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Working IPv4 & IPv6 DNS resolution for single and multiple hosts
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@sjanusz-r7
sjanusz-r7 committed Dec 11, 2023
1 parent 6858efc commit 7f588d3
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Showing 2 changed files with 116 additions and 71 deletions.
186 changes: 115 additions & 71 deletions c/meterpreter/source/extensions/stdapi/server/net/resolve.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5,95 +5,138 @@
#include <winsock2.h>
#include <ws2tcpip.h>

DWORD resolve_host(LPCSTR hostname, u_short ai_family, struct in_addr *result, struct in6_addr *result6)
/// <summary>
/// Resolve a hostname. Don't forget to call `freeaddrinfo` on the `address_info` parameter once done with it.
/// </summary>
/// <param name="hostname">Long pointer to a string</param>
/// <param name="ai_family">The family to get the IP address for (IPv6 / IPv4)</param>
/// <param name="address_info">The resulting addrinfo structure</param>
/// <returns>0 on success, a Windows error code on error</returns>
DWORD resolve_host(const LPCSTR hostname, UINT ai_family, struct addrinfo **address_info)
{
struct addrinfo hints, *list;
struct in_addr addr;
struct in6_addr addr6;
struct sockaddr_in *sockaddr_ipv4;
struct sockaddr_in6 *sockaddr_ipv6;
int iResult;
if (hostname == NULL)
{
dprintf("Hostname not set");
return ERROR_INVALID_PARAMETER;
}

if (address_info == NULL)
{
dprintf("Null pointer provided as output to resolve_host");
return ERROR_INVALID_PARAMETER;
}

WSADATA wsaData;
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != NO_ERROR)
DWORD iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != ERROR_SUCCESS)
{
dprintf("Could not initialise Winsock: %x.", iResult);
return iResult;
}

memset(&hints, 0, sizeof(hints));
struct addrinfo hints = { 0 };
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
hints.ai_family = ai_family;

dprintf("Attempting to resolve '%s'", hostname);

iResult = getaddrinfo(hostname, NULL, &hints, &list);

if (iResult != NO_ERROR)
iResult = getaddrinfo(hostname, NULL, &hints, address_info);
if (iResult != ERROR_SUCCESS)
{
dprintf("Unable to resolve host Error: %x.", iResult);
dprintf("Unable to resolve host '%s' Error: %x.", hostname, iResult);
dprintf("Error msg: %s", gai_strerror(iResult));
return iResult;
}
else
dprintf("Resolved host '%s' successfully", hostname);

dprintf("Performing Win Socket cleanup");
iResult = WSACleanup();
if (iResult != ERROR_SUCCESS)
{
switch (list->ai_family) {
dprintf("WSACleanup failed with return code %x", iResult);
return iResult;
}
dprintf("WSACleanup completed successfully");

return ERROR_SUCCESS;
}

/// <summary>
/// Add in all resolved IP addresses for a specific hostname to a TLV group.
/// </summary>
/// <param name="group">The group to insert resolved host IP addresses into.</param>
/// <param name="host">The hostname or a list of hostnames to add to the group.</param>
/// <returns>0 on success.</returns>
DWORD add_all_host_ips_to_group(Packet* group, struct addrinfo* host)
{
if (group == NULL)
{
dprintf("Null pointer provided as group");
return ERROR_INVALID_PARAMETER;
}

for (struct addrinfo* current = host; current != NULL; current = current->ai_next)
{
switch (current->ai_family)
{
case AF_INET:
sockaddr_ipv4 = (struct sockaddr_in *) list->ai_addr;
addr = sockaddr_ipv4->sin_addr;
memcpy((void*)result, &addr, sizeof(result));
dprintf("Adding IP v4 Family to Group TLV");
met_api->packet.add_tlv_uint(group, TLV_TYPE_ADDR_TYPE, (UINT)current->ai_family);
dprintf("Adding IP v4 Address to Group TLV");
struct in_addr ipv4_addr = ((struct sockaddr_in*)(current->ai_addr))->sin_addr;
met_api->packet.add_tlv_raw(group, TLV_TYPE_IP, &ipv4_addr, sizeof(struct in_addr));
break;
case AF_INET6:
sockaddr_ipv6 = (struct sockaddr_in6 *) list->ai_addr;
addr6 = sockaddr_ipv6->sin6_addr;
memcpy((void*)result6, &addr6, sizeof(struct in6_addr));
default:
dprintf("Adding IP v6 Family to Group TLV");
met_api->packet.add_tlv_uint(group, TLV_TYPE_ADDR_TYPE, (UINT)current->ai_family);
dprintf("Adding IP v6 Address to Group TLV");
struct in6_addr ipv6_addr = ((struct sockaddr_in6*)(current->ai_addr))->sin6_addr;
met_api->packet.add_tlv_raw(group, TLV_TYPE_IP, &ipv6_addr, sizeof(struct in6_addr));
break;
default:
dprintf("Unknown family, skipping entry.");
continue;
}
}

freeaddrinfo(list);
WSACleanup();

return iResult;
return ERROR_SUCCESS;
}

DWORD request_resolve_host(Remote *remote, Packet *packet)
{
Packet *response = met_api->packet.create_response(packet);
LPCSTR hostname = NULL;
struct in_addr addr;
struct in6_addr addr6;
u_short ai_family = AF_INET;
int iResult;
LPCSTR hostname = met_api->packet.get_tlv_value_string(packet, TLV_TYPE_HOST_NAME);
UINT ai_family = met_api->packet.get_tlv_value_uint(packet, TLV_TYPE_ADDR_TYPE);
DWORD iResult = ERROR_SUCCESS;

hostname = met_api->packet.get_tlv_value_string(packet, TLV_TYPE_HOST_NAME);
struct addrinfo* result;
iResult = resolve_host(hostname, ai_family, &result);
if (iResult != ERROR_SUCCESS || result == NULL)
{
dprintf("Could not resolve_host for '%s': %x", hostname, iResult);
goto done;
}

if (!hostname)
dprintf("Creating group for resolve host entry");
Packet* resolved_hosts = met_api->packet.create_group();
if (resolved_hosts == NULL)
{
iResult = ERROR_INVALID_PARAMETER;
dprintf("Hostname not set");
dprintf("Could not create TLV Group");
goto done;
}
else

if (add_all_host_ips_to_group(resolved_hosts, result) != ERROR_SUCCESS)
{
ai_family = met_api->packet.get_tlv_value_uint(packet, TLV_TYPE_ADDR_TYPE);
iResult = resolve_host(hostname, ai_family, &addr, &addr6);
if (iResult == NO_ERROR)
{
if (ai_family == AF_INET)
{
met_api->packet.add_tlv_raw(response, TLV_TYPE_IP, &addr, sizeof(struct in_addr));
} else {
met_api->packet.add_tlv_raw(response, TLV_TYPE_IP, &addr6, sizeof(struct in_addr6));
}
met_api->packet.add_tlv_uint(response, TLV_TYPE_ADDR_TYPE, ai_family);
}
else
{
dprintf("Unable to resolve_host %s error: %x", hostname, iResult);
}
dprintf("Error adding resolved host IP addresses to group");
}

dprintf("Adding IP TLVs to Group TLV in response packet");
met_api->packet.add_group(response, TLV_TYPE_RESOLVE_HOST_ENTRY, resolved_hosts);
dprintf("Freeing addrinfo");
freeaddrinfo(result);

done:
dprintf("Sending return packet for resolve_host");
met_api->packet.transmit_response(iResult, remote, response);
return ERROR_SUCCESS;
}
Expand All @@ -103,33 +146,34 @@ DWORD request_resolve_hosts(Remote *remote, Packet *packet)
Packet *response = met_api->packet.create_response(packet);
Tlv hostname = {0};
int index = 0;
int iResult;
u_short ai_family = met_api->packet.get_tlv_value_uint(packet, TLV_TYPE_ADDR_TYPE);
int iResult = 0;
UINT ai_family = met_api->packet.get_tlv_value_uint(packet, TLV_TYPE_ADDR_TYPE);

while( met_api->packet.enum_tlv( packet, index++, TLV_TYPE_HOST_NAME, &hostname ) == ERROR_SUCCESS )
{
struct in_addr addr = {0};
struct in6_addr addr6 = {0};
struct addrinfo* addr = NULL;

iResult = resolve_host((LPCSTR)hostname.buffer, ai_family, &addr);

iResult = resolve_host((LPCSTR)hostname.buffer, ai_family, &addr, &addr6);
Packet* resolved_host_group = met_api->packet.create_group();

if (iResult == NO_ERROR)
if (iResult != ERROR_SUCCESS || addr == NULL)
{
if (ai_family == AF_INET)
{
met_api->packet.add_tlv_raw(response, TLV_TYPE_IP, &addr, sizeof(struct in_addr));
} else {
met_api->packet.add_tlv_raw(response, TLV_TYPE_IP, &addr6, sizeof(struct in_addr6));
}
dprintf("Unable to resolve_host %s error: %x", hostname.buffer, iResult);
goto done;
}
else

if (add_all_host_ips_to_group(resolved_host_group, addr) != ERROR_SUCCESS)
{
dprintf("Unable to resolve_host %s error: %x", hostname.buffer, iResult);
met_api->packet.add_tlv_raw(response, TLV_TYPE_IP, NULL, 0);
dprintf("Error adding resolved host IP addresses to group");
goto done;
}
met_api->packet.add_tlv_uint(response, TLV_TYPE_ADDR_TYPE, ai_family);

met_api->packet.add_group(response, TLV_TYPE_RESOLVE_HOST_ENTRY, resolved_host_group);
if (addr != NULL) { dprintf("Freeing Address Info for hostname: %s", hostname.buffer); freeaddrinfo(addr); }
}

met_api->packet.transmit_response(NO_ERROR, remote, response);
done:
met_api->packet.transmit_response(iResult, remote, response);
return ERROR_SUCCESS;
}
1 change: 1 addition & 0 deletions c/meterpreter/source/extensions/stdapi/stdapi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -171,6 +171,7 @@
#define TLV_TYPE_LOCAL_HOST_RAW MAKE_CUSTOM_TLV( TLV_META_TYPE_RAW, TLV_TYPE_EXTENSION_STDAPI, 1507 )

#define TLV_TYPE_SHUTDOWN_HOW MAKE_CUSTOM_TLV( TLV_META_TYPE_UINT, TLV_TYPE_EXTENSION_STDAPI, 1530 )
#define TLV_TYPE_RESOLVE_HOST_ENTRY MAKE_CUSTOM_TLV( TLV_META_TYPE_GROUP, TLV_TYPE_EXTENSION_STDAPI, 1550 )

// Ui
#define TLV_TYPE_IDLE_TIME MAKE_CUSTOM_TLV( TLV_META_TYPE_UINT, TLV_TYPE_EXTENSION_STDAPI, 3000 )
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