rose: Add length checks to CALL_REQUEST parsing, CVE-2011-1493

rose: Add length checks to CALL_REQUEST parsing, CVE-2011-1493

Define some constant offsets for CALL_REQUEST based on the description
at <http://www.techfest.com/networking/wan/x25plp.htm> and the
definition of ROSE as using 10-digit (5-byte) addresses.  Use them
consistently.  Validate all implicit and explicit facilities lengths.
Validate the address length byte rather than either trusting or
assuming its value.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

(cherry picked from commit e0bccd315db0c2f919e7fcf9cb60db21d9986f52)
CVE-2011-1493
BugLink: http://bugs.launchpad.net/bugs/816550
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>