[PATCH iproute2-next] ip: error out if iplink does not consume all options

[PATCH iproute2-next] ip: error out if iplink does not consume all options

[Jakub Kicinski]

dummy does not define .parse_opt, which make ip ignore all
trailing arguments, for example:

 # ip link add type dummy a b c d e f name cheese

will work just fine (and won't call the device "cheese").
Error out in this case with a clear error message:

 # ip link add type dummy a b c d e f name cheese
 Garbage instead of arguments "a ...". Try "ip link help".

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 ip/iplink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ip/iplink.c b/ip/iplink.c
index 6c5d13d53a84..f60cff9c4b5f 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -1112,7 +1112,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
 		argc -= ret;
 		argv += ret;
 
-		if (lu && argc) {
+		if (lu && lu->parse_opt && argc) {
 			struct rtattr *data;
 
 			data = addattr_nest(&req.n, sizeof(req), iflatype);
-- 
2.41.0

Re: [PATCH iproute2-next] ip: error out if iplink does not consume all options

[Stephen Hemminger]

On Fri, 28 Jul 2023 11:33:29 -0700
Jakub Kicinski <kuba@kernel.org> wrote:

> dummy does not define .parse_opt, which make ip ignore all
> trailing arguments, for example:
> 
>  # ip link add type dummy a b c d e f name cheese
> 
> will work just fine (and won't call the device "cheese").
> Error out in this case with a clear error message:
> 
>  # ip link add type dummy a b c d e f name cheese
>  Garbage instead of arguments "a ...". Try "ip link help".
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Looks good, but then the latter check for lu->parse_opt in the if
clause is redundant.  Coverity would flag that (assuming I get
Coverity running again on iproute).