diff -ur -x configure tcpdump-2004.02.24/acconfig.h tcpdump-2004.02.23.new/acconfig.h
--- tcpdump-2004.02.24/acconfig.h	Thu Jan 22 11:51:30 2004
+++ tcpdump-2004.02.23.new/acconfig.h	Wed Feb 25 09:04:41 2004
@@ -129,3 +129,6 @@
 
 /* define if should drop privileges by default */
 #undef WITH_USER
+
+/* define if should chroot when dropping privileges */
+#undef WITH_CHROOT
diff -ur -x configure tcpdump-2004.02.24/configure.in tcpdump-2004.02.23.new/configure.in
--- tcpdump-2004.02.24/configure.in	Sat Jan 31 07:26:51 2004
+++ tcpdump-2004.02.23.new/configure.in	Wed Feb 25 09:23:03 2004
@@ -111,6 +111,15 @@
        AC_MSG_RESULT(no)
 fi
 
+AC_ARG_WITH(chroot, [  --with-chroot=DIRECTORY when dropping privileges, chroot to DIRECTORY])
+AC_MSG_CHECKING([where to chroot to])
+if test ! -z "$with_chroot" ; then
+        AC_DEFINE_UNQUOTED(WITH_CHROOT, "$withval")
+       AC_MSG_RESULT(to \"$withval\")
+else
+       AC_MSG_RESULT(no)
+fi
+
 AC_MSG_CHECKING([whether to enable ipv6])
 AC_ARG_ENABLE(ipv6,
 [  --enable-ipv6           enable ipv6 (with ipv4) support
diff -ur -x configure tcpdump-2004.02.24/tcpdump.c tcpdump-2004.02.23.new/tcpdump.c
--- tcpdump-2004.02.24/tcpdump.c	Tue Feb 24 10:12:18 2004
+++ tcpdump-2004.02.23.new/tcpdump.c	Wed Feb 25 09:56:25 2004
@@ -129,7 +129,7 @@
 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
-static void droproot(const char *);
+static void droproot(const char *, const char *);
 
 #ifdef SIGINFO
 RETSIGTYPE requestinfo(int);
@@ -324,15 +324,26 @@
 #define U_FLAG
 #endif
 
-/* Drop root privileges */
+/* Drop root privileges and chroot if necessary */
 static void
-droproot(const char *username)
+droproot(const char *username, const char *chroot_dir)
 {
 	struct passwd *pw = NULL;
 
+	if (chroot_dir && !username) {
+		fprintf(stderr, "Chroot without dropping root is insecure\n");
+		exit(1);
+	}
+	
 	pw = getpwnam(username);
 	if (pw) {
-		if (initgroups(pw->pw_name, 0) != 0 || setgid(pw->pw_gid) != 0 ||
+		if (chroot_dir) {
+			if (chroot(chroot_dir) != 0 || chdir (".") != 0) {
+				fprintf(stderr, "Couldn't chroot/chdir to '%.64s'\n", chroot_dir);
+				exit(1);
+			}
+		}
+		if (initgroups(pw->pw_name, pw->pw_gid) != 0 || setgid(pw->pw_gid) != 0 ||
 				 setuid(pw->pw_uid) != 0) {
 			fprintf(stderr, "Couldn't change to '%.32s' uid=%d gid=%d\n", username, 
 							pw->pw_uid, pw->pw_gid);
@@ -386,6 +397,7 @@
 	u_char *pcap_userdata;
 	char ebuf[PCAP_ERRBUF_SIZE];
 	char *username = NULL;
+	char *chroot_dir = NULL;
 #ifdef HAVE_PCAP_FINDALLDEVS
 	pcap_if_t *devpointer;
 	int devnum;
@@ -704,6 +716,15 @@
 	if (tflag > 0)
 		thiszone = gmt2local(0);
 
+#ifdef WITH_CHROOT
+	/* if run as root, prepare for chrooting */
+	if (getuid() == 0 || geteuid() == 0) {
+		/* future extensibility for cmd-line arguments */
+		if (!chroot_dir)
+			chroot_dir = WITH_CHROOT;
+	}
+#endif
+
 #ifdef WITH_USER
 	/* if run as root, prepare for dropping root privileges */
 	if (getuid() == 0 || geteuid() == 0) {
@@ -885,9 +906,8 @@
 	 * We cannot do this earlier, because we want to be able to open
 	 * the file (if done) for writing before giving up permissions.
 	 */
-	if (username) {
-		droproot(username);
-	}
+	if (username || chroot_dir)
+		droproot(username, chroot_dir);
 #endif /* WIN32 */
 #ifdef SIGINFO
 	(void)setsignal(SIGINFO, requestinfo);