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-rw-r--r--addrfilt.c405
1 files changed, 405 insertions, 0 deletions
diff --git a/addrfilt.c b/addrfilt.c
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index 0000000..6208b46
--- /dev/null
+++ b/addrfilt.c
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+/*
+ chronyd/chronyc - Programs for keeping computer clocks accurate.
+
+ **********************************************************************
+ * Copyright (C) Richard P. Curnow 1997,1998,1999,2000,2001,2002,2005
+ * Copyright (C) Miroslav Lichvar 2009, 2015
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ **********************************************************************
+
+ =======================================================================
+
+ This module provides a set of routines for checking IP addresses
+ against a set of rules and deciding whether they are allowed or
+ disallowed.
+
+ */
+
+#include "config.h"
+
+#include "sysincl.h"
+
+#include "addrfilt.h"
+#include "memory.h"
+
+/* Define the number of bits which are stripped off per level of
+ indirection in the tables */
+#define NBITS 4
+
+/* Define the table size */
+#define TABLE_SIZE (1UL<<NBITS)
+
+typedef enum {DENY, ALLOW, AS_PARENT} State;
+
+typedef struct _TableNode {
+ State state;
+ struct _TableNode *extended;
+} TableNode;
+
+struct ADF_AuthTableInst {
+ TableNode base4; /* IPv4 node */
+ TableNode base6; /* IPv6 node */
+};
+
+/* ================================================== */
+
+static void
+split_ip6(IPAddr *ip, uint32_t *dst)
+{
+ int i;
+
+ for (i = 0; i < 4; i++)
+ dst[i] = (uint32_t)ip->addr.in6[i * 4 + 0] << 24 |
+ ip->addr.in6[i * 4 + 1] << 16 |
+ ip->addr.in6[i * 4 + 2] << 8 |
+ ip->addr.in6[i * 4 + 3];
+}
+
+/* ================================================== */
+
+inline static uint32_t
+get_subnet(uint32_t *addr, unsigned int where)
+{
+ int off;
+
+ off = where / 32;
+ where %= 32;
+
+ return (addr[off] >> (32 - NBITS - where)) & ((1UL << NBITS) - 1);
+}
+
+/* ================================================== */
+
+ADF_AuthTable
+ADF_CreateTable(void)
+{
+ ADF_AuthTable result;
+ result = MallocNew(struct ADF_AuthTableInst);
+
+ /* Default is that nothing is allowed */
+ result->base4.state = DENY;
+ result->base4.extended = NULL;
+ result->base6.state = DENY;
+ result->base6.extended = NULL;
+
+ return result;
+}
+
+/* ================================================== */
+/* This function deletes all definitions of child nodes, in effect
+ pruning a whole subnet definition back to a single parent
+ record. */
+static void
+close_node(TableNode *node)
+{
+ int i;
+ TableNode *child_node;
+
+ if (node->extended != NULL) {
+ for (i=0; i<TABLE_SIZE; i++) {
+ child_node = &(node->extended[i]);
+ close_node(child_node);
+ }
+ Free(node->extended);
+ node->extended = NULL;
+ }
+}
+
+
+/* ================================================== */
+/* Allocate the extension field in a node, and set all the children's
+ states to default to that of the node being extended */
+
+static void
+open_node(TableNode *node)
+{
+ int i;
+ TableNode *child_node;
+
+ if (node->extended == NULL) {
+
+ node->extended = MallocArray(struct _TableNode, TABLE_SIZE);
+
+ for (i=0; i<TABLE_SIZE; i++) {
+ child_node = &(node->extended[i]);
+ child_node->state = AS_PARENT;
+ child_node->extended = NULL;
+ }
+ }
+}
+
+/* ================================================== */
+
+static ADF_Status
+set_subnet(TableNode *start_node,
+ uint32_t *ip,
+ int ip_len,
+ int subnet_bits,
+ State new_state,
+ int delete_children)
+{
+ int bits_to_go, bits_consumed;
+ uint32_t subnet;
+ TableNode *node;
+
+ bits_consumed = 0;
+ bits_to_go = subnet_bits;
+ node = start_node;
+
+ if ((subnet_bits < 0) ||
+ (subnet_bits > 32 * ip_len)) {
+
+ return ADF_BADSUBNET;
+
+ } else {
+
+ if ((bits_to_go & (NBITS-1)) == 0) {
+
+ while (bits_to_go > 0) {
+ subnet = get_subnet(ip, bits_consumed);
+ if (!(node->extended)) {
+ open_node(node);
+ }
+ node = &(node->extended[subnet]);
+ bits_to_go -= NBITS;
+ bits_consumed += NBITS;
+ }
+
+ if (delete_children) {
+ close_node(node);
+ }
+ node->state = new_state;
+
+ } else { /* Have to set multiple entries */
+ int N, i, j;
+ TableNode *this_node;
+
+ while (bits_to_go >= NBITS) {
+ subnet = get_subnet(ip, bits_consumed);
+ if (!(node->extended)) {
+ open_node(node);
+ }
+ node = &(node->extended[subnet]);
+ bits_to_go -= NBITS;
+ bits_consumed += NBITS;
+ }
+
+ /* How many subnet entries to set : 1->8, 2->4, 3->2 */
+ N = 1 << (NBITS-bits_to_go);
+
+ subnet = get_subnet(ip, bits_consumed) & ~(N - 1);
+ assert(subnet + N <= TABLE_SIZE);
+
+ if (!(node->extended)) {
+ open_node(node);
+ }
+
+ for (i=subnet, j=0; j<N; i++, j++) {
+ this_node = &(node->extended[i]);
+ if (delete_children) {
+ close_node(this_node);
+ }
+ this_node->state = new_state;
+ }
+ }
+
+ return ADF_SUCCESS;
+ }
+
+}
+
+/* ================================================== */
+
+static ADF_Status
+set_subnet_(ADF_AuthTable table,
+ IPAddr *ip_addr,
+ int subnet_bits,
+ State new_state,
+ int delete_children)
+{
+ uint32_t ip6[4];
+
+ switch (ip_addr->family) {
+ case IPADDR_INET4:
+ return set_subnet(&table->base4, &ip_addr->addr.in4, 1, subnet_bits, new_state, delete_children);
+ case IPADDR_INET6:
+ split_ip6(ip_addr, ip6);
+ return set_subnet(&table->base6, ip6, 4, subnet_bits, new_state, delete_children);
+ case IPADDR_UNSPEC:
+ /* Apply to both, subnet_bits has to be 0 */
+ if (subnet_bits != 0)
+ return ADF_BADSUBNET;
+ memset(ip6, 0, sizeof (ip6));
+ if (set_subnet(&table->base4, ip6, 1, 0, new_state, delete_children) == ADF_SUCCESS &&
+ set_subnet(&table->base6, ip6, 4, 0, new_state, delete_children) == ADF_SUCCESS)
+ return ADF_SUCCESS;
+ break;
+ default:
+ break;
+ }
+
+ return ADF_BADSUBNET;
+}
+
+ADF_Status
+ADF_Allow(ADF_AuthTable table,
+ IPAddr *ip,
+ int subnet_bits)
+{
+ return set_subnet_(table, ip, subnet_bits, ALLOW, 0);
+}
+
+/* ================================================== */
+
+
+ADF_Status
+ADF_AllowAll(ADF_AuthTable table,
+ IPAddr *ip,
+ int subnet_bits)
+{
+ return set_subnet_(table, ip, subnet_bits, ALLOW, 1);
+}
+
+/* ================================================== */
+
+ADF_Status
+ADF_Deny(ADF_AuthTable table,
+ IPAddr *ip,
+ int subnet_bits)
+{
+ return set_subnet_(table, ip, subnet_bits, DENY, 0);
+}
+
+/* ================================================== */
+
+ADF_Status
+ADF_DenyAll(ADF_AuthTable table,
+ IPAddr *ip,
+ int subnet_bits)
+{
+ return set_subnet_(table, ip, subnet_bits, DENY, 1);
+}
+
+/* ================================================== */
+
+void
+ADF_DestroyTable(ADF_AuthTable table)
+{
+ close_node(&table->base4);
+ close_node(&table->base6);
+ Free(table);
+}
+
+/* ================================================== */
+
+static int
+check_ip_in_node(TableNode *start_node, uint32_t *ip)
+{
+ uint32_t subnet;
+ int bits_consumed = 0;
+ int result = 0;
+ int finished = 0;
+ TableNode *node;
+ State state=DENY;
+
+ node = start_node;
+
+ do {
+ if (node->state != AS_PARENT) {
+ state = node->state;
+ }
+ if (node->extended) {
+ subnet = get_subnet(ip, bits_consumed);
+ node = &(node->extended[subnet]);
+ bits_consumed += NBITS;
+ } else {
+ /* Make decision on this node */
+ finished = 1;
+ }
+ } while (!finished);
+
+ switch (state) {
+ case ALLOW:
+ result = 1;
+ break;
+ case DENY:
+ result = 0;
+ break;
+ case AS_PARENT:
+ assert(0);
+ break;
+ }
+
+ return result;
+}
+
+
+/* ================================================== */
+
+int
+ADF_IsAllowed(ADF_AuthTable table,
+ IPAddr *ip_addr)
+{
+ uint32_t ip6[4];
+
+ switch (ip_addr->family) {
+ case IPADDR_INET4:
+ return check_ip_in_node(&table->base4, &ip_addr->addr.in4);
+ case IPADDR_INET6:
+ split_ip6(ip_addr, ip6);
+ return check_ip_in_node(&table->base6, ip6);
+ default:
+ return 0;
+ }
+}
+
+/* ================================================== */
+
+static int
+is_any_allowed(TableNode *node, State parent)
+{
+ State state;
+ int i;
+
+ state = node->state != AS_PARENT ? node->state : parent;
+ assert(state != AS_PARENT);
+
+ if (node->extended) {
+ for (i = 0; i < TABLE_SIZE; i++) {
+ if (is_any_allowed(&node->extended[i], state))
+ return 1;
+ }
+ } else if (state == ALLOW) {
+ return 1;
+ }
+
+ return 0;
+}
+
+/* ================================================== */
+
+int
+ADF_IsAnyAllowed(ADF_AuthTable table, int family)
+{
+ switch (family) {
+ case IPADDR_INET4:
+ return is_any_allowed(&table->base4, AS_PARENT);
+ case IPADDR_INET6:
+ return is_any_allowed(&table->base6, AS_PARENT);
+ default:
+ return 0;
+ }
+}
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