From: Dan Carpenter <error27@gmail.com>
To: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Simon Arlott <simon@fire.lp0.eu>,
Ben McKeegan <ben@netservers.co.uk>,
Stephen Hemminger <shemminger@vyatta.com>,
Len Sorensen <lsorense@csclub.uwaterloo.ca>,
linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: [patch] ppp: potential NULL dereference in ppp_mp_explode()
Date: Fri, 10 Sep 2010 11:58:10 +0000 [thread overview]
Message-ID: <20100910115809.GF5959@bicker> (raw)
Smatch complains because we check whether "pch->chan" is NULL and then
dereference it unconditionally on the next line. Partly the reason this
bug was introduced is because code was too complicated. I've simplified
it a little.
Signed-off-by: Dan Carpenter <error27@gmail.com>
---
Compile tested only. Perhaps it would be better to set pch->speed to
zero? The comments say that zero implies the speed hasn't been set.
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 6695a51..736b917 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1314,8 +1314,13 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
i = 0;
list_for_each_entry(pch, &ppp->channels, clist) {
- navail += pch->avail = (pch->chan != NULL);
- pch->speed = pch->chan->speed;
+ if (pch->chan) {
+ pch->avail = 1;
+ navail++;
+ pch->speed = pch->chan->speed;
+ } else {
+ pch->avail = 0;
+ }
if (pch->avail) {
if (skb_queue_empty(&pch->file.xq) ||
!pch->had_frag) {
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <error27@gmail.com>
To: Paul Mackerras <paulus@samba.org>
Cc: "David S. Miller" <davem@davemloft.net>,
Simon Arlott <simon@fire.lp0.eu>,
Ben McKeegan <ben@netservers.co.uk>,
Stephen Hemminger <shemminger@vyatta.com>,
Len Sorensen <lsorense@csclub.uwaterloo.ca>,
linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: [patch] ppp: potential NULL dereference in ppp_mp_explode()
Date: Fri, 10 Sep 2010 13:58:10 +0200 [thread overview]
Message-ID: <20100910115809.GF5959@bicker> (raw)
Smatch complains because we check whether "pch->chan" is NULL and then
dereference it unconditionally on the next line. Partly the reason this
bug was introduced is because code was too complicated. I've simplified
it a little.
Signed-off-by: Dan Carpenter <error27@gmail.com>
---
Compile tested only. Perhaps it would be better to set pch->speed to
zero? The comments say that zero implies the speed hasn't been set.
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 6695a51..736b917 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -1314,8 +1314,13 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
hdrlen = (ppp->flags & SC_MP_XSHORTSEQ)? MPHDRLEN_SSN: MPHDRLEN;
i = 0;
list_for_each_entry(pch, &ppp->channels, clist) {
- navail += pch->avail = (pch->chan != NULL);
- pch->speed = pch->chan->speed;
+ if (pch->chan) {
+ pch->avail = 1;
+ navail++;
+ pch->speed = pch->chan->speed;
+ } else {
+ pch->avail = 0;
+ }
if (pch->avail) {
if (skb_queue_empty(&pch->file.xq) ||
!pch->had_frag) {
next reply other threads:[~2010-09-10 11:58 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-10 11:58 Dan Carpenter [this message]
2010-09-10 11:58 ` [patch] ppp: potential NULL dereference in ppp_mp_explode() Dan Carpenter
2010-09-13 19:45 ` David Miller
2010-09-13 19:45 ` David Miller
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