NET: NETROM: When adding a route verify length of mnemonic string.
struct nr_route_struct's mnemonic permits a string of up to 7 bytes to be
used. If userland passes a not zero terminated string to the kernel adding
a node to the routing table might result in the kernel attempting to read
copy a too long string.
Mnemonic is part of the NET/ROM routing protocol; NET/ROM routing table
updates only broadcast 6 bytes. The 7th byte in the mnemonic array exists
only as a \0 termination character for the kernel code's convenience.
Fixed by rejecting mnemonic strings that have no terminating \0 in the first
7 characters. Do this test only NETROM_NODE to avoid breaking NETROM_NEIGH
where userland might passing an uninitialized mnemonic field.
Initial patch by Dan Carpenter <dan.carpenter@oracle.com>.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Walter Harms <wharms@bfs.de>
Cc: Thomas Osterried <thomas@osterried.de>
Acked-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/netrom/nr_route.c b/net/netrom/nr_route.c
index 915a87b..8d7716c 100644
--- a/net/netrom/nr_route.c
+++ b/net/netrom/nr_route.c
@@ -678,6 +678,11 @@
}
switch (nr_route.type) {
case NETROM_NODE:
+ if (strnlen(nr_route.mnemonic, 7) == 7) {
+ ret = -EINVAL;
+ break;
+ }
+
ret = nr_add_node(&nr_route.callsign,
nr_route.mnemonic,
&nr_route.neighbour,