[PATCH] connector: bump skb->users before callback invocation
From: Florian Westphal <fw@strlen.de>
Date: 2015-12-31 13:26:47
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Subsystem:
networking drivers, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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); }