Commit 90aa7993 authored Feb 13, 2017 by WANG Cong Committed by Greg Kroah-Hartman Feb 26, 2017

kcm: fix a null pointer dereference in kcm_sendmsg()



[ Upstream commit cd27b96bc13841ee7af25837a6ae86fee87273d6 ]

In commit 98e3862ca2b1 ("kcm: fix 0-length case for kcm_sendmsg()")
I tried to avoid skb allocation for 0-length case, but missed
a check for NULL pointer in the non EOR case.

Fixes: 98e3862ca2b1 ("kcm: fix 0-length case for kcm_sendmsg()")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 14099354

net/kcm/kcmsock.c

+4 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1044,9 +1044,11 @@ static int kcm_sendmsg(struct socket sock, struct msghdr msg, size_t len)
	} else {		} else {
	/* Message not complete, save state */		/* Message not complete, save state */
	partial_message:		partial_message:
			if (head) {
	kcm->seq_skb = head;		kcm->seq_skb = head;
	kcm_tx_msg(head)->last_skb = skb;		kcm_tx_msg(head)->last_skb = skb;
	}		}
			}

	KCM_STATS_ADD(kcm->stats.tx_bytes, copied);		KCM_STATS_ADD(kcm->stats.tx_bytes, copied);