[media] cec-funcs.h: add length checks

Add msg->len sanity checks to fix static checker warning:

	include/linux/cec-funcs.h:1154 cec_ops_set_osd_string()
	warn: setting length 'msg->len - 3' to negative one

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/cec-funcs.h b/include/linux/cec-funcs.h
index 19486009693a..8d217ce53034 100644
--- a/include/linux/cec-funcs.h
+++ b/include/linux/cec-funcs.h
@@ -788,7 +788,7 @@ static inline void cec_msg_set_timer_program_title(struct cec_msg *msg,
 static inline void cec_ops_set_timer_program_title(const struct cec_msg *msg,
                                                    char *prog_title)
 {
-        unsigned int len = msg->len - 2;
+        unsigned int len = msg->len > 2 ? msg->len - 2 : 0;
 
         if (len > 14)
                 len = 14;
@@ -1167,7 +1167,7 @@ static inline void cec_ops_set_osd_string(const struct cec_msg *msg,
                                           __u8 *disp_ctl,
                                           char *osd)
 {
-        unsigned int len = msg->len - 3;
+        unsigned int len = msg->len > 3 ? msg->len - 3 : 0;
 
         *disp_ctl = msg->msg[2];
         if (len > 13)
@@ -1192,7 +1192,7 @@ static inline void cec_msg_set_osd_name(struct cec_msg *msg, const char *name)
 static inline void cec_ops_set_osd_name(const struct cec_msg *msg,
                                         char *name)
 {
-        unsigned int len = msg->len - 2;
+        unsigned int len = msg->len > 2 ? msg->len - 2 : 0;
 
         if (len > 14)
                 len = 14;