Date: Sat, 05 Sep 1998 14:10:30 -0700 From: Mike Haertel <mike@ducky.net> To: current@FreeBSD.ORG Cc: dfr@nlsystems.com, wollman@khavrinen.lcs.mit.edu Subject: DANGER: new IP fragment code breaks SLIP Message-ID: <199809052110.OAA00369@ducky.net>
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I've been experiencing crashes with recent 3.0 kernels using SLIP based dialin networking. Haven't had time yet to set up kernel debugging, however I spent a half an hour doing binary search via kernel builds on recent CVS commits. The bug is either contained in, or perhaps exposed by, the following commit: >dfr 1998/08/24 00:47:39 PDT > > Modified files: > sys/sys mbuf.h > sys/netinet ip_input.c ip_var.h tcp_input.c > tcp_subr.c tcp_var.h udp_usrreq.c > Log: > Re-implement tcp and ip fragment reassembly to not store pointers in the > ip header which can't work on alpha since pointers are too big. > > Reviewed by: Garrett Wollman <wollman@khavrinen.lcs.mit.edu> > > Revision Changes Path > 1.29 +5 -1 src/sys/sys/mbuf.h > 1.100 +80 -90 src/sys/netinet/ip_input.c > 1.45 +3 -32 src/sys/netinet/ip_var.h > 1.80 +49 -38 src/sys/netinet/tcp_input.c > 1.46 +12 -15 src/sys/netinet/tcp_subr.c > 1.48 +2 -13 src/sys/netinet/tcp_var.h > 1.48 +3 -6 src/sys/netinet/udp_usrreq.c Here's how I can reliably reproduce the crash: 1. reboot my system normally. as part of my boot process, my system automatically dials up and slattaches (on sl0) my permanent network link. 2. dial in to my employer's dialin (behind a firewall), and slattach via sl1. the slattach works ok. 3. attempt an ssh login to a machine in my employer's network, via the sl1 interface. this reliably either hangs or crashes the machine. Some further comments: 3a. usually after establishing the sl1 connection, I can telnet a few times before crashing the machine. however attempting an ssh login to the remote site always crashes the machine instantly. i hypothesize that the cause is large packets containing public key challenges sent by ssh. 3b. i haven't tried to reproduce the bug using just one SLIP connection. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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