Fix possible SEGFAULT conditions

[project/odhcpd.git] / src / dhcpv4.c

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index 6f15a0a..49b75f4 100644 (file)
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -38,6 +38,8 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
                enum dhcpv4_msg msg, const uint8_t *mac, struct in_addr reqaddr,
                const char *hostname);
 
+// Magic option for hnet internal (4B enterprise ID, 1B data-len, 1B subopt-code, 1B subopt-len)
+static uint8_t hnet_internal_data[7] = {0x00, 0x00, 0x76, 0xfe, 2, 1, 0};
 
 // Create socket and register events
 int init_dhcpv4(void)
@@ -59,6 +61,11 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                        INIT_LIST_HEAD(&iface->dhcpv4_assignments);
 
                int sock = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
+               if (sock < 0) {
+                       syslog(LOG_ERR, "Failed to create DHCPv4 server socket: %s",
+                                       strerror(errno));
+                       return -1;
+               }
 
                // Basic IPv6 configuration
                int val = 1;
@@ -137,7 +144,11 @@ int setup_dhcpv4_interface(struct interface *iface, bool enable)
                        // Construct entry
                        size_t hostlen = strlen(lease->hostname) + 1;
                        struct dhcpv4_assignment *a = calloc(1, sizeof(*a) + hostlen);
-
+                       if (!a) {
+                               syslog(LOG_ERR, "Calloc failed for static lease on interface %s",
+                                       iface->ifname);
+                               return -1;
+                       }
                        a->addr = ntohl(lease->ipaddr.s_addr);
                        memcpy(a->hwaddr, lease->mac.ether_addr_octet, sizeof(a->hwaddr));
                        memcpy(a->hostname, lease->hostname, hostlen);
@@ -285,6 +296,10 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
                } else if (opt->type == DHCPV4_OPT_SERVERID && opt->len == 4) {
                        if (memcmp(opt->data, &ifaddr.sin_addr, 4))
                                return;
+               } else if (opt->type == DHCPV4_OPT_VENDOR_SPECIFIC_INFORMATION &&
+                               opt->len == sizeof(hnet_internal_data)) {
+                       if (!memcmp(opt->data, hnet_internal_data, sizeof(hnet_internal_data)))
+                               return; // Ignoring hnet internal routers
                }
        }
 
@@ -464,6 +479,10 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 
                if (!a && !iface->no_dynamic_dhcp) { // Create new binding
                        a = calloc(1, sizeof(*a) + hostlen);
+                       if (!a) {
+                               syslog(LOG_ERR, "Failed to calloc binding on interface %s", iface->ifname);
+                               return NULL;
+                       }
                        memcpy(a->hwaddr, mac, sizeof(a->hwaddr));
                        memcpy(a->hostname, hostname, hostlen);
 
@@ -472,6 +491,10 @@ static struct dhcpv4_assignment* dhcpv4_lease(struct interface *iface,
 
                if (assigned && !a->hostname[0] && hostname) {
                        a = realloc(a, sizeof(*a) + hostlen);
+                       if (!a) {
+                               syslog(LOG_ERR, "Failed to realloc binding on interface %s", iface->ifname);
+                               return NULL;
+                       }
                        memcpy(a->hostname, hostname, hostlen);
 
                        // Fixup list