Commit ac1a1de3 by Ralf Baechle Committed by David S. Miller

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 <>. Signed-off-by: 's avatarRalf Baechle <> Cc: Dan Carpenter <> Cc: Walter Harms <> Cc: Thomas Osterried <> Acked-by: 's avatarDan Carpenter <> Signed-off-by: 's avatarDavid S. Miller <>
parent be639ac6
......@@ -678,6 +678,11 @@ int nr_rt_ioctl(unsigned int cmd, void __user *arg)
switch (nr_route.type) {
if (strnlen(nr_route.mnemonic, 7) == 7) {
ret = -EINVAL;
ret = nr_add_node(&nr_route.callsign,
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