All of lore.kernel.org
 help / color / mirror / Atom feed
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) {

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 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) {

             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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20100910115809.GF5959@bicker \
    --to=error27@gmail.com \
    --cc=ben@netservers.co.uk \
    --cc=davem@davemloft.net \
    --cc=kernel-janitors@vger.kernel.org \
    --cc=linux-ppp@vger.kernel.org \
    --cc=lsorense@csclub.uwaterloo.ca \
    --cc=netdev@vger.kernel.org \
    --cc=paulus@samba.org \
    --cc=shemminger@vyatta.com \
    --cc=simon@fire.lp0.eu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.