libnetwork: Fixed getifaddrs() implementation.

* It overwrote the request buffer, and tried to access its previous
    contents afterwards.
* It incorrectly copied sockaddrs.
* It did not initialize all members.
* It did not check for error codes from ioctl().
* It did not properly set errno in many cases, but just returned an
  error right away.
* This hopefully fixes bug #12156. Adrien obviously had a bad day :-)

src/kits/network/getifaddrs.cpp

@@ -4,74 +4,105 @@
  *
  * Authors:
  *		Adrien Destugues, [email protected]
+ *		Axel Dörfler, [email protected]
  */
 
 
+#include <algorithm>
+#include <new>
+
 #include <errno.h>
 #include <net/if.h>
+#include <netinet/in.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/sockio.h>
 #include <unistd.h>
 
-#include <new>
-
 #include <AutoDeleter.h>
 
 #include <ifaddrs.h>
 
 
-int getifaddrs(struct ifaddrs **ifap)
+static sockaddr*
+copy_address(const sockaddr& address)
 {
-	if (ifap == NULL) {
+	if (address.sa_family == AF_UNSPEC)
+		return NULL;
+
+	sockaddr_storage* copy = new (std::nothrow) sockaddr_storage;
+	if (copy == NULL)
+		return NULL;
+
+	size_t length = std::min(sizeof(sockaddr_storage), (size_t)address.sa_len);
+	switch (address.sa_family) {
+		case AF_INET:
+			length = sizeof(sockaddr_in);
+			break;
+		case AF_INET6:
+			length = sizeof(sockaddr_in6);
+			break;
+	}
+	memcpy(copy, &address, length);
+	copy->ss_len = length;
+	return (sockaddr*)copy;
+}
+
+
+/*! Returns a chained list of all interfaces.
+
+	We follow BSD semantics, and only return one entry per interface,
+	not per address; since this is mainly used by NetBSD's netresolv, it's
+	probably what it expects.
+*/
+int
+getifaddrs(struct ifaddrs** _ifaddrs)
+{
+	if (_ifaddrs == NULL) {
 		errno = B_BAD_VALUE;
 		return -1;
 	}
 
-#if 0
-	uint32 cookie;
-#endif
-
-	// get a list of all interfaces
-
 	int socket = ::socket(AF_INET, SOCK_DGRAM, 0);
 	if (socket < 0)
-		return errno;
+		return -1;
 
 	FileDescriptorCloser closer(socket);
 
-	// get interface count
+	// Get interface count
 	ifconf config;
 	config.ifc_len = sizeof(config.ifc_value);
 	if (ioctl(socket, SIOCGIFCOUNT, &config, sizeof(struct ifconf)) < 0)
-		return errno;
+		return -1;
 
 	size_t count = (size_t)config.ifc_value;
-	if (count == 0)
+	if (count == 0) {
-		return B_BAD_VALUE;
+		errno = B_BAD_VALUE;
+		return -1;
+	}
 
-	// allocate a buffer for ifreqs for all interfaces
+	// Allocate a buffer for ifreqs for all interfaces
 	char* buffer = (char*)malloc(count * sizeof(struct ifreq));
-	if (buffer == NULL)
+	if (buffer == NULL) {
-		return B_NO_MEMORY;
+		errno = B_NO_MEMORY;
+		return -1;
+	}
 
 	MemoryDeleter deleter(buffer);
 
-	// get interfaces configuration
+	// Get interfaces configuration
 	config.ifc_len = count * sizeof(struct ifreq);
 	config.ifc_buf = buffer;
 	if (ioctl(socket, SIOCGIFCONF, &config, sizeof(struct ifconf)) < 0)
-		return errno;
+		return -1;
 
 	ifreq* interfaces = (ifreq*)buffer;
 	ifreq* end = (ifreq*)(buffer + config.ifc_len);
-
 	struct ifaddrs* previous = NULL;
-	struct ifaddrs* current = NULL;
 
 	for (uint32_t i = 0; interfaces < end; i++) {
-		current = new(std::nothrow) ifaddrs();
+		struct ifaddrs* current = new(std::nothrow) ifaddrs();
 		if (current == NULL) {
 			freeifaddrs(previous);
 			errno = B_NO_MEMORY;
@@ -83,73 +114,45 @@ int getifaddrs(struct ifaddrs **ifap)
 		previous = current;
 
 		current->ifa_name = strdup(interfaces[0].ifr_name);
-		current->ifa_addr = new sockaddr(interfaces[0].ifr_addr);
+		current->ifa_addr = copy_address(interfaces[0].ifr_addr);
-		// still needs: flags, netmask, dst:broadcast addr
+		current->ifa_netmask = NULL;
+		current->ifa_dstaddr = NULL;
+		current->ifa_data = NULL;
 
-		ioctl(socket, SIOCGIFFLAGS, &interfaces[0], sizeof(struct ifconf));
+		ifreq request;
-		current->ifa_flags = interfaces[0].ifr_flags;
+		strlcpy(request.ifr_name, interfaces[0].ifr_name, IF_NAMESIZE);
-		ioctl(socket, SIOCGIFNETMASK, &interfaces[0], sizeof(struct ifconf));
-		current->ifa_netmask = new sockaddr(interfaces[0].ifr_mask);
-		ioctl(socket, SIOCGIFDSTADDR, &interfaces[0], sizeof(struct ifconf));
-		current->ifa_dstaddr = new sockaddr(interfaces[0].ifr_dstaddr);
 
-		// TODO we may also need to get other addresses for the same interface?
+		if (ioctl(socket, SIOCGIFFLAGS, &request, sizeof(struct ifreq)) == 0)
-#if 0
+			current->ifa_flags = request.ifr_flags;
-		BNetworkInterfaceAddress address;
+		if (ioctl(socket, SIOCGIFNETMASK, &request, sizeof(struct ifreq))
-		int32 i = 0;
+				== 0) {
-		while (interface->GetAddressAt(i++, address) == B_OK) {
+			current->ifa_netmask = copy_address(request.ifr_mask);
-			if (interface == NULL) {
+		}
-				freeifaddrs(previous);
+		if (ioctl(socket, SIOCGIFDSTADDR, &request, sizeof(struct ifreq))
-				errno = B_NO_MEMORY;
+				== 0) {
-				return -1;
+			current->ifa_dstaddr = copy_address(request.ifr_dstaddr);
-			}
-
-			current = new(std::nothrow) ifaddrs();
-			if (current == NULL) {
-				freeifaddrs(previous);
-				errno = B_NO_MEMORY;
-				return -1;
-			}
-
-			// Chain this interface with the next one
-			current->ifa_next = previous;
-			previous = current;
-
-			current->ifa_data = interface;
-			current->ifa_name = interface->Name();
-				// Points to the name in the BNetworkInterface instance, which
-				// is added as ifa_data so freeifaddrs can release it.
-			current->ifa_flags = address.Flags();
-			current->ifa_addr = new sockaddr(address.Address().SockAddr());
-			current->ifa_netmask = new sockaddr(address.Mask().SockAddr());
-			current->ifa_dstaddr = new sockaddr(address.Destination().SockAddr());
 		}
 
-		interface = new(std::nothrow) BNetworkInterface();
+		// Move on to next interface
-#endif
-
-		// move on to next interface
 		interfaces = (ifreq*)((uint8_t*)interfaces
 			+ _SIZEOF_ADDR_IFREQ(interfaces[0]));
 	}
 
-	*ifap = current;
+	*_ifaddrs = previous;
-
 	return 0;
 }
 
 
 void
-freeifaddrs(struct ifaddrs *ifa)
+freeifaddrs(struct ifaddrs* ifa)
 {
-	struct ifaddrs* next;
 	while (ifa != NULL) {
-		free ((void*)ifa->ifa_name);
+		free((void*)ifa->ifa_name);
 		delete ifa->ifa_addr;
 		delete ifa->ifa_netmask;
 		delete ifa->ifa_dstaddr;
 
-		next = ifa->ifa_next;
+		struct ifaddrs* next = ifa->ifa_next;
 		delete ifa;
 		ifa = next;
 	}