Multiple Platform remote CPU load issue in Samba 1.x and2.x
J. Robert von Behren
jrvb at cs.berkeley.edu
Wed Jun 14 00:38:28 GMT 2000
FWIW, I can reproduce this on my test machine (Redhat 6.0, kernel
2.2.5-15). The following command does the trick:
nc localhost 139 < /dev/zero
After watching smbd with gdb and strace, I found that the child smbd
that was spawned in response to the nc connection just keeps reading
zeros from the socket, and writing out error responses, ad infinitum. A
simple fix would be to abort the connection after a certain number of
successive bad requests, or after a certain number of bad requests
within a given time period.
Best regards,
-Rob von Behren
"Allen, Michael B (RSCH)" wrote:
>
> > -----Original Message-----
> > From: Allen, Michael B (RSCH)
> >
> >
> > but smbd seems to drop the conn.
> [Allen, Michael B (RSCH)]
>
> Actually , I'm sorry this is not true. It appears to maintain the
> connection and then close when the netcat program stops but there only a few
> packets transpire on connection and then again on disconnect.
>
> PS:
>
> [root at prodlinux lib]# cat /dev/zero > /dev/null
>
> This runs the cpu up to 100% so I'm getting zeros
>
> [root at prodlinux lib]# cat /dev/zero | ./netcat localhost 139
>
> and this too does nothing.
>
> Michael B. Allen
> http://jcifs.samba.org
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