net: kcm: fix memory leak in kcm_sendmsg
Syzbot reported memory leak in kcm_sendmsg()[1].
The problem was in non-freed frag_list in case of error.
In the while loop:
if (head == skb)
skb_shinfo(head)->frag_list = tskb;
else
skb->next = tskb;
frag_list filled with skbs, but nothing was freeing them.
backtrace:
[<
0000000094c02615>] __alloc_skb+0x5e/0x250 net/core/skbuff.c:198
[<
00000000e5386cbd>] alloc_skb include/linux/skbuff.h:1083 [inline]
[<
00000000e5386cbd>] kcm_sendmsg+0x3b6/0xa50 net/kcm/kcmsock.c:967 [1]
[<
00000000f1613a8a>] sock_sendmsg_nosec net/socket.c:652 [inline]
[<
00000000f1613a8a>] sock_sendmsg+0x4c/0x60 net/socket.c:672
Reported-and-tested-by: syzbot+b039f5699bd82e1fb011@syzkaller.appspotmail.com
Fixes: ab7ac4eb9832 ("kcm: Kernel Connection Multiplexor module")
Cc: stable@vger.kernel.org
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>