From f39479363e0361c8bb4397481c01a7c3a1a3c8ac Mon Sep 17 00:00:00 2001 From: Chen Gang Date: Thu, 7 Mar 2013 18:25:41 +0000 Subject: drivers/isdn: checkng length to be sure not memory overflow 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 Signed-off-by: David S. Miller --- drivers/isdn/i4l/isdn_tty.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/isdn/i4l/isdn_tty.c') diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c index d8a7d832341..ebaebdf30f9 100644 --- a/drivers/isdn/i4l/isdn_tty.c +++ b/drivers/isdn/i4l/isdn_tty.c @@ -902,7 +902,9 @@ isdn_tty_send_msg(modem_info *info, atemu *m, char *msg) int j; int l; - l = strlen(msg); + l = min(strlen(msg), sizeof(cmd.parm) - sizeof(cmd.parm.cmsg) + + sizeof(cmd.parm.cmsg.para) - 2); + if (!l) { isdn_tty_modem_result(RESULT_ERROR, info); return; -- cgit v1.2.3-70-g09d2