From: Jesper Juhl Date: Fri, 18 Apr 2008 06:22:54 +0000 (-0700) Subject: [NETLABEL]: Fix NULL deref in netlbl_unlabel_staticlist_gen() if ifindex not found X-Git-Tag: v2.6.26-rc1~1138^2~3 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=794eb6bf20ebf992c040ea831cd3a9c64b0c1f7a;p=linux-2.6 [NETLABEL]: Fix NULL deref in netlbl_unlabel_staticlist_gen() if ifindex not found dev_get_by_index() may return NULL if nothing is found. In net/netlabel/netlabel_unlabeled.c::netlbl_unlabel_staticlist_gen() the function is called, but the return value is never checked. If it returns NULL then we'll deref a NULL pointer on the very next line. I checked the callers, and I don't think this can actually happen today, but code changes over time and in the future it might happen and it does no harm to be defensive and check for the failure, so that if/when it happens we'll fail gracefully instead of crashing. Signed-off-by: Jesper Juhl Acked-by: Paul Moore Signed-off-by: David S. Miller --- diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c index a547c6320e..d282ad1570 100644 --- a/net/netlabel/netlabel_unlabeled.c +++ b/net/netlabel/netlabel_unlabeled.c @@ -1339,6 +1339,10 @@ static int netlbl_unlabel_staticlist_gen(u32 cmd, if (iface->ifindex > 0) { dev = dev_get_by_index(&init_net, iface->ifindex); + if (!dev) { + ret_val = -ENODEV; + goto list_cb_failure; + } ret_val = nla_put_string(cb_arg->skb, NLBL_UNLABEL_A_IFACE, dev->name); dev_put(dev);