[master] Altered v4 lease time handling better handle infinite and large times

    Merged in rt41976

diff --git a/RELNOTES b/RELNOTES
index 4d7b3899ce2c5ae7f5dc6706af3c183acd8eb663..a14122701d2c3b82c77d611465ed6f46dee2a85b 100644 (file)
--- a/RELNOTES
+++ b/RELNOTES
@@ -187,6 +187,13 @@ by Eric Young (eay@cryptsoft.com).
   Mritunjaykumar Dubey at Nokia for reporting the issue.
   [ISC-Bugs #41473]
 
+- Altered DHCPv4 lease time calculation to avoid roll over errors on 64-bit
+  OS systems when using -1 or large values for default-lease-time.  Rollover
+  values will be replaced with 0x7FFFFFFF - 1.  This alleviates unintentionally
+  short expiration times being handed out when infinite lease times (-1) in
+  conjuction with failover.
+  [ISC-Bugs #41976]
+
                        Changes since 4.3.0 (bug fixes)
 
 - Tidy up several small tickets.

diff --git a/includes/dhcpd.h b/includes/dhcpd.h
index 5a3888d59de8827894f291ddec9a520d0942255d..5d5e1d0f720a6fe6bc4b7239e75fbbb0227b6006 100644 (file)
--- a/includes/dhcpd.h
+++ b/includes/dhcpd.h
@@ -1588,8 +1588,9 @@ typedef unsigned char option_mask [16];
 #define DHCPD_LOG_FACILITY     LOG_DAEMON
 #endif
 
-#define MAX_TIME 0x7fffffff
-#define MIN_TIME 0
+#define INFINITE_TIME  0xffffffff
+#define MAX_TIME       0x7fffffff
+#define MIN_TIME       0
 
 #ifdef USE_LOG_PID
 /* include the pid in the syslog messages */

diff --git a/server/dhcp.c b/server/dhcp.c
index 1109e204fb695fc3729de9d838f684f54114215a..5b4e0b96dd70a7c8031eb505f611c280eda09a63 100644 (file)
--- a/server/dhcp.c
+++ b/server/dhcp.c
@@ -85,6 +85,8 @@ const int dhcp_type_name_max = ((sizeof dhcp_type_names) / sizeof (char *));
 # define send_packet trace_packet_send
 #endif
 
+static TIME leaseTimeCheck(TIME calculated, TIME alternate);
+
 void
 dhcp (struct packet *packet) {
        int ms_nulltp = 0;
@@ -2878,8 +2880,15 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp, hp)
                         * the desired lease time upon renewal.
                         */
                        if (offer == DHCPACK) {
-                               lt->tstp = cur_time + lease_time +
-                                               (new_lease_time / 2);
+                               if (lease_time == INFINITE_TIME) {
+                                       lt->tstp = MAX_TIME;
+                               } else {
+                                       lt->tstp =
+                                               leaseTimeCheck(
+                                                   (cur_time + lease_time
+                                                    + (new_lease_time / 2)),
+                                                   MAX_TIME - 1);
+                               }
 
                                /* If we reduced the potential expiry time,
                                 * make sure we don't offer an old-expiry-time
@@ -2896,12 +2905,16 @@ void ack_lease (packet, lease, offer, when, msg, ms_nulltp, hp)
                }
 #endif /* FAILOVER_PROTOCOL */
 
-               /* If the lease duration causes the time value to wrap,
-                  use the maximum expiry time. */
-               if (cur_time + lease_time < cur_time)
-                       state -> offered_expiry = MAX_TIME - 1;
-               else
-                       state -> offered_expiry = cur_time + lease_time;
+               if (lease_time == INFINITE_TIME) {
+                       state->offered_expiry = MAX_TIME;
+               } else {
+                       /* If the lease duration causes the time value to wrap,
+                        use the maximum expiry time. */
+                       state->offered_expiry
+                               = leaseTimeCheck(cur_time + lease_time,
+                                                MAX_TIME - 1);
+               }
+
                if (when)
                        lt -> ends = when;
                else
@@ -5670,3 +5683,29 @@ reuse_lease (struct packet* packet,
        lease->cannot_reuse = (!reusable && offer == DHCPOFFER);
        return (reusable);
 }
+
+/* \brief Validates a proposed value for use as a lease time
+ *
+ * Convenience function used for catching calculeated lease
+ * times that overflow 4-byte times used in v4 protocol.
+ *
+ * We use variables of type TIME in lots of places, which on
+ * 64-bit systems is 8 bytes while on 32-bit OSs it is int32_t,
+ * so we have all sorts of fun places to mess things up.
+ * This function checks a calculated lease time for and if it
+ * is unsuitable for use as a lease time, the given alternate
+ * value is returned.
+ * \param calculated
+ * \param alternate
+ *
+ * \returen either the calculated value if it is valid, or
+ * the alternate value supplied
+ */
+TIME leaseTimeCheck(TIME calculated, TIME alternate) {
+    if ((sizeof(TIME) > 4 && calculated >= INFINITE_TIME) ||
+        (calculated < cur_time)) {
+        return (alternate);
+    }
+
+    return (calculated);
+}

diff --git a/server/dhcpv6.c b/server/dhcpv6.c
index d18758ba3c7d56f772a56b4301493adf06f70c7f..a8bae63c4ff46d065a23afb60c8a1f13411060b0 100644 (file)
--- a/server/dhcpv6.c
+++ b/server/dhcpv6.c
@@ -2090,7 +2090,7 @@ reply_process_ia_na(struct reply_state *reply, struct option_cache *ia) {
         * A not included IA ("cleanup" below) could give a Renew/Rebind.
         */
        oc = lookup_option(&dhcpv6_universe, packet_ia, D6O_IAADDR);
-       reply->min_valid = reply->min_prefer = 0xffffffff;
+       reply->min_valid = reply->min_prefer = INFINITE_TIME;
        reply->client_valid = reply->client_prefer = 0;
        for (; oc != NULL ; oc = oc->next) {
                status = reply_process_addr(reply, oc);
@@ -2845,7 +2845,7 @@ reply_process_ia_ta(struct reply_state *reply, struct option_cache *ia) {
         * Deal with an IAADDR for lifetimes.
         * For all or none, process IAADDRs as hints.
         */
-       reply->min_valid = reply->min_prefer = 0xffffffff;
+       reply->min_valid = reply->min_prefer = INFINITE_TIME;
        reply->client_valid = reply->client_prefer = 0;
        oc = lookup_option(&dhcpv6_universe, packet_ia, D6O_IAADDR);
        for (; oc != NULL; oc = oc->next) {
@@ -3567,10 +3567,10 @@ reply_process_is_addressed(struct reply_state *reply,
         * The following doesn't work on at least some systems:
         * (cur_time + reply->send_valid < cur_time)
         */
-       if (reply->send_valid != 0xFFFFFFFF) {
+       if (reply->send_valid != INFINITE_TIME) {
                time_t test_time = cur_time + reply->send_valid;
                if (test_time < cur_time)
-                       reply->send_valid = 0xFFFFFFFF;
+                       reply->send_valid = INFINITE_TIME;
         }
 
        if (reply->client_prefer == 0)
@@ -3579,7 +3579,7 @@ reply_process_is_addressed(struct reply_state *reply,
                reply->send_prefer = reply->client_prefer;
 
        if ((reply->send_prefer >= reply->send_valid) &&
-           (reply->send_valid != 0xFFFFFFFF))
+           (reply->send_valid != INFINITE_TIME))
                reply->send_prefer = (reply->send_valid / 2) +
                                     (reply->send_valid / 8);
 
@@ -3634,7 +3634,7 @@ reply_process_is_addressed(struct reply_state *reply,
                 * when connecting to the lease file MAX_TIME is
                 */
                if (reply->buf.reply.msg_type == DHCPV6_REPLY) {
-                       if (reply->send_valid == 0xFFFFFFFF) {
+                       if (reply->send_valid == INFINITE_TIME) {
                                reply->lease->soft_lifetime_end_time = MAX_TIME;
                        } else {
                                reply->lease->soft_lifetime_end_time =
@@ -3921,7 +3921,7 @@ reply_process_ia_pd(struct reply_state *reply, struct option_cache *ia) {
         * For each prefix in this IA_PD, decide what to do about it.
         */
        oc = lookup_option(&dhcpv6_universe, packet_ia, D6O_IAPREFIX);
-       reply->min_valid = reply->min_prefer = 0xffffffff;
+       reply->min_valid = reply->min_prefer = INFINITE_TIME;
        reply->client_valid = reply->client_prefer = 0;
        reply->preflen = -1;
        for (; oc != NULL ; oc = oc->next) {
@@ -4813,10 +4813,10 @@ reply_process_is_prefixed(struct reply_state *reply,
         * The following doesn't work on at least some systems:
         * (cur_time + reply->send_valid < cur_time)
         */
-       if (reply->send_valid != 0xFFFFFFFF) {
+       if (reply->send_valid != INFINITE_TIME) {
                time_t test_time = cur_time + reply->send_valid;
                if (test_time < cur_time)
-                       reply->send_valid = 0xFFFFFFFF;
+                       reply->send_valid = INFINITE_TIME;
         }
 
        if (reply->client_prefer == 0)
@@ -4825,7 +4825,7 @@ reply_process_is_prefixed(struct reply_state *reply,
                reply->send_prefer = reply->client_prefer;
 
        if ((reply->send_prefer >= reply->send_valid) &&
-           (reply->send_valid != 0xFFFFFFFF))
+           (reply->send_valid != INFINITE_TIME))
                reply->send_prefer = (reply->send_valid / 2) +
                                     (reply->send_valid / 8);
 
@@ -4865,7 +4865,7 @@ reply_process_is_prefixed(struct reply_state *reply,
                 * when connecting to the lease file MAX_TIME is
                 */
                if (reply->buf.reply.msg_type == DHCPV6_REPLY) {
-                       if (reply->send_valid == 0xFFFFFFFF) {
+                       if (reply->send_valid == INFINITE_TIME) {
                                reply->lease->soft_lifetime_end_time = MAX_TIME;
                        } else {
                                reply->lease->soft_lifetime_end_time =
@@ -8089,8 +8089,10 @@ set_reply_tee_times(struct reply_state* reply, unsigned ia_cursor)
        } else if (set_tee_times) {
                /* Setting them is enabled so T1 is either infinite or
                 * 0.5 * the shortest preferred lifetime in the IA_XX  */
-               reply->renew = (reply->min_prefer == 0xFFFFFFFF ? 0xFFFFFFFF
-                                : reply->min_prefer / 2);
+               if (reply->min_prefer == INFINITE_TIME)
+                       reply->renew = INFINITE_TIME;
+               else
+                       reply->renew = reply->min_prefer / 2;
        } else {
                /* Default is to let the client choose */
                reply->renew = 0;
@@ -8122,8 +8124,10 @@ set_reply_tee_times(struct reply_state* reply, unsigned ia_cursor)
        } else if (set_tee_times) {
                /* Setting them is enabled so T2 is either infinite or
                 * 0.8 * the shortest preferred lifetime in the reply */
-               reply->rebind = (reply->min_prefer == 0xFFFFFFFF ? 0xFFFFFFFF
-                                : (reply->min_prefer / 5) * 4);
+               if (reply->min_prefer == INFINITE_TIME)
+                       reply->rebind = INFINITE_TIME;
+               else
+                       reply->rebind = (reply->min_prefer / 5) * 4;
        } else {
                /* Default is to let the client choose */
                reply->rebind = 0;