4.17-stable review patch. If anyone has any objections, please let me know.
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From: John Fastabend john.fastabend@gmail.com
commit 7ebc14d507b4b55105da8d1a1eda323381529cc7 upstream.
Currently, when a sock is closed and the bpf_tcp_close() callback is used we remove memory but do not free the skb. Call consume_skb() if the skb is attached to the buffer.
Reported-by: syzbot+d464d2c20c717ef5a6a8@syzkaller.appspotmail.com Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks") Signed-off-by: John Fastabend john.fastabend@gmail.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/bpf/sockmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -471,7 +471,8 @@ static int free_sg(struct sock *sk, int while (sg[i].length) { free += sg[i].length; sk_mem_uncharge(sk, sg[i].length); - put_page(sg_page(&sg[i])); + if (!md->skb) + put_page(sg_page(&sg[i])); sg[i].length = 0; sg[i].page_link = 0; sg[i].offset = 0; @@ -480,6 +481,8 @@ static int free_sg(struct sock *sk, int if (i == MAX_SKB_FRAGS) i = 0; } + if (md->skb) + consume_skb(md->skb);
return free; }