[PATCH net-next 01/17] tipc: fix message importance range check

[Jon Maloy <jon.maloy@ericsson.com>]

From: Erik Hugne <erik.hugne@ericsson.com>

Commit 3b4f302d8578 ("tipc: eliminate
redundant locking") introduced a bug by removing the sanity check
for message importance, allowing programs to assign any value to
the msg_user field. This will mess up the packet reception logic
and may cause random link resets.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
---
 net/tipc/port.h   |    4 +++-
 net/tipc/socket.c |    2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/tipc/port.h b/net/tipc/port.h
index 3f93454..a69118f 100644
--- a/net/tipc/port.h
+++ b/net/tipc/port.h
@@ -179,8 +179,10 @@ static inline int tipc_port_importance(struct tipc_port *port)
 	return msg_importance(&port->phdr);
 }
 
-static inline void tipc_port_set_importance(struct tipc_port *port, int imp)
+static inline int tipc_port_set_importance(struct tipc_port *port, int imp)
 {
+	if (imp > TIPC_CRITICAL_IMPORTANCE)
+		return -EINVAL
 	msg_set_importance(&port->phdr, (u32)imp);
 }
 
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 7d423ee..ff8c811 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1973,7 +1973,7 @@ static int tipc_setsockopt(struct socket *sock, int lvl, int opt,
 
 	switch (opt) {
 	case TIPC_IMPORTANCE:
-		tipc_port_set_importance(port, value);
+		res = tipc_port_set_importance(port, value);
 		break;
 	case TIPC_SRC_DROPPABLE:
 		if (sock->type != SOCK_STREAM)
-- 
1.7.9.5


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