system-linux: fix segfault on alloc failure in system_if_check()

Detected by Coverity in CID 1433686

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>

diff --git a/system-linux.c b/system-linux.c
index b839b4c..9933201 100644 (file)
--- a/system-linux.c
+++ b/system-linux.c
@@ -1571,6 +1571,9 @@ int system_if_check(struct device *dev)
        };
        int ret = 1;
 
+       if (!cb)
+               return ret;
+
        msg = nlmsg_alloc_simple(RTM_GETLINK, 0);
        if (!msg)
                goto out;