[PATCH 3.16 11/55] tipc: fix message importance range check

[Greg Kroah-Hartman]

3.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Erik Hugne <erik.hugne@xxxxxxxxxxxx>

[ Upstream commit ac32c7f705692b92fe12dcbe88fe87136fdfff6f ]

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@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tipc/port.h   |    5 ++++-
 net/tipc/socket.c |    2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

--- a/net/tipc/port.h
+++ b/net/tipc/port.h
@@ -229,9 +229,12 @@ static inline int tipc_port_importance(s
 	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);
+	return 0;
 }
 
 #endif
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1841,7 +1841,7 @@ static int tipc_setsockopt(struct socket
 
 	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)


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