From 794eb6bf20ebf992c040ea831cd3a9c64b0c1f7a Mon Sep 17 00:00:00 2001
From: Jesper Juhl <jesper.juhl@gmail.com>
Date: Thu, 17 Apr 2008 23:22:54 -0700
Subject: [PATCH] [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 <jesper.juhl@gmail.com>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/netlabel/netlabel_unlabeled.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/netlabel/netlabel_unlabeled.c b/net/netlabel/netlabel_unlabeled.c
index a547c6320eb3..d282ad1570a7 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);
--
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