4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: John Fastabend <john.fastabend@xxxxxxxxx>
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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks")
Signed-off-by: John Fastabend <john.fastabend@xxxxxxxxx>
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
}
