If we're reading from a savefile, don't try to install a kernel packet

filter.

It appears that "recvfrom()", in 2.2 and later kernels, doesn't check
whether the starting buffer address plus the byte count goes into an
unmapped region of the address space - it (or code it calls) presumably
only checks the locations into which it's actually copying data - so
there doesn't appear to be, on systems with 2.2 and later kernels, any
need to ensure that the buffer size is at least large as the snapshot
length.  We therefore only do so if we're using the old
PF_INET/SOCK_PACKET mechanism; if we're using PF_PACKET, we're on a
2.2 or later kernel, so we don't do it there.

diff --git a/pcap-linux.c b/pcap-linux.c
index 1ba7343aab35d3cbc5053111ddb8255a03e7330d..32fb31b3339e3362f6fc79daec2304d696e3aa8b 100644 (file)
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -26,7 +26,7 @@
  */
 #ifndef lint
 static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.35 2000-10-20 06:55:28 guy Exp $ (LBL)";
+    "@(#) $Header: /tcpdump/master/libpcap/pcap-linux.c,v 1.36 2000-10-25 05:59:04 guy Exp $ (LBL)";
 #endif
 
 /*
@@ -420,6 +420,13 @@ pcap_setfilter(pcap_t *handle, struct bpf_program *filter)
         */
        handle->md.use_bpf = 0;
 
+       /*
+        * If we're reading from a savefile, don't try to install
+        * a kernel filter.
+        */
+       if (handle->sf.rfile != NULL)
+               return 0;
+
        /* Install kernel level filter if possible */
        
 #ifdef SO_ATTACH_FILTER
@@ -582,7 +589,7 @@ live_open_new(pcap_t *handle, char *device, int promisc,
                                break;
                }
 
-               /* Select promiscous mode on/off */
+               /* Select promiscuous mode on/off */
 
 #ifdef SOL_PACKET
                /* 
@@ -611,8 +618,6 @@ live_open_new(pcap_t *handle, char *device, int promisc,
                if (mtu == -1)
                        break;
                handle->bufsize  = MAX_LINKHEADER_SIZE + mtu;
-               if (handle->bufsize < handle->snapshot)
-                       handle->bufsize = handle->snapshot;
                
                /* Fill in the pcap structure */