NETROM: Fix use of static buffer

The static variable used by nr_call_to_digi might result in corruption if
multiple threads are trying to usee a node or neighbour via ioctl.  Fixed
by having the caller pass a structure in.  This is safe because nr_add_node
rsp. nr_add_neigh will allocate a permanent structure, if needed.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 9 deletions

diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index e943c16552a2..4eb1ac9a7679 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -630,23 +630,23 @@ out:
         return dev;
 }
 
-static ax25_digi *nr_call_to_digi(int ndigis, ax25_address *digipeaters)
+static ax25_digi *nr_call_to_digi(ax25_digi *digi, int ndigis,
+        ax25_address *digipeaters)
 {
-        static ax25_digi ax25_digi;
         int i;
 
         if (ndigis == 0)
                 return NULL;
 
         for (i = 0; i < ndigis; i++) {
-                ax25_digi.calls[i]    = digipeaters[i];
-                ax25_digi.repeated[i] = 0;
+                digi->calls[i]    = digipeaters[i];
+                digi->repeated[i] = 0;
         }
 
-        ax25_digi.ndigi      = ndigis;
-        ax25_digi.lastrepeat = -1;
+        digi->ndigi      = ndigis;
+        digi->lastrepeat = -1;
 
-        return &ax25_digi;
+        return digi;
 }
 
 /*
@@ -656,6 +656,7 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg)
 {
         struct nr_route_struct nr_route;
         struct net_device *dev;
+        ax25_digi digi;
         int ret;
 
         switch (cmd) {
@@ -673,13 +674,15 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg)
                         ret = nr_add_node(&nr_route.callsign,
                                 nr_route.mnemonic,
                                 &nr_route.neighbour,
-                                nr_call_to_digi(nr_route.ndigis, nr_route.digipeaters),
+                                nr_call_to_digi(&digi, nr_route.ndigis,
+                                                nr_route.digipeaters),
                                 dev, nr_route.quality,
                                 nr_route.obs_count);
                         break;
                 case NETROM_NEIGH:
                         ret = nr_add_neigh(&nr_route.callsign,
-                                nr_call_to_digi(nr_route.ndigis, nr_route.digipeaters),
+                                nr_call_to_digi(&digi, nr_route.ndigis,
+                                                nr_route.digipeaters),
                                 dev, nr_route.quality);
                         break;
                 default: