nmap/account-for-VLAN-header-in-pcap-packets.patch

commit 5f6bc6998351303b0149c89e215bdb778466c88b
Author: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date:   Thu Apr 10 19:00:50 2025 +0000

    Account for VLAN header in pcap packets if needed.

diff --git a/libnetutil/netutil.cc b/libnetutil/netutil.cc
index 88bb9a507..5a43c73f9 100644
--- a/libnetutil/netutil.cc
+++ b/libnetutil/netutil.cc
@@ -4202,9 +4202,22 @@ int read_reply_pcap(pcap_t *pd, long to_usec,
       netutil_fatal("Error from pcap_next_ex: %s\n", pcap_geterr(pd));
     }
 
-    if (pcap_status == 1 && *p != NULL && accept_callback(*p, *head, *datalink, *offset)) {
-      break;
-    } else if (pcap_status == 0 || *p == NULL) {
+    if (pcap_status == 1 && *p != NULL) {
+      /* Offset may be different in the case of 802.1q */
+      if (*datalink == DLT_EN10MB
+          && (*head)->caplen >= sizeof(struct eth_hdr)
+          && 0 == memcmp((*p) + offsetof(struct eth_hdr, eth_type), "\x81\x00", 2)) {
+        *offset += 4;
+      }
+      if (accept_callback(*p, *head, *datalink, *offset)) {
+        break;
+      } else {
+        /* We'll be a bit patient if we're getting actual packets back, but
+           not indefinitely so */
+        if (badcounter++ > 50)
+          timedout = 1;
+      }
+    } else {
       /* Should we timeout? */
       if (to_usec == 0) {
         timedout = 1;
@@ -4214,11 +4227,6 @@ int read_reply_pcap(pcap_t *pd, long to_usec,
           timedout = 1;
         }
       }
-    } else {
-      /* We'll be a bit patient if we're getting actual packets back, but
-         not indefinitely so */
-      if (badcounter++ > 50)
-        timedout = 1;
     }
   } while (!timedout);
 
@@ -4258,7 +4266,7 @@ static bool accept_arp(const unsigned char *p, const struct pcap_pkthdr *head,
     return false;
 
   if (datalink == DLT_EN10MB) {
-    return ntohs(*((u16 *) (p + 12))) == ETH_TYPE_ARP;
+    return ntohs(*((u16 *) (p + offset - 2))) == ETH_TYPE_ARP;
   } else if (datalink == DLT_LINUX_SLL) {
     return ntohs(*((u16 *) (p + 2))) == ARPHRD_ETHER && /* sll_hatype */
       ntohs(*((u16 *) (p + 4))) == 6 && /* sll_halen */
diff --git a/nping/ProbeMode.cc b/nping/ProbeMode.cc
index f2bbe4674..cbdec9e58 100644
--- a/nping/ProbeMode.cc
+++ b/nping/ProbeMode.cc
@@ -1565,7 +1565,7 @@ void ProbeMode::probe_nping_event_handler(nsock_pool nsp, nsock_event nse, void
  const unsigned char *link=NULL;
  size_t linklen=0;
  size_t packetlen=0;
- u16 *ethtype=NULL;
+ u16 ethtype=0;
  u8 buffer[512+1];
  size_t link_offset=0;
  static struct timeval pcaptime;
@@ -1632,9 +1632,9 @@ void ProbeMode::probe_nping_event_handler(nsock_pool nsp, nsock_event nse, void
             /* If we are on a Ethernet network, extract the next packet protocol
              * from the Ethernet frame. */
             if( nsock_iod_linktype(nsi) == DLT_EN10MB ){
-                ethtype=(u16*)(link+12);
-                *ethtype=ntohs(*ethtype);
-                switch(*ethtype){
+                ethtype=*(u16*)(link + linklen - 2);
+                ethtype=ntohs(ethtype);
+                switch(ethtype){
                     case ETHTYPE_IPV4:
                     case ETHTYPE_IPV6:
                         ip=true;
@@ -1644,7 +1644,7 @@ void ProbeMode::probe_nping_event_handler(nsock_pool nsp, nsock_event nse, void
                         ip=false;
                     break;
                     default:
-                        nping_warning(QT_1, "RCVD (%.4fs) Unsupported protocol (Ethernet type %02X)", o.stats.elapsedRuntime(t), *ethtype);
+                        nping_warning(QT_1, "RCVD (%.4fs) Unsupported protocol (Ethernet type %02X)", o.stats.elapsedRuntime(t), ethtype);
                         print_hexdump(VB_3, packet, packetlen);
                         return;
                     break;
diff --git a/nsock/src/nsock_pcap.c b/nsock/src/nsock_pcap.c
index 098f8b9f1..8fd0b5d6c 100644
--- a/nsock/src/nsock_pcap.c
+++ b/nsock/src/nsock_pcap.c
@@ -476,8 +476,15 @@ void nse_readpcap(nsock_event nsev, const unsigned char **l2_data, size_t *l2_le
     return;
   }
 
-  l2l = MIN(mp->l3_offset, n->caplen);
-  l3l = MAX(0, n->caplen-mp->l3_offset);
+  l2l = mp->l3_offset;
+  if (mp->datalink == DLT_EN10MB
+      && n->caplen >= sizeof(struct eth_hdr)
+      && 0 == memcmp(n->packet + offsetof(struct eth_hdr, eth_type), "\x81\x00", 2))
+    l2l += 4;
+  }
+  if (l2l > n->caplen)
+    l2l = n->caplen;
+  l3l = MAX(0, n->caplen - l2l);
 
   if (l2_data)
     *l2_data = n->packet;
diff --git a/tcpip.cc b/tcpip.cc
index 1f1857fe7..f704dcf72 100644
--- a/tcpip.cc
+++ b/tcpip.cc
@@ -1610,7 +1610,7 @@ int setTargetMACIfAvailable(Target *target, struct link_header *linkhdr,
   if (!linkhdr || !target || !src)
     return 1;
 
-  if (linkhdr->datalinktype != DLT_EN10MB || linkhdr->headerlen != 14)
+  if (linkhdr->datalinktype != DLT_EN10MB || linkhdr->headerlen < 14)
     return 2;
 
   if (!overwrite && target->MACAddress())
commit 5b52e7a3f21ba256541fe24d5b7ccff8b700872b
Author: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date:   Thu Apr 10 19:24:22 2025 +0000

    Build fixes

diff --git a/libnetutil/netutil.cc b/libnetutil/netutil.cc
index 5a43c73f9..5cedf5baf 100644
--- a/libnetutil/netutil.cc
+++ b/libnetutil/netutil.cc
@@ -137,6 +137,8 @@ typedef unsigned __int8 u_int8_t;
 #include <sys/resource.h>
 #endif
 
+#include <stddef.h>
+
 #define NBASE_MAX_ERR_STR_LEN 1024  /* Max length of an error message */
 
 #ifndef PCAP_NETMASK_UNKNOWN
diff --git a/nsock/src/nsock_pcap.c b/nsock/src/nsock_pcap.c
index 8fd0b5d6c..b791efd55 100644
--- a/nsock/src/nsock_pcap.c
+++ b/nsock/src/nsock_pcap.c
@@ -478,8 +478,8 @@ void nse_readpcap(nsock_event nsev, const unsigned char **l2_data, size_t *l2_le
 
   l2l = mp->l3_offset;
   if (mp->datalink == DLT_EN10MB
-      && n->caplen >= sizeof(struct eth_hdr)
-      && 0 == memcmp(n->packet + offsetof(struct eth_hdr, eth_type), "\x81\x00", 2))
+      && n->caplen >= 14 /* size of ethernet header */
+      && 0 == memcmp(n->packet + 12 /* offset of eth_type */, "\x81\x00", 2)) {
     l2l += 4;
   }
   if (l2l > n->caplen)