From: Florian Westphal <fw@strlen•de>
To: Dmitry Vyukov <dvyukov@google•com>
Cc: "David S. Miller" <davem@davemloft•net>,
Herbert Xu <herbert@gondor•apana.org.au>,
Thomas Graf <tgraf@suug•ch>,
Daniel Borkmann <daniel@iogearbox•net>,
Ken-ichirou MATSUZAWA <chamaken@gmail•com>,
Nicolas Dichtel <nicolas.dichtel@6wind•com>,
Florian Westphal <fw@strlen•de>, netdev <netdev@vger•kernel.org>,
LKML <linux-kernel@vger•kernel.org>,
syzkaller <syzkaller@googlegroups•com>,
Kostya Serebryany <kcc@google•com>,
Alexander Potapenko <glider@google•com>,
Sasha Levin <sasha.levin@oracle•com>,
Eric Dumazet <edumazet@google•com>,
zbr@ioremap•net
Subject: [PATCH] connector: bump skb->users before callback invocation
Date: Thu, 31 Dec 2015 14:26:33 +0100 [thread overview]
Message-ID: <20151231132633.GA30790@breakpoint.cc> (raw)
In-Reply-To: <CACT4Y+bKYO2XfY74tgUiOC7WotQ8DRBcMT=2yy3S=Ubz8bnj_g@mail.gmail.com>
Dmitry reports memleak with syskaller program.
Problem is that connector bumps skb usecount but might not invoke callback.
So move skb_get to where we invoke the callback.
Reported-by: Dmitry Vyukov <dvyukov@google•com>
Signed-off-by: Florian Westphal <fw@strlen•de>
---
I wonder wth userspace can cram skb->len < NLMSG_HDRLEN
down the kernel, it seems to beg for trouble...
diff --git a/drivers/connector/connector.c b/drivers/connector/connector.c
index d7373ca..25693b0 100644
--- a/drivers/connector/connector.c
+++ b/drivers/connector/connector.c
@@ -179,26 +179,21 @@ static int cn_call_callback(struct sk_buff *skb)
*
* It checks skb, netlink header and msg sizes, and calls callback helper.
*/
-static void cn_rx_skb(struct sk_buff *__skb)
+static void cn_rx_skb(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
- struct sk_buff *skb;
int len, err;
- skb = skb_get(__skb);
-
if (skb->len >= NLMSG_HDRLEN) {
nlh = nlmsg_hdr(skb);
len = nlmsg_len(nlh);
if (len < (int)sizeof(struct cn_msg) ||
skb->len < nlh->nlmsg_len ||
- len > CONNECTOR_MAX_MSG_SIZE) {
- kfree_skb(skb);
+ len > CONNECTOR_MAX_MSG_SIZE)
return;
- }
- err = cn_call_callback(skb);
+ err = cn_call_callback(skb_get(skb));
if (err < 0)
kfree_skb(skb);
}
next prev parent reply other threads:[~2015-12-31 13:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-31 11:51 net/netlink: memory leak in netlink_sendmsg Dmitry Vyukov
2015-12-31 13:26 ` Florian Westphal [this message]
2016-01-05 2:47 ` [PATCH] connector: bump skb->users before callback invocation David Miller
2016-01-11 20:03 ` Evgeniy Polyakov
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