Hello,
> Pingflood simply sends a lot of SIGALRM signals to the ping process.
> It can
> do this because the ping process is owned by the user.
Here's a fix I just did, for ping from Linux's NetKit 0.09 -- nothing
complicated, I'm posting it just to save some BugTraq readers a minute.
Note: I'm doing it this weird way since just doing a setuid() would also
make it impossible for users to kill their ping processes (with SIGTERM).
--- ping.c.orig Sun Dec 29 19:13:01 1996
+++ ping.c Mon May 18 14:09:03 1998
@@ -64,6 +64,7 @@
#include <sys/socket.h>
#include <sys/file.h>
#include <sys/time.h>
+#include <sys/times.h>
#include <sys/signal.h>
#include <netinet/in.h>
@@ -270,6 +271,11 @@
options |= F_SO_DONTROUTE;
break;
case 's': /* size of packet to send */
+ if (!am_i_root) {
+ (void)fprintf(stderr,
+ "ping: %s\n", strerror(EPERM));
+ exit(2);
+ }
datalen = atoi(optarg);
if (datalen > MAXPACKET) {
(void)fprintf(stderr,
@@ -488,12 +494,22 @@
* quality of the delay and loss statistics.
*/
static void
-catcher(int ignore)
+catcher(int signum)
{
+ struct tms buf;
+ clock_t current;
+ static clock_t last = 0;
int waittime;
- (void)ignore;
- pinger();
+ if (signum) {
+ current = times(&buf);
+ if (current - last >= CLK_TCK - 1 || current < last) {
+ last = current;
+ pinger();
+ }
+ } else
+ pinger();
+
(void)signal(SIGALRM, catcher);
if (!npackets || ntransmitted < npackets)
alarm((u_int)interval);
Signed,
Solar Designer
This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:53:59 PDT