)) +
+                msz;
+        r = entry_fill_basics(entry, protocol, in_interface, source, source_prefixlen, NULL, destination, destination_prefixlen);
+        if (r < 0)
+                return r;
+
+        /* Fill in first match */
+        m = (struct ipt_entry_match*) ((uint8_t*) entry + XT_ALIGN(sizeof(struct ipt_entry)));
+        m->u.match_size = msz;
+        if (protocol == IPPROTO_TCP) {
+                struct xt_tcp *tcp;
+
+                strncpy(m->u.user.name, "tcp", sizeof(m->u.user.name));
+                tcp = (struct xt_tcp*) m->data;
+                tcp->dpts[0] = tcp->dpts[1] = local_port;
+                tcp->spts[0] = 0;
+                tcp->spts[1] = 0xFFFF;
+
+        } else {
+                struct xt_udp *udp;
+
+                strncpy(m->u.user.name, "udp", sizeof(m->u.user.name));
+                udp = (struct xt_udp*) m->data;
+                udp->dpts[0] = udp->dpts[1] = local_port;
+                udp->spts[0] = 0;
+                udp->spts[1] = 0xFFFF;
+        }
+
+        /* Fill in second match */
+        m = (struct ipt_entry_match*) ((uint8_t*) entry + XT_ALIGN(sizeof(struct ipt_entry)) + msz);
+        m->u.match_size =
+                XT_ALIGN(sizeof(struct ipt_entry_match)) +
+                XT_ALIGN(sizeof(struct xt_addrtype_info_v1));
+        strncpy(m->u.user.name, "addrtype", sizeof(m->u.user.name));
+        m->u.user.revision = 1;
+        at = (struct xt_addrtype_info_v1*) m->data;
+        at->dest = XT_ADDRTYPE_LOCAL;
+
+        /* Fill in target part */
+        t = ipt_get_target(entry);
+        t->u.target_size =
+                XT_ALIGN(sizeof(struct ipt_entry_target)) +
+                XT_ALIGN(sizeof(struct nf_nat_ipv4_multi_range_compat));
+        strncpy(t->u.user.name, "DNAT", sizeof(t->u.user.name));
+        mr = (struct nf_nat_ipv4_multi_range_compat*) t->data;
+        mr->rangesize = 1;
+        mr->range[0].flags = NF_NAT_RANGE_PROTO_SPECIFIED|NF_NAT_RANGE_MAP_IPS;
+        mr->range[0].min_ip = mr->range[0].max_ip = remote->in.s_addr;
+        if (protocol == IPPROTO_TCP)
+                mr->range[0].min.tcp.port = mr->range[0].max.tcp.port = htobe16(remote_port);
+        else
+                mr->range[0].min.udp.port = mr->range[0].max.udp.port = htobe16(remote_port);
+
+        mask = alloca0(sz);
+        memset(mask, 0xFF, sz);
+
+        if (add) {
+                /* Add the PREROUTING rule, if it is missing so far */
+                if (!sym_iptc_check_entry(chain_pre, entry, (unsigned char*) mask, h)) {
+                        if (errno != ENOENT)
+                                return -EINVAL;
+
+                        if (!sym_iptc_insert_entry(chain_pre, entry, 0, h))
+                                return -errno;
+                }
+
+                /* If a previous remote is set, remove its entry */
+                if (previous_remote && previous_remote->in.s_addr != remote->in.s_addr) {
+                        mr->range[0].min_ip = mr->range[0].max_ip = previous_remote->in.s_addr;
+
+                        if (!sym_iptc_delete_entry(chain_pre, entry, (unsigned char*) mask, h)) {
+                                if (errno != ENOENT)
+                                        return -errno;
+                        }
+
+                        mr->range[0].min_ip = mr->range[0].max_ip = remote->in.s_addr;
+                }
+
+                /* Add the OUTPUT rule, if it is missing so far */
+                if (!in_interface) {
+
+                        /* Don't apply onto loopback addresses */
+                        if (!destination) {
+                                entry->ip.dst.s_addr = htobe32(0x7F000000);
+                                entry->ip.dmsk.s_addr = htobe32(0xFF000000);
+                                entry->ip.invflags = IPT_INV_DSTIP;
+                        }
+
+                        if (!sym_iptc_check_entry(chain_output, entry, (unsigned char*) mask, h)) {
+                                if (errno != ENOENT)
+                                        return -errno;
+
+                                if (!sym_iptc_insert_entry(chain_output, entry, 0, h))
+                                        return -errno;
+                        }
+
+                        /* If a previous remote is set, remove its entry */
+                        if (previous_remote && previous_remote->in.s_addr != remote->in.s_addr) {
+                                mr->range[0].min_ip = mr->range[0].max_ip = previous_remote->in.s_addr;
+
+                                if (!sym_iptc_delete_entry(chain_output, entry, (unsigned char*) mask, h)) {
+                                        if (errno != ENOENT)
+                                                return -errno;
+                                }
+                        }
+                }
+        } else {
+                if (!sym_iptc_delete_entry(chain_pre, entry, (unsigned char*) mask, h)) {
+                        if (errno != ENOENT)
+                                return -errno;
+                }
+
+                if (!in_interface) {
+                        if (!destination) {
+                                entry->ip.dst.s_addr = htobe32(0x7F000000);
+                                entry->ip.dmsk.s_addr = htobe32(0xFF000000);
+                                entry->ip.invflags = IPT_INV_DSTIP;
+                        }
+
+                        if (!sym_iptc_delete_entry(chain_output, entry, (unsigned char*) mask, h)) {
+                                if (errno != ENOENT)
+                                        return -errno;
+                        }
+                }
+        }
+
+        if (!sym_iptc_commit(h))
+                return -errno;
+
+        return 0;
+}
+
+static int dlopen_iptc(void) {
+        return dlopen_many_sym_or_warn(
+                        &iptc_dl,
+                        "libip4tc.so.2", LOG_DEBUG,
+                        DLSYM_ARG(iptc_check_entry),
+                        DLSYM_ARG(iptc_commit),
+                        DLSYM_ARG(iptc_delete_entry),
+                        DLSYM_ARG(iptc_free),
+                        DLSYM_ARG(iptc_init),
+                        DLSYM_ARG(iptc_insert_entry),
+                        DLSYM_ARG(iptc_strerror));
+}
+
+int fw_iptables_init_nat(struct xtc_handle **ret) {
+        _cleanup_(sym_iptc_freep) struct xtc_handle *h = NULL;
+        int r;
+
+        r = dlopen_iptc();
+        if (r < 0)
+                return r;
+
+        h = sym_iptc_init("nat");
+        if (!h)
+                return log_debug_errno(errno, "Failed to init \"nat\" table: %s", sym_iptc_strerror(errno));
+
+        if (ret)
+                *ret = TAKE_PTR(h);
+
+        return 0;
+}