[PATCH net] netdev: remove potentially harmful checks

[PATCH net] netdev: remove potentially harmful checks

[Veaceslav Falico]

Currently we're checking a variable for != NULL after actually
dereferencing it, in netdev_lower_get_next_private*().

It's counter-intuitive at best, and can lead to faulty usage (as it implies
that the variable can be NULL), so fix it by removing the useless checks.

Reported-by: Daniel Borkmann <dborkman@redhat.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Jiri Pirko <jiri@resnulli.us>
CC: stephen hemminger <stephen@networkplumber.org>
CC: Jerry Chu <hkchu@google.com>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
---
 net/core/dev.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 5777018..14dac06 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4589,8 +4589,7 @@ void *netdev_lower_get_next_private(struct net_device *dev,
 	if (&lower->list == &dev->adj_list.lower)
 		return NULL;
 
-	if (iter)
-		*iter = lower->list.next;
+	*iter = lower->list.next;
 
 	return lower->private;
 }
@@ -4618,8 +4617,7 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
 	if (&lower->list == &dev->adj_list.lower)
 		return NULL;
 
-	if (iter)
-		*iter = &lower->list;
+	*iter = &lower->list;
 
 	return lower->private;
 }
-- 
1.8.4

Re: [PATCH net] netdev: remove potentially harmful checks

[David Miller]

From: Veaceslav Falico <vfalico@redhat.com>
Date: Mon,  7 Apr 2014 11:25:12 +0200

> Currently we're checking a variable for != NULL after actually
> dereferencing it, in netdev_lower_get_next_private*().
> 
> It's counter-intuitive at best, and can lead to faulty usage (as it implies
> that the variable can be NULL), so fix it by removing the useless checks.
> 
> Reported-by: Daniel Borkmann <dborkman@redhat.com>
> CC: "David S. Miller" <davem@davemloft.net>
> CC: Eric Dumazet <edumazet@google.com>
> CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
> CC: Jiri Pirko <jiri@resnulli.us>
> CC: stephen hemminger <stephen@networkplumber.org>
> CC: Jerry Chu <hkchu@google.com>
> Signed-off-by: Veaceslav Falico <vfalico@redhat.com>

Applied, thanks.