sizeof (cmd.parm.cmsg.para) is 50 (MAX_CAPI_PARA_LEN).
sizeof (cmd.parm) is 80+, but less than 100.
strlen(msg) may be more than 80+ (Modem-Commandbuffer, less than 255).
isdn_tty_send_msg is called by isdn_tty_parse_at
the relative parameter is m->mdmcmd (atemu *m)
the relative command may be "+M..."
so need check the length to be sure not memory overflow.
cmd.parm is a union, and need keep original valid buffer length no touch
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
f39479363e