Re: [PATCH 2/4] NET: NETROM: When adding a route verify length of mnemonic string.

Dan Carpenter <dan.carpenter@xxxxxxxxxx> · Fri, 25 Nov 2011 14:36:03 +0300

On Fri, Nov 25, 2011 at 09:08:49AM +0000, Ralf Baechle wrote:
> 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.

Good point...  I missed that.

Acked-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

regards,
dan carpenter