Use dynamically allocated buffer for GetAdaptersAddresses()

GS-IPv6-Forwarder

@@ -1 +1 @@
-Subproject commit 6fc14fa95e6d3c6bc620e3147735ea61891b6110
+Subproject commit 851eac0e727301e93dc424559bb17118c0e77f6e

miss/miss.cpp

@@ -39,6 +39,7 @@ bool PCPMapPort(PSOCKADDR_STORAGE localAddr, int localAddrLen, PSOCKADDR_STORAGE
 #define POLLING_DELAY_SEC 120
 #define PORT_MAPPING_DURATION_SEC 3600
 #define UPNP_DISCOVERY_DELAY_MS 5000
+#define GAA_INITIAL_SIZE 8192
 
 static struct port_entry {
     int proto;
@@ -233,10 +234,7 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
 
 bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 {
-    union {
+    PIP_ADAPTER_ADDRESSES addresses;
-        IP_ADAPTER_ADDRESSES addresses;
-        char buffer[8192];
-    };
     ULONG error;
     ULONG length;
     PIP_ADAPTER_ADDRESSES currentAdapter;
@@ -245,22 +243,34 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 
     inet_pton(AF_INET, lanAddressString, &targetAddress);
 
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            printf("malloc(%u) failed" NL, length);
+            return false;
+        }
+
         // Get a list of all interfaces with IPv4 addresses on the system
-    length = sizeof(buffer);
         error = GetAdaptersAddresses(AF_INET,
             GAA_FLAG_SKIP_ANYCAST |
             GAA_FLAG_SKIP_MULTICAST |
             GAA_FLAG_SKIP_DNS_SERVER |
             GAA_FLAG_SKIP_FRIENDLY_NAME,
             NULL,
-        &addresses,
+            addresses,
             &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
     if (error != ERROR_SUCCESS) {
         printf("GetAdaptersAddresses() failed: %d" NL, error);
+        free(addresses);
         return false;
     }
 
-    currentAdapter = &addresses;
+    currentAdapter = addresses;
     currentAddress = nullptr;
     while (currentAdapter != nullptr) {
         currentAddress = currentAdapter->FirstUnicastAddress;
@@ -271,6 +281,7 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 
             if (RtlEqualMemory(&currentAddrV4->sin_addr, &targetAddress, sizeof(targetAddress))) {
                 *prefixLength = currentAddress->OnLinkPrefixLength;
+                free(addresses);
                 return true;
             }
 
@@ -281,6 +292,7 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
     }
 
     printf("No adapter found with IPv4 address: %s" NL, lanAddressString);
+    free(addresses);
     return false;
 }
 

mist/mist.cpp

@@ -29,6 +29,8 @@
 
 #define LOOPBACK_SERVER_PORT_OFFSET -10000
 
+#define GAA_INITIAL_SIZE 8192
+
 static struct port_entry {
     int proto;
     int port;
@@ -864,31 +866,40 @@ bool FindLocalInterfaceIPAddress(int family, PSOCKADDR_STORAGE addr)
 
 bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
 {
-    union {
+    PIP_ADAPTER_ADDRESSES addresses;
-        IP_ADAPTER_ADDRESSES addresses;
-        char buffer[8192];
-    };
     ULONG error;
     ULONG length;
     PIP_ADAPTER_ADDRESSES currentAdapter;
     PIP_ADAPTER_UNICAST_ADDRESS currentAddress;
 
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            fprintf(LOG_OUT, "malloc(%u) failed\n", length);
+            return false;
+        }
+
         // Get all IPv4 interfaces
-    length = sizeof(buffer);
         error = GetAdaptersAddresses(AF_INET,
             GAA_FLAG_SKIP_ANYCAST |
             GAA_FLAG_SKIP_MULTICAST |
             GAA_FLAG_SKIP_DNS_SERVER |
             GAA_FLAG_SKIP_FRIENDLY_NAME,
             NULL,
-        &addresses,
+            addresses,
             &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
     if (error != ERROR_SUCCESS) {
         fprintf(LOG_OUT, "GetAdaptersAddresses() failed: %d\n", error);
+        free(addresses);
         return false;
     }
 
-    currentAdapter = &addresses;
+    currentAdapter = addresses;
     while (currentAdapter != NULL) {
         // Look for ones that correspond to a ZeroTier device
         if (wcsstr(currentAdapter->Description, L"ZeroTier")) {
@@ -897,6 +908,7 @@ bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
             while (currentAddress != NULL) {
                 if (currentAddress->Address.lpSockaddr->sa_family == AF_INET) {
                     RtlCopyMemory(addr, currentAddress->Address.lpSockaddr, currentAddress->Address.iSockaddrLength);
+                    free(addresses);
                     return true;
                 }
 
@@ -907,15 +919,13 @@ bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
         currentAdapter = currentAdapter->Next;
     }
 
+    free(addresses);
     return false;
 }
 
 bool FindDuplicateDefaultInterfaces(void)
 {
-    union {
+    PIP_ADAPTER_ADDRESSES addresses;
-        IP_ADAPTER_ADDRESSES addresses;
-        char buffer[8192];
-    };
     ULONG error;
     ULONG length;
     MIB_IPFORWARDROW defaultRoute;
@@ -928,8 +938,17 @@ bool FindDuplicateDefaultInterfaces(void)
         return false;
     }
 
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            fprintf(LOG_OUT, "malloc(%u) failed\n", length);
+            return false;
+        }
+
         // Get all IPv4 interfaces
-    length = sizeof(buffer);
         error = GetAdaptersAddresses(AF_INET,
             GAA_FLAG_SKIP_UNICAST |
             GAA_FLAG_SKIP_ANYCAST |
@@ -938,14 +957,17 @@ bool FindDuplicateDefaultInterfaces(void)
             GAA_FLAG_INCLUDE_GATEWAYS |
             GAA_FLAG_SKIP_FRIENDLY_NAME,
             NULL,
-        &addresses,
+            addresses,
             &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
     if (error != ERROR_SUCCESS) {
         fprintf(LOG_OUT, "GetAdaptersAddresses() failed: %d\n", error);
+        free(addresses);
         return false;
     }
 
-    currentAdapter = &addresses;
+    currentAdapter = addresses;
     while (currentAdapter != NULL) {
         if (currentAdapter->OperStatus == IfOperStatusUp &&
             currentAdapter->FirstGatewayAddress != NULL &&
@@ -958,6 +980,7 @@ bool FindDuplicateDefaultInterfaces(void)
         currentAdapter = currentAdapter->Next;
     }
 
+    free(addresses);
     return matchingInterfaces > 1;
 }