[network-manager-openvpn] service: use correct length in string comparison

[Thomas Haller <thaller src gnome org>]

commit 5d1b309e31aea9484c70e2cb86610795622a1372
Author: Timo Juhani Lindfors <timo lindfors iki fi>
Date:   Wed Apr 5 12:48:42 2017 +0300

    service: use correct length in string comparison
    
    This should not be a security issue. Old code just accepted
    e.g. "CRV1foo" when only "CRV1:foo" should be parsed.
    
    https://mail.gnome.org/archives/networkmanager-list/2017-April/msg00008.html
    
    Fixes: 5b96fecb97c752e08fdcebb331b983196f4b8935

 src/nm-openvpn-service.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/nm-openvpn-service.c b/src/nm-openvpn-service.c
index 862248f..20f86bf 100644
--- a/src/nm-openvpn-service.c
+++ b/src/nm-openvpn-service.c
@@ -652,7 +652,7 @@ parse_challenge (const char *failure_reason, char **challenge_state_id, char **c
        char *colon[4];
        int challenge_len;
 
-       if (!(failure_reason && !strncmp (failure_reason, "CRV1:", 4)))
+       if (!(failure_reason && !strncmp (failure_reason, "CRV1:", 5)))
                return FALSE;
 
        colon[0] = strchr (failure_reason, ':');