Messages in this thread | | | Date | Fri, 21 Sep 2012 16:38:15 -0500 | From | Venkat Venkatsubra <> | Subject | Re: [PATCH] rds: Error on offset mismatch if not loopback |
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On 9/21/2012 4:32 PM, John Jolly wrote: > Attempting an rds connection from the IP address of an IPoIB interface > to itself causes a kernel panic due to a BUG_ON() being triggered. > Making the test less strict allows rds-ping to work without crashing > the machine. > > A local unprivileged user could use this flaw to crash the system. > > Signed-off-by: John Jolly<jjolly@suse.com> > --- > net/rds/ib_send.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c > index e590949..7920c85 100644 > --- a/net/rds/ib_send.c > +++ b/net/rds/ib_send.c > @@ -544,7 +544,7 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm, > int flow_controlled = 0; > int nr_sig = 0; > > - BUG_ON(off % RDS_FRAG_SIZE); > + BUG_ON(!conn->c_loopback&& off % RDS_FRAG_SIZE); > BUG_ON(hdr_off != 0&& hdr_off != sizeof(struct rds_header)); > > /* Do not send cong updates to IB loopback */ Hi John,
How do you trigger this BUG_ON ? With rds-ping I could not hit this condition of non-zero "off % RDS_FRAG_SIZE". rds-ping uses zero byte messages to ping or pong back. How does the "off" become non-zero ?
Thanks.
Venkat
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