[PATCH iproute2] lwtunnel: fix argument parsing

[PATCH iproute2] lwtunnel: fix argument parsing

[Paolo Abeni]

Currently parse_encap_ip() does not update correctly argv/argc;
if multiple lwtunnel arguments are provided, the parsing fails after
the first one, i.e.

 ip route add 172.16.101.0/24 dev vxlan1 encap ip id 42 dst 192.168.255.1

fails with:

 Error: either "to" is duplicate, or "dst" is a garbage.

This commit addresses the issue, stepping to next argument at each iteration
of the parsing loop.

Fixes: 1e5293056a02 ("lwtunnel: Add encapsulation support to ip route")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 ip/iproute_lwtunnel.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/ip/iproute_lwtunnel.c b/ip/iproute_lwtunnel.c
index 63322a1..c825b82 100644
--- a/ip/iproute_lwtunnel.c
+++ b/ip/iproute_lwtunnel.c
@@ -178,10 +178,14 @@ static int parse_encap_ip(struct rtattr *rta, size_t len, int *argcp, char ***ar
 		} else {
 			break;
 		}
+		argc--; argv++;
 	}
 
-	*argcp = argc;
-	*argvp = argv;
+	/* argv is currently the first unparsed argument,
+	 * but the lwt_parse_encap() caller will move to the next,
+	 * so step back */
+	*argcp = argc + 1;
+	*argvp = argv - 1;
 
 	return 0;
 }
-- 
1.8.3.1

Re: [PATCH iproute2] lwtunnel: fix argument parsing

[Stephen Hemminger]

On Tue, 15 Dec 2015 12:18:04 +0100
Paolo Abeni <pabeni@redhat.com> wrote:

> Currently parse_encap_ip() does not update correctly argv/argc;
> if multiple lwtunnel arguments are provided, the parsing fails after
> the first one, i.e.
> 
>  ip route add 172.16.101.0/24 dev vxlan1 encap ip id 42 dst 192.168.255.1
> 
> fails with:
> 
>  Error: either "to" is duplicate, or "dst" is a garbage.
> 
> This commit addresses the issue, stepping to next argument at each iteration
> of the parsing loop.
> 
> Fixes: 1e5293056a02 ("lwtunnel: Add encapsulation support to ip route")
> Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Applied, thanks