[PATCH] rds: Error on offset mismatch if not loopback

John Jolly
2012-09-21T21:32:40Z

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 */
--
1.7.7